Thanks to everyone who replied. I learned a lot from this thread. Obviously I'm not going to find a cookbook approach that works for every board. Too many people and processes involved in creating an assembled board. I just want to know enough about the materials and processes to be able to get a little creative with the stackup when needed without creating problems. Robert ----- Original Message ----- From: "Dam, Phil" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, January 28, 2004 2:19 PM Subject: Re: [TN] PCB warp > Forgot to mention that the finished pwb can only be as good as the raw > materials used to make it. At times fab mfg's are scratching their heads > just as assembly people do because of core material manufacturing variation > that doesn't show up until etching and/or subsequent ML lamination. > --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------