---------------------------- Forwarded with Changes --------------------------- From: Edwin P Lopez at PO897CC1 Date: 12/22/95 9:59AM To: Carol Adkins at MAPSNET-PO1 Subject: Supercritical CO2 Cleaning ---------------------------------- Forwarded ---------------------------------- From: Floyd L Gentry at Mail-Sandia Date: 12/13/95 4:15PM To: edwin p LOPEZ at PO897CC1 Receipt Requested Subject: Supercritical CO2 Cleaning ---------------------------- Forwarded with Changes --------------------------- From: [log in to unmask] at hubsmtp Date: 12/13/95 10:32AM *To: [log in to unmask] at hubsmtp Subject: Supercritical CO2 Cleaning ------------------------------------------------------------------------------- RE: Supercritical CO2 Cleaning, Jim Wrezel at Motorola Inc. We would be happy to test some of your boards in our supercritical CO2 systems, although you would have to cut them up for preliminary tests. We cannot handle the 18" X 24" board in any of our systems. The 6" x 6" board would possibly fit in our 6" ID, 1500 psi system. Our 5000 psi system has an ID of 3". What are you looking to do with the technology? We did some testing several years ago on PC boards and determined that the technology was not suitable for DOEs needs in flux removal. We found that most electronic components are compatible with the CO2 and pressure. However, hermetically sealed components with a sealed open volume (metal cover seal - hybrid microcircuits) suffered severe damage upon pressurization. Since DOE has a lot of this sort of component, we abandoned the technology for that purpose. The Kester 197 RMA flux we tested was not soluble in SCCO2. Occasionally it would pop off due to infiltration of the high pressure CO2 into microcracks that would expand upon depressurization. However, if a solvent and SCCO2 are combined into a hybrid cleaning system, the volume of solvent is greatly reduced and a dry board results upon removal from the system. Again, the effect of pressure on the sealed components forced us to stop research on the technology for cleaning PWBs. If you would like to talk further, please give me a call. Carol Adkins Sandia National Labs (505) 845-9119 [log in to unmask] ______________________________ Forward Header __________________________________ Subject: Supercritical CO2 Cleaning Author: Edwin P Lopez at PO897CC1 Date: 12/22/95 9:59 AM Ed: This is a request that I got through the IPC TechNet. Do you have any ideas? If you do, let me know, or send a response directly back to [log in to unmask] Thanks Floyd Gentry ______________________________ Forward Header __________________________________ Subject: Supercritical CO2 Cleaning Author: [log in to unmask] at hubsmtp Date: 12/13/95 10:32 AM Does anyone know of a source where we could clean some populated printed wiring boards using supercritical carbon dioxide (CO2)? We are interested in evaluating component compatiblity as well as board/solder resist compatiblity. Cleanliness analysis and reliability tests will also be performed. The boards range in size from 6" X 6" to 18" X 24". Thank you for your assistance, Jim Wrezel Motorola Inc. (708) 632-6513