Is additive manufacturing ever tested in space or are there some future missions which plan to do so?

Question

Unlike ISS where astronauts can count on supply of mission critical parts from Earth, future interplanetary travelers must have sufficient number of spare parts onboard, or technology to produce them during flight. Among all technologies additive manufacturing seems to be most promising for such purpose. It would be handy to have several 3D printers, each for on flight production of metal, plastic, ceramic parts or maybe even some electronic components.

Some additive manufacturing techniques like Powder bed fusion, Vat photopolymerization etc. simply wouldn't work in low/zero gravity. But others like Material extrusion, Binder jetting, Direct energy deposition, if perfected and adjusted, could produce workable pieces under low/zero gravity. Plus near perfect vacuum in space would reduce need for and many problems related to inert gasses.

To this date, are there 3D printers designed for use in space and tested? If yes, were results promising? If not, are there future missions which plan to do so?

Answer 1

At least in 2014, the ISS had an experimental 3D printer.

The International Space Station’s 3-D printer has manufactured the first 3-D printed object in space, paving the way to future long-term space expeditions. The object, a printhead faceplate, is engraved with names of the organizations that collaborated on this space station technology demonstration: NASA and Made In Space, Inc., the space manufacturing company that worked with NASA to design, build and test the 3-D printer.

Source

Answer 2

There are multiple projects related to 3d printing for housing on mars or on the moon. For instance this NASA competition for Mars habitats or this ESA project on Moon habitats.