Sorry I did not provide more parameters... No wave solder. Process is: 1) Screen paste bottom side. 2) place comps. 3) reflow. 4) screen paste top side. 5) place comps. 6) reflow. 7) clean. (etc, etc.). And the bottom side joints look pretty good. I do not have more process info such as reflow profile. And thanks Dave, we will need to have a cross-section FA done to really get at the bottom of this, but I will now be able to put together some specific questions that need to be asked of the EMS. Have a conference call tonight, means I'll have to tape CSI... Rgds, Roger -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Cheryl Tulkoff Sent: Thursday, January 06, 2005 1:28 PM To: [log in to unmask] Subject: Re: [TN] Solder Joint Failures after Short-term Vibration Roger - Does this board go through the wave solder process after SMT? You could be seeing secondary reflow of the SMT joint at the wave. This happens when the temperature of the wave process is sufficient to remelt topside joints. It usually happens only on fine pitch QFPs(smaller joints with less solder volume). To avoid this, most people will run the wave solder temperature lower (240-250 C rather than 260C) and the conveyor faster (5.5 ft/min or higher). I can send more info if you're interested in checking it out. Thanks, Cheryl Tulkoff Phone:(512) 683-8586 Fax: (512) 683-8847 National Instruments 11500 N. Mopac Expressway Building A Austin, TX 78759-3504 Hello all, We are having an ongoing problem with solder joint failures on a 144-pin PQFP processor, after short-term vibration. The board layout and mechanical mounting apparatus were designed with vibration in mind, and have passed vibration testing in the past. The same processor is used on a dozen other assemblies, none of which have this problem. The solder joints appear to exhibit dewetting, although there is a toe and heel fillet. The heel fillet is unusually large, and the top of the PQFP lead has a grainy appearance instead of a matte or shiny appearance. Some leads can be pushed off the solder joint with very little pressure. Sn62Pb36Ag2 solder is being used, and our EMS provider continues to claim that boards meet IPC-A-610 class 2 requirements. Any ideas as to what may be causing solder joint failures? Also, any suggestions or recommendations (preferred) for a test house to provide x-ray, microsection and composition analysis? TIA & Best Regards, Roger M. Stoops, CID+ Trimble Navigation Ltd., Dayton, OH, USA Ph: +01 937.245.5288 Fax: +01 937.233.7511 Oh, and BTW, changing EMS providers is not an option... --------------------------------------------------- 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 -----------------------------------------------------