October 3, 2008 We have an OEM that is wave soldering a 0.125 inch thick backplane assembly. The assembly contains just press-fit VME connectors (added after wave soldering) and some PTH and SMT passive parts (capacitors and resistor networks). The SMT parts are hand soldered. Board material is IPC-4101/21, 24, 26. The OEM wave soldering machine settings are one single bottom preheater set at 350C with solder pot set at 260C. Conveyor speed is 0.9 feet/minute. Solder is Kester Sn63pb37; flux is Kester 971M; flux applied by foam method. Solder machine is older Soltec Model 6551. My question is; for this specific application, what is the recommended maximum preheat temperature? Seems to me that 350C is too high. Is this high a temperature compatible with the Tg of the FR4 board material? Is there any concern with damaging the board material from overheating? --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------