FEM analysis and simulation of temperature changes are interesting tools, you get information about the tensions and forces in different parts of the solder joint, and so you can give the joint geometry an optional design. It's like aching muscles, you need know exactly where and how to make massage. If not you may cause even more pain. One guy at our company has done impressive such works, can link you together, if you want. Regards Ingemar Hernefjord Ericsson Microwave Systems -----Original Message----- From: Werner Engelmaier [mailto:[log in to unmask]] Sent: den 26 juni 2002 13:37 To: [log in to unmask] Subject: Re: [TN] fractured solder joints Hi Patti, What you have is most likely a combination of the large ceramic/FR-4 thermal expansion mismatch causing cyclic creep-fatigue and tensile displacements frozen-in during hand-soldering causing creep rupture. "More ductile solder" is not a solution. More uniform soldering and lower thermal expansion mismatch strains are; the latter can be accomplished by more compliant lead geometries, and if that is not possible, to a lesser extent by an increased stand-off to increase solder joint thickness. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 386-437-8747, Fax: 386-437-8737 E-mail: [log in to unmask], Website: www.engelmaier.com --------------------------------------------------------------------------------- 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 To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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/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 To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------