Richard, I am assuming you are talking about traditional FR-4. We have not had to preheat PCBs since 1990, when we were dealing with a particular far eastern supplier. Since then that company has pulled up its socks and manufactures a better product, stores the boards properly, maintains a minimal stock, packs them properly and gets them to us faster than the proverbial slow boat. We have never had problems in my eight years in the industry with suppliers like Via Systems, Hadco, etc. Its been so long ago I can't remember the conditions we used, and I don't want to! I would change suppliers before I went back to heating boards. Bev Christian Nortel 613-967-5407 >---------- >From: Blanchet,Richard[SMTP:[log in to unmask]] >Sent: Thursday, November 27, 1997 2:03 PM >To: [log in to unmask] >Subject: [TN] Assy: Pre-heating of PCBs > >Hi, > >I'd like to get your input on pre-heating PCBs in an oven before wave >soldering. Do you do it ? On all your PCBs or only on multilayer ones ? > For how long and at what temperature ? >Aside from humidity that can be entraped and suddenly released, thus >creating delamination, what other problems may some one face if they don't >pre-heat their PCBs in an oven before wave soldering ? > >Thank you. > >Richard Blanchet >Manufacturing Engineer >Canadian Marconi Company > >############################################################## >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 >############################################################## > ############################################################## 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 ##############################################################