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March 1997

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Subject:
From:
"Leo P. Lambert" <[log in to unmask]>
Date:
Mon, 31 Mar 1997 21:45:25 -0500 (EST)
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Hello.  Lots of things could be happening in the scenario you provided.
Various temperature gradients across the wave is doubtful however, as this
would cause many other problems, to numerous to mention.

I would suggest:
1. Evaluating the pad sizes or the visible portion of the pads where the
skip      has occurred.
2. Evaluate the orientation of the components in regards to the direction
the      board is being processed over the wave solder system. A shadowing
effect        could be preventing the solder from reaching the pads.
3. If you have a chip wave check to see whether or not it is adjusted to
high      where it would be rendered useless as it would also shadow the
components and    use up some of the flux.
4. Finally for an initial go around I would check the fluxer to verify good
flux    coverage on all the pads.

Good luck, keep us posted.

Leo Lambert
Technical Director
EPTAC Corp.

Check out our web page at www.eptac.com

At 02:52 PM 3/27/97 GMT, Maurice Dore wrote:
>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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