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Date: | Thu, 27 Mar 97 16:33:54 cst |
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Hi Maurice -
Take a look at the solderability of the boards. You may have pads
where the nickel underplate has diffused to the pad surface via the
gold grain boundaries or porosity in the gold finish. Check out
"Assessment of Circuit Board Surface Finishes for Electronic Assembly
with Lead free Solders" by Dr.U. Ray, et all, SMI 96 Proceedings page
656 for more info.
Dave Hillman
Rockwell Collins
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Subject: ass- gold/Ni solder skips
Author: [log in to unmask] at ccmgw1
Date: 3/27/97 9:16 AM
Date 27/3/97
Subject ass- gold/Ni solder skips
>From Maurice Dore
To Tech net
ass: gold/Ni solder skips
Hi
I'm wave soldering a board with gold/nickel finish and I've recently seen
some bizarre incidents of certain pads entirely not wetting, some with a
slight degree of wetting and the majority showing very good wetting.
I have a gut feeling that it's related to variation of temperature in the
solder bath but I really am not sure why its recently started happening.
Any opinions welcome.
Thanks in advance.
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