Hello TechNetters, Why does FR4 material is so common in PCB manufacturing and the demand is great? Why not poliyimide? Teflon? etc. What are FR4 advantages over those mentioned above? Was it Tg? By the way FR4 Tg is 145? If this is so if we subject the material in 320 Deg C, Is this material degrades? Any expalanation for this is highly appreciated Thanks ############################################################## 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 ##############################################################