Have you checked your plating racks for possible fractures or breaks under the coating ( if you use coated racks)? I have seen similar instances that you describe- but not with the border condition- when there is intermittent continuity thru the racks. Also, the sulfuric concentration and brightners have a direct impact on how the panels plate. Have these been checked? Does the hull cell show a problem? These are just a few thinks to check. I would recommend calling your supplier if the problem is not readily identifiable. Ed Cosper Graphic Electronics Inc. ---------- From: sam mccorkel[SMTP:[log in to unmask]] Sent: Tuesday, April 15, 1997 8:31 AM To: [log in to unmask] Subject: FAB: Plating mystery We're experiencing a strange phenomenon at copper and tin plating. We have 3 copper baths with a separate rectifier for each. Some boards will only plate a thin layer of copper and then a thin to no amount of tin. A strange, but consistent occurrence is a perfect image of a "frame" around the outside edge of the board that does not plate at all. This "frame" SHAPE is from the tape that we use to adhere our artwork to glass packs while imaging. The tape DOES NOT contact the board, it's between the glass pack and the artwork. We have not changed anything and it suddenly is happening. There is no dry film breakdown, no copper adhesion problem, and no copper voids. Also, it does not happen on all boards, it's lot specific. Lots that have this problem have a larger area of copper burned away from the contact area of the plating rack. Boards that plate properly will have a small area of copper burned away at each contact. We also found that if we scotch brite the contact area, before plating lots that have been identified as having this phenomenon, they plate better. Any help with this mystery would be greatly appreciated! *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************