Transcript Conformal Coatings - EMT India Associates
Slide 1
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 2
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 3
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 4
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 5
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 6
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 7
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 8
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 9
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 10
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 11
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 12
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 13
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 14
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 15
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 16
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 17
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 18
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 19
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 20
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 21
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 22
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 23
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 24
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 25
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 26
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 27
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 28
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 29
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 30
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 31
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 32
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 33
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 34
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 35
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 36
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 37
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 2
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 3
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 4
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 5
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 6
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 7
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 8
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 9
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 10
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 11
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 12
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 13
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 14
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 15
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 16
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 17
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 18
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 19
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 20
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 21
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 22
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 23
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 24
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 25
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 26
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 27
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 28
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 29
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 30
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 31
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 32
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 33
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 34
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 35
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 36
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
o
o
o
Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com
Slide 37
Conformal Coatings
Enhanced protection for enhanced PCB performance
Introduction
Why Coat?
CONFORMAL COATINGS
A newly manufactured printed circuit board will generally perform
well but performance will quickly deteriorate.
Common causes of deterioration and PCB failure include:
o Atmospheric moisture
o Contamination of the surface with airborne ionic material
o Electrostatic attraction of dust to the surface
o Corrosive environments, such as salt fog
Conformal coatings can be applied to a PCB giving protection
against the environment, extending the life of the board and
therefore can be used in a vast array of electronic applications.
CONFORMAL COATINGS
Conformal coatings are thin coatings, typically 25-75 microns, which
‘conform’ to the contours of a PCB.
The ideal conformal coating will have performance requirements that
include:
o Good electrical properties
o Low moisture permeability
o Good mechanical durability
o Excellent adhesion properties
o Good thermal resistance
Additional properties such as flame retardance or chemical resistance
may also be required.
CONFORMAL COATING TERMINOLOGY
Different chemistries utilised in conformal coating technology require different types of
cure. It is important to understand the terms used in conformal coating in under to
understand cure schedules:
‘Tack Free’ – this is the time at which the coating is no longer tacky but slight indentations
may be left in the coating when pressed firmly
‘Touch Dry’ – this is the time at which the coating is dry enough to touch without leaving
any fingerprints on the surface of the coating
It is important to note that some coatings are very soft and can feel tacky even when fully
cured. The touch dry time in these cases is more a reference to when you can move the
board without affecting the coating
‘Cure Time’ – this is the time at which the coating is fully cured and will offer protection
It is also important to note that most coatings actually reach their optimum cure level after
around 7 days but they will provide protection prior to this
CONFORMAL COATING APPLICATION
Conformal coatings can be brushed, dipped or sprayed depending on the
requirements. Customers often specify their desired application method.
Brushing:
Advantages
Disadvantages
Cost effective
Uneven coating
Ideal for small scale
production
Difficult to get under
components
Selective coating
Only one side at a time can
be coated
CONFORMAL COATING APPLICATION
Dip Coating:
Advantages
Disadvantages
Ideal for medium scale
production
Initial capital outlay
Uniform coating thickness
Masking essential for
connectors
Easy to operate machinery
Special extraction may be
required
Both sides can be coated
at the same time
Suitable for higher
viscosity materials
Coating can penetrate under
components
Operator training required
but not difficult
CONFORMAL COATING APPLICATION
Spraying – aerosol or manual spray gun:
Advantages
Disadvantages
Cost effective
Overspray can occur
Ideal for bench top work and
repair
Difficult to get under
components
Ideal for small to medium
scale production
Special extraction may be
required
Convenient
Only one side at a time can
be coated
SPRAYING
CONFORMAL COATING APPLICATION
Selective Spraying:
Advantages
Disadvantages
No masking required
Initial capital outlay
Uniform thickness
Low under component
penetration – requires good
flow properties with the coating
Automated process – good for
Special extraction may be
inline procedures
required – but can be linked to
the machine easily
Ideal for all scales of
production
Requires a trained operator to
set the software
SELECTIVE COATING
SELECTIVE COATING
Application Conditions
• Temperature – Affects viscosity and evaporation rate
• Humidity – Contaminates dip coat tanks, blooming in hand spray
and affects curing / pot life.
• Ventilation – Affects operators
Product Choice
Coating Options
Considerations for Choice
As there are many different applications for conformal coatings, there are also a
number of elements that must be considered as part of the selection process:
Coating properties
•
•
•
•
•
•
•
•
Adhesion
Flexibility
Temperature range
Mechanical durability
Electrical performance
Environmental performance
Flame retardance
Mould resistance
Application
•
•
•
•
•
•
•
•
Viscosity/application
Touch dry time
Full cure time
Curing conditions
Is re-work required?
Cost
Quality
Approvals required?
CONFORMAL COATING TYPES
Conformal coatings are available in a number of different chemistry types
and also cure via different mechanisms.
The different types of conformal coating include:
o Solvent-based – Evaporation Cure
o Solvent-based – Heat Cure
o Low VOC/Water-based – Evaporation/Heat Cure
o Non-VOC – Moisture Cure
o UV Cure – Dual Cure: Moisture/Heat
Common conformal coating chemistries include:
o Acrylic
o Polyurethane
o Silicone
o Modified-silicone
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a flexible, transparent & unique modified silicone conformal
coating specifically designed for the protection of electronic circuitry.
Key Features:
o Resistant to most solvents, lubricants and chemicals associated
with most aerospace and automotive applications.
o Excellent adhesion under various climatic conditions to a variety of
substrates, including high altitude/decompression
o Fluoresces under UV light for ease of inspection.
o Extreme operating temperature range (-70˚C to +200˚C)
o Excellent electrical properties
DCA (SCC3) MODIFIED SILICONE COATING
DCA is a solvent based coating and can be sprayed, dipped or brushed.
For optimum properties, DCA should be heat cured (2hrs at RT, 2hrs @ 90˚C
advised). If RT cured then the solvent resistance will be significantly reduced.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
Def-Stan 59/47 – Standard now obsolete
o
UL746 – File Number E138403
DCA (SCC3) MODIFIED SILICONE COATING
The DCA (SCC3) Range includes:
o
o
o
o
o
o
DCA-FD – Fast-dry version
DCA-HT – With improved high temperature performance
DCR – Opaque red version
DCB – Opaque black version
DCRT – Opaque red, high viscosity version
DCE – Thixotropic gel version (dam and fill applications)
Unique range of products based on a silicone modified alkyd
Avoids issues associated with silicone migration
Easier processing than standard silicones
Performance compares with many silicone conformal coatings
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a flexible and transparent acrylic conformal coating for the protection of
electronic circuitry.
It has been formulated to meet many of today’s commercial applications, meeting
both Military and IPC standards.
Key Features:
o Toluene free product.
o Fluoresces under UV light for ease of inspection.
o Wide operating temperature range (-65˚C to +125˚C)
o Excellent Dielectric properties
o Clear coating with excellent resistance to yellowing when exposed
to UV light
TFA – TOLUENE FREE ACRYLIC COATING
TFA is a solvent based coating and can be sprayed, dipped or brushed.
Should be used with DCT thinners and removed with CCRG – Electrolube
Conformal Coating Remover Gel
Approvals
o
UL746 Approved
IPC-CC-830 approved
Automatically meets MIL-46058-C
Also available: AFA – Aromatic Free Acrylic
o
o
VOCs or Volatile Organic Compounds are carbon based
compounds which vaporise easily under ambient
conditions
VOCs contribute towards the formation of ground level
ozone
Such pollution can have many detrimental effects on the
environment, damaging forests and vegetation
In addition, some materials classed as VOCs can act as
irritants and over exposure can lead to a variety of health
problems
VOC DEFINITION
EU Solvents Emissions Directive
“Any organic compound having at 20˚C a vapour
pressure of 0.01kPa or more, or having
corresponding volatility under the particular
conditions of use”
UVCL - UV Cure
• Extremely rapid initial cure schedule
• Ideal for high volume production
• In-line process, curing equipment required
• Very high level of protection; highly cross-linked coating
• Excellent chemical and solvent resistance
• Using a dual cure system can ensure that in shadowed areas under
components the coating still cures and protects the PCB
• Moisture
• Heat
• UV cure coatings are available as 100% solids materials
• Non-VOC options
WBPS – WATER-BASED COATING
WBPs is a water-based conformal coating, based on polymeric
materials which has been specifically formulated for the protection of
electronic circuitry.
It offers an excellent blend of both physical and electrical properties in a
more environmentally and user friendly package when compared to
conventional solvent based conformal coatings.
Non-flammable and contains very low levels of VOC’s.
WBP is for dipping/brushing applications whilst WBPS (Sprayable) has
been specifically formulated for use in selective film coater equipment.
WBPS – WATER-BASED COATING
Key Features:
o
o
o
o
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Environmentally friendly and eliminates hazards associated with
solvent based conformal coatings
Excellent solvent resistance.
Very low VOC content
NMP (N-Methyl pyrrolidone) free.
Fluoresces under UV light for ease of inspection.
Excellent adhesion on a wide variety of substrates.
Excellent Dielectric properties and resistant to mould growth.
PUC – POLYURETHANE COATING
PUC is a tough, flexible, modified polyurethane conformal coating and is
specifically designed for the protection of electronic circuitry, particularly in harsh
conditions.
Key Features
o Excellent adhesion to a wide variety of substrates.
o Fluoresces under UV light for ease of inspection.
o Good resistance to a wide variety of chemicals including acids and
alkalis.
o Wide operating temperature range.
o Excellent mechanical properties including abrasion resistance
o Solvent-based, can be sprayed, dipped or brushed
o Should be used with PTH thinners and removed with CCRG
OTHER COATINGS
Modified Silicone – LFCC, FSC (Modified with acrylic; up to 125˚C)
Acrylic – HPA (MIL Approved), APL, AFA, APLSP (Sprayable version), TRV
Water-Based – WBP (Dipping Version)
Polyester – CPL
Surface Modifier – TFCF (Fluorinated)
CHOOSING THE RIGHT PRODUCT
High Temperature – DCA (SCC3) Range
Excellent Clarity – TFA or an Acrylic Coating
Chemical Resistance – PUC or DCA (SCC3) Range
Cosmetic Appearance – CPL (no UV trace)
Low Solvent Content – WBP or WBPs
Reworkable – Acrylic Coatings or FSC
UL Approved – DCA and TFA
UV Cure - UVCL
Polyester
Modified Silicone
DCA
FSCP
FSC
CPL
UV Cure
UVCL
Polyurethane
PUC
PUCAF
Opaque
DCRT
DCR
Acrylic
DCB
HPA
TFA
Water-Based
APL
AFA
WBP
WBPs
Electrolube Conformal Coating Selector Chart
YES
UVCL
WBP(s)
Is low/non VOC required?
DCA (UL746)
UVCL (IPC-CC-830)
WBP(s)
PUC
PUCAF
NO
HPA (MIL-I-46058C)
TFA (IPC-CC-830/UL746)
AFA (UL746)
FSC (IEC61086)
YES
YES
NO
Is optical clarity required?
YES
Is chemical resistance
required?
YES
Is an approval
required?
NO
NO
Is an approval
required?
NO
YES
YES
Is a fast touch dry
time required?
YES
Is the operating temperature
below -55°C?
DCA/WBP(s)
NO
NO
APL
YES
Is easy removal for
re-work required?
NO
Is the operating temperature
above 130°C?
DCA
Conformal Coatings
Potential Problems
Adhesion Loss
Incorrect curing could cause adhesion loss. This could be due to
insufficient curing, i.e. the coating has not finished cross-linking.
It could also be a problem with removing masking material – ideally
this should be done when the coating is still soft.
Conformal Coatings
Rework Considerations
Coating Removal Products
• For acrylics, a solvent based product like Electrolube ULS is ideal
for quick and clean removal of the coating.
• For coatings with a higher chemical resistance, a product such as
Electrolube RRS will be required.
• For localised rework, a remover gel like Electrolube CCRG is ideal.
OTHER PRODUCTS
In order for conformal coatings to be applied correctly some complimentary
products are required:
• Thinners – where applicable conformal coatings are diluted to the required viscosity,
Electrolube have a range of thinners suitable for this process
• Masking – PCM and PCS are coating masks suitable for covering connectors during
the coating process
Thank You
For further information please visit www.electrolube.com