I was only aware of this recent problem of fillet lifting and it was when Bismuth was part of the solder formulation. It was a relationship of percentages and the final finished alloy formulation. There are several papers on this, but making the pads larger did not appear to be one of the choices. Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Roland Dollinger Sent: Friday, September 23, 2005 2:39 AM To: [log in to unmask] Subject: [TN] lead free soldering "fillet lifting" Dear all, who has detailed info for me about lead free soldering due to "fillet lifting" What is the root cause of fillet lifting? - Low cooling rate after soldering? - contamination of Bi? - contamination of Pb? - amount of latent heat released during solidification? - Does fillet lifting not occurs, when the FRI (fillet-lifting resistant index) is bigger than 0,75? How can we avoid fillet lifting? Has anybody read the US patent US6617529A1_anti solder fillet lifting? This patent recommend a pad width bigger than 0,4mm to avoid fillet lifting. Does everybody know, what this patent will mean for us? I read the old aged MIL-STD-275E and in my opinion I´m convinced, that due to this MIL standard the US-patent US6617529A1is covered too. What do you think about this? Thank you for your comments. Roland Dollinger Valeo Process Engineer Valeostraße 1 86650 Wemding Germany [log in to unmask] --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------