In the beginning, the NC machine tool selects the aircraft parts with complex surfaces as the processing objects, which solves the difficult problem of common machining methods. The biggest characteristic of NC machining is to use the perforation belt (or tape) to control the machine tool for automatic machining. Because of the different characteristics of aircraft, rocket and engine parts, the aircraft and the rocket's 0, the component size is big, the shape surface is complex, the engine 0, the component size is small, the precision is high. Therefore the aircraft, the rocket manufacture department and the engine manufacture department selected the numerical Control machine tool to be different. In the aircraft and rocket manufacturing to adopt a continuous control of large-scale CNC milling machine, while in the engine manufacturing both the use of continuous control machine tools, but also the use of point-bit control CNC machine tools (such as CNC drilling, CNC boring machines, machining centers, etc.).