I sympathize. I do not believe the spec applies to tinning although I do have a customer with a req. of visible clearance from the tin line to the body. However J-STD 5.4.1 says gold shall be removed from 95% of the surface to be soldered on THROUGH HOLE components with more than 2.5 micro meters of gold. It does not mention SMT parts. We have eliminated tinning on most through hole parts by checking the Manuf. data sheet for gold thickness. Most are less than 2.5 uM. -----Original Message----- From: d. terstegge [mailto:[log in to unmask]] Sent: Wednesday, November 26, 2003 9:29 AM To: [log in to unmask] Subject: Re: [TN] Pretinning height on fine-pitch gull wing leads Hi Steve, I forgot to tell that my problem is that our QA rejects parts because the solder has wicked to far onto the leads during pretinning. It's treated like a solder fillet that touches the body, which to my opinion makes no sense. It's not a problem with gold embrittlement. Daan Terstegge Thales Communications Unclassified mail Personal Website: http://www.smtinfo.net >>> "Sauer, Steven T." <[log in to unmask]> 11/26/03 03:44pm >>> Hi Daan, I'll go back to the old testament (MIL-STD-2000 para 5.4.17.2 on p. 114) that states "...Only the portion of the lead subsequently to be soldered need be..." Similarly, J-STD-001 para 5.4.1 states that gold shall be removed from at least 95% of the to-be-soldered surface. The elimination of gold removal prior to soldering can be done with objective evidence that solder embrittlement is not compromised. Depending on your customer and quantifying how much gold is in the final solder connection are the bumps on that road. Good luck. Steve Sauer NG Xetron Cincinnati, OH -----Original Message----- From: d. terstegge Subject: [TN] Pretinning height on fine-pitch gull wing leads Hi Technet, We're using some ceramic QFP's here with gold-plated leads that need to be pretinned prior to assembly. Does anyone know a specification that prescribes how far the pretinning solder coverage for these parts may be for boards that have to meet ANSI-J-STD-001C class 3 requirements ? --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------