yep, looks like ENIG is lifting over some of the filled vias. At 09:23 AM 7/29/2014, Steve Herring wrote: >It looks to me like their Screen Printer is doing a poor job of >under stencil wiping, leaving solder paste on the underside of the >stencil that gets transferred to the gold areas on the edge of the pcb. >During reflow, the small balls of paste flow into nice circles. >Not all stencil wiping paper is created equal. > >Steven E. Herring >Engineering Manager >Pennatronics >75 Technology Drive >California, Pa 15419-0638 >P 724-938-1800 x 214 >F 724-938-1809 >[log in to unmask] > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of John Foster >Sent: Tuesday, July 29, 2014 12:13 PM >To: [log in to unmask] >Subject: [TN] Trying to figure out possible mechanism for contamination > >We have been seeing a problem recently on several different CCA'S >that we are having assembled. >The boards are ENIG with plug and plate. The assembly shop is >assuring us that these gold areas are being Protected during the >entire assembly process with kapton tape. >I was thinking it was flux splatter since the areas are always >almost perfectly circular. >The locations are very random and range from nothing to what is in >the picture. >Is there any other mechanism that might be causing this? On our next >run I am going to go to the shop To witness the taping. But I was >curious if maybe it's some other cause. >Mr. Gregory was kind enough to post a picture. >http://stevezeva.homestead.com/spots.jpg > >Any thoughts would be appreciated >Thank You >John Foster >L3 Communicatons > >Confidentiality Notice: The information contained in this message >is intended only for the use of the addressee, and may be >confidential and/or privileged. If the reader of this message is >not the intended recipient, or the employee or agent responsible to >deliver it to the intended recipient, you are hereby notified that >any dissemination, distribution of copying of this communication is >strictly prohibited. if you have received this communication in >error, please notify the sender immediately. > >Warning: This document may contain technical data within the >definition of the International Traffic in Arms Regulation (ITAR) >and is subject to the export control laws of the U.S. >Government. Transfer of this data by any means to a foreign person, >whether in the United States or abroad, without an export license or >other approval from the U.S. Department of State, is strictly prohibited > > >______________________________________________________________________ >This email has been scanned by the Symantec Email Security.cloud service. >For more information please contact helpdesk at x2960 or >[log in to unmask] >______________________________________________________________________ > >______________________________________________________________________ >This email has been scanned by the Symantec Email Security.cloud service. >For more information please contact helpdesk at x2960 or [log in to unmask] >______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________