It is possible to treat the heatsink as another PCB layer to be pressed to the rest of the board using pre-preg. If you need the heatsink to be electrically conductive, don't anodise it, but rather alchromate it instead, but still watch how thick you allow the alchromation to get, as it will also increase electrical resistance. It doesn't matter if it's just thermal conductivity you want, or even just mechanical stiffness, but you will have to passivate the aluminium surface somehow, though. Talk to your fab house. My old slave pit in the UK did this with PTH technology boards many years ago to provide heatladders for conduction-cooled boards. Peter Duncan William Sullivan <wsullivan@LUMINE To: [log in to unmask] NTINC.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Sent by: TechNet Aero/ST Group) <[log in to unmask]> Subject: [TN] bottom side heat sink attachment 10/11/01 01:48 AM Please respond to "TechNet E-Mail Forum." Hello Tec Netters,,, Is there anyone out there that can point me in the right direction to fabricating a bottom side aluminum heat sink that is part of the pcb itself,, im really looking for process of attachment and cost escalation. Thanks Bill Sullivan William Sullivan C.I.D SR. PCB Design Engineer Luminent Inc 20550 nordhoff St. Chatsworth CA, 91311 818-773-9044 EX 2114 --------------------------------------------------------------------------------- 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 --------------------------------------------------------------------------------- [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.] --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------