Joyce, I must disagree with your position that materials compatibility testing should not be done on production hardware. In my opinion, it is a serious oversight if you do NOT do such testing. Most testing is done on flat boards, like the B-24 or B-25A, because such substrates are cheap, easily available, have industry standard evaluation criteria, and do not take up time on production equipment. I might take a B-25A board, made by my chosen fabricator (Collins Printed Circuits to put in a shameless plug), apply my chosen mask, run through my chosen reflows, fluxes and cleaning, coat it and test. That may be enough if all my boards are dead flat, but ours here have these nasty 3D objects called components that give rise to all kinds of variations (err. or so I've heard happens elsewhere). Being a hi-rel hi-mix shop, there is an incredible array of profiles and function. How can you assure that your material set works on a product family or verify that a change in materials or processes is not detrimental unless you fully check out form fit and function on actual product? Doug Pauls Joyce Koo <[log in to unmask] com> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 12/16/2004 12:44 Re: [TN] solder mask/conformal PM coating compatability Please respond to [log in to unmask] om material compatiability study should not be done at production level. Why you are doing it on the populated board? If you done the work at front (in the design stage as part of material selection), you should not see the need to do it at production level. Why? jk --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------