Development of rubber extruder plunger extruder
Screw hot feed extruder
Ordinary cold feed extruder
Cold feed exhaust extruder
Pin cold feed extruder
Compound extruder
The ternary compound extruder composed of MC T D-9 0, M C T D- 1 5 0 and MC T D-2 0 0 has the characteristics of small volume and energy saving of 20%, and is used in tire turning in North America. Although MC T and MC T D extrusion technologies have introduced many advantages in the publicity of developers, not all MC T extruders are successful. Mct 95/50/503 compound equipment was introduced in China, which was originally planned to be used to extrude tire tread, but failed due to uneven plasticization. According to the opinion of the German company T r o e s t e r, this design is unsuccessful.
Application status of rubber extruder in China
With the appearance and wide application of cold feed extruder, the application range of hot feed extruder is gradually reduced. Rubber extruder has developed from hot feed to cold feed, and cold feed pin extruder has become the mainstream of development. At present, pin extruder has been widely used in China's rubber industry, involving tire tread, radial tire sidewall, bead rubber, various hoses and lining film. The machine platform used is imported from China, with a screw diameter of 85 ~ 250 m and an aspect ratio of 1.2 ~ 1.6. Compared with hot feed extruder and common cold feed extruder, pin cold feed extruder has many advantages. In recent ten years, it has been widely used in China's rubber industry, and its uses have been expanding. The needle-type cold feed extruder introduced in China in the early days is mainly used for the rubber core and rubber coating production process of radial tire tread rubber extrusion and rubber hose production. At present, most semi-steel and all-steel tire treads are produced by pin cold feed extruder. In the production process of rubber products such as bias tires, many manufacturers have adopted pin-type cold feed extruder. In the production of rubber industry, the traditional production process is to use extruder as molding extrusion equipment, while the pin-type cold feed extruder is widely used for rubber supply for steel wire, fiber cord calendering and airtight film calendering because of its large extrusion capacity and good plasticizing effect. In recent years, pin-type cold feed extruder is also widely used in rubber filtration, which is well received by users. Pin-type cold feed internal compound extruder has also been widely used in radial tire production and has become the key equipment in radial tire production. Although some enterprises still use external compound extrusion technology in production, with the improvement and update of new technology and new process and the development of market economy, the old production technology and equipment will be eliminated, and internal compound extruder is the inevitable development direction of compound production technology. However, at present, hot feed extruders still account for a large proportion in China's rubber industry production enterprises. According to incomplete statistics, about 70% of the production process of hot-feed extrusion with rubber supplied by an open mill is used in China. Many old rubber production enterprises in China use extrusion equipment from 1950s, and the technical equipment is backward. Some enterprises think that the old extrusion equipment has certain advantages, such as the good dispersion of the mixed rubber in the open mill, good operability and skilled operators, but the advantage of the pin cold feed extruder is greater than that of the hot feed extruder. Pin cold feed extruder represents the development direction of rubber extruder and has great development potential. It can be seen that there is still a lot of room for further popularizing the use of pin-type cold feed extruder in the technological transformation of extrusion process in rubber production enterprises in China.
[Edit this paragraph] Development trend of rubber extruder
Screw is developing to multi-screw.
The meshing area of screw extruder has a large speed gradient, so the meshing area is beneficial to the full mixing of materials. The number of meshing zones of twin-screw, linear three-screw, triangular three-screw and four-screw extruders is 1, 2, 3 and 4 respectively. With the increase of the number of meshing areas, the mixing ability of materials is gradually enhanced. Triangular three-screw and four-screw extruders have a special structure-central area. The circulation of materials in the central area promotes the mixing of materials in the central area and increases the mixing time of materials in the central area. After analysis, the material will not stay in the central area. The flow rate, reflux rate, reflux coefficient and average shear rate of twin-screw, linear triple-screw, triangular triple-screw and quadruple-screw extruders increase gradually in turn, which proves theoretically that multi-screw extruders have good production capacity in material conveying capacity and material mixing capacity, and multi-screw extruders are more suitable for polymer processing.
Multichannel transfer mixing screw (MC T) extruder
MC T extruder is divided into feeding section, transfer mixing section and discharging section along the axial direction of screw. In the transfer mixing section, the inner walls of the screw and the barrel have opposite spiral threads. The number of runner on the screw increases, and the thread depth decreases. After reaching an extreme value in the middle of the mixing transfer zone, it gradually returns to its original state. In the process of increasing the number of flow channels in the inner wall of the cylinder, the number and depth of flow channels are opposite to those of screws. There are essential differences between MC T extruder and ordinary cold feed screw extruder. Ordinary screw extruder plasticizes by friction, while the plasticization of rubber in MC T extruder depends on mechanical action, and the friction is very small, so the screw length of MC T extruder is much shorter than that of ordinary extruder, only about 7 times of the screw diameter. MC T extruder can be used not only to produce easy-to-extrude rubber compounds and semi-finished products such as truck tire tread compounds, but also to produce materials with high synthetic rubber components that are difficult to extrude, with good surface quality and corner shape of outer contour. The screw of M C T extruder is shorter than that of ordinary extruder, so it is easy to combine two or three MC T extruders together to realize "compounding" and co-extrusion of complex products. For example, a "ternary compound" extruder consisting of a 9 5 mm main MC T extruder and two 50 m auxiliary MC T extruders can be used. Because the plasticizing mixing zone of MC T extruder is very short (about 2.5 D), there is no obstacle interference element in the flow channel, the screw wing and the flow channel have a boosting effect on the material, and the temperature rise of the material in the machine is low, so that the screw rotates at high speed and the production capacity is large. Generally speaking, MC T extruder is equipped with temperature regulating ports in screw, die, bearing and feed area. Under the same temperature rise condition, the production capacity of MC T extruder is greater than that of pin barrel extruder, even greater than that of smooth barrel extruder. At the end of 1990s, hundreds of MC T extruders have been put into use all over the world. In North America alone, there are more than 65,438+0,000 extruders for hot and cold tires. In addition, with the extruder/molding machine of CTC-SBI and CTC-SBII, MC T is directly extruded onto the carcass, which not only improves the quality, but also saves manpower and material resources. 2 5 4 m m/m MC T After industrial test, German Rubber Technology Institute began to explore the use of ultrasonic wave to reduce the viscosity of elastomer in the late 1990s, in order to solve the shortage of MC T extruder in extrusion quality, output and energy saving for common industrial rubber compounds. Major rubber extruder manufacturers in Europe and America will take the development of MC T extruder as a new direction. In recent years, the focus of development is the improved MC T extruder. The third generation M C T extruder MC T D and pin-type MC T extruder may be the future development direction, especially the pin-type M C T extruder has the advantages of pin screw extruder and MC T extruder, and has broad market prospects and development space.
The nose is developing in the direction of multi-compounding.
Extrusion head is the key component to determine the final quality of extruded products. The traditional single-screw extruder head can only be used to extrude products with a single kind of rubber compound. The head structure is relatively simple, the head pressure is relatively low, and the technical problems are easy to deal with. With the development of extrusion technology and the need of production, the structure and technology of extruder head have made great progress compared with that of more than ten years ago, especially in tire production, it is required to use mixed rubber with different properties to extrude components such as tread, sidewall and triangle rubber in the head. Therefore, since the 1960s, the German company T r o e s t e r and the German company B R S T O R F have first developed double compound extruder heads for extruding two kinds of rubber compounds. By the 1980s and 1990s, three kinds of compound extruder heads and four kinds of compound extruder heads have been developed, and five kinds of compound extruder heads are currently being developed, and the products will come out soon.
New driving technology of high-power hydraulic motor and its application
With the improvement of performance requirements of extruder and the progress of driving technology, many changes have taken place in the driving system of extruder. The traditional AC motor constant speed drive, commutator motor variable speed drive and AC motor gearbox step speed drive have been eliminated in modern extruders at home and abroad, and replaced by DC motor stepless speed change drive. DC motor has good low-speed torque performance and wide speed range. Domestic DC motor has reached the international first-class level with the support of Siemens technology, and has been widely used in various cold feed extruders. Sweden's Ha g g l u n d s D r i v e r s A B company began to produce high-power hydraulic motors more than 30 years ago, which have been used in the drive systems of high-power equipment such as mill, internal mixer, twin-screw extrusion tablet press and calender, and also in the drive systems of rubber screw extruder. Because the development of domestic hydraulic technology is relatively backward, there is no large torque hydraulic motor and the imported matching is expensive, so this driving technology has not been used in domestic screw extruder so far.
Intelligent networked control system
Extruders in developed countries have generally adopted modern electronic and computer control technology, and the process parameters of the whole extrusion process, such as melt pressure and temperature, body temperature of each section, rotation speed of main screw and feeding screw, feeding speed, various raw material ratios, motor current and voltage, are detected online, and closed-loop control is adopted by microcomputer. Some companies have adopted online remote monitoring, diagnosis and control to control the extrusion production line. This is very beneficial to ensure the stability of process conditions and improve the accuracy of products. With the compounding of extruder, its mechanical properties are bound to be more complicated, and the corresponding control system is also more complicated and the control accuracy is higher. Therefore, how to design a suitable control system to ensure its economic, safe and reliable operation and not become an outdated or transitional product in a short time is a problem that our engineering designers must consider. In the control of multiple compound extruders, the bus technology and network structure are simple and the technical performance is stable, which not only greatly reduces the number of wires and is convenient for installation, debugging and maintenance, but also greatly enhances the flexibility and reliability of the system, and achieves good social and economic benefits while ensuring the advanced nature of the system.
Small shrinkage deformation, high dimensional accuracy and fast extrusion speed.
With the development of new screw extruder in internal mixer and the continuous maturity of compound co-extrusion technology, the rapid development of rubber industry in recent years has promoted the rapid improvement of rubber extrusion technology in China. Among them, radial tire co-extrusion technology is a typical representative of rubber extrusion technology.
Need to develop precision extrusion technology
Extrusion molding is an efficient, continuous, low-cost and widely applicable processing method, but people mistakenly think that extrusion molding is a processing method with low precision and low added value. With the increasing market demand for various high-precision products such as optical fiber, medical catheter, audio-visual film base, photographic film base and projection film, the requirements for precision extrusion molding equipment and technology are becoming higher and higher. For some special processing and molding, such as the processing of some dangerous and toxic materials and the process of reactive extrusion, it is necessary to strictly control the process parameters such as temperature, pressure, residence time and distribution of materials, heat transfer between the corresponding materials and the outside world, which are often beyond the competence of ordinary extruders. Precision extrusion molding machine provides necessary equipment for various complex reactive extrusion processes. At present, there is still a big gap between domestic manufacturers and the world advanced level in high-speed precision equipment. Experts believe that there is a gap of 1.5-2 o years between the actual level and the processing level of high-yield extrusion equipment and the advanced level abroad. There is also a big gap in real-time monitoring of process parameters and product parameters, and the adoption of advanced control technology. Advanced high-precision on-line detection instruments mainly rely on imports, with few domestic products, and the gap with foreign products is more than 1 O years. Generally speaking, the precision extrusion molding equipment in China is still in its infancy, which has great development space.
Modularization and specialization of extruder design
Modular production can meet the special needs of different users, shorten the research and development cycle of new products and strive for greater market share; And "specialized" production can arrange fixed-point production and even global procurement of each system module of extrusion molding equipment, which is very beneficial to ensure the quality of the whole machine, reduce costs and accelerate capital turnover.
[Edit this paragraph] Conclusion
Since the advent of pin cold feed extrusion technology, extruder manufacturers at home and abroad are still exploring new extrusion technology. But so far, both MC T D, gear pump extrusion technology and other extrusion technologies have certain advantages, but they are not dominant in increasing output, reducing glue temperature and reducing energy consumption. On the contrary, because of their complex structure and difficult maintenance, they are difficult to be accepted by users, so they do not have the advantages of standard models in practical use. In the future field of extrusion technology, pin cold feed extrusion technology will still occupy a dominant position. At the same time, China's compound extrusion technology is becoming more and more perfect, which can completely meet the needs of different users.
[Edit this paragraph] References
[1] translated by He Min. The latest development of extrusion technology for tire parts. Modern rubber technology [J], 2002,28 (4): 48-51. [2] Zhao Guangxian Development trend of rubber extrusion equipment and technology [J]. Rubber Industry, 2002,49 (7): 434-437. [3] Sue peace. Technical characteristics analysis and research progress of multi-channel transmission mixing screw rubber extruder. Journal of Inner Mongolia University for Nationalities (Natural Science Edition) [R], 2005,20 (2):176-179. [4] 182- 185, [5] Han Fucheng. General situation of extruder development in China. Rubber Technology and Equipment [J], 2004,30 (4):19-21. [6] Yang Shungen. Review on the development of rubber extrusion technology in the world. 2005,32 (11): 36-39. [7] Yuan, et al. Technical progress and development of rubber extrusion equipment. Rubber and plastic technology and assembly [J], 2006,32 (2):1/kloc-0.
[Edit this paragraph] Rubber machinery
Used for manufacturing various rubber products such as tires, including general rubber machinery, tire machinery and other rubber products machinery. General rubber machinery is a machine for preparing rubber or semi-finished products, including raw material processing machinery, rubber mixer, extruder, calender, cord fabric pretreatment device, cutting machine and so on. Rubber mixers are divided into open and closed types. Open rubber mixer is mainly used for rubber hot refining, tabletting, rubber breaking, plastic refining, mixing and so on. The open rubber mixer began to be used in production in 1826, and its structure is relatively simple, and it is still widely used in modern times. The closed rubber mixer is mainly used for plasticizing and mixing rubber, and has one more mixing chamber than the open rubber mixer. Since 19 16 invented the closed rubber mixer with oval rotor, the closed rubber mixer has developed rapidly in the rubber industry, and later closed rubber mixers with other rotors appeared. The mixing cycle of modern internal mixer is 2.5 ~ 3 minutes, and the maximum capacity of mixing chamber is 650 liters. Extruder is a rubber machine used to extrude tread, inner tube, rubber hose and various rubber strips, and also used to coat cable and wire products. Common is the screw extruder. When working, the rubber material is stirred, mixed, plasticized and compacted in the barrel with the help of the rotation of the extrusion screw, and then moves to the die, and finally the product with a certain shape is extruded from the die. Calender is mainly used for bonding or wiping curtain canvas, pressing, laminating and embossing rubber compounds. 1857 made the first calender and put it into production, and has been continuously improved since then. Especially since 1950s, the development of plastic industry has strongly promoted the development of high-precision and high-speed calender. Tire machinery includes tire forming machine, tire traveler machine, tire setting vulcanizer, capsule vulcanizer, cushion belt vulcanizer, inner tube joint machine and inner tube vulcanizer, as well as power tire machine, tire retreader and reclaimed rubber production machine. More than 60% rubber in the world is used to make tires, so tire machinery plays an important role in rubber machinery. Tire forming machine is mainly used to process suspended rubber cord fabric, traveler, tread and other components into tire blanks. According to different uses, it can be divided into two categories: ordinary tire building machine and radial tire building machine. The whole process of radial tire molding is completed by a molding machine, which is called one-step molding method; The carcass is made of modified ordinary tire building machine and then molded on radial tire building machine, which is called two-stage molding method. Tire setting vulcanizer is a machine used to vulcanize pneumatic tires such as automobiles, engineering vehicles, tractors and airplanes. This machine appeared in the 1940s. The operations of tire loading, tire setting, vulcanization, tire unloading and cooling after inflation can be completed on the setting vulcanizer. The temperature, pressure and steam chamber temperature of superheated water in the capsule can be measured, recorded and controlled, and the whole production process can be automatically carried out. Other rubber products machinery includes machinery used to manufacture adhesive tapes, hoses, rubber shoes, model products, adhesives and latex products. At present, among the top 32 companies in the world, Kobe Steel Works, VMI Company of the Netherlands, Jingyuan Company of Taiwan Province and Dongyu Hydraulic Company have all set up joint ventures or wholly-owned enterprises in Chinese mainland. In addition to the top 32, there are more than 10 foreign-funded rubber machinery enterprises in China, such as Shanghai Ximaweili, Anhui Panshi, Shenzhen Jiaxin Electronic Equipment Technology, Qingdao Guangxu and Yadong, Guilin Yinhe, Jianyang Longxiang, Guangdong Huada, Shaoxing Jingcheng, etc. Most of them are small professional factories. In addition, Slovak Matado and Qingdao University Soft Control have carried out technical cooperation to jointly develop radial tire calendering, extrusion, cutting and molding equipment. RMS Canada and Dalian Iceberg Rubber & Plastic Co., Ltd. jointly produce a three-compound extrusion production line, and Ishikawa Shimada Heavy Industry and Dalian Iceberg Rubber & Plastic Co., Ltd. jointly produce a steel cord calender. Peleg and Qingdao University jointly distribute, assemble and maintain internal mixers. In 2006, Qingdao Global Group and Indian L & ampt Company jointly invested and established Lasenboro (Qingdao) Rubber Machinery Co., Ltd. ... From 65438 to 0995, Kobe Steel Works successively settled in China, and carried out various forms of cooperation in production, technology, capital and marketing. Most of these enterprises have developed rapidly and achieved impressive results. For example, the sales volume of Shanghai Jingyuan Machinery has surpassed the headquarters of Taiwan Province Province, ranking 13 in the world, and the sales volume of Yantai Feimai (VMI) machinery has accounted for more than 1/4 of the total VMI in the Netherlands. 80% of Hunan Yishen's products are exported, and it has become the main overseas rubber machine enterprise of Kobe Steel in Japan. With the commissioning of Ningbo Dongyu, Taiwan Province Dongyu Oil Pressure consolidated the leading position of Pingla vulcanizer in Asia. After the cooperation between Slovak Matado and Qingdao University Soft Control, the sales of all-steel tire building machine in China increased greatly, becoming the most active enterprise in Central Europe, and in 2006, it entered the 22nd place in the rubber machine world. In addition, Krupp, Belstoff, VMI, Mitsubishi Heavy Industries and other top global rubber machinery 10 all have permanent offices in China, followed by Daisuke Manufacturing Co., Ltd. and Nakata Manufacturing Co., Ltd. other than the top 32. Dafan and Microelectronics also set up corporate companies. China is the largest rubber machinery producer in the world, the fastest developing region of rubber machinery in the world, and is becoming the center of rubber machinery in the world.