We bake for 4 hours at 125 degrees C. We must then either vacuum pack or use within an hour. This is working wonderfully. No problems. We bulid to Class II. Thanks, Kathy Palumbo > ---------- > From: BOB HAYNES[SMTP:[log in to unmask]] > Sent: Tuesday, February 24, 1998 9:43 AM > To: [log in to unmask] > Subject: [TN] [ASSY} Prebake > > Ladies and Gentlemen, > > This issue was the subject of a lively amount of discussion a couple > of years ago. The question has once again come up in the company I > work for so thought would get the opinion of others. There does not > seem to be any exact guidance in any of the IPC publications that I > am aware of. > > When we worked to MIL-C-28809B Par. 3.5.7 left no doubt of what > to do. One was required to bake at 105 Deg. C for an unspecified > time to remove absorbed moisture. Also if the time interval between > baking and soldering was greater than 8 hours you were required to > rebake. > > My company set this unspecified time as 12 hours (overnight) and has > continued to use the same process even though most of our production > is now commercial. Also most of the assembly is now surface mount and > when MIL-C-28809 was written (1988) most assembly was TH. > > What are other assembly houses doing baking or not baking? > > ################################################################ > 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 web site (http://jefry.ipc.org/forum.htm) for > additional information. > For the technical support contact Dmitriy Sklyar at [log in to unmask] or > 847-509-9700 ext.311 > ################################################################ > ################################################################ 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 web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################