Transcript FMEA - Daum

FMEA
1. Definition
2. Process FMEA
3. When to create FMEA
4. Preparation
5. Process FMEA Creation
Procedure
6. Check List
Measurement (FMEA)
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1. Definition
• FMEA (Failure Mode and
Effects Analysis)
– Failure mode and effects
analysis
– a series of systematic activities
leading to the next target
• find and analyze potential
failures and effects of a
product or process
• find a way to eliminate or
reduce the occurrence of
potential failure
• documentation of process
• Ranking
– System FMEA
• the highest level of FMEA
done during the initial design
phase of a system or
subsystem
– Design FMEA
• used to identify and prevent
failures associated with
product design
– Process FMEA
• FMEA that identify and
prevent failures associated
with manufacturing or any
other processes
Measurement (FMEA)
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What is FMEA(Failure Mode and Effects
Analysis)?
FMEA: find the potential failure modes of
designed system or apparatus, and when such
failure occurs during the operation of a system
or apparatus, investigate and evaluate its
effect to the performance, and prevent the
occurrence of a failure in advance applying
proper measures of correction to the failure
mode that has big effects.
Measurement (FMEA)
3
History of FMEA

early 1950s: propeller airplane  Jet airplane
(reliability design of Jets that has complicated control
systems)
 mid 1960s: introduced to Aero-Space industry (Apollo)
(big achievement in reliability warranty and safety
assessment)
 1974: used in U.S. Navy (MILSTD1629)
late 1970s: wide-spread due to the introduction of
Product Liability
Measurement (FMEA)
4
Where do Risks come from?
Potential
safety
risk
Imperfect
control plan
Uncertain
customer
needs
Unclear
operation
standard
Insufficient
process
capability
Cumulative
Risks
Machine
reliability
Measurement
variation
Measurement (FMEA)
Material
variation
Imperfect
standard
limits
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Defects
-
Cause of Defects -
 defects during design stage
 out-of-normal during manufacturing process
 unsatisfied performance that can not meet customer needs
 dangerous state due to the lack of proper warning and training
- Types  Design Defects
- affects the whole line
 Manufacturing Defects
- Defects from raw material
- Production mistake
 Service Defects
- can’t meet the standards defined by the design and the customers
Measurement (FMEA)
6
Benefits of FMEA
• Improve product quality, reliability, and safety
• Improve company image and competition
• Increase customer satisfaction
• Reduce product development time and cost
• Reduce risks with documentation
Measurement (FMEA)
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Application of FMEA
System FMEA :
• applied to the analysis of system/subsystem during product
planning and design stage in early development
• focus: potential failure mode associated with system function
Design FMEA
:
• before production, applied to product analysis
• focus : product function
Process FMEA
:
• applied to the analysis of manufacturing and assembly
• focus : process input variable
Big 3 (Chrysler,Ford, GM)
Measurement (FMEA)
QS 9000
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2. Process FMEA
 Usage
 Contents
 A detailed document which
identifies ways in which a
process or product fails to
meet critical customer
requirements (Ys).
 A living document which lists
all possible causes of failure
(X)
 Ultimately captures the entire
process




Identifies failures from
products or process due
to X.
Facilitates the
documentation of a plan
to prevent these failures.
Used as a basic
information from which a
list of items for the control
plan can be generated.
Used to track necessary
treatment to improve
processes and identify
priorities.
Measurement (FMEA)
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Purpose of Process FMEA
• Helps to analyze new manufacturing process
• Can identify defects of process control plan
• Determine priorities of actions
• risk analysis from process change
• identify potential variables considered later
• allows process design engineers understand
current processes’ weak points and guides them
to develop new manufacturing processes
• steps for leaping
Measurement (FMEA)
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Process Improvement Plan
C & E Matrix
Process Map
문서 작업
DICY 탱크
steam
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장착
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점
성
시간
↑청결 도
↑원료
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색
장착정확성
↑환경상
↑원료
 혼합속도
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input
척도정확
성
 예열
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DICY
장착
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재료목록
ISO 진행
재생
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output
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FMEA
공정 단계
/ 입력
잠재적
고장모드
잠재적
고장 영향
관 리
치
명
도
발생
원 인 빈도
감
지
도
RPN
Initial evaluation of process capability
and control plan
공정
단계
Measurement (FMEA)
주요 공정
입력
Failure Modes
Effects Cause Current
Controls
-잘 못 될 수 있는 것
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Input and Output Elements of FMEA
Output
Input
• Process Map
• C & E Matrix
• Risk Analysis
• action statement to find out
failures, identify causes, and
prevent failures
• record solutions
• Process History
Measurement (FMEA)
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3. When to create FMEA

General Points
-
-

System FMEA
- after system functions are
defined
- before specific H/W is
selected
design new system,
product, and process, or
new technology is
introduced
• Design FMEA
when an existing design
- after product function is
defined
or process is changed
- before design is approved
when applied to a new
application or
• Process FMEA
environment
- when preliminary product
drawing is complete and
related process flow is
developed
Measurement (FMEA)
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FMEA Execution Table
Product
Development
System
FMEA
Conceptual Design
start
Simulation Design
complete
Design
FMEA
Process
FMEA
start
start
Detail Design
correction
Prototype Test
complete
Production Start
Customer Use
correction
complete
correction
correction
correction
Comments) Since FMEA is a Living Document, its completion means that
it becomes the basis for the input to the next level. It never means it is finished.
Measurement (FMEA)
14
4. Preparation
• Confirmation of purpose
– product quality, reliability,
safety improvement
– setup analysis and test
method for the intended
design
– risk analysis and reduced
warranty cost
– evaluation of product
design
– documentation of past
experience
– increased customer
satisfaction
– reduced product
development time and cost
• Who:
– project team
– person who has a role in
defining, executing, or
changing process
• operators
• maintenance
technicians
• engineers
• supervisors
• managers
• design engineers
• etc.
Measurement (FMEA)
15
• Collect necessary info. • Preparation for proper block diagram
– past documentation of
similar product or process
– A/S data of similar
products
– design standard and
parameter check list guide,
rules
– related technology
advancement status
check
– test results analysis
– customer requirements
– specification list of basic
functions
– predicted environment
and conditions for use
– government and safety
regulations
– related standards
– System FMEA
• hierarchical block diagram
– create a tree diagram of subsystem
that makes up for product, assembly,
module, parts, and components
• function block diagram
– shows flow relations between
components for successful
operation of product
• reliability block diagram
– shows dependence or
independence relations in terms of
reliability
– Process FMEA
• Process map
• C&E matrix
Measurement (FMEA)
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FMEA Definitions
System
: combination of subsystems that has all functions to
accomplish required duty

Subsystem
: a portion of a system, where it shares the system’s role
and accomplishes the functions of the system

Measurement (FMEA)
17

Component
: represents functional and assembly part that form
system or subsystem
functional part : a few to hundreds of parts joined,
and itself performs independent and general functions

assembly : 2 or more parts joined, and functions
as a subsystem
 part : an object which is not disassembled if not
broken down. Has a given characteristics by the design.

Measurement (FMEA)
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Formation of a System
Subsystem
Component
System
Subsystem
Functional
part
Assembly
Part
Component
Subsystem
Measurement (FMEA)
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Important Terms of FMEA (1)
Failure Mode
Effect
• a process fails to perform its
intended function.
• If not found during processing,
it will eventually give undesirable
effect to the customer.
- related to defects
- process input variable that
deviates from standard
- Any matters that a operator
determines as a failure mode
• effect that reaches to
the customer
• target :
- outside customer
- following process
Measurement (FMEA)
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
Types of a Failure Mode
• defects during design
- defects that can be seen as inherent to the design
principle
- absent or missing engineering drawing
• defects during manufacturing
- manufacturing defects
- assembly mistake
• defects during quality control
- insufficient inspection or mistake
- improper process control
• defects during use
- wrong operation
- use under different pattern to the design condition
• defects during storage
- mistake from storage
- absent of storage manual
Measurement (FMEA)
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Important Terms of FMEA (2)
Cause
Current Controls
• origin of process change
that causes failure mode
• cause examination
: give preference to the
failure mode with highest
fatality
• failure mode and cause
examination, and systematic method
to prevent failure in advance
• prevention : Fool Proof design
Fail Safe design
• control : audit, check list,
inspection, lab test, training,
prevention, etc.
Measurement (FMEA)
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FMEA Preparation Procedures
• Define system function
- confirm and define the system function which FMEA performed on
• Decision of decomposition level of the system
-decision of decomposition level and degree of the system
-decide up to which level it is considered as a component
System
Subsystem
Subsystem
Assembly
Part
Single part
Assembly
Part
Single part
Part
Single part
Measurement (FMEA)
Single part
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• Block Diagram Generation
- Generation of functional block diagram of a ystem
- method
: following the operations of a system,
link the part serially if the part fails the system also fails,
link parts parallel if several parts fails the system fails.
- two types
1. By function
2. Write out fatal failure, medium failure, light failure
Measurement (FMEA)
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기능별 블록 다이어그램 예
Electric refrigerator
Cooling
function
Control
function
Storage
function
Cooling
Condenser
Compress
or
Cooling
Condenser
Compress
or
Heat
exchanger
Cooling
Condenser
Compresso
r
Measurement (FMEA)
25
FMEA Methodology :
start with C&E Matrix
• Merit : C&E matrix helps problem definition
- customer’s critical requirements
- process input that gives potential effect to the customer requirements
- assign priority to major process input variables that affect output variable
• C & E Matrix offers
quantitative measures that can be used to determine the severity of FMEA
Measurement (FMEA)
26
5. Process FMEA creation procedures
Step1. Basic item entry
– FMEA number
• tracking
– First target date
• initial FMEA duty
completion date
– FMEA type
• analysis level
• applicable process
– process responsibility
(department)
– prepared by
• name
• contact
– related product model name
– Origination date
• first origination date
• final correction date
fill in all together
– team member list
all team member’s
• name
• contact
Measurement (FMEA)
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Step 2. List process functions
- list process function clear and short (noun + verb)
- list separately if several functions
Delay in process
2
2
Part is loaded
Incorrectly
Final Assembly
Width / Length
Out of Print
Delay in process
8
Delay in process
2
Delay in process
2
Machine will not
weld
Welds appear
Small or “light”
Delay in process
2
Airbag housing
will not sustain
deployment
10
3
4
Fixture A: Initiate
Cycle Start
Fixture A: Clamps
Machine will not
cycle
Machine will not
clamp
5
6
Fixture A: Welds
7
2
8
Fixture A:
Unclamps
Machine will not
unclamp
Delay in process
2
9
Remove and
Transport
SubAssy
Dropped /
Damaged
subassembly
Final Assembly
Width / Length
Out of Print
8
C
I
a
s
s
Potential Causes
of failure (KPIVs)
Potential
cause
O
C
C
Current Process
Current
Contols
process
control status
detection
Parts do not fit
Effects (KPOVs)
S
E
V
occurrence
Potential
Failure
potential
failure
Modes (process
(process
Defects)
ranking
Function
# Process
process
step
(Step)
effect
(process
function)
1
Load
Brckt
1&
Load
bracket1
Housing into
and housing
FixtureA
into fixture
defects)
Potential
Failure
mode
potential
severity
#
D RR
E P
P
P N
N
incoming
component
dimensions out of
print
Operator Error
3
Receiving
Inspection (1%
dimentional audit)
6
36
5
4
160
Power off, sensor
out
Air pressure low,
Sensor out
Part not loaded
properly
Not enough
voitage supplied
Welds schedule
out of adjustment
2
100% Final Dim
Gauge / 100%
Visual inspection
1 / month PM
7
28
2
1 / month PM
7
28
2
2
8
2
4
4
200
Air Pressure
release valve
broken
Operator Error
2
Sensor installed
(poke yoke)
Voitage regulrator
And Visual alarm
100% Visual
inspection, 2 /
shift destructive
testing
1 / month PM
7
28
100% Final Dim
Gauge / 100%
Visual inspection
4
64
Measurement (FMEA)
1
5
2
28
Step 3. List potential failure mode
3
4
Machine will not
cycle
Machine will not
clamp
5
6
Fixture A: Welds
7
2
Final Assembly
Width / Length
Out of Print
Delay in process
8
Unfit part size
Part is loaded
Incorrectly
Inexact load
Fixture A: Initiate
Cycle Start
Fixture A: Clamps
Delay in process
Machine will not
weld
Welds appear
Small or “light”
8
Fixture A:
Unclamps
Machine will not
unclamp
9
Remove and
Transport
SubAssy
Dropped /
Damaged
subassembly
Potential Causes
Potential
of failure (KPIVs)
cause
incoming
component
dimensions out of
print
Operator Error
2
D RR
E PP
P NN
O
C
C
Current Process
Current
Contols
3
Receiving
Inspection (1%
dimentional audit)
6
36
5
100% Final Dim
Gauge / 100%
Visual inspection
1 / month PM
4
160
7
28
7
28
2
8
2
4
4
200
7
28
4
64
process
control status
Power off, sensor
2
out
Delay in process
2
Air pressure low,
2
1 / month PM
Sensor
out
List all potential failure modes (incorrect
Delay in process
Part not loaded
Sensor installed
operation) that2 can occur
under actual2 operation
properly
(poke yoke)
environment
(temp,
moisture,
etc)
Delay
in process
2
Not enoughdust, vibration,
1
Voitage
regulrator
voitage supplied
And Visual alarm
Airbag housing
10
Welds schedule
5
100% Visual
will not sustain
out of adjustment
inspection, 2 /
deployment
shift destructive
testing
Delay in process
2
Air Pressure
2
1 / month PM
release valve
broken
Final Assembly
8
Operator Error
2
100% Final Dim
Width / Length
Gauge / 100%
Out of Print
Visual inspection
Measurement (FMEA)
detection
2
Parts do not fit
C
I
a
s
s
occurrence
Load Brckt 1 &
Load
bracket1
Housing
into
and housing
FixtureA
into fixture
S
E
V
ranking
1
severity
#
Process Function
Potential Failure
Potential
Failure
#
process
step
potential
failure mode
potential
(Step)
Modes
(process
Effects
(KPOVs)
effect
Defects) defects)
(process function) (process
29
FMEA Model
Causes
Failure modes
(detection)
Effects
material or
process
input
process
step
outside customer,
following process
Controls
Measurement (FMEA)
30
Step 4. List potential effects
Parts do not fit
2
defects)
1
Load
Brckt
1&
Load
bracket1
Housing into
and housing
FixtureA
into fixture
2
3
4
5
6
7
8
9
Unfit part size Process
delayed
Part is loaded
Inexact load
Incorrectly
Fixture A: Initiate
Cycle Start
Fixture A: Clamps
Delay in process
Machine will not
cycle
Machine will not
clamp
• extent of effects
recognized by
Fixture A: Welds
Machine will not
internalweld
or external
customers.
Welds appear
Small
or can
“light”
• dangers
that
affect safety or
Fixture A: regulations,
Machineetc.
will not
Unclamps
unclamp
Remove and
Transport
SubAssy
Dropped /
Damaged
subassembly
Final Assembly
Unable
to final
Width
/ Length
Outassembly
of Print
Delay in process
8
Delay in process
2
Delay in process
2
Delay in process
2
Airbag housing
will not sustain
deployment
10
Delay in process
2
Final Assembly
Width / Length
Out of Print
8
2
C
I
a
s
s
Potential Causes
Potential
of failure (KPIVs)
detection
S
E
V
occurrence
potential
failure mode
potential
Potential
Failure
Potential
Failure
Modes (process
Effects (KPOVs)
(process
Defects)
ranking
# Process
process
step
Function
effect (Step)
(process function)
severity
#
D
E
P
R
R
P
P
N
N
Receiving
Inspection (1%
dimentional audit)
6
36
4
160
2
100% Final Dim
Gauge / 100%
Visual inspection
1 / month PM
7
28
2
1 / month PM
7
28
2
Sensor installed
(poke yoke)
Voitage regulrator
And Visual alarm
100% Visual
inspection, 2 /
shift destructive
testing
1 / month PM
2
8
2
4
4
200
7
28
100% Final Dim
Gauge / 100%
Visual inspection
4
64
O
C
C
Current
Process
Current
Contols
process
incoming
component
dimensions out of
print
Operator Error
3
5
Power off, sensor
out
Air pressure low,
Sensor out
Part not loaded
properly
Not enough
voitage supplied
Welds schedule
out of adjustment
Air Pressure
release valve
broken
Operator Error
2
cause
Measurement (FMEA)
1
5
2
control status
31
Relations between failure mode and
effects
Failure mode 1
effect 1
Failure mode 2
effect 1
Failure mode 1
effect 2
Failure mode 1
effect 1
Failure mode 2
Failure mode and effect is not a 1 to 1 relations.
Measurement (FMEA)
32
Step 5. List Severity Ranking
Parts do not fit
2
defects)
1
Load
Brckt
1&
Load
bracket1
Housing into
and housing
FixtureA
Unfit part size
Delay in process
Process delay
2
into fixture
2
3
4
Part is loaded
Inexact load
Incorrectly
Fixture A: Initiate
Cycle Start
Fixture A: Clamps
Machine will not
cycle
Machine will not
clamp
Fixture A: Welds
7
8
Potential Causes
Potential
of failure (KPIVs)
cause
incoming
component
dimensions out of
print
Operator Error
8
2
Delay in process
2
Delay in process
2
Machine will not
weld
Welds appear
Small or “light”
Delay in process
2
Airbag housing
will not sustain
deployment
10
5
6
Final Assembly
Unable
to
Width
/ Length
Out offinal
Print
assembly
Delay in process
C
I
a
s
s
8
Fixture A:
Unclamps
Machine will not
unclamp
Delay in process
2
9
Remove and
Transport
SubAssy
Dropped /
Damaged
subassembly
Final Assembly
Width / Length
Out of Print
8
detection
S
E
V
occurrence
potential
failure mode
potential
Potential
Failure
Potential
Failure
Modes (process
Effects (KPOVs)
(process
Defects)
ranking
# Process
process
step
Function
effect (Step)
(process function)
severity
#
D
E
P
R
R
P
P
N
N
Receiving
Inspection (1%
dimentional audit)
6
36
100% Final Dim
Gauge / 100%
Visual inspection
1 / month PM
4
160
7
28
7
28
2
8
2
4
4
200
7
28
4
64
O
C
C
Current
Process
Current
Contols
process
3
5
control status
Power off, sensor
2
out
Air pressure low,
2
1 / month PM
Sensor out
Part not loaded
2
Sensor installed
• severity
properly ranking of
(poke yoke)
potential
effects
Not enough
1
Voitage regulrator
voitage
supplied
• each failure mode hasAnd Visual alarm
Weldsone
schedule
100% Visual
only
severity 5ranking
out of adjustment
inspection, 2 /
(the most severe effects)
shift destructive
testing
Air Pressure
2
1 / month PM
release valve
broken
Operator Error
2
100% Final Dim
Gauge / 100%
Visual inspection
Measurement (FMEA)
33
Severity Ranking Guidelines
•
–
–
•
•
Moderate
convenience item(s) inoperable
2 points
– Very Minor
– finish defect noticed by
discriminating customers
6 points
–
–
3 points
– Minor
– finish defect noticed by
average customers
Very High
major disruption to product line
High
minor disruption to product line
customer dissatisfied
4 points
– Very Low
– Defect seen by most customers
7 points
–
–
–
•
•
•
8 points
–
–
•
Hazardous with warning
conflict with safety or government
regulations with warning
5 points
– Low
– convenience item(s) operable
at reduced level of performance
Hazardous without warning
conflict with safety or government
regulations without warning
9 points
–
–
•
•
10 points
•
1 points
– None
Measurement (FMEA)
34
Step 6. List potential cause and failure mechanism
1
2
Load Brckt 1 &
Load bracket1
Housing
into
and housing
FixtureA
Parts do not fit
Unfit part size
Delay in process
Process delay
2
Final Assembly
Unable to
Width / Length
Out offinal
Print
assembly
Delay in process
8
8
Delay in process
2
C
I
a
s
s
into fixture
2
3
4
5
6
7
8
9
Part is loaded
Incorrectly
Inexact load
Fixture A: Initiate
Cycle Start
Fixture A: Clamps
•
Machine will not
cycle
Machine will not
clamp
weakness
point
2
Delay of
in process
• list all possible causes
potential 2failure
Fixture A: Weldsmode.
Machine will not
Delay in process
2
weld
• Through repeated what? and why?
Welds appear
Airbag housing
Questions,
list fundamental
causes 10
Small or “light”
will not sustain
•In order to find fundamental
deployment causes,
can use cause and effect diagram or FTA.
Fixture A:
Unclamps
Machine will not
unclamp
Delay in process
2
Remove and
Transport
SubAssy
Dropped /
Damaged
subassembly
Final Assembly
Width / Length
Out of Print
8
Potential
Causes
Potential
of failure (KPIVs)
cause
incoming
Incoming
component
part dim out
dimensions out of
print of print
Operator Error
detection
S
E
V
occurrence
# Process
process
step
potential
failure mode
potential
Function
Potential
Failure
Potential
Failure
Modes (process
Effects (KPOVs)
effect (Step)
(process function) (process
Defects)
defects)
ranking
severity
#
D RR
E PP
P NN
O
C
C
Current
Process
Current
Contols
process
3
Receiving
Inspection (1%
dimentional audit)
6
36
4
160
7
28
3
Power off, sensor
out
Air pressure low,
Sensor out
Part not loaded
properly
Not enough
voitage supplied
Welds schedule
out of adjustment
2
100% Final Dim
Gauge / 100%
Visual inspection
1 / month PM
2
1 / month PM
7
28
2
2
8
2
4
4
200
Air Pressure
release valve
broken
Operator Error
2
Sensor installed
(poke yoke)
Voitage regulrator
And Visual alarm
100% Visual
inspection, 2 /
shift destructive
testing
1 / month PM
7
28
100% Final Dim
Gauge / 100%
Visual inspection
4
64
Operator error
Measurement (FMEA)
5
control status
5
1
5
2
35
Step 7. List rankings
• Used to classify special • Reversed triangle
product characteristics
representation
– characteristics necessary
– used for characteristics
for additional process
whose severity is greater
control.
than 8.
– characteristics that affect
– possible to use for
safety.
characteristics whose
– characteristics specified
severity is between 4 and
in government
8
regulations.
• Usage and Fill-in
– to reflect company
standards or procedures
– first list severity ranking
and failure cause then
– filled in by the FMEA
leader
Measurement (FMEA)
36
Step 8. Occurrence Ranking
Guidelines
• 5 points
• 10 points
– 1 in 400
–  1 in 2
– failure is almost
inevitable
• 9 points
– 1 in 3
• 8 points
– 1 in 8
– repeated failures
• 7 points
– 1 in 20
• 6 points
– 1 in 80
– occasional failures
• 4 points
– 1 in 2,000
• 3 points
– 1 in 15,000
– relatively low failures
• 2 points
– 1 in150,000
• 1 points
–  1 in 1,500,000
– unlikely failures
Measurement (FMEA)
37
Step 9. List current process control status
Load
Brckt
1&
Load
bracket1
Housing into
and housing
FixtureA
Parts do not fit
Unfit part size
Delay in process
2
Process delay
2
Final
Assembly
Unable
to
Width / Length
final
Out of Print
assembly
Delay
in process
8
into fixture
2
3
4
Part is loaded
Incorrectly
Inexact load
Fixture A: Initiate
Cycle Start
Fixture A: Clamps
Machine will not
cycle
Machine will not
clamp
5
6
Fixture A: Welds
7
Machine will not
weld
Welds appear
Small or “light”
8
Potential Causes
ofPotential
failure (KPIVs)
cause
incoming
Incoming
component
part dim out
dimensions out of
print of print
Operator Error
Operator error
O
C
C
3
3
5
5
2
Power off, sensor
2
out
Delay in process
2
Air pressure low,
2
Sensor out
• current2control items
eliminate2
Delay in process
Part notto
loaded
properly
causes of potential
failure modes
Delay in process
2
Not enough
1
• preventive itemsvoitage supplied
• find causes
for corrections
Airbag housing
10
Welds schedule
5
will not sustain
out
of
adjustment
• find failure mode itself
deployment
8
Fixture A:
Unclamps
Machine will not
unclamp
Delay in process
2
9
Remove and
Transport
SubAssy
Dropped /
Damaged
subassembly
Final Assembly
Width / Length
Out of Print
8
Air Pressure
release valve
broken
Operator Error
Measurement (FMEA)
2
2
Current
Current
Process
Contols
process
control status
Receiving
Receiving
Inspection
(1%
dimentional
audit)
inspection
100%
Final
Dim
100%
visual
Gauge / 100%
inspection
Visual
inspection
1 / month PM
detection
1
C
I
a
s
s
occurrence
defects)
S
E
V
ranking
Defects)
severity
# Process
process
step
potential
failure mode
potential
Function
Potential
Failure
Potential
Failure
# effect
(Step)
Modes
(process
Effects
(KPOVs)
(process function) (process
R
D R
E PP
P NN
6
36
6
4
160
7
28
1 / month PM
7
28
Sensor installed
(poke yoke)
Voitage regulrator
And Visual alarm
100% Visual
inspection, 2 /
shift destructive
testing
1 / month PM
2
8
2
4
4
200
7
28
100% Final Dim
Gauge / 100%
Visual inspection
4
64
4
38
Step 10. Detection Ranking
Guidelines
•
•
•
•
•
10 points
– Absolute Uncertainty
– unable to detect causes and related
failures with current controls
9 points
– Very Remote
– very unlikely to detect causes and
related failures with current controls
8 points
– Remote
– unlikely to detect causes and related
failures with current controls
7 points
– Very Low
– low possibility to detect causes and
related failures with current controls
6 points
– Low
– low possibility to detect causes and
related failures with current controls
•
•
•
•
•
5 points
– Moderate
– average possibility to detect causes
and related failures with current
controls
4 points
– Moderately High
– above average possibility to detect
causes and related failures with current
controls
3 points
– High
– high possibility to detect causes and
related failures with current controls
2 points
– Very High
– very high possibility to detect causes
and related failures with current
controls
1 points
– Almost Certain
– sure to detect causes and related
failures with current controls
Measurement (FMEA)
39
FMEA Model
prevention Causes
detection
Failure Mode
(Analyze) detection
Effects detection
Material or
process
input
process
step
Outside customer,
following process
Control
Which is an optimal status?
Which is an optimal status?
Measurement (FMEA)
40
Step 12. Take action
Step 11. Fill in RPN
– RPN = severity ranking
* occurrence ranking
* detection ranking
– focus on failure mode
with the highest RPN
– For failure mode with a
not so high RPN, but with
high severity, pay special
attention.
– very important to finish
this part, track, and
confirm
– detection ranking
• improvement through
process confirmation and
verification
– occurrence ranking
• Improvement through
process change
– severity ranking
• improvement through
process change and
failure mode elimination.
Measurement (FMEA)
41
Risk Priority Number
• RPN : outcome from FMEA
• RPN calculation:
• potential failure mode
• effect of failure mode
• possible to find failure mode before a product
is delivered to the customer.
Measurement (FMEA)
42
RPN Calculation
RPN = Severity * Occurrence * Detection
Effects
Causes
Controls
• possible to add other items
• RPN doesn’t have a value inherent to product category.
Measurement (FMEA)
43
RPN Ranking Example
Rate
Severity
10
Hazardous without warning
9
Hazardous with warning
8
Lost major function
7
6
5
Occurrence
Can not detect
Very unlikely detect
Unlikely detect
Reduce major functional
performance
Lost minor function
4
Reduce minor functional
performance
Noticed by most customers
3
Noticed by average customers
2
Noticed by discriminating
customers
No effect
1
Very High:
Failure is almost inevitable
Detection
High:
Repeated Failures
Very low possibility to detect
Low possibility to detect
Moderate:
Frequent Failures
Average possibility to detect
Above average possibility to
detect
High possibility to detect
Low:
Almost no Failures
Very high possibility to detect
Failure unlikely.
Sure to detect
Measurement (FMEA)
44
Step 14. Actual action date
- items acted upon
actually
Step 13. Assign
responsibility
- responsible person
- date
Step 15. RPN recalculation
. contact
. department
- severity
- occurrence
- detection
find RPN after recalculating it .
- expected completion date
#3
Wells
appear small
or “light”
Part is
loaded
incorrectly
Dropped
Damaged
subassembly
Airbag housing
will not sustain
deployment
Final Assembly
With / Length
Out of Print
Final Assembly
With / Length
Out of Print
tools
8
2
4
160
8
2
4
64
Need BB
statistical
2000/1/15
tools
Need fixture
re-design
Install
transfer
conveyer
Measurement (FMEA)
S
E
V
detection
#2
Failure Effect
Person and
AppliedDate
actions
Target
occurrence
#1
Failure Mode
Recommended
Person and
Action
target
date
severity
Priority
S Recommended
O D R
E
C actions
E P
V
C T N
10 5Need4 statistical
200
O D RR
C E PP
N
C T N
Black
Belt
Attribute Sampling
?
/
?
/
?
single sampling inspection
Mfg Engineer
?/?/?
Fill in numbers changed after
recommend actions have been tak
Maintenance
8
2 2 32
Technician
(done)
45
Quiz!
• Complete the following table : 5 minutes
• Discuss about the results : 10 minutes
Occurrence
1
1
1
1
10
10
10
10
Severity
1
1
10
10
1
1
10
10
Detection
1
10
1
10
1
10
1
10
Measurement (FMEA)
Results
Actions
46
Quiz! (Results)
Occurrence
1
1
1
1
10
10
10
10
Severity
1
1
10
10
1
1
10
10
Detection
Results
Actions
1
optimal status
no action
no action
10
guaranteed control
1
failure not reaching the customer no action
10
action
failure reaching the customer
frequent failure, detection, cost
1
action
frequent failure, reaching the customer action
10
Main effect from frequent failure
action
1
Big problem
action
10
Measurement (FMEA)
47
Taking Actions against RPN Value
•
Necessary to establish improvement actions if RPN
is greater than 100 or Ranking of Failure Occurrence,
Severity, or Detection is greater than 8
•
Mark star (*) in the applicable items in FMEA
•
If it is not necessary to plan improvement actions,
mark NOR (Not Requirement) in the applicable item.
Measurement (FMEA)
48
6. Process FMEA Check List
•
• Preparation
– FMEA team formed?
– Background information
confirmed?
• Process Map
– Process map generated?
– Ys for each process step
listed?
– Xs for each process step
listed?
• Fundamental items
– fundamental items filled in?
• Fill in function
– each operation’s function
listed clearly?
Failure Mode
– does it explain why this failure
mode results in parts being out of
specification?
– Did you list the part
characteristics which resulted
from failure mode?
– Are inspection and test related
items included in failure modes??
• Defective part received
• Qualified parts rejected
– If failure mode passes bad effects
to the following process,
• Is the failure mode identified
as the cause of the following
operation?
• Is the failure of the following
operation identified?
Measurement (FMEA)
49
•
•
Effect of Failure
– Is it considered the dangerous effects
of machine, operator, and final
customers?
– Are the effects of the following lines
listed?
• Later operation
• next user and final customer
• transport method
• government regulations
Cause of Failure/ Mechanism
– Is there a confirmation of the possible
failures in the process?
– Is it presented as features requiring
correction or control?
– Are process characteristics considered?
– Is there a consideration for design
weakness?
– Are materials and subparts for each
operation considered?
– Is there a consideration for the
operators’ work?
•
•
•
•
Current control status
– Is it ready to detect defectives?
– Can it detect defectives before the
completion of operation?
– Can you tell whether it is for
detection or prevention?
Severity Ranking
– Is it sorted according to the
highest severity effects of failure
mode?
– Does it conflict to extent of the
effect to customers?
Occurrence Ranking
– Is it ranked, considering
preventive control?
Detect Ranking
– Is it determined based on the
possibility that the current control
can detect it before the completion
of the operation?
Measurement (FMEA)
50
•
•
Ranking Classification
– Is it confirmed the main
characteristics and its special
control?
– Are the main characteristics
represented by the reversed
triangle?
– Are the main characteristics
understood as process or part
characteristics?
– Are the main characteristics
and its special control notified
to the design manager?
RPN
– Is RPN sorted according to the
highest order?
•
Warning
– Is the action to reduce fatal
defects of the main
characteristics considered?
– Is special control to the main
characteristics considered?
– Are all main characteristics
considered?
– Is treatment action related to
the failure mode that has the
highest RPN?
– Are persons responsible for the
warning treatment and the time
limit specified?
– Is preventive action considered
first?
– Is action to eliminate or reduce
the occurrence of dangerous
failure mode considered?
Measurement (FMEA)
51
FMEA (Example) - 1
Following FMEA procedures ...
Main process input variable : scale accuracy, steam heat DICY tank
Process
step
Steam heat
DICY tank
Main process
input
Failure
mode
Effect
Cause
Control
scale
accuracy
Measurement (FMEA)
52
FMEA (Example) - 2
• Input failure mode based on the main
process input variable
Process Main process
step
input
Steam heat
DICY tank
scale
accuracy
Failure
mode
Effect
Cause
Control
scale > 0
scale
inaccuracy
scale
out of zero setting
Measurement (FMEA)
53
FMEA (Example) - 3
• List effects due to failure mode
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
Effect
scale > 0
low DMF recharge
scale
inaccuracy
scale
out of zero setting
Cause
Control
high DMF recharge
wrong DMF
recharge
Measurement (FMEA)
54
FMEA (Example) - 4
• List cause of the failure mode
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
scale > 0
scale
inaccuracy
scale
out of zero setting
Effect
Cause
Control
low DMF recharge water in Jacket
high DMF recharge Tank delay
wrong DMF
recharge
Measurement (FMEA)
unstable scale
55
FMEA (Example) - 5
• List current control methods to each cause
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
scale > 0
scale
inaccuracy
scale
out of zero setting
Effect
Cause
Control
Jacket: Visual
low DMF recharge water in Jacket check(SOP 5681)
high DMF recharge
wrong DMF
recharge
Tank delay
unstable scale
Visual check
(SOP 5681)
None
FMEA confirms initial defects in control.
Measurement (FMEA)
56
FMEA (Example) - 6
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
scale > 0
scale
inaccuracy
scale
out of zero setting
DMF
installation
DMF
installation
accurately
Effect
Cause
Control
Jacket: Visual
low DMF recharge water in Jacket check(SOP 5681)
high DMF recharge
wrong DMF
recharge
Tank delay
unstable scale
Visual check
(SOP 5681)
None
wrong DMF
recharge
Measurement (FMEA)
57
FMEA (Example) - 7
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
scale > 0
scale
inaccuracy
DMF
installation
DMF
installation
accurately
Effect
Cause
Control
Jacket: Visual
low DMF recharge water in Jacket check(SOP 5681)
high DMF recharge
scale
out of zero setting
wrong DMF
recharge
wrong DMF
recharge
Extent to
out of print
Measurement (FMEA)
Tank delay
unstable scale
Visual check
(SOP 5681)
None
58
FMEA (Example) - 8
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
scale > 0
scale
inaccuracy
DMF
installation
DMF
installation
accurately
Effect
Cause
Control
Jacket: Visual
low DMF recharge water in Jacket check(SOP 5681)
high DMF recharge
scale
out of zero setting
wrong DMF
recharge
wrong DMF
recharge
Extent to
out of print
Tank delay
unstable scale
Visual check
(SOP 5681)
None
Broken
apparatus
Out of SOP
standards
Measurement (FMEA)
59
FMEA (Example) - 9
Process Main process
input
step
Steam heat
DICY tank
scale
accuracy
Failure
mode
scale > 0
scale
inaccuracy
DMF
installation
DMF
installation
accurately
Effect
Control
Cause
Jacket: Visual
low DMF recharge water in Jacket check(SOP 5681)
high DMF recharge
scale
out of zero setting
wrong DMF
recharge
wrong DMF
recharge
Extent to
out of print
unstable scale
None
Maintenance repair
Broken
procedure
(SOP 5821)/
apparatus
visual check
Out of SOP
standards
Measurement (FMEA)
Visual check
(SOP 5681)
Tank delay
Operator certificate/
process audit
60
FMEA (Example) - 10_1
• assign ranking to each severity, occurrence, and detection
• RPN calculation
Process steps/
Failure mode
input
Steam heat
DICY tank/
scale accuracy
DMF charge/
DMF accurate
installation
Effect
severity
Cause
Occurrence
control
Detection RPN
low DMF charge
3
Water in Jacket
2
Jacket: visual
check (SOP 5681)
1
6
Scale inaccuracy High DFM charge
3
Tank delay
2
Visual check
(SOP 5681)
3
18
Scale
wrong DMF charge
out of zero setting
3
9
54
Maintenance repair
procedure (SOP 5821)/ 3
visual check
42
scale > 0
Extent to
wrong DMF charge out of print
Unstable scale
2
7
Broken
apparatus
2
7
Out of SOP
standard
5
Measurement (FMEA)
None
Operator certificate/
process audit
5
175
61
FMEA (Example) - 10_2
•
Process steps/
Failure mode
input
DMF charge/
wrong DMF charge
DMF accurate
installation
sort by RPN
Effect
severity
Extent to
out of print
Steam heat
Scale
DICY tank/ out of zero setting wrong DMF charge
scale accuracy
DMF charge/
7
3
Cause
Occurrence
Out of SOP
standard
Unstable scale
5
2
control
Detection RPN
Operator certificate/
process audit
None
5
175
9
54
7
Broken
apparatus
2
Maintenance repair
procedure (SOP 5821)/
visual check
3
42
Steam heat
DICY tank/
Scale inaccuracy High DFM charge
scale accuracy
3
Tank delay
2
Visual check
(SOP 5681)
3
18
Steam heat
DICY tank/
scale accuracy
3
DMF accurate
installation
wrong DMF charge
scale > 0
Extent to
out of print
low DMF charge
Water in Jacket
Measurement (FMEA)
Jacket: visual
2 check
(SOP 5681) 1
6
62
FMEA (Example) - 11
•
decide necessary action (only for higher RPN)
Process steps/
Failure mode
input
DMF charge/
wrong DMF charge
DMF accurate
installation
Effect
severity
Cause
Occurrence
7
Out of SOP
standard
5
Extent to
out of print
Steam heat
Scale
DICY tank/ out of zero setting wrong DMF charge
scale accuracy
DMF charge/
3
Unstable scale
2
control
DetecNecessary
tion RPN action
Operator certificate/
process audit
None
5
175
Full proof
design
9
54
Daily checkup
scale function
7
Broken
apparatus
2
Maintenance repair
procedure (SOP 5821)/
visual check
3
42
Steam heat
DICY tank/
Scale inaccuracy High DFM charge
scale accuracy
3
Tank delay
2
Visual check
(SOP 5681)
3
18
Steam heat
DICY tank/
scale accuracy
3
2
Jacket: visual
check (SOP 5681)
1
6
DMF accurate
installation
wrong DMF charge
scale > 0
Extent to
out of print
low DMF charge
Water in Jacket
Measurement (FMEA)
63
FMEA (Example) - 12
• proper action and documentation
• RPN recalculation
cause
Occurrence
control
Out of SOP
standard
5
Operator certificate/
process audit
Unstable scale
2
Broken
apparatus
Tank delay
Water in Jacket
Detection RPN Necessary action
Resp.
Occur-DetecAction taken severityrence tion RPN
automatic DMF
recharger
8/96
5 175
Full proof
design
None
9 54
Daily checkup
scale function
2
Maintenance repair
procedure (SOP 5821)/
visual check
3 42
0
2
Visual check
(SOP 5681)
3 18
0
2
Jacket: visual
check (SOP 5681)
6
0
1
SZ
7
1
2
0
PQ
Measurement (FMEA)
14
64
FMEA Approach
• Method 1 : Focus of C & E Matrix
- Start with the main input factor with the highest point in C & E Matrix anal
- Fill in the worksheet the above input factors.
- Calculate RPN, then develop control methods for the failure mode with
the highest RPN.
- Complete process FMEA for all other input factors.
• Method 2 : Focus of FMEA itself
- Fill in the worksheet failure mode and effects.
- List causes of failure mode with the highest Severity ranking, and
evaluate possibility of occurrence.
- Evaluate current control status for high value of (severity X occurrence).
- Develop control methods for the item with the highest RPN.
Measurement (FMEA)
65
• Method 3: Total Approach
- Good approach for small processes.
- List in the worksheet from start process to finish process.
- Calculate severity, occurrence, and detection ranking for all causes.
- Develop control methods for the item with the highest RPN.
• Method 4: Super Focused
- Generate Pareto chart and sort out main defects items or failure modes
- FMEA focuses on defects or failure modes.
- Purpose : disappearance of failure modes
Measurement (FMEA)
66
Catapult Device
1
2
Ball type
1
1
2
Golf ball
Table tennis
ball
Pin
position
2
Hook
position
3
4
Number of
rubber bands
(1 - 3)
Stop
position
3
2
1
Throwing
angle
4
5
6
Measurement (FMEA)
67
Measurement (FMEA)
68