SLM is a 3D printing technology that uses metal powder to directly print metal parts. When printing, the scraper spreads a layer of metal powder on the base plate of the forming cylinder, and the laser beam will selectively melt the powder according to the cross-sectional profile of each layer of the part to process the current layer. After one layer of melting is completed, the lifting system lowers the height of one cross-sectional layer, and the powder spreading roller spreads another layer of metal powder on the formed cross-sectional layer, sintering the next layer, and so on, until the whole part is sintered. The whole molding process is carried out in a vacuum-pumped or protective gas-filled processing chamber to avoid the metal from reacting with other gases at high temperature.

SLM uses a laser with high energy density and fine spot diameter, which can complete the construction of complex parts that take weeks or even months by conventional methods in a very short period. The molded parts not only have accurate dimensional accuracy, high strength and high mass density, but also have excellent mechanical properties and other aspects. It is mainly used for rapidly manufacturing high-precision and high-quality metal parts.