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August 1999

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Subject:
From:
KELLY M SCHRIVER <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 31 Aug 1999 09:31:00 -0400
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Mornin' Steve and Earl and  All -

Reviewing the photo's Steve mentioned sort of puts this thing in a different
light -

The delams look as if they have occurred INTERNAL to the circuit side cap
layer, raising the question of just exactly how did the fabricator lay them
up, and of what materials?

Second, the boards have a deep amber color, not dark enough to suggest
polyimide, but dark enough to suggest that the laminate saw an extended heat
cycle during the fab cycle.

Steve, I'd take a real good look at the fabricator and his construction of
this item -  I haven't seen a double clad cap delaminate since the bad old
days when we were just getting started in multilayers.  I have had a bunch of
heartburn with folks who overheated, repressed, etc., then didn't mention it.

So far as baking goes - my own preference is to have the fab house package in
vapor barrier bags immediately after cleaning and postlaminate bake.  Then the
boards are ready to use when I get them, and I'm not having to play games with
something that was supposed to be finished goods, as received.

One last item - different subject - Wave solder operators - IMHO the home
grown kind usually work out better - they have no biases and often have a
higher level of interest in getting the job done right.  Look for a bright
youngster with a high aptitude for mechanics and chemistry and you've usually
got  a good candidate.

Yall have a fun day - Kelly

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