Transcript PowerPoint slides

Aerospace Soldering & Electronic Assembly
Techniques
Randall Pearl
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RCA/GE Astro Space 1981-1989
• Ground Systems Manufacturing
• Flight Systems Manufacturing
• Battery/Solar Engineering
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Basic Tools, Materials and Procedure of Hand Soldering
Basic Elements of Hand Soldering
• Temperature controlled Soldering Iron with
stand and sponge
• Solder Material
Basic Additional Materials
• Flux
• Flux removal solvent such as Isopropyl Alcohol
• Brush to use with solvent
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Basic Tools, Materials and Procedure of Hand Soldering
Basic Procedure
• Clean the surfaces to be soldered (dirt free, grease free and oxide-free)
• Put two target objects (to be soldered) together
• Wet the joint area with flux, if needed
• Pre-heat the joint area with soldering iron
• Apply solder at the joint and remove when sufficient solder has flowed down to
the joint
• Remove solder wire and then soldering iron, and allow the joint to cool down
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Cleaning, Wetting and Pre-heating, Solder Flow
Cleaning
 Iron tip cleaning
 Component lead cleaning
 Circuit board cleaning
Wetting (Tinning)
 Iron tip wetting with molten solder
 Contact wetting with molten solder
Preheating
 Pre-heat the contacts before soldering
Solder Flow
 Allowing molten solder to flow freely
Contact Area Between Iron and Work
Incorrect: Very Small contact Area
Correct: Sufficient Contact Area
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Size of Solder Fillet
a) Minimum amount of solder
b) Optimal
c) Excessive solder
Basic Safety Procedures and Practices
Safety Hazards
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Hot Iron (temperature as high as 430oC)
Fumes
High Voltage
Loose Clothing and Hair
Lead of the solder
Basic Safety Procedures and Practice
• Work in a ventilated place, or use fume extractor
• Put the hot iron in its holder when not used
• Avoid touching the metallic part of the iron while it is hot and/or
connected with the power-line
• Wear appropriate clothes and tie back long hair
• No food or drink in the lab while working
• Wear safety glasses
• Keep flammable materials away from the hot soldering iron
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Other materials
Kapton Tape
• DuPont Kapton™ HN general purpose film. It
has been used in applications at temperatures as
low as -269°C (-452°F) and as high as
400°C (752°F).
Solder Sleeves
• Solder sleeves are primarily used to attach a ground wire (lead) to the
shielding braid of a shielded cable by means of a shrinkable tubing
assembly having an integral solder pre-form.
• Solder sleeves are also used to splice two or more conductors together.
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Other materials
Lacing Tape (or cord)
•Cable lacing is a method for tying wiring
harnesses and cable looms, traditionally used in
telecommunication, naval, and aerospace
applications. This cable management technique
is still used in some modern applications since
it does not create obstructions along the length
of the cable, avoiding the handling problems of
cables groomed by plastic or velcro cable ties.
•Harnesses are usually fabricated on a harness jig or forming board.
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Resources
NASA Training Program - Student Workbook for Hand Soldering:
•http://www.protostack.com/download/NASA
%20Student%20Handbook%20for%20Hand%
20Soldering.pdf
NASA-STD 8739.3 Soldered Electrical Connections:
•http://www.protostack.com/download/NASASTD8739.3%20including%20Change%203.pdf
Wiring and Cabling:
•http://en.wikipedia.org/wiki/Cable_lacing
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