Not an extruder for 3D printing, but for making foam sheet.
Looking to use supercritical CO2.
Currently researching casting/milling methods- seems most appropriate to cast a rough shape with the blades then mill it rather than milling a cylinder down. Willing to build a vacuum chamber for the casting.
I did notice screws can break under the pressure & temperature gradients involved in extrusion.
Will first have search literature for optimal blade design. I noticed a lapsed Japanese patent describing the particular foam I want to produce. I've been researching this for a year or so now, but other projects come first.
Enjoy this project?