Not silly. I am not an expert on paste but suggest you look at the soak before reflow. We had some voiding while qualifying a paste for a customer. We were using their recomended paste and profile. We had to increase the soak slightly because of the mass of the BGA. Charle Caswell -----Original Message----- From: Yannick Brisson [mailto:[log in to unmask]] Sent: Tuesday, January 28, 2003 8:29 AM To: [log in to unmask] Subject: [TN] Silly Question Hi, I'm just wondering if someone could answer this silly question...we have on a board some BGA and other discretes components, when we look at the X-Ray picture we see that we have void (flux entrapment), We look at our BGAs and there are no trace of void before we pass it to the oven. Our finnish is a Tin Lead the surface is not flat( HASL), we check our profile and everything is perfect. Could our void could came from the finnish? like this is not a flat surface could we find a void in the pad?? I know this sound silly but I really don't see where those voids could came of. We didn't pass a empty board on the X-ray. Thanks You Yannick Brisson ============================ Technicien SMT Technician SMT M2S Électronique 2855, Rue de Celles Québec, Québec G2C 1K7 Téléphone: (418) 842-1312 Ext: 264 Télécopie: (418) 842-0123 [log in to unmask] ============================ --------------------------------------------------- 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------