@spirit532 this is unbelievably cool! I would never have guessed it would be that simple.

If I'm reading correctly, it sounds like the kinematics from a modest CNC metalworking mill would easily handle the needed forces, just need to swap out the tool for a big ultrasonic transducer and tip/wire-feeding system? Not as cheap as FDM but that feels pretty achievable for a hobbyist already!

I'd be very curious to see how the parts respond to heat treatment. As-is it seems like the parts are basically annealed during the process (and have properties comparable to the annealed input), would whole-part annealing get them closer? Does the gap widen with tempering or do they temper like the bulk material? I hope they keep working on this :)