The CNC machine works as follows:After the computer in the numerical control device has processed a series of information recorded by the input device in the form of digital and character codes, through the SERVO system and the Programmable logic controller to the machine tool spindle and feed and other executive agencies issued instructions, the machine tool main body according to these instructions, and in coordination with the detection feedback device, the workpiece processing needs of various actions, such as the tool relative to the workpiece trajectory, displacement and feed speed requirements to achieve automatic control, so as to complete the processing of the workpiece.