Paul, Just for completeness, did you run the experiment with different solder pastes? Have you been getting solder paste lots that are closer to the end of their shelf life? Have you run a Mole or similar device through to check the profile? Has there been any change in air flow patterns in the oven due to residue built-up, line move/stack changes? I know some of these are fairly obvious, but I don't know you and don't know what you have and haven't done, so please take these in the spirit given. Bev Christian Research in Motion -----Original Message----- From: Black, Paul [mailto:[log in to unmask]] Sent: September 24, 2003 7:57 AM To: [log in to unmask] Subject: [TN] Solder Balls Hi TechNet Gurus, Has anyone experienced solder balls resulting from the board fabrication process? We have been getting them from our offshore supplier for a few months now and have had to add a wash step to our no-clean process. We know that it's fro the board because we have run bare boards through the reflow oven using the normal reflow recipe from that board and we are seeing 25-60 random solder balls on our 9" x 7", 8 layer, .062", HASL FR4 board. We believe the problem is caused by uncured solder mask that erupts when exposed to reflow temperatures but have been unsuccessful trying to eliminate the problem. We have tried baking the board @ 320 F for anywhere from 1.5 - 6 hours. This has reduced the number of solder balls to maybe a dozen or less. Anyone have a suggestion? Thank you, Paul Black Manufacturing Engineer Kronos --------------------------------------------------- Technet Mail List provided as a free 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------