Dave: In the world of PCB fabrication, your problem is called "shadow plating". Rudy Sedlak RD Chemical Company --- On Thu, 3/5/09, Dave Connitt <[log in to unmask]> wrote: From: Dave Connitt <[log in to unmask]> Subject: [TN] ENIG Question To: [log in to unmask] Date: Thursday, March 5, 2009, 12:09 PM Hello All, I have a question regarding a strange situation regarding reflow soldering ENIG finish boards. We have seen a few boards that have what seems to be gold "washing " down between pads and creating shorts. This seems to come and go. This is a flex circuit that is placed on a pallet to go through our SMT line. One other bothersome issue is that we are having difficulty getting proper solder stencil alignment across all the flexes in the pallet. I am pushing to have the flex "panelized" from the vendor to increase positional accuracy but the jury is still out on that. I suspect these two issues are related. If the solder gets deposited "off pad"slightly could the washing process be moving some of the gold in between pads? I attached an example. Has anybody come across this? If so, what was the solution? Thanks, Dave Connitt CID+ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 -----------------------------------------------------