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Date: | Fri, 24 Mar 2000 14:51:32 -0500 |
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Isn't this stuff supposed to have been baked already during manufacture =
of
the cores?
Alain Savard, B.Sc.
Chemical Process Analyst
CAE Electronics Ltd.
e-mail: [log in to unmask]
-----Original Message-----
From: Bob Dube=20
Subject: Re: [TN] laminate stress relief
Stress releif baking needs to be done above the Tg for the material. =
Most
would hold at that temperature for 4 hours min. The cool down rate is
critical because of the various CTEs of the laminate constituents =
(glass,
epoxy, copper). Somewhere around 4 deg/min F back thru the Tg is =
usually
what's recommended.
Bob Dube
-----Original Message-----
From: Timothy Reeves=20
Subject: [TN] laminate stress relief
board fabs: what (if any) baking of incoming core material do you do to
minimize movement of layers. We try to have the material at 250=B0F for =
one
hour based on what someone told us quite a while back. Without going =
through
a big DOE, I'd like to ascertain if that's enough.
Timothy Reeves
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