SLM printing uses selective laser melting technology which melts metal powders and solidifies layer by layer until a three-dimensional part is built. During the process, the ruler in the build chamber will pave one layer of the metal powder, a high powered laser selectively fuses the powder by tracing cross-section of the part on the surface of a powder bed and then a new coat of material is applied for the next layer. The whole process is in a high vacuum chamber or full of protective gas chamber to avoid the metal powder reacts with oxygen at high temperature.

SLS Printing uses selective CO₂ laser sintering technology which sinters plastic powders(ceramic or metal powders with binding agent) into solid cross-sections layer by layer until a three-dimensional part is built. Before making the parts, need to fill the build chamber with nitrogen and rise the chamber temperature. When the temperature is ready, a computer controlled CO₂ laser selectively fuses powdered materials by tracing cross-sections of the part on the surface of a powder bed and then a new coat of materiel is applied for the new layer. The working platform of the powder bed will go one layer down and then the roller will pave a new layer of the powder and the laser will selectively sinter the cross-sections of the parts. Repeat the process until the parts completed

SLA(Stereolithography) is an additive manufacturing process that works by focusing an UV laser on to a vat of photopolymer resin. With the help of computer aided manufacturing or computer aided design(CAM/CAD) software, the UV laser is used to draw a pre-programmed design or shape on to the surface of the photopolymer vat. Photopolymers are sensitive to ultraviolet light, so the resin is photochemically solidified and forms a single layer of the desired 3D object. This process is repeated for each layer of the design until the 3D object is complete