Scheme is to do this for aircraft parts on carriers.
Reduce inventory.
Need 3d parts to meet flight certified criteria, however.
The concept goes way back. On wooden ships,ship carpenters made things, and did repairs from planks of wood. Modern ships carry machine shops. It makes even more sense in space — given the cost of lifting spare parts to orbit.
Don’t you need metal for some tools?
Ah yes - instead of the Blue Angels," you'll have plastic Flying Flamingos.
Very tough to pass any certified structural aircraft part from sintered metal (3D printing method from powdered metal). It is not predictable and not in the Mil Handbook 5. I am sure there are some working on it but I don’t think anything outside of experimental non-structural or testing for a long long time.
As for the printed part in the space station. I can already hear the wailing and gnashing of teeth from the union goons who will sue over a non union manufacturing job being outsourced to orbit.