I don't know a great deal about their construction but are you seeing delamination of two of the multiple layers of the capacitor? I can imagine CTA mismatch between the PWB and cap causing a difference in stress between the top and bottom of the cap irrespective of which way it was aligned to the PWB edges. Regards, Igoshev, Vladimir wrote: > Different locations, identical caps placed along and normal to the board. :-) > > Regards, > > Vladimir > > ----- Original Message ----- > From: Allen Maddox <[log in to unmask]> > To: TechNet E-Mail Forum <[log in to unmask]>; Igoshev, Vladimir > Sent: Mon Jul 14 11:19:16 2008 > Subject: Re: [TN] Ceramic caps > > Just curious if there is any consistency in the size of the cap or it's place on the board and direction it faces? > It seems like you've covered all the obvious failures so far. > > Allen Maddox, CID+ > > > "Igoshev, Vladimir" <[log in to unmask]> wrote: > > That was the first thing I asked and was told "No", they hadn't been re-worked or placed manually. > > What bugs me the most is that I have a hard time imagining how a top half of a cap can be separated from the bottom one. If it wasn't a manufacturing problem, then how it should have been loaded (mechanically) to crack like that. > > Regards, > > Vladimir > > ----- Original Message ----- > From: TechNet > To: [log in to unmask] > Sent: Mon Jul 14 10:39:57 2008 > Subject: Re: [TN] Ceramic caps > > In addition to the very good info you have already received, consider > how the caps are being soldered or reworked. I would check to make sure > none were soldered by hand using conventional solder irons. Rework such > as solder touchup should only be done with a hand-held hot air device > such as a Hakko or JVC. > Never, ever allow an MLCCC to be soldered with a conventional soldering > tool, as the sudden thermal shock will crack the body of the connector, > and/or the large heat transfer can melt the high-temp solder connections > internally (plate to terminal connections). > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Igoshev, Vladimir > Sent: Monday, July 14, 2008 8:08 AM > To: [log in to unmask] > Subject: [TN] Ceramic caps > > Hi TechNeters, > > I came across an unusual (at least to me) failure mode of ceramic caps. > They crack along the component body in either normal (from top all the > way through to the bottom), or parallel (from one side all the way > through to the other side) direction to the board the caps are mounted > on. > > Has anyone seen something similar? > > Thanks a lot in advance. > > 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 > ----------------------------------------------------- > > > > > -- Eric Christison Msc Mechanical Engineer Consumer & Micro group Imaging Division STMicroelectronics (R&D) Ltd 33 Pinkhill Edinburgh EH12 7BF United Kingdom Tel: +44 (0)131 336 6165 Fax: + 44 (0)131 336 6001 --------------------------------------------------- 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 -----------------------------------------------------