Steve, It may end up being one of life's little unexplained mysteries. David A. Douthit Manager LoCan LLC ========================== Steve Gregory wrote: > Hi David! I guess the reason I call this strange, is because I've had > rework performed on literally hundreds of these type of parts, with > the heat sink in the top, and haven't seen this problem before. When I > say hundreds, I refer to a situation where a part was installed on an > assembly, don't want to name names, at three-per, and the assembly > didn't work. The manufacturer of the device says there was no die > change, but for some reason, earlier date-code parts worked fine. So > we changed out all these parts....same design, heat-sink in the top, > but never saw cracking like this. To emphasize, this was just one part > that did this, but it was so strange...I had to share. -Steve Gregory- > > Steve, > > You might consider the fact that metal will change > temperature much faster than polymers. > This thermal gradient "split" can cause serious temporary > CTE mismatches. > > David A. Douthit > Manager > LoCan LLC > > --------------------------------------------------- > Technet Mail List provided as a free service by IPC using LISTSERV > 1.8e > To unsubscribe, send a message to [log in to unmask] with following text > in the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: > http://listserv.ipc.org/archives > Please visit IPC web site > http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional > information, or contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------