Hi David, (1) You do not say what the cyclicenvironment for product life is. (2) Even though -55 to 125 degC cycling is widely used because it produces results FAST, this cyclic temperature range confounds at least 2 different damage mechanisms of solder. As a consequence, there can be no valid translation to other cyclic environments that are more characteristic of product use. You can assume a non-confounding scenario, ignoring the impact of the damage mechanism(s) not present in the product cyclic environment and obtain a conservative low-ball limit. For a better understandingy you should read IPC-SM-785, Guidelines for Accelerated Reliability Testing of Surface Mount Solder Attachments, and IPC-D-279, Design Guidelines for Reliable Surface Mount Technology Printed Board Assemblies, Appendix A. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 904-437-8747, Fax: 904-437-8737 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 Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------