`3D metal printing propeller test for US Navy`

Physical samples displayed. Tom's own ~1994-era work using high-energy electron beam to build parts, originally aimed at US Navy propeller fabrication. Shows the defects characteristic of the process.

[Tom holds up sample parts.] These are things that I made by high-energy electron beam about twenty-five years ago. That was supposed to be a way for the US Navy to build propellers — it's a manganese aluminum bronze, which is what they build propellers out of. This is a piece of stainless steel, and you can see the defects that form. This is a piece of Inconel. Those are all things that we made twenty-five years ago.