Current situation and development trend of China's

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The current situation and development trend of China's extrusion industry

there are about 600 major plastic machinery manufacturing enterprises in China, including more than 100 extruder manufacturers. As the second largest category of plastic machinery products, the output of extruders accounts for about a quarter of the total output of plastic machines, second only to injection molding machines. The output and sales of existing extrusion molding units in China account for about 20 ~ 25% of plastic machinery, and the varieties of extruders account for 30% of plastic machinery. Most of the existing extruder manufacturers are private or township enterprises, mainly concentrated in Jiangsu and Zhejiang, Guangdong, Shandong, Liaoning and other coastal areas

status quo of extrusion equipment industry

the progressiveness of extrusion technology represents the development level of the plastic industry. Although there has been no breakthrough or revolutionary achievements in the international plastic machinery manufacturing technology in recent years, it has been rapidly improved and improved on the original basis, and there is still a certain gap between China's plastic machinery manufacturing technology and foreign developed countries. It is mainly reflected in the complete set capacity of the equipment, the processing level of the equipment and the application of technology. In recent years, the technological progress of plastic machinery in China is reflected in the accelerated development of new products and technologies, and the high starting point. The main way is to introduce, digest and absorb foreign advanced manufacturing technology

take pipe equipment as an example. Since the first aluminum-plastic composite pipe production line was introduced in the mid-1990s, more than 50 manufacturers have produced the equipment in five years. Its key technologies such as welding and lamination of aluminum pipes have been well solved, and the integrity and progressiveness of most products have reached the international advanced level

during the same period, the steel plastic compound vibration wear-resistant testing machine has been successfully developed. The specific use method is combined with advanced equipment such as gas PE pipe unit, and some key technologies have been solved, such as high-speed and high-efficiency single screw machine suitable for medium and high-density PE processing; High precision die head with good mixing effect, short residence time, no melting trace and advanced configuration of shaping, cooling, traction, cutting, thickness measurement, etc. In recent years, domestic extruders have also developed towards high torque, high speed and high efficiency, and have achieved certain results. Domestic extruders have also generally adopted advanced separation screws and slotting barrels. The internationally popular basket head and plate head suitable for polyolefin processing are widely used. Programmable devices and LCD touch screen industrial control computers have also been mature applications

the manufacturing technology of spiral die is gradually popularized in plastic film processing equipment, and the superposition die is popularized and applied. The multi-layer coextrusion film has reached 5 layers, and the geomembrane has adopted internal cooling technology, etc., and the width of coextrusion casting film has reached 2 meters

The second way is to strengthen the development of technology with intellectual property rights through technological innovation. Professor Jiangbo of Beijing University of chemical technology and Beijing Fengji Plastic Machinery Co., Ltd. have successively developed a grinding plate mixing extruder. Compared with traditional mixing equipment, it improves the mixing effect of material fineness and dispersion, expands the range of processing raw materials, and has significant advantages for processing magnetic, nano and other composite materials. The steel plastic composite profile extruder production line developed by Beijing Jiancheng Machinery Co., Ltd. also solves the key technologies of compounding, foaming, coextrusion, cutting and so on. Shanghai Jinwei extruder Manufacturing Co., Ltd. has developed a pet/gpet coextrusion line with a width of up to 2 meters

the improvement of the level of plastic machinery and equipment is also reflected in the fact that the complete set of equipment has been widely valued. Especially in extrusion molding, the concept of main and auxiliary machines has been deeply rooted for many years. Most manufacturers only provide main machines, and the proportion of main and auxiliary machines is out of balance. This situation has changed greatly. At present, most extruder manufacturers can provide a full set of extrusion production lines, and even undertake turnkey projects

the development of the international market is also an important symbol of the development of China's plastic machinery. One third of the enterprises' products have been exported, and the export volume has accounted for about 30% of the domestic sales volume, with an export growth rate of 20%

development and application of plastic pipes

the development of plastic pipes in the world has a history of 70 years, and the development of plastic pipes in China has a history of more than 50 years. At present, there are nearly 1000 plastic pipe production enterprises in China, with more than 3000 pipe production lines and a production capacity of more than 2million tons. The scale of enterprises is generally small, with a production capacity of less than 3000 tons/year, and there are only more than 30 10000 ton enterprises. In 2003, the sales volume of plastic pipes was about 1.5 million tons

according to the Tenth Five Year Plan of the national chemical building materials industry and the outline of the 2010 development plan, by 200, but as a printing material for five years, the promotion and application of plastic pipes are mainly UPVC and PE plastic pipes, and other new plastic pipes are vigorously developed. Plastic pipes have a market share of more than 50% of all kinds of pipes in the country

with the rapid growth of national economy, plastic pipes are increasingly used in construction, agriculture, environmental governance and other aspects. New technologies for various plastic pipes are emerging

Beijing University of chemical technology has introduced the precision extrusion technology of plastic pipes. Precision extrusion molding technology is a kind of molding process that realizes high precision of product size and high uniformity of material micro morphology by accurately controlling the elements of extrusion process. The fluctuation of technological parameters in the extrusion process is very small, and the working state of the extrusion equipment is stable, which can greatly improve the accuracy of pipe during extrusion, save about 2.4% of raw materials, and have obvious cost-effectiveness. Precision extrusion technology especially analyzes the evolution law of decarburized structure morphology. It is suitable for the production of medical plastic pipes with small pipe size, complex cross-section, multi-layer and multi cavity, and high precision requirements. At present, medical plastic catheters in China basically rely on imports. According to information, the cost of introducing catheters from abroad in a hospital in Beijing is nearly 300000 US dollars every year. It can be seen that the research and development of precision technology to produce domestic medical catheters to replace imports plays a positive role in promoting the development of medical technology in China

the problems existing in the development of plastic pipes in China are:

◆ the technical level of equipment is uneven, and the overall level is low. The degree of automation of the equipment is low, and the production capacity and control accuracy are poor. Some equipment processing enterprises only stay in the study of an imported equipment to imitate production and sales

◆ the production capacity ratio of plastic pipes and fittings is unreasonable. At present, the production capacity ratio of pipes and fittings is about 20:1, which is far from the normal ratio of 8:1, and there are few varieties of fittings. Generally speaking, the quality of pipes is slightly better, while the problems of pipe fittings are relatively more

technical progress of plastic profiled materials and plastic doors and windows

after 20 years of rapid development, China's plastic doors and windows industry has formed an industry with huge scale, mature technology, complete varieties and great potential

in terms of the molding process of profiles, the technologies of two-color coextrusion, two material coextrusion, wood plastic composite coextrusion, steel plastic composite extrusion, low foaming profiles, the first mock examination double strand extrusion and so on are basically mature. The surface decoration technologies of plastic doors and windows, such as film covering method, printing method, heat transfer printing, spraying method, etc., have also been localized

there are 4500 production lines of plastic profile production equipment in China, and the imported lines account for nearly one third. It gathers the equipment of world famous manufacturers from the 1980s to the 1990s, and is known as the "world factory". In 1978, China successfully developed the first parallel twin-screw extruder. The conical twin-screw introduced in the early 1990s made a sensation, and domestic plastic machinery manufacturers began to map and imitate. On the basis of digestion and absorption, various twin-screw profile equipment basically reached the level of the 1990s abroad. There are more than ten important domestic profile equipment manufacturers, which basically meet the domestic market needs

the technological gap between plastic profile extrusion die and foreign countries is narrowing. The mold structure includes European structure, American structure, and self-designed according to the national conditions. The quality of domestic molds has been continuously improved, and many manufacturers' molds have been sold abroad. In terms of processing means, the equipment level of several large-scale mold manufacturers in China is not much worse than that in foreign countries. They basically use CNC machine tool machining centers to realize the application of CAD-CAM integration. Some scientific research achievements have been made in the special CAD software technology for profile extrusion die design. For example, exmold CAD, a practical CAD system for plastic profile extrusion die developed by Hefei University of technology. The system successfully combines the rheological theoretical calculation of plastic profile extrusion die design with practical experience, and realizes the integration of calculation and drawing. While outputting the part drawings and assembly drawings of the die, it can also directly output the wire cutting processing data. It significantly improves the efficiency and reliability of mold design, and greatly shortens the mold design and manufacturing cycle. The z-swell software developed by the National Engineering Research Center of rubber and plastic mold of Zhengzhou University of technology realizes the effective combination of initial design, finite element/finite difference analysis, graphic processing and CAD technology of the mold. By analyzing the results, the mold design can be modified interactively, so as to obtain reasonable process parameters, processing parameters and die size in extrusion molding, avoid repeated mold trial and repair, improve the internal quality of products and reduce the mold cost

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