The "SLM" procedure for "Selective Laser Melting" is used in additive manufacturing, sometimes known more commonly as 3D printing, to create metal parts. The procedure entails making a part out of metal powder according to specifications specified by an STL file from a 3D design (Inventor, Catia, Solidworks, Unigraphics). A laser beam is used to fuse the powder grains very accurately and along the curves of the part in layers of at least 20 microns.