One of our costumer ask for dielectric constant certification on all batches of PWB. There are PWB fabricator that certifies it?. Is it a PBW fabricator or base material fabricators responsability?. Could press parameters afects so much the Er? (more then ± 5%). Knows somebody the Er for fiver glass and Er for epoxy resin?. There is a way to calculate it?. I know, a lot of questions but I will realy apreciate your answers. Thank in advance. J. Muelas. ############################################################## 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. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################