Unless the circuit is really long what they are asking is very excessive. If the part is a reasonable size the covercoats can be cut into sections to maximize lay-up (this is normal in the industry). If it is long they can measure the movement in the panel before covercoat lay-up and compensate the drill program. .15 is standard in my world and .1 can be done with care and some $. Good luck. Steve Kelly PFC Flexible Circuits Limited -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Roger Stoops Sent: Wednesday, July 02, 2003 1:16 PM To: [log in to unmask] Subject: [TN] Flex Circuit specifications Hiya folks! We are having some difficulty getting a flex supplier to build a circuit to our specs. The issue has to do with coverlay tolerance. They are requesting we open the coverlay openings so that they can use +/-0.50mm location tolerance. This allows for exposed copper between pads/lands to be soldered during installation. We have asked for +/-0.20mm tolerance, but might live with +/-0.25mm to +/-0.30mm. They **keep** coming back asking for the loose tolerance each time we say no. We have already taken into consideration the annular ring and adhesive squeeze-out, and cannot enlarge the openings by more than .10 or .15mm. These are typically 2 to 4 layer flex circuits with plated holes, polyimide lam with thermoset acrylic adhesive. Am I just being to picky? hardnosed? stiff-necked? all the above? What tolerances can I expect or ask for? Any alternatives or other details I may not be aware of? (Don't assume I know a lot about flex.. thanks.) Looking forward to your assistance, Sincerely, Roger M. Stoops, CID Trimble Navigation Ltd., Dayton, OH, USA Ph: +01 937.245.5288 Fax: +01 937.233.7511 --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------