CNC turning parts are mainly used to manufacture helicoid parts, like bearings and wheels. By operating the CNC machining program, the cutting of internal and external of columns, cone, surface, whorl and end face, slot turning, drilling, reaming, and fraising can be done automatically with high precision. But for CNC, no matter it is manual programmed or automatic programmed, the technology analysis of the target parts has to be done before the programming, like the cutting point, manufacturing route, as well as manufacturing plan, suitable cutter and quantity of cutting. Finally, only the accurate control of the precision can produce qualified products.