Analysis of development trend of CNC plasma cutting technology at home and abroad

I. Overview

CNC plasma cutting technology is a high-tech integrating CNC technology, computer software, hardware technology, plasma cutting technology and precision machinery technology. The development of CNC plasma cutting machine can completely change the equipment level of the domestic thermal cutting industry, and reverse the current low efficiency, poor quality, high labor intensity, low material utilization rate, and dirty environment of the hot cutting industry. difference. At the same time, the development of CNC plasma cutting technology can bring relevant fields and disciplines to the international advanced level.

Flame cutting, plasma cutting and laser cutting are the three main methods of thermal cutting.

Flame cutting has large cutting deformation, can not meet the needs of high-precision cutting, and the cutting speed is low. It needs to be preheated before cutting, which takes time and is difficult to adapt to the needs of unmanned operation. Plasma cutting has a wide cutting range and can cut all metal sheets and many non-metallic materials. The cutting speed is up to 10m/min, which is 10 times that of flame cutting. Underwater cutting can eliminate the noise generated during cutting, dust, harmful gases and arc light, which is conducive to environmental protection and meets the environmental protection requirements of the 21st century. At present, with the maturity of high-power plasma cutting technology, the cutting thickness has reached 130mm, and the high-power plasma cutting with water jet technology has made the cutting quality close to the lower limit of laser cutting (±0.2mm). Because the laser cutting machine is expensive, and currently only suitable for thin plate cutting (usually long plate drilling time is long), the cutting precision of fine plasma cutting machine can reach the lower limit of laser cutting, the cutting surface quality is similar, but the cutting cost is much lower than the laser. Cutting, about 1/3, the maximum cutting thickness can reach 12mm, so the use of a fine plasma cutting machine to replace the expensive laser cutting machine, is conducive to the high-cost fine cutting of the medium and thin plates with larger dosage in the most economical way. . In addition, CNC plasma cutting and automatic nesting programming software can improve the material utilization rate by 5% to 10%, and cut 20 million tons per year, which can save 1 to 2 million tons of steel and worth several billion yuan. Therefore, in the industrialized countries, the development trend of replacing the flame cutting machine and the laser cutting machine with a numerical control plasma cutting machine has appeared. Therefore, research and promotion of CNC plasma cutting technology is of great significance.

Second, the development of China's CNC plasma cutting technology

China's CNC flame cutting technology started in the mid-1980s, while the CNC plasma cutting machine is even later. Most of the CNC plasma cutting machines are based on economical machine tools (microcontrollers as the core and stepper motors as the driving components). At present, there were more than 50 manufacturers engaged in the manufacture of CNC cutting machines in China, and the power was scattered. Many of the manufacturers' predecessors were welding and cutting tools factories with poor technical foundation. Throughout the 1980s, domestic companies were unable to compete with foreign companies in terms of product structure and production scale.

After entering the 1990s, some domestic companies aim at the world's advanced level, and constantly develop new products for CNC cutting machines, and the main technical indicators of some products have reached the advanced level of similar foreign equipment, and with the regulation of the market economy, currently Domestic manufacturers of CNC cutting machines have been adjusted to more than 20 companies. But the comprehensive strength and competitive strength are only Messer Cutting & Welding Co., Ltd., Shanghai Isahan Co., Ltd., Harbin Huasheng Welding and Cutting Equipment Co., Ltd., Harbin Sihai CNC Machinery Manufacturing Co., Ltd., Shenzhen Bo Lichang CNC Cutting Equipment Co., Ltd., Wuxi Hualian Welding and Cutting Equipment Factory, Beijing Baihui Hongda Technology Co., Ltd. and so on. They generally have independent research and development capabilities, large scale production, complete product specifications, variety, quality and stability, and high credibility. Therefore, in the bidding activities often win, the single output is generally more than three or forty units, and some even exceed one hundred. Of course, some enterprises have their own characteristics, but they can adapt to the needs of different enterprises.

Some CNC plasma cutting products in China have formed their own unique characteristics in many aspects, achieving "automation, multi-function and high reliability". In some respects, the technical performance of the product even exceeds that of foreign products, as reflected in:

1. Electromagnetic compatibility technology between numerical control system and plasma system
This is the key to the success of CNC plasma cutting machines. Only by solving this problem can we achieve plasma cutting under digital control.

2. Special control software that meets the requirements of thermal cutting process

The characteristics of this type of control software are as follows:

(1) Adopting graphic input mode, it is more intuitive than code input, and the operation is quick and convenient.
(2) Chinese interface, more suitable for China's national conditions.
(3) Diversified input methods, all control instructions.
(4) Using automatic nesting programming software, the utilization rate of the board can be increased by about 10%.

3. High power plasma system

The system has a 100% duty cycle and a complete CNC interface, arc voltage interface, remote control interface, and provides a full set of interface accessories, thus achieving a close integration with the CNC system.

Third, the development status of foreign CNC plasma cutting technology

The manufacturers of foreign CNC cutting machines are mainly concentrated in Germany, the United States and Japan. Its main manufacturers are Germany's Esa (E SAB), Messer (MESSER), Japan's Tanaka (TANAKA), Koike (KOIKE), the United States' L-TEC, Linde (LINDA) and so on. The manufacturer who can represent the highest level of CNC plasma cutting technology is concentrated in Germany. The CNC cutting machine in Isa, Germany is the most complete, most functional and highest level in the world, including almost all non-contact cutting tools. The NEC520 continuous trajectory controller can be used with the RPC600 (single or dual parallel) water jet plasma system to cut metal sheets up to 130mm; with the HD3070 fine plasma, high speed (7.6m/min) can be applied to 1~12mm metal materials. High precision (near laser cutting lower limit) cutting.

The above configuration represents the highest configuration of the CNC plasma cutting machine, and its main features are as follows:

(1) The whole process of automatic cutting, ie plasma cutting (such as initial positioning, arc striking, perforation, cutting, heightening, lifting water, etc.) is completed under the control of CNC, and its parameters can be modified by programming.
(2) Multi-function means increasing the flexibility of CNC machine tools by adding different accessories, and providing positioning, welding and storage basis for the next process. For example, the marking function provides installation and positioning benchmarks. Plasma cutting can be used for X, V, Y and K shape beveling, and not only can the straight groove be completed, but also the curved and arc-shaped groove can be completed, which is convenient for welding.
(3) Underwater cutting can effectively reduce the thermal deformation of the steel plate and fully suppress dust, arc, noise and splash.

The Hypertherm Plasma System represents the highest level of plasma systems in the world today, and its product specifications cover all plasma plasma cutting systems from ordinary plasma, water jet plasma to fine plasma. Ordinary plasma power supply output current is 20 ~ 200A, cutting thickness can be less than 50mm; water jet plasma power supply output current up to 1000A, cutting thickness up to 130mm; fine plasma power supply output current up to 100A, cutting thickness up to Below 12mm, the fine plasma slit is 0.65~0.75mm wide, and it can match the cutting precision of ±0.2mm with the CNC cutting machine.

Fourth, the domestic gap in digital plasma cutting technology and foreign countries

90% of the cutting industry in developed countries is CNC cutting machine cutting, only 10% is manual cutting, while China's CNC cutting machine only accounts for less than 10% of the total amount of blanking, of which CNC plasma cutting ratio is smaller. Most of them still use manual or semi-automatic cutting, which is cumbersome and backward, labor intensive, low in production efficiency, and material waste is serious. Therefore, it is very necessary to develop and popularize CNC plasma cutting machines to change this backward situation.

Regarding the gap between domestic CNC cutting machines and foreign products, there is no big gap in the numerical control flame cutting machine, and the performance is relatively stable. Only the domestic cutting machine guarantees the quality, and some main components such as electromagnetic valve and pressure reducing valve. Imported parts are used in AC servo systems, and the quality of domestic parts is still unstable. The total performance of CNC plasma cutting machine is also similar to that of imported equipment. However, the plasma power supply matched with CNC plasma cutting machine has a larger gap with foreign countries. At present, many users are willing to use imported plasma power supply to explain the problem, so the development of CNC plasma cutting Related technologies are also very important.

In short, there is still a certain gap between domestic and imported from the quality of the incision and the durability of the wearing parts. Therefore, in order to completely replace the import, we must work hard on the production of the basic parts.

V. Market and application prospects

Before the early 1980s, the domestic market of CNC cutting machines was all occupied by foreign cutting machines. In the mid-to-late 1980s, domestic CNC cutting machines were gradually produced and put on the market. In the early 1990s, with the development of domestic CNC cutting machines, the market expanded rapidly. Forcing foreign companies to develop in China, the price of cutting machines has also dropped significantly. In the late 1990s, the quality of domestic CNC flame cutting machines has stabilized and the price has dropped significantly compared with previous years. Therefore, imported machines have been gradually replaced.

As China's industry moves toward modernization, the demand for CNC cutting machines in the domestic market has increased year by year. In addition, due to the large number of CNC flame cutting machines in developed countries, the popularization of CNC plasma cutting machines is subject to certain restrictions. Machine technology started and applied late, forming a gap between supply and demand, which led to huge potential market for CNC cutting machines, especially CNC plasma cutting machines.

According to statistics, in recent years, the market demand for CNC plasma cutting machines in China is about 500 per year, and there is a trend of increasing year by year. The economic development of China's surrounding areas has shown us a good international market prospect. At present, the development trend of CNC plasma cutting machine should be developed in the direction of automatic, multi-functional, high-power and high-quality.

Conclusion

In the 21st century, China's CNC cutting industry faces various new challenges, and the international market is more competitive. We should aim at the world's advanced level, continuously develop new products, and promote the general improvement of the domestic technical level in the same industry. Only in this way can we eliminate low-grade and inferior products, purify the market, and drive industry manufacturers to change their business philosophy. At the same time, we must strengthen scientific research and development and technological innovation. Working hard with quality management, China's CNC cutting industry has quickly reached the world's advanced level, thereby revitalizing national industry and improving China's overall national strength.

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