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 ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################