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Date: | Fri, 2 Oct 1998 07:51:31 -0500 |
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Neil,
I'm no chemist, so this is from a manufacturing viewpoint, but we have had
similar problems in the past, and using 62/36/2 (2% silver) solder paste
formulations have helped with some finishes as you described. For what It's
worth...
Jeff Hempton
United Technology Electronic Controls
______________________________ Forward Header __________________________________
Subject: [TN] Solderability Problems
Author: Neil Atkinson <[log in to unmask]> at Internet
Date: 10/1/98 8:00 AM
Technetters,
This is the second time I have asked this question but so far I haven't
had a reply. Maybe I'll ask in a different way this time!
We are trying to solder a microswitch to a PCB and are having serious
problems with dry joints (i..e de-wetting of the legs).
Having spoken with the supplier of the switch he has informed me that
the switch legs(there are two of them) have different platings these
are:
Material: CuZn37-F37
Finish: 2 microns Silver Plated. Nominal 0.2 microns gold.
and
Material: CuZn37-F37
Finish : Nominal 0.2 microns gold
My questions are:
What does the silver do to solderability?
Why would a switch manufacturer use these finishes?
Should the second leg have a barrier layer (Nickel?) between the brass
and the gold?
My swich supplier is willing to listen but what would be the best finish
for us to solder whilst meeting the switch manufacturers requirements?
HELP!!!!
Neil Atkinson
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