How 3D printers work

AT FIRST, 3D printing was known as stereolithography, a process invented in 1986 by Chuck Hull of 3D Systems. Variations of this process are still used. It begins, like all 3D printing, with software that takes a series of digital slices through a computer model of an object. The shape of each slice is used selectively to harden a layer of light-sensitive liquid, usually with ultraviolet light, to form the required shape. After each layer has been made, the build tray lowers by a fraction, another layer of liquid is added and the process is repeated until the object is complete.