The filament is fed into a heating chamber in the printer’s extruder assembly, where it is heated to its melting point and then extruded (squirted) through a metal nozzle as the extruder assembly moves, tracing a path programmed into a 3D object file to create, layer by layer, the printed object
Resin or synthetic resin are UV-curing liquid plastics. These materials are used in stereolithography 3D printers. … The liquid resin is exposed at the desired locations with the 3D printer, curing the resin. This technique makes it possible to produce components with high surface quality and level of detail.
SLM printers use powder bed fusion to create parts. A laser melts metal powder layer by layer to build up to the desired shape. To keep the temperature constant and avoid any drafts, SLM printers tend to have a controlled build space and atmosphere.