> ---------- > From: Geoff Layhe > Sent: 12 June 2000 09:47 > To: [log in to unmask] > Subject: RE: [TN] Wrinkles in copper foil > > Jan, > Just a few quick thoughts on wrinkled copper. > > It can be due to different expansion rates of the material on either side > of the copper, i.e. the laminate and the separator plates. If this is your > problem it will usually be worse on high layer count boards, in the middle > of a stack and on larger panel sizes. > Try different separator plates, aluminium may work better than steel, use > a release film in contact with the copper, or release coated aluminium > separators this will allow the copper to expand and contract easier. > > Have you tried a lower pressure? > > Is your copper foil tooled? if so does the wrinkling occur around the > tooling holes? Maybe the tooling holes are not quite in the the right > position or are too tight on the copper and the copper has to be > "stretched" on them. > > Hope the ideas help > > Geoff Layhe > www.lamar-uk.co.uk. > ---------- > From: Jan Thuesen[SMTP:[log in to unmask]] > Reply To: [log in to unmask] > Sent: 09 June 2000 10:33 > To: [log in to unmask] > Subject: [TN] Wrinkles in copper foil > > Dear Technetters, > we have been seeing increasingly problems with wrinkles in > outerlayer copper foil on certain jobs. > The wrinkles are coming from the press-lamination of multilayers. > > We have tried different things to minimize the problem like > optimising heat up and cool down time and temperature, different types of > presspads, awareness at lay up, adding copper areas to the underlying > layers, different prepregstyles amo. > > If any of you have some additional inputs to the cause of the > problems, we will be very interested in hearing from you. > > With best regards > > Jan Thuesen > > ############################################################## > 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 > ############################################################## > > ############################################################## 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 ##############################################################