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 <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Friday, March 24, 2000 12:56 PM
Subject: [TN] laminate stress relief


Good Day, TechNet!
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°F 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.
Danke schön.

Timothy Reeves
ECD Circuit Board Division
13626 South Freeman Road
Mulino, OR 97042
[log in to unmask]
(503) 829-9108 (800) 228-8198  FAX (503) 829-5482

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