Richard
Sure sounds like a vendor fault, probably an insufficiently cured mask.
The puzzling thing, though, is how they went through the HASL and the
wash without it happening.
FWIW
Brian
"Richard E. Ackerson" wrote:
>
> I am looking for some input regarding a possible cause for a problem we are
> having with one board, part number.
>
> We recieved a lot of boards from a vendor, all with the same date code. This is
> one of meny boards we have recieved and are still recieving.
> This board, however, is causing problems after wave soldering, by the soldermask
> peeling, reveling bare copper.
>
> The boards are 4 layers, with a thickness of .093". They are SMOBC/HAL boards.
>
> The boards are assembled and then wave soldered using water soluble flux. The
> mask begins peeling during water wash in our Trieber SMT Cleaner.
>
> The wave temperature is 500F. Kester Water soluble flux #2235 is used with
> Kester #4662 thinner to reach SG. The flux is applied with a foam fluxer.
> Preheat temperature is 220F.
>
> The mask does not peel prior to wave soldering, only after.
>
> My inital feelings is that there was contamination left on the copper prior to
> the soldermask operation. The vendor feels, since the mask dosen't peel prior to
> wave soldering, and didn't peel prior to their shipping, the problem is in our
> process.
>
> This is occurring with one part number, one single lot of boards from one
> vendor. We have not experienced this situation with any other of this vendors
> boards, or any othe vendor's boards.
>
> Any Ideals?
>
> All input will be appreciated.
> Sincerely,
>
> ____________________
> Richard E. Ackerson
> Sr. Industrial Engineer
> ABB Automation, Inc.
> Electronics & Systems Assembly
> Phone: 440-585-7646
> Fax: 440-585-8860
> [log in to unmask]
>
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