Daan, We normally specify +/- .007" (+/- .18 mm) for boards up to 12 layers. Above that, we specify +/- .010" (+/- .25 mm). Of course, we're manufacturing these in the States. European manufacturers may have different requirements. I suggest you do an informal poll of your vendors for recommendations. Michael Hiteshew Lockheed Martin NE&SS-Baltimore [log in to unmask] (410) 682-1259 > ---------- > From: d. terstegge[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;d. terstegge > Sent: Wednesday, July 05, 2000 11:55 AM > To: [log in to unmask] > Subject: [TN] Tolerance on board thickness > > Hi Technet, > > It's quiet on Technet. Or is it just me ? Problems with the server again ? > Compensation for all the double messages from a few weeks ago ? > Anyway, I've got a small question : > We've ordered a 4 layer FR4 board with a thickness specification of 1.6 > +/- 0.05 mm. The supplier says he can't build it with such narrow > tolarances. The customer won't accept anything worse than this. > What do you think, should the average fabhouse be able to build a board > like this or is it completely unrealistic ? > Hope to hear from you. > > Kind Regards, > > Daan Terstegge > SMT Centre > Signaal Communications > Unclassified mail > Personal Website: http://surf.to/smtinfo > > ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################