Through a computer-driven additive process of adding layers upon layers of material on top of each other to form a piece, 3D printers can create an object from a 3D model. 

Laser cutting is done either with a flat sheet laser or a 3D tube laser. It’s a “subtractive” technology that creates parts by cutting material away from a source. 

CNC milling machines take a block of solid material (e.g. aluminum or marble) and use sharp rotating tools or cutters to remove all parts that are not needed.