Ok, before I get hammered for posing this question, let me say that my answer is "Don't do it, solder will creep and it will short out". Anyways, here is the question: Some of our designers have come up with a design using about eight 560 BGAs as well as many other SMT packages on a board which will be pressed up against a sheet of thermal tranfer type spongy material which is then pressing against a solid metal chassis. They are worried about dissipating 6 watts per BGA and therefore need to envelope the thermal pad around the BGA by applying 30 psi according to the spec sheet. This part is only 1.5" square so I calculate that we need to apply approx 65 pounds of pressure to the component. I take this to mean that they want to compress the solid tin lead solderballs with this huge amount of force and believe that this will definitely cause the solder to deform/creep. Any comments (please be nice....). Phil Phillip A. Bavaro QUALCO/\/\/\/\ Incorporated Manufacturing Engineer, Staff [log in to unmask] Cell (619) 602-8644 (offsite, after hours) Pager (619) 271-3640 Tel (619) 658-2542 Office/voice mail Cell (619) 845-9968 (workday) Fax (619) 658-1584 ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################