We deal almost exclusively with military applications and have always used tweezers and irons for SMT rework or hand installation. In fact, we have a few CCA's that we install approximately 30 SMT ceramic caps to the bottom side after wave, all with tweezers or an iron. I have yet to see a documented failure of any of these components during initial Test and have never seen a return for a cracked cap that was not physically damaged (by outside forces). I have seen absolutely no decrease in reliability nor increase fall out at Test on hand installed surface mount components. Bruce Stilmack GDLS-TO Manufacturing Engineer (850) 574-4773 [log in to unmask] "Morse, Carrie" To: [log in to unmask] <CMorse@CIRTR cc: ONICS.COM> Subject: Re: [TN] Not that our process is out of control or Sent by: anything, but -- TechNet <[log in to unmask] ORG> 11/17/2003 04:52 PM Please respond to "TechNet E-Mail Forum."; Please respond to "Morse, Carrie" Eric, How about Rework techniques for SMT components? Any recommendations? (I'm desperate) Do you use irons or hot air tools? -----Original Message----- From: Eric Laroche [mailto:[log in to unmask]] Sent: Monday, November 17, 2003 4:50 PM To: [log in to unmask] Subject: [TN] Not that our process is out of control or anything, but -- It is the preheat it the wave that is controlled (the infamous 2C/sec) to prevent thermal shock. Once the chip has achieved a specified temp, all the materials have expanded equally and after this point the rapid thermal change of hitting the wave does not affect the chip. It is the different expanding properties of the two materials that cause the chip to crack. Once they have both expanded to their maximum state, the temperature curve is irrelevant. -----Message d'origine----- De : TechNet [mailto:[log in to unmask]] De la part de Charles Caswell Envoyé : 17 novembre, 2003 16:46 À : [log in to unmask] Objet : Re: [TN] Not that our process is out of control or anything, but -- Our Space customers require us to use hot air to preheat chips before soldering with an iron. With wave solder the parts go through preheat and do not see the temp. change as with a soldering iron. We had a difficult time convincing some customers of this many years ago. -----Original Message----- From: Morse, Carrie [mailto:[log in to unmask]] Sent: Monday, November 17, 2003 2:27 PM To: [log in to unmask] Subject: [TN] Not that our process is out of control or anything, but -- Just wondering what would be considered the "Industry Standard" on rework method (remove and replace, or touch-up) for ceramic chip caps? We are currently using Metcal Irons or Tweezers and periodically a hot air tool (hand held wand) We have a customer asking us to use ONLY the Hot Air Tool. He feels that the thermal shock of bringing the cap from room temp to liquidous causes stresses within the cap which may cause a failure in time. To minimize the rapid temp changes the irons introduce, we have been asked to use the Hot Air Tool only. I was surprised at this request as we build some boards for this customer that have ceramic chip caps that get wave soldered. I can only imagine the rapid temp changes those caps see. Any input or feedback concerning this customer's request would be appreciated. Thanks, Carrie --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------