We have similar boards and we bake them at 125C for 12 to 14 hours in a nitrogen inerted oven. This has solved our delamination problems with polyimide. Not what you wanted to hear I'm sure but hope this helps. At 10:30 AM 9/22/98 -0400, you wrote: >Dear Ann, > >(Oops, wrong advice column...) > >Dear Technet: > >We assembly an 8 layer polyimide SMT board (approximately 6" x 11" x .062 >thick). Our standard bake cycle for these boards prior to assembly has been >250 F for 6 hours. We recently ran into a rash of delamination after reflow. >A board vendor recommended we bake at 275 F for 16 hours. We feel that this is >excessive, and that our bake cycle should be adequate. What do you think? > >Thanks for your assistance, >Over-baked in NY Ken Bloomquist Sr. Principal Process Engineer PRIMEX Aerospace Company P.O. Box 97009 Redmond, WA 98073-9709 Northcon/98, Show Director <www.northcon.com> Electronics Manufacturers Association (EMA), Secretary <www.ema-wa.org> ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################