Sep.2023 14
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The Working Principle of CNC Machine Tools

With the rapid development of the manufacturing industry and the increasing demand for improved product quality and production efficiency, CNC (Computer Numerical Control) machine tools, as an important type of machining equipment, continuously utilize their functions of high precision, high speed, and high flexibility to empower modern manufacturing. So, how do we understand the working principle of CNC machine tools? This article will provide a detailed explanation of the basic concepts, structure, and working principles of CNC machine tools.

I. Basic Concepts of CNC Machine Tools

CNC machine tools are a type of machine tool controlled by digital information. They operate by inputting pre-programmed machining instructions, which are interpreted by a computer or other digital devices. The input signals generated by the command device drive various axes through a servo system to execute corresponding machining actions. Simultaneously, a monitoring system provides real-time monitoring and feedback, allowing the machine tool to process workpieces based on programmed parameters such as sequence, direction, speed, and position. CNC systems offer a high degree of automation and are widely used in various manufacturing processes.

II. Main Structure and Functions of CNC Machine Tools

CNC machine tools primarily consist of the CNC unit (Computer Numerical Control), servo system, detection system, as well as the driving and control components. The quality, performance, and precision of CNC machine tools depend largely on the performance of these components.

  1. CNC Unit

The CNC unit is the core component that controls the operation of the machine tool. It receives input of machining programs, interprets and processes various commands within the NC program, and sends command signals to the servo system. The CNC unit is also responsible for functions like display and detection system reception and processing. Modern CNC units are typically computer-based and have robust data processing and storage capabilities.

  1. Servo System

The servo system receives command signals from the CNC unit and drives motion components such as the spindle and worktable to perform corresponding actions. The servo system includes components like servo motors and servo drivers, and its performance and precision significantly influence the accuracy, speed, and responsiveness of CNC machine tools.

  1. Detection System

The detection system comprises position detection devices and speed detection devices. It continuously monitors data such as spindle speed and worktable position and transmits detection signals to the CNC unit. Based on the detection results, the CNC unit can perform real-time monitoring and adjustments of the actions executed by the servo system, thereby enhancing the machining precision and automation level of CNC machine tools.

  1. Driving and Control Components

The driving components encompass motors, hydraulic systems, pneumatic systems, etc., responsible for tasks like spindle rotation, tool change, and hydraulic clamping. The control components include manual and automatic control modes used for machine tool operation.

III. Working Principle of CNC Machine Tools

In simplified terms, the working principle of CNC machine tools involves inputting machining programs into the CNC unit, interpreting these programs, sending signals to the servo system, and thereby driving the machine tool to achieve precise machining. During this process, the detection system continuously monitors various parameters of the machining process and transmits them to the CNC motion system for adjustments to ensure machining precision.

In detail, the operation of CNC machine tools can be divided into several steps:

  1. Program Creation

Machining programs composed of letters, numbers, and symbols are created based on the machining requirements of the workpiece and stored on storage media (e.g., floppy disks, hard disks, IC cards).

  1. Program Input

The stored machining programs are input into the CNC unit to create a control command system.

  1. CNC Unit Interpretation of Commands

The CNC unit, based on the instructions in the machining program, calculates motion trajectories, speeds, and machining parameters to generate a pulse sequence for driving motors.

  1. Servo System Drives Machine Tool for Machining

Upon receiving the pulse sequence from the CNC unit, the servo system sends currents to the motors as per instructions, driving the machine tool to perform actions such as spindle rotation and worktable movement.

  1. Detection System Monitors the Machining Process

The detection system continuously monitors various parameters of the machining process, transmitting them to the CNC unit for real-time adjustments.

  1. Output of Machined Products

Through the coordinated operation of these processes, CNC machine tools can precisely achieve high-precision machining according to programmed parameters and requirements.

In summary, the working principle of CNC machine tools involves precise control of the machine tool through the CNC unit, servo system, and detection system, enabling high-precision and efficient machining processes. As the manufacturing industry continues to develop, CNC machine tools will play an increasingly vital role in future production activities.