The easiest way to accomplish this is with the of external heatsinks. If

the design is such that it cannot accommodate external heatsinks the
next technology that would be available is internal metal cores. This is

a technology that has been used in military avionics for quite sometime.

The core can be made out of aluminum or copper depending on the amount
of heat to be applied to them. If they are surface mount boards it can
also be copper invar copper or copper moly depending on the amount of
heat that is needed to be dissipated through the board. Because of the
high heat application the polymer material is usually polyimide.
Polyimide is capable of handling the hotter temperatures and conducting
it through to the core and typically out to the edge card connectors
which is an exposed area of the core connected to the metal box for
dissipating the heat. If the parts are particularly hot, machined areas
in the substrate can be cut out through to the core and parts can be
mounted directly to the core. Hope this helps.

Regards,
Tim Snodgrass

################################################################
TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################