Check out _Electronic Packaging Materials and Their Properties_, by Pecht et al, published by CRC Press. It shows it depends on resin fraction and varies from 12-20 ppm/deg C in plane, and 60-80 ppm/deg C in the "z-axis". (Don't forget the units...a lesson NASA recently re-learned the hard way!) Hope that helps. 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 > ---------- > From: John Brewer > Sent: Tuesday, October 5, 1999 10:16 AM > Subject: FR-4 Coeff of thermal expansion? Material Data? > > Can anyone point me to > > (specifically) coeff of thermal expansions for FR4 > (generally) material properties for same? > > Thanks! > John > ############################################################## 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 Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################