If the PCBs were shrink wrapped than maoisture is not the issue, but
manufacturing defect of the PCB, probably resins in the lamionate.

If they were not shrink wrapped than maoisture could be one of the cause
and you should re-bake them before assembly and solder them in 3 days time.

regards

Sunil Gupta
Manager- Process Engineering





"Stephen R. Gregory" <[log in to unmask]> on 28-08-99 20:07:34

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
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To:   [log in to unmask]
cc:    (bcc: Sunil Gupta/TTL)
Subject:  [TN] Blisters or Delamination after Wave...




Hi ya'll!

Well, I'm in onna Saturday...(Months end, you know how that goes!). Just
finished waving a small lot of boards (9 assemblies) and 5 of them came off
the wave with these dime to quarter-sized delaminated blisters, maybe 3-4
of
them on each board, and the other 4 boards looked fine! What would cause
that? Entrapped moisture? The boards were supposedly baked before wave (At
least the traveler said they were). Any ideas?

-Steve Gregory-

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