Metal 3D printing: is it useful? So I haven't really done too much research into metal 3D printing, but from what I've seen, it takes a long time and a lot of money. Using plastic 3D printed parts as investment molds ("lost wax" casting except with PLA/ABS instead of wax) to cast metal parts seems a lot more efficient (quality and cost wise), although I don't see it as much. What are the benefits of metal 3D printing?