Electronics Forum | Wed Jun 05 14:24:57 EDT 2002 | davef
IPC/WHMA-A-620, Requirements and Acceptance for Cable and Wire Harness Assemblies It took the fine folk at IPC forever and a week to produce A-620. So, we continue to use NASA-STD-8739.4, Crimping, Interconnecting Cables, Harnesses, And Wiring that
Electronics Forum | Thu Jun 11 22:57:45 EDT 2009 | davef
NASA recommends baking a PCB for a minimum of 4 hours at 93+/- 5.5�C before conformally coating. [NASA-STD-8739.1, �Workmanship Standard for Staking and Conformal Coating of Printed Wiring Boards and Electronic Assemblies,� August 6, 1999]
Electronics Forum | Tue Jun 13 22:42:36 EDT 2000 | Dave F
Jeff: Last place I can recall seeing something like that is NASA-STD-8739.3 Requirements like this are not currently in vogue. A modern solder process should conform to J-STD-001, which makes no mention of prebaking boards.
Electronics Forum | Thu Mar 12 21:14:16 EDT 2009 | davef
Mask: * I/O connector contact surfaces * Bus connector contact surfaces * Configuration jumper blocks * Test points * Surfaces that contact heat sinks (heat sinks are removed prior to coating) * Board mounting holes * Adjustable potentiometers * P
Electronics Forum | Fri May 14 14:35:51 EDT 2004 | davef
Try: * NASA-STD-8739.1 Workmanship Standards For Staking And Conformal Coating Of Printed Wiring Boards And Electronic Assemblies * NHB 5300.4(3J) Requirements for Conformal Coating and Staking of Printed Wiring Boards and Electronic Assemblies
Electronics Forum | Wed Nov 06 19:59:39 EST 2002 | davef
Consider checking with your CC materials supplier for suggestions. It's to their benefit to help you do a good job using their product. Regardless of your current requirements, consider basing your workmanship on NASA-STD-8739.1 Workmanship Standar
Electronics Forum | Thu Jan 30 14:37:45 EST 2003 | davef
NASA-STD-8739.1 , Workmanship Standard for Staking and Conformal Coating of Printed Wiring Boards and Electronic Assemblies, says words to the effect of : 10.1 Purpose Conformal coatings are intended to provide electrical insulation and environmental
Electronics Forum | Fri Nov 14 07:56:49 EST 2008 | davef
Section 9 of J-STD-001 gives you what you need. Further: * Flattened [coined] lead: http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/files/711.pdf * Flat lug lead: Look for the Package Designator �LT� on page 7 of http://www.allegromicr
Electronics Forum | Tue Aug 25 08:04:26 EDT 2009 | davef
Trapped moisture can be a problem, and one standard recommends baking a PCB for a minimum of 4 hours at 93+/- 5.5ºC before conformally coating. [NASA-STD-8739.1, “Workmanship Standard for Staking and Conformal Coating of Printed Wiring Boards and Ele
Electronics Forum | Wed Jun 24 18:41:23 EDT 1998 | Bill Chrisitian
| Dennis, thanks for your input. I myself can't remember having any caps fail due to thermal stress/cracking. But the guru's here says it happens and since the assembly is for space flight, it's a requirement to preheat. Also, your process is exactl
