Hi All, Does anyone know where I can find information on air bubbles or voids within completed circuit boards? We have a group here which is concerned about any voids left when the laminates are pressed together, either within or between layers, and the effects they might have at high altitudes. Are there any IPC specs which state allowable values or anything like that? These are boards made with IPC-4101/ 40, 41 or 42 materials. Thanks for any help! Bill ############################################ William G. Brown Senior Electrical Engineer - PWD Engineering Support > xBAE SYSTEMSx - Information & Electronic Warfare Systems Phone: 603-885-4930 Fax: 603-885-5435 ############################################ --------------------------------------------------- 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 -----------------------------------------------------