Hi Werner and All Just finished evaluating a lot of boards that had gross inner layer separation - not just on layer 2 and n-1, but all layers in "as received" microsections. Subsequent to Thermal Stress testing the number of occurances increased. A second lot from the same mfgr. had only one panel with separation "as received", but all opened after Thermal Stress. I'm not certain what your comment regarding board mfgrs not being able to produce boards that exhibit inner layer separation. My experience is that they can do this in many different ways. Some show up before Thermal Stress testing and others after. Susan Mansilla Robisan Lab --------------------------------------------------- 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 -----------------------------------------------------