High-precision CNC machine tools are typical complex mechatronics products. According to the different components and working media used in the transmission form, they can be divided into three parts: electrical transmission and control system, mechanical transmission and control system, and hydraulic and pneumatic transmission and control system. The basic structure and principle of various high-precision CNC machine tool electrical transmission and control systems are the same.

　　The entire electrical control system can be divided into a CNC computer numerical control system and a high-current control system. The CNC computer numerical control system is a special CNC device composed of a numerical control system, input/output interface, drive unit, and actuator. Execution processing is the core of the control system. The high-power part of a high-precision CNC machine tool includes a programmable control unit, a spindle control unit and spindle motor, a high-power circuit, and the machine tool's electrical and speed regulation unit and feed motor. This mainly introduces the high-current part.

　　(1) High-precision CNC machine tool data input device. The data input device is a necessary device for inputting instruction information and various application data into the CNC system. It can be a punched tape reader (rarely used), a CNC keyboard (MDL panel), a hard disk and drive device equipped with a CNC system (used to store and protect a large amount of data), a tape drive (rarely used), a PC, etc.

　　(2) High-precision CNC machine tool numerical control device. The numerical control device is the center of the high-precision CNC machine tool. It decodes and calculates all the received functional commands, and then sequentially issues various required motion commands and control commands for various machine tool functions until the motion and function are completed. The CNC system has a perfect self-diagnosis capability. In daily use, more attention should be paid to strict operation according to regulations. Daily maintenance is mainly to protect the hardware environment and prevent damage to the system software.

　　(3) High-precision CNC machine tool programmable controller. The programmable controller is the logical control center for various functions of the machine tool. It logically sorts various motion and function instructions from the CNC, allowing it to operate accurately, orderly, and safely; at the same time, it transmits various information and operating status of the machine tool to the CNC, allowing the CNC to issue further control instructions in a timely and accurate manner, thereby achieving control of the entire machine tool.

　　Modern PLCs are mostly integrated into the CNC system, mainly referring to the integration of control software, while PLC hardware often adopts a distributed structure in large systems. The integration of PLC and CNC is achieved through a software interface. Typically, the system will allocate various communication information between the two to their fixed storage addresses. The system monitors the information status of all addresses in real time, analyzes and judges the current status of each interface signal, and then issues further control commands to complete the control of motion or function.

　　Different manufacturers' PLCs have the same and different PLC languages and different language expressions. Therefore, the premise of being familiar with the machine tool's PLC program is to first be familiar with the machine tool's PLC language.

　　(4) High-precision CNC machine tool spindle drive. The spindle driver receives the drive command from the CNC, outputs the drive signal, drives the main motor to rotate through speed and torque (power) adjustment, and receives the speed feedback signal to achieve speed closed-loop control. It also notifies the CNC of the various actual operating statuses of the spindle through the PLC to complete the control of various functions of the spindle.

　　The spindle drive system itself has many parameter settings, and these parameter settings directly affect the rotational characteristics of the spindle. Some of these parameters cannot be lost or changed, such as the parameters indicating the motor specifications; some can be adjusted according to the train's operating status, such as zero-point drift. Generally speaking, the CNC also has machine tool data related to the spindle, and its functions are the same as the parameters of the spindle drive system. Therefore, it is necessary to pay attention to the consistency between the two and avoid conflicts.

　　(5) High-precision CNC machine tool feed servo. The feed servo receives the speed command provided by the CNC for each motion coordinate axis, outputs the drive signal, drives the servo motor to rotate through speed and current (torque) adjustment, and realizes the movement of the machine tool coordinate axis. At the same time, it receives the speed feedback signal to achieve speed closed-loop control. It also communicates with the CNC through the PLC, reports the current operating status, and accepts control from the CNC. The correct adjustment of the speed regulator of the feed servo system is very important. Optimal adjustment should be carried out under open-loop position conditions, not only without punching, but also with certain hard characteristics. It is subject to the mechanical characteristics of the machine tool coordinate axis. Once the state of the guide rail and mechanical transmission chain changes, the speed loop regulator needs to be readjusted.