Heat bondable preforms work well. Once the material bonds and hardens it does not go any where. There are more than one manufacturer of these types. Regards, Ramon > -----Original Message----- > From: Genny Gibbard [SMTP:[log in to unmask]] > Sent: Wednesday, November 06, 2002 10:53 AM > To: [log in to unmask] > Subject: [TN] heatsinking a PCB > > We have a small PCB with SM components mounted on one side and a heatsink > mounted against the other side over the entire surface of the PCB. The > heatsink is grounded, so we use a thermally conductive, electrically > isolative thermal interface material in between (0.5mm thick), to protect > signal vias. We also use some strips of electrically conductive gasket in > strategic areas to provide good electrical grounding between the two. > Migration of some substances out of the thermal material onto the PCB over > time has caused performance problems on random, not all, units. > > I was wondering what other methods might exist for heatsinking a PCB, > possibly permanently bonding the metal heatsink to the PCB in some way. > Any sources of information for alternatives is appreciated. We cannot > change the construction materials of the original PCB, which is a > multilayer (4 layer) FR4, but we may be able to bond an additional layer > onto the PCB, in place of the gasketing we use now. > > Thanks in advance, > Genny > --------------------------------------------------- Technet Mail List > provided as a free 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/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 1.8e 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------