The manufacturer's production is related to mechanical equipment. With the help of machinery, our workload, effect and speed are much faster. Although there are mechanical equipment to help, but in the face of customer requirements for product quality so high. Naturally, the accuracy of the processing process is required to be high, such as precision machining of parts.

During the processing of precision machine parts, the contour system controlled by digital program is widely used in milling machine, including the phase system with extensive process capability, simple and reliable, and low price. These systems are adopted by many factories, especially for controlling the processing of large-scale solid surface precision machine parts.

It is one of the main conditions to ensure the machining quality of precision machine parts to make the control program correctly. For the digital program control phase system, the preparation of the control program is carried out by using the automatic program preparation system, and its quality level largely depends on the price of the preparation control program.

The others are the processing errors caused by the manual control of the equipment. These errors include the accidental errors and system errors of the process system. System error plays an important role in all machining errors. As a whole, it will cause a series of CNC process system errors.

For example, clearance has the same consequences as the insensitive belt in the machine tool drive chain, but does not include the reverse drive chain clearance; the amplification factor of unstable drive; the phase error on the control program tape; the periodic step instability of sensor feedback, the main form of which is the instability of the phase form.