https://www.esa.int/ESA_Multimedia/Imag ... r_ceramics
These spur gears – seen here with a euro cent coin for scale – have been produced in stainless steel to a space standard of quality using nothing more than an off-the-shelf desktop 3D printer.
ESA-supported startup TIWARI Scientific Instruments in Germany has developed a technique allowing low cost 3D printing using a variety of metals and ceramics. Ordinarily producing precision parts in such high-performance materials would be costly in both time and money, but the company can instead shape them using standard 3D printing techniques.