Hi Steve, Can't quite tell if you're concerned with the film image size or the etched circuit image size. I'll bet that IPC-D-310, Guidelines for phototool generation and measurement techniques, contains some definitive answers. Unfortunately, I don't have a copy. But: In the old taped artwork days (pre-surface mount), typical artwork (film) tolerance was +/- 0.005". Towards the end of the taped artwork era, tolerances were often tightened to +/- 0.002". Occassionally, PCB Fab drawings include an image size tolerance (often +/- 0.002"). Currently our PCB Imaging Dept. uses a +/- 0.0025" (inhouse) tolerance for photoplotted artwork (panel lengths up to 22"). There's some give & take based on PCB complexity & technology. We chose the 2 1/2 mil tolerance to ensure that, when added to the other manufacturing tolerances (imaging registration, drilling, material stretch, etc.), the resulting PCB complies to IPC-A-600 & 6012 tolerances (annular ring, trace to hole, hole to edge, etc.). On boards with large pads & small holes (or no holes), we add panel registration holes & targets to ensure that the image size and registration are accurate. (I can't see where this is required by IPC-A-600, 6012, etc). Good Luck, Mark Hargreaves -----Original Message----- From: Steve Vargas [SMTP:[log in to unmask]] Sent: Friday, January 17, 2003 10:52 AM To: [log in to unmask] Subject: [TN] PWB artwork Technetters: Can someone tell me what the requirements are for PWB artwork stretch? I have a 12" long board where the artwork appears to be about .004" longer than the data from the gerber files. This is causing us much heartache during our screenprint process. As you would expect, it is also causing problems with 0402 tombstoning and fine pitch soldering as well. I could not find this in IPC-A-600. Thanks. Regards, Stephen M. Vargas Polaris Contract Mfg. Inc. [log in to unmask] --------------------------------------------------- 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 -----------------------------------------------------