CNC is the abbreviation of Computer numerical control and lathes automatic controlled by procedure. Control system can handle procedure with code and other symbols. Specific actions are carried out by translation of computer. Rough staff is cutted and processed into semi-manufactured and finished products. Compared with general machine tool, the characteristic of numerically-controlled machine tool as following: 1. High machining precision, stable processing quality. 2. Flexible mobility 3. Wring out extra production time when machining part is changed. 4. Mass production, product quality is easily controlled.