Dan, Just to throw my 2 cents in....we found that with solder paste we get much better coverage of the PWB pad with solder, resulting in a more consistent solder connection. With just flux we were getting a small percentage of the connections with a thin solder contact to the pad. Although percentage was small, it was frequent enough on a large ball count to reduce our rework yields. Paste also helps to cancel any co-planarity problems. Jim Kittel -----Original Message----- From: d. terstegge [mailto:[log in to unmask]] Sent: Monday, February 05, 2001 9:56 AM To: [log in to unmask] Subject: Re: [TN] BGA REWORK Hi Robert, Are there any data that support your statement ? If you calculate the amount of solder from the solderpaste and compare this with the volume of a ball, you'll see that about 90% of the solder joint's volume comes from the ball. 10 percent more or less of total solder volume shouldn't make out the difference between a short and a long product life. Kind regards, Daan Terstegge SMT Centre Thales Communications Unclassified mail Personal Website: http://www.smtinfo.net >>> "Furrow, Robert Gordon (Bob)" <[log in to unmask]> 02/05 4:27 pm >>> Trevor, I think it will depend on the expected useful life of the repair. If you are looking at short life product with eutectic solder balls, and coplanarity is not an issue, then using just flux should not be an issue. If you require long term reliability then in most cases paste is preferable. Thanks, Robert Furrow New Product Engineering Lucent Technologies 978-960-3224 [log in to unmask] > -----Original Message----- > From: Trevor Goddard [SMTP:[log in to unmask]] > Sent: Monday, February 05, 2001 9:44 AM > To: [log in to unmask] > Subject: [TN] BGA REWORK > > Hi all. > I have a question about reworing BGAs. Do you have to reprint the solder > paste before placing the component or can you lay down some flux and rely > on > the solder balls of the BGA? > Thanks in advance > > Trevor Goddard, > SMT Supervisor > XLTEK > (905) 829-5300 x 348 > [log in to unmask] <mailto:[log in to unmask]> > > -------------------------------------------------------------------------- > ------- > 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 the following message: SET > Technet NOMAIL > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail 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 the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------