Suppose we had a 3D printer that can spew molten metal out of a 0.1mm hot nozzle and that we can control the heat at the last 5mm of the Tungsten hot nozzle's tip.
I'm wondering then how would you get the metal to "stick" to the flatbed (the work surface)?
Also (another question) as far as printing traces on a flat circuit board, I think you could could put down layers of fiber (of something insulative say fiberglass) and put on a layer of epoxy out of a third print head, and right before the epoxy dries, you have a window of time in which the freshly solidified metal will stick to the epoxy. Do you think that should work?
The picture above is of the Tungsten hot head I made a long time ago. It does have a 0.1mm emitter hole, and the bottom side is flat and the base (with flange) is about 10mm wide. There is a 0.7mm (iirc) material feed hole. The material has to be stiff enough so that you can kind of force it through the nozzle like how a hot glue gun works, in principle.