Bob, One thing I would suggest you do is to do a detailed comparison of what capacitors are cracking. You need to determine not only what physical size is cracking but what the capacitance value is. The reason may not be obvious unless you've cross sectioned lots of capacitors. For example; 1812 size ceramic capacitors are notorious for "flexure cracks". The difficulty is you don't usually find out there is a capacitor flexure crack until your product is put into service and the capacitor shorts out whenever there is a moisture increase (e.g., thunder storm, rain, air conditioner fails, someone spills water on the floor when mopping, etc.). the moisture gets into the flexure crack and since capacitors are typically used on power supplies the moisture short-circuits the power supply. If you had been using 1812 size ceramic chip capacitors with capacitance of a couple of tenths of a uF your probably had flexure cracks and didn't know it because they probably never failed because the internal electrodes weren't very close to the bottom and didn't extend into the end-cap areas where the flexure cracks are. Moisture would get into the crack but since the crack isn't across opposite electrodes they can't short-circuit. If the capacitors you are currently using have increased capacitance values in the range of a couple of uF rather than a couple of tenths then even though the capacitor size is the same the internal electrodes are closer to the bottom of the cap and probably extend further out into the region where flexure cracks occur. If this is the case you would be seeing an increase in the number of shorted capacitors, the number of cracked capacitors won't have increased but the number of failed cracked capacitors would have. Regards, George George M. Wenger Andrew Corporation 40 Technology Drive, Warren, NJ 07059 (908) 546-4531 [log in to unmask] -----Original Message----- From: Bob Perkins [mailto:[log in to unmask]] Sent: Wednesday, August 27, 2003 7:42 PM To: [log in to unmask] Subject: [TN] Cracking Ceramic SMT Capacitors Cracking Ceramic SMT Capacitors " Is anyone else seeing an increase in the number of cracked and shorting ceramic chip capacitors? In our experience as a contract manufacturer we have, in the past, seen the occasional instance of ceramic capacitors cracking and shorting out. The cause of this problem is generally obvious, as it is isolated to components situated in areas of the PCB that are subject to flexing. Recently however we have seen more frequent instances of this problem; very often in areas of the board that should not be experiencing any appreciable flex. Our process has not changed and neither have our sources of these components. Have chip capacitors themselves become more fragile?" Rod Lafond Manager, Quality Assurance and Technical Training APEX-Micro Manufacturing Corporation [log in to unmask] --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------------------------------ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any unauthorized use of this email is prohibited. ------------------------------------------------------------------------------------------------ --------------------------------------------------- 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 ----------------------------------------------------- [mf2]