|Using the vacuum chamber from my Farnsworth Fusor project, and my SeeMe CNC Rostock Max 3D printer, I'm doing some testing of 3D printing IIIIIIN SPAAACE...|
I had surprisingly good results down to about 1/3th of an atmosphere (250 torr), with the top layer getting just a bit smeary at the lowest pressure.
However, when I went further down, to about 1/20th of an atmosphere (35 torr), the plastic filament melted up into the supply tube and clogged due to the top half of the hot-end not being able to cool itself.
This was not surprising, as without air to fan the heat away, the only thing cooling the hot-end was the movement of filament itself.
The good news is that nothing catastrophic broke, caught fire, or imploded, and the best news, the single most important fact I was looking for was: The stepper motors continued to function and did not overheat.
Also, after I cleared the blockage in the hot-end, it's back to full function!
My intention with this experiment was not to see if FDM works, unmodified in space, but whether the basic motion system (belts, guides, motors, electronics) work. Because they do, I can now move on to more robotics projects in vacuum. Stay tuned!