I would like to make prototype heat sinks. Has anyone found an additive to make parts thermally conductive? obviously it wouldn’t be super conductive, but a little would help. Is Formlabs working on a material?
I experimented with adding aluminum and copper to the standard resins back in the day (Form 1). It worked ok.
I think I used clear resin and printed with the black setting. Aluminum powder is cheap. Copper or brass powder not as cheap but easy to google up.
I think you will get better heat conductivity with this rather than adding something in the resin, as I ffel you can have a much higher metal content in the cold cast material than in the resin.
You can also electroplate them. I have not found any recent data on the thermal conductivity of SLA resins but you can find the conductivity for a number of plastics here. https://www.electronics-cooling.com/2001/05/the-thermal-conductivity-of-unfilled-plastics/ If we assume SLAresins have a thermal conductivity similar to epoxy (which is in the middle of the pack and probably related chemically) then the conductivity is ~0.2 W/mK. Copper has a thermal conductivity of 385 W/mK so a little copper will go a long way, as long as you keep a lot of metal in a continuous path from the heat source to the heat sink. Thin walled vanes (0,75 mm), perforations in the base plate the vanes are attached to and 125 microns of copper coating on each side of the vane will get you a heat sink with a composite with a conductivity in the direction of heat flow of nearly 100 w/mK which is a quarter of copper, half of aluminum but almost equivalent to brass.