The composition of CNC machine tools in high-precision CNC processing plants

CNC machine tool is a widely used electromechanical device that adopts digital control to achieve high speed, high precision and high automation of precision CNC machining. Understanding the composition principle of CNC machine tools in high-precision CNC machining plants helps to master its operation methods and troubleshooting.

For CNC machining customization, CNC machine tools are essential. CNC machine tools processed by precision CNC are generally composed of control medium, numerical control device, servo system, detection feedback device and machine body.

1. Control medium

The control medium is the intermediate medium of the information carrier that establishes a certain connection between the human and the machine tool. It is used to record various information of parts processing in high-precision CNC processing plants (such as processing process, process parameters and displacement data, etc.), and transmit the information to the numerical control device, thereby controlling the movement of the machine tool and realizing the machining of parts. Commonly used control media are perforated paper tape, magnetic tape, magnetic disk and so on. Some CNC machine tools processed by precision CNC can also directly input the processing program through the buttons and keyboard on the operation panel; or input the processing program written on the computer into the CNC system through the serial port.

2. Numerical control device

The numerical control device is the core of the precision CNC machining numerical control machine tool, which usually consists of four major parts: input device, controller, arithmetic unit and output device. It receives the digital information on the control medium, and after compiling, computing and logical processing by the control software or logic circuit, it outputs various signals and instructions to control various parts of the machine tool and perform prescribed and orderly actions. At present, high-precision CNC processing plants all use microcomputers as numerical control devices to complete functions such as numerical calculation, logical judgment, and input and output control.

3. Servo system

The servo system is the executive part of the precision CNC machining numerical control system, which consists of a servo drive motor and a servo drive device. It will accept the command information of the numerical control device, and control the feeding speed, direction and displacement of the executing part according to the requirements of the command information. The command information is embodied by pulse information. The displacement generated by each pulse of the moving parts of the machine tool is called the pulse equivalent (the commonly used pulse equivalent is 0.001~0.1mm).

At present, in the servo system of CNC machine tools in high-precision CNC processing plants, the commonly used displacement actuators are power stepper motors, DC servo motors and AC servo motors, the latter two have position measuring elements such as photoelectric encoders.

4. Machine tool body

The bed body is the main body of the CNC machine tool for precision CNC machining, and it is the mechanical part used to complete various cutting processes. Such as bed, base, column, beam, sliding seat, worktable, spindle box, feeding mechanism, tool rest and automatic tool changing device, etc., are the main body of CNC machine tools.

5. Detection and feedback device

The function of the detection feedback device is to detect the actual position, speed and other parameters of the machine tool, convert it into an electrical signal, and transmit it to the numerical control device. resulting errors. Detection and feedback devices mainly use inductive synchronizers, magnetic gratings, gratings, laser measuring instruments, etc.

In addition, CNC machine tools also have some auxiliary devices and auxiliary equipment, such as electrical, hydraulic, pneumatic systems and cooling, chip removal, lubrication, lighting, storage and transportation devices, as well as programming machines, tool setting instruments, etc.