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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