Gaby, In a previous life, IBM, I saw a similar type BGA defect on several cross section. The x-ray revealed irregular shape bumps. Temp. parameters were characterized, etc. The works. After all the dust settled it came to be a plugged stencil on the PCB side. Insufficient solder paste/flux to reflow the bump to the PCB pad. This clue came about after several samples exhibited the same anomaly, PCBA date code dependant. Others vendors of the same product line and technology did not exhibit this type of defect. The stencil was found to be restricted. Food for thought. Victor, -----Original Message----- From: Gaby Bogdan [mailto:[log in to unmask]] Sent: Wednesday, June 26, 2002 2:55 PM To: [log in to unmask] Subject: Re: [TN] Reflow on Wave. Maybe this article will help. http://www.alphametals.com/products/solder_solutions/pdf/pillowhead.pdf Gaby ----- Original Message ----- From: "Henry Rekers" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, June 26, 2002 4:07 PM Subject: [TN] Reflow on Wave. > Does anybody have any suggestions on avoiding reflow of a 357 ball bga on > the wave? I'm dealing with a 6 layer board and I've kept the preheat as low > as possible. Kapton tape doesn't seem to help. Has anybody tried any > custom manufactured sheilding? > > Thanks. > > Henry J. Rekers > Manufacturing Engineer. > > -------------------------------------------------------------------------- ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL > 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 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------