Stan, The glue upon curing does become brittle. However, unless the warpage was extra-ordinarily severe, I cannot see that to be the cause. Was the boards cured properly accordance with the manufacturer? Tom Han Ardent Systems On Wed, 7 Oct 1998 14:16:00 PDT "Traxler, Stan" <[log in to unmask]> writes: >We recently had a small lot of pwa's (qty 3),where a large quantity of >the >SMT chips on the backside of the boards (approximately 60 on each >board) >came off during the wave solder process. It appears that the glue >failed >during some stress, (not a poor bond line), when viewing the "failed" >locations,(within the same glue dot) some of the glue stayed on the >board >and some came off with the part. (Also the glue dot size was adequate) > > The boards are mixed technology boards where all the thru-hole >components >are assembled to the top side of the board, then the SMT components >(chip >capacitors, mainly 1210's) are glued to the back side of the board >using >Loctite 348 and the glue is cured in an inline oven. > >We ran 3 other lots (similar designs) the same morning, using the same >glue, >and the same process, with no part loss. (also this board has been run >in >the past without these failures) The only visible difference between >these >boards and the other 3 lots is they appear more warped. > > I'm wondering if when loading the board onto the wave solder fingers >(removing the warp that was on the board) could this have caused the >glue to >crack and weaken to a point where they could have fallen off in the >wave. >(we did see the parts in the wave after the boards were processed). > >Has anyone out there had a similar experience or have some >theories???? > > >Thanks....... >Stan >Raytheon >Towson, Md > >################################################################ >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 >################################################################ > > ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com or call Juno at (800) 654-JUNO [654-5866] ################################################################ 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 ################################################################