Bob gets my vote for best possibility. Moisture, residual or added by an operator, is the best possible answer for on large delamination. Is there a ground plane behind the blister? Sometimes just a whole lotta heat in one place can cause a failure too. Chuck Brummer Acuson Bob Dube wrote: > Sounds like residual moisture or some other volatile in the board. > > Bob Dube > > -----Original Message----- > From: Stephen R. Gregory <[log in to unmask]> > To: [log in to unmask] <[log in to unmask]> > Date: Wednesday, February 09, 2000 12:15 PM > Subject: [TN] Delamination > > >Hi ya'll! > > > >We just finished building a lot of 48-boards through SMT. Out of that 48 > >there was one board that we just discovered a big delamination blister on > the > >backside...it's about 1.5" wide and maybe 2.5 - 3" long. There was no > rework > >done on the board, and it was reflowed under the same profile in a > >Conceptronic HVA-70 that the rest of them were...and they don't exhibit any > >problems. There no sign of overheating at all around the blister, and the > >silkscreen is nice and bright white...we just have this big blister. What > >might cause that? The boards are polyimide. We didn't bake them, and they > >were real fresh boards date code was 0300. Like I said, it was the only > board > >that had a problem...the rest are fine. > > > >TIA > > > >-Steve Gregory- > > > >############################################################## > >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. > >If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or > >847-509-9700 ext.5365 > >############################################################## > > > > ############################################################## > 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. > If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or > 847-509-9700 ext.5365 > ############################################################## ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################