Rich, Depending on the locations of the Pems, you might consider taking a few cross-sections from the areas around the damaged sites. You'll be able to evaluate what the impact was on inner layers, especially with respect to distortions - and the potential for shorts between the vcc-gnd planes. Bruce Tostevin Benchmark Electronics Hudson, NH > -----Original Message----- > From: Rich Lasko [SMTP:[log in to unmask]] > Sent: Thursday, November 09, 2000 10:49 AM > To: [log in to unmask] > Subject: Re: [TN] Stress Cracks on PCB > > My guess is that the set-up of the pressing operation was not done > correctly > and the operator used too much force when inserting the PEM spacer. I > guess > what I am looking for is criteria to make an accept or reject decision on > the product that exhibits this condition. > > Thoughts? Are there test methods, examples, or is this purely a judgement > decision? > > Thanks for your help everyone. > > Rich > > -----Original Message----- > From: Boldt, Mike (msd) USX [mailto:[log in to unmask]] > Sent: Thursday, November 09, 2000 9:40 AM > To: [log in to unmask] > Subject: Re: [TN] Stress Cracks on PCB > > > Hi Rich, > We routinely use press-in hardware and I'm not aware that we've ever had a > PWB cracking problem. Have you double checked your hole size, both > specification and actual, to make certain they're correct? > Mike > > Michael E. Boldt > Electronic Packaging Engineer > Moog Inc., Motion Systems Division > > -----Original Message----- > From: Rich Lasko [SMTP:[log in to unmask]] > Sent: Thursday, November 09, 2000 9:40 AM > To: [log in to unmask] > Subject: [TN] Stress Cracks on PCB > > Good morning everyone. > > I need some input from you guys. We have a product (pcb assembly) in > which > we needed to "press in" a PEM spacer. Unfortunately when we pressed in > the > spacer, it has caused stress cracks in the pcb. I have looked in the > IPC-A-610 to find out acceptable and rejectable criteria for stress > cracks, > however, I have not been able to find any. The closest I can come is > crazing. However, the defect appears to be more of a stress crack then > crazing. > > Need help. Is there any other accept/reject criteria or anyone else > experience with stress cracks from pressing in hardware. > > Please advise. > > Rich > > -------------------------------------------------------------------------- > -- > ----- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > -------------------------------------------------------------------------- > -- > ----- > > -------------------------------------------------------------------------- > ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > -------------------------------------------------------------------------- > ------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------