Best heat conductivity with least warping??

[DarkStarCEO]

Hello all, I am working on a project that requires a 8”x8”x 3/8 heat bed that can conduct heat efficiently 90-212F quickly without warping more than .015. The current 5052 Aluminum heat bed has been problematic due to warping from corner to corner .030+. I was considering a copper/brass alloy or Aluminum/Magnesium alloy but wanted to check with the experts.

 

[Compositepro]

I assume that a "heat bed" is what I would call a hot plate. So is this heated on one side to apply heat to something on the other side? What is the heat source, and what is the heat load?

The simplest solution is to make the plate thicker to make it stiffer. Once it is thicker you can also place heat cartridges, or other heat source, in the middle thickness of the plate to improve heat transfer and reduce temperature differences within the plate. Most heated presses are much larger than 8"x8" and use steel platens.

 

[TugboatEng]

Warping is caused by uneven heating or constraint of the material. You can simply compare coefficient of thermal expansion to select a material that will warp less but you can design your system to support the material better to prevent warpage despite expansion.

It does seem that thermal conductivity and coefficient of thermal expansion are directly related. You can get materials like Invar that will have little expansion for you to manage but they won't be very conductive either.