Additive manufacturing is a process that adds successive layers of material to create an object, often referred to as 3D printing. Subtractive manufacturing, as the name suggests, is the opposite. Rather than adding layers, subtractive manufacturing involves removing sections of a material by machining or cutting it away. It can be carried out manually or, more commonly, by a process known as Computer Numerically Control (CNC) machining and takes many forms, such as milling, turning, turn-mill machining, wire-EDM and others.