A CNC, or computer numerical control machine, is a machine used mainly in manufacturing that is controlled by programming via computer without the need for constant manual supervision. A CNC machine can automate operations by turning hand-wheels that are impossible for a human machinist to turn.
CAD programs are used to create drawings of the part to be machined. The drawings are then used by CAM programs to produce the g-code the CNC machines use to function. A CNC calculator helps calculate feeds and spreads of the machine, allowing measurements for cuts to be precise. A CNC machinist will typically need basic machining skills, an understanding of feeds and speeds and knowledge of some electronics.