Flattery will get you nowhere.

See if you can microsection the scrap in the area that outgassed.
This may give a clue as to which layers are failing.

Generally, I would expect the soldermask cure bake to be enough to
prevent moisture from remaining and moisture is what blows boards apart.

The other culprit is the preclean line.  If you are not drying well and
don't have adequate preheat ahead of the fluxer you can have problems.
Check the dryer out by running a board with small holes and rapping it on
a clean table afterward.  If you see water on the table, the dryer didn't
get it.  Try slowing down the conveyor or raising the dryer temp.

-----Original Message-----
From: Anne Ledger [mailto:[log in to unmask]]
Sent: April 04, 2000 10:03 AM
To: [log in to unmask]
Subject: [TN] Outgassing


Good Morning Technet

Hope that a few of the "all knowing, all powerful" are available for
questions
and not all out at IPC.  I have been tasked with a corrective action on
a
16 layer board, .125 thick that exhibited some outgassing during
leveling.
I lost 4 or 5 of a run of 30.  Where should I start to look for the
culprit?  All
normal bake cycles were observed (at least signed off on the work
order).
Somebody give me a clue?!?

Anne Ledger
EMDS, Inc
[log in to unmask]

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