Hello, Has anyone ever seen any studies or papers about the effects of running FR-4, .062"Thk, boards across the wave solder twice. These are 2-sided, SMT (no BGA's), .062" Thk. and about 7.5"W X 8.0"L. The first pass resulted in boards sagging in the middle (approx .080" bow along the 7.5" width), and then being held in a warped state when the thru hole joints solidified. When these boards are placed in a custom fixture and ran across the wave again they relax and are straight. I'd like to know if anyone has had any experiences like this and did the results have any effect on the life of the boards? Did it effect the board function. Are there any papers written or data available in someone's archives that would support no harm has been done to the SMT solder joints being flexed (twice). Or no degradation of the 0603 ceramic caps being flexed. No harm, no foul so to speak? I haven't been able to find any white papers to support it or critique the process so I'd appreciate any feed back. Thanks. Jack Bryant --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------