Steve, Does the board have any blind via hole groups. I had some boards once that called for 1oz min after plating, but they had 6 blind via groups (3 from each side) and the board was fabbed "conventionally", i.e. as a series of through-hole sub-boards that were stacked after each group had been drilled and plated. The end result was some (variable) copper thinkness going to 2.5 oz - considerably more than the 1 oz min called for in the stack-up, but still acceptable according to spec. I'm puzzled by the "skip" in your case though - any sign of any material that might have effectively masked that portion during the plating process? Peter Steve Gregory <[log in to unmask]> 29/05/2003 01:53 AM Sent by: TechNet <[log in to unmask]> Please respond to "TechNet E-Mail Forum."; Please respond to SteveZeva To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: [TN] Trace thickness problem... Hi all! I'd like your opinion on something. We're building a prototype assembly for a customer, and discovered something at final inspection that we didn't see when we received the bare fabs. We ordered 16-boards in four, 4-up panels. We found a trace that has a spot where it looks like it didn't plate up during final plating. Take a look at "Trace Thickness" at http://www.stevezeva.homestead.com There's 4-boards we've found that have this problem, 1 on one panel, and 3 on another panel, and of course they're all built up. The 6012 says that thickness can't be reduced by more than 20% of the minimum conductor thickness. I can't really tell if it's 20% or 50%. I've sent pictures both to our customer and the fab vendor. The customer wants the spot repaired, and there are a number of ways to do that. The fab vendor says it's not a problem because the stack-up drawing calls out 1-oz. copper after plating on the surface layer, and they said that there's more like 2-oz. on the surface layer, so there shouldn't be any problem, at least that's what I was told, I didn't speak to anyone directly. The stack-up is on my page too, look at "Stack-up"... The first question that comes to my mind, if 1-oz after plating was called on the stack-up, why was 2-oz plated? Or is that normal?. The drawing references our customers internal spec for fabrication, but it uses MIL-PRF-55110 for references. What are your opinions about this? Thanks everyone! -Steve Gregory- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------