I don't know. They reportedly showed a short and it happened during a test (the boards had been functional for quite a few hours and then failed). I was assured (or should I say told) that the board temperature should have been holding steady. Regards, Vladimir -----Original Message----- From: Guy Ramsey [mailto:[log in to unmask]] Sent: Monday, July 14, 2008 4:00 PM To: 'TechNet E-Mail Forum'; Igoshev, Vladimir Subject: RE: [TN] Ceramic caps If you energize them, do they get hot or do they then open up? My experience with caps that fractured from end to end, the length of the plates, the parts opened up. It was caused by a shearing force as two different materials expanded at different rates. I don't see how they would short. Once when I was auditing a facility I heard the sound of boards sliding into each other. They had built a little ramp off the reflow oven so the parts could slide down onto a table to cool. Things piled up at the end while the operator was engaged in other activities. Little SIMMs, in six up panels, in this case the caps were sheared off the board. Needless to say they had some explaining to do. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Igoshev, Vladimir Sent: Monday, July 14, 2008 3:05 PM To: [log in to unmask] Subject: Re: [TN] Ceramic caps Yes. They are all identical and they all show a short, which doesn't make much sense to me. That is why I keep thinking it's a manufacturing defect. Regards, Vladimir -----Original Message----- From: Stadem, Richard D. [mailto:[log in to unmask]] Sent: Monday, July 14, 2008 3:01 PM To: Igoshev, Vladimir; TechNet E-Mail Forum Subject: RE: [TN] Ceramic caps Totally understand. The MLCCCs are in a sort of laminated configuration, with the capacitive plates stacked on top of dialectrics. They vary depending on the value, ie, the higher the capacitance, the more layers and the thinner/thicker the dielectric in between each one. As a result, I know that higher values of capacitance have more of a tendency to fracture with a lateral delamination than smaller capacitance values do (I think I said that correctly). Are the caps that are fracturing all of the same value? -----Original Message----- From: Igoshev, Vladimir [mailto:[log in to unmask]] Sent: Monday, July 14, 2008 1:55 PM To: TechNet E-Mail Forum; Stadem, Richard D. Subject: RE: [TN] Ceramic caps I know Steve would do it, but I need a permission form the "local authorities" so to say :-) Regards, Vladimir -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Monday, July 14, 2008 2:49 PM To: [log in to unmask] Subject: Re: [TN] Ceramic caps Vladimer, if you have photos you can email them to Steve Gregory. Steve is a gentleman and a scholar of the industry who posts photos so all of us can see, then it is easier to make a "root cause" analysis or just a WAG. Steve's email address is [log in to unmask] -----Original Message----- From: John Maxwell [mailto:[log in to unmask]] Sent: Monday, July 14, 2008 1:44 PM To: TechNet E-Mail Forum; Stadem, Richard D. Subject: Re: [TN] Ceramic caps Richard & Vladimir, It would be helpful to post the photos and then I can comment. John Maxwell > Vladimir > Here are potential causes of MLCCC cracking, and how to tell what > caused the crack based on the crack's position, run direction, etc. > http://www.ami.ac.uk/courses/topics/0179_fmcc/index.html#3 > > http://www.syfer.com/category_docs/AN0005_Mechanical_Cracking.pdf > > And an authorative paper on the subject by John Maxwell, who I think > knows more about root causes of cap cracking than anyone: > > http://www.avx.co.il/docs/techinfo/cracks.pdf > > And a potential solution to the problem: > > http://www.avx.co.il/docs/techinfo/mlccflex.pdf > > Qualify it first. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Igoshev, Vladimir > Sent: Monday, July 14, 2008 1:13 PM > To: [log in to unmask] > Subject: Re: [TN] Ceramic caps > > Well, in the case I was asking about none of the failures were in that > direction (across the body) but always along it splitting both ends in > half either vertically or horizontally. Still a puzzle to me :-) > > Regards, > > Vladimir > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 -----------------------------------------------------