Hello Bob, Lots of questions there for one message... ;-) There are a couple of different types of vacuum lamination processes vacuum autoclave and vacuum press. The former was developed for rigid flex in the late 1970s and early 1980s and the latter followed to my recollection as a less exotic way to get similar results. The benefits include a lower pressure lamination, air exclusion under vacuum and the ability to more easily build bookbinder type constructions. High and low are relative terms for pressure. The pressure need be only enough to cause flow and full encapsulation of all of the features. Lots of things can influence that such as metal thickness and feature density and spacing, material flow to name a few. So in short and in terms familiar to this crowd, it depends. It is more economical and productive with presses to run them hot and with thermal lagging materials, you should not have any major problems. Autoclaves start cold by the nature of the process. Most traditional techniques for lamination registration work but multilayer and rigid flex makers often use internal pins, sometimes many of them, to help keep things aligned. General dangers? Hmmm... taking a job in the circuit manufacturing industry in the US perhaps?... ;-) Others might have some addition thoughts to share. Welcome back and enjoy. Joe In a message dated 6/8/2007 11:17:09 AM Pacific Daylight Time, [log in to unmask] writes: 1. Benefits of vacuum ? 2. Low pressure vs. High pressure lamination in a Vacuum press. 3. Cold start up vs. Hot start up 4. Any methods to control registration in sequential, redundant, as well as general lamination 5. General dangers ************************************** See what's free at http://www.aol.com. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 -----------------------------------------------------