The status quo and development trend of CNC machining technology

Zhang Wei: Honorary Director, Doctoral Supervisor, Institute of Modern Manufacturing Technology, Tongji University

First, CNC is the core technology of modern machine tools

Traditional machine tools extend the physical strength of the human body and become the working machine. CNC technology gives the machine a brain, making the machine more and more "smart". CNC technology has evolved from passive execution of motion commands to the ability to “perceive” the machine's temperature, vibration, energy consumption, etc., and to adjust and control, measure workpiece size, tool breakage and predict tool life online, and prevent tool and moving parts from interfering. Even for the operator to navigate the voice or send a short message. The intelligent function of the CNC machine tool can ensure that the machine tool automatically adapts to the change of the machining environment, which makes the machine tool operation more convenient, the accuracy is more stable, and the efficiency is improved.

The five-axis linkage greatly expands the processing range of the machine tool, making it possible to process complex shapes and space curved parts, providing a broad prospect and space for structural innovation and optimization of various products. Composite machining can complete complex parts in one machine, avoiding workpiece handling and multiple clamping between processes, shortening the processing chain and improving the processing quality.

High-speed machining greatly improves machining efficiency, and high-efficiency machining considers high efficiency and high efficiency in addition to high efficiency. Automated system integration such as automatic skateboarding, robotic loading and unloading, flexible manufacturing units and systems is an important measure to further improve labor productivity and an important way for the sustainable development of the machine tool industry.

Linear motors and direct drives greatly simplify the mechanical transmission of the machine. The movement and rotation of the moving parts of the machine tool are directly provided by the servo motor, which significantly improves the dynamic performance of the machine tool, making the “zero-drive” machine tool a reality, and is more suitable for high-speed and high-precision machining.

The forward-looking control and trajectory smoothing technology of the CNC system, precise position and speed control technology, factory bus and network technology significantly improve the dynamic performance and control accuracy of the system, ensuring the high-speed, high-precision and multi-axis linkage stability of CNC machine tools. And reliability.

Second, the status quo of China's CNC machining technology

In recent years, China's CNC machining technology has developed rapidly, and domestic CNC lathes have fully met the needs of the domestic market. High-performance horizontal turning center and turning and milling center, through joint ventures, introduction of technology and independent development, some products have been able to meet some of the domestic high-end user requirements. However, the horizontal turning and milling combined machining center, the horizontal turning center with Y-axis or C-axis, the double-spindle horizontal turning center and the high-precision horizontal turning center still rely mainly on imports.

The domestic vertical machining center is relatively mature in technology, and its technical performance is close to the international level. There are many manufacturers and a certain batch, which has been recognized by domestic users. Due to the advantage in cost performance, the maintenance service cost is lower after the expiration date, which can basically meet the needs of the domestic market. The key now is to greatly improve the quality and reliability of products, and strengthen pre-sales and after-sales services.

Although the domestic horizontal machining center can meet the needs of the market, there is still a certain gap in accuracy and performance compared with similar foreign products. Most of the foreign horizontal machining centers are equipped with temperature compensation systems, which have high positioning accuracy and good precision retention. Therefore, in recent years, horizontal machining centers have imported more. In the high-speed machining center and five-axis machining center, many domestic companies have developed many new products. However, most of the products have not undergone rigorous production tests, and it is difficult to obtain universal recognition from users. Only individual varieties enter the production site of the enterprise. The key lies in the need to go through the production assessment of different types of users, and to continuously improve and improve. High-precision (sub-micron and nano-scale) machining centers are basically in a blank state, and most rely on foreign imports.