NASA is successful cutting production cost down of their rockets by printing the parts

NASA is successful cutting production cost down of their rockets by printing the parts with a 3D printer. What else does this technology hold that could revolutionize science and manufacturing.

Can 3D-printing be used to make spare parts on the space station with zero-G?

Certainly as the FDM/FFF printers use adhesion rather than gravity to append new layers. Some printers even build upside down, growing the new build against gravitational attraction. NASA is also looking at wire-feed EBM technologies that can work sideways, etc all the same.

Plus, it has been reported that NASA has been experimenting LENS machines with lunar regolith simulant spraying powder into a molten pool produced by means of a high power laser.

There’s a 3D printer slated to go up to the ISS next year, IIRC. An FDM printer that is indeed capable of doing without gravity.