Heat Sink Material

[tetwin11]

We are placing three electrical components in close proximity to one another and it has been determined that there must be a heat sink/heat spreader plate to keep the temperature within operating range. What would you suggest as a material to use for this heat spreader plate. I've heard aluminum 6061 and 6063 suggested.

 

[mcgyvr]

Or if possible, just redesign it to put these parts in direct contact with the chassis..avoid the need for a spreader at all.