Machinists typically use blueprints, sketches, or computer-aided design (CAD) and computer-aided manufacturing (CAM) files. Machinists set up and operate a variety of computer-controlled and mechanically controlled machine tools to produce precision metal parts, instruments, and tools. A machinist works with precision cutting machines to produce extremely accurate mechanical components. These machines may be manual or computer controlled. Parts may be produced in a variety of materials, commonly metal and plastic.