Hello Steve, Depending on the configuration of the baking oven you will be using and the number of panel per stacks, you must set baking temperature above the Tg of your material and allow enough time for that temperature to be reached in the middle of every stack of panels. Once this is done, the key to this baking process is the cooling cycle, if possible, panels must be allowed to cool slowly so the internal stress of the material will be distributed uniformly across the entire surface of panels. If you try to cool them down to fast, it is very possible that you will achieve nothing to improve the Bow & Twist condition of your panels. Regards, Charles Desroches Technical Advisor Viasystems Granby Voice: 450-372-8111 (2257) Fax: 450-378-5110 > -----Original Message----- > From: Steve Collins [SMTP:[log in to unmask]] > Sent: Tuesday, July 14, 1998 12:53 PM > To: [log in to unmask] > Subject: [TN] Fab: Bow & Twist > > We have several boards that are single sided with massive grounds on > one > side. I know this is not the correct way to have designed this board > but it > was designed many years ago and it cannot be changed easily at this > point. > The problem is extreme Bow and Twist and the material is FR-4. In a > past > life I remember situations like this and we would have the boards > baked > but I have over the years lost the baking recipe. Can anyone help out. > > Steve Collins > > ################################################################ > 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 > ################################################################ ################################################################ 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 ################################################################