[This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] Phil, We don't have quite the same application as you, but we're having to extract heat from the top of vulnerable chips using thermallly conductive material between the chips and an overhead heat-dissipation plate. We have been using a product called T-ply by Thermagon and it comes in various thicknesses. Thermagon claim that it's been used in satellites, so it stands up to quite a challenging set of temperatures, pressures and vibration levels. It does have some silicon associated with it, but it doesn't ooze, doesn't change phase, isn't electrically conductive and can be compressed to up to 50% of its native thickness. It is quite expensive though, but pretty effective thermally at 5.3W/mK. They can be found at www.thermagon.com Regards Pete Duncan Phil Nutting <PNutting@KAISERSY To: [log in to unmask] STEMS.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Sent by: TechNet Subject: [TN] Thermal Compound considerations <[log in to unmask]> 08/20/01 09:42 PM Please respond to "TechNet E-Mail Forum." Here is this morning's question(s). I posted a note last week about using the old style thermal grease. I agree with your comments about using some of the new Berquist or Power Devices insulator pads, some of which we currently use. Today I am looking for some of your thoughts on an alternate style material (grease "replacement"). There are several products on the market which are phase change (at 60 $B!k (BC/140 $B!k (BF) thixotropic, non-silicon products which prevent run out (oozing out from under the device) at operating temperature. Now assuming we use this material on TO-220 packages and mount the device with the standard mounting hole in the tab the device tends to not sit completely flat on the heat sink (This is a problem not associated with the thermal compound but the mechanical design of the device). On concern brought to my attention is water trapped under the device. And our intent is to solder these devices to the PWB (through hole) and de-flux (OA flux) the boards after assembly in a batch DI wash with no saponifiers. Do any of you see this as an issue? We presently use the old style thermal grease in this manner mostly with TO-220 devices and heat sinks which are the same size as the body. If our DI wash is running at 120 $B!k (BF and the wash chamber is set for 135 $B!k (BF are there any significant issues with approaching the phase change point that will degrade the thermal compound's operational characteristics? We may end up using one of the pad style items, but I wanted to tap into your collective wisdom to help with the end decision. This manual application tends to be messy, time consuming and different by each assembler. Thanks in advance. Phil Nutting --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------