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With the continuous expansion of the extruder application field and the continuous progress in technology, the extruder market still maintains a certain upward trend, but the price of domestic extruder has fallen substantially.Crudely produced by some manufacturers and vicious price war have affected the overall image and market competitiveness of domestic plastic machines, but also hindered the development of plastic processing industry.Experts believe that the extruder host and production line in the future market will be high-tech content, the price of the direction of lower development.From the perspective of molding equipment, domestic main machines are mainly conical twin screw extruder and single screw extruder, with mature technology and the largest market sales. However, the supply of general specifications of this kind of products exceeds the demand, which can only maintain at about 50%~60% of the peak market.The main engine market in China should focus on the development of parallel and opposite twin screw extruders in order to meet the needs of large amount of extrusion.Parallel twin screw extrusion machine to the sixth generation, the seventh generation of high-speed, large aspect ratio direction development.Single screw extruder is toward the super large, super miniature, large aspect ratio, high output, good exhaust and other directions, and adapt to the special processing needs of the screw barrel structure, has become the focus of research and development.In fact, the single screw extruder is a kind of low energy consumption, low cost model, as long as the technology is proper, reasonable structure design, can also achieve the efficiency of the twin screw extruder.According to the introduction, the United States is now using the plastic extruder on the single screw.The high - tech single - screw extruder is gradually replacing the double - screw extruder in some fields.With the demand of market development in recent years, different manufacturers at home and abroad have introduced various kinds of special structure of single screw extruders to meet the special market needs.The following introduces the research and development progress of several special extruders in China.Beijing University of Chemical Technology has successfully developed an ultra-high speed miniature portable single screw extruder.The screw diameter of the machine is only 12mm, the total weight of the machine is less than 2.5kg;Screw working speed of 800~1200rpm, can achieve continuous or intermittent work.In addition, due to the processing of materials with high wall slippage and the characteristics of easy bridging, with a specially designed forced feeding device;Because the extruder is a portable operation, a special multi-channel exhaust device is designed to fully ensure the discharge of gas.In addition, the machine also has deep groove large pitch, two kinds of drive mode optional (electric, pneumatic), the machine is easy to clean, maintenance, repair and other characteristics.The machine is originally designed for processing a special kind of low density and low viscosity material, and can be used for various low viscosity material extrusion processing, such as hot melt adhesive, low molecular weight resin, various paraffin wax, fuel, pigment, cosmetics, etc.The research and development of super micro extruder, there are many difficult to imagine in the process of general equipment design and processing, according to the introduction, the key of the development of the equipment lies in the micro extruder feeding, exhaust, the realization of low temperature extruder transportation and other problems to solve.A number of domestic manufacturers have completed the development of the mill disc extruder, to achieve the commercial production of the mill disc extruder.It is difficult for high filling material to be processed by single screw or double screw extrusion machine.When the twin-screw extruder is used for the glass fiber reinforced blend, the processing becomes very difficult if the glass fiber content exceeds 45%.In the processing of magnetic materials, the amount of magnetic powder is usually as high as 60%~70%, sometimes even more than 90%.It is almost impossible to process and granulate magnetic materials with ordinary extruders.Some domestic manufacturers and research institutes, according to the needs of domestic magnetic materials and other high filling materials, carefully developed an independent design of grinding disc extruder.Typical examples are Beijing Fengji and Beijing University of Chemical Technology.The grinding disc extruder can adjust the grinding disc combination to adapt to different high filling materials, such as glass fiber reinforced, magnetic plastics, conductive materials, new ceramics and other materials.In order to meet the needs of high filling material extrusion processing, Beijing University of Chemical Technology is also conducting the experimental research on the direct extrusion molding of grinding disc extrusion machine, and has been successfully applied to a variety of composite materials extrusion processing experiments.Reciprocating screw extruder Series Reciprocating screw extruder in the past few years in the domestic market is booming, but also become different manufacturers show the technical strength of a symbol of the product.In particular, the twin screw extruder manufacturers have introduced reciprocating screw extruder.Because the twin-screw market is extremely hot, the reciprocating screw extruder market is relatively flat, the manufacturers or to push the twin-screw extruder as the main product.The most important characteristic of the reciprocating moving single screw extruder is to realize the high filling processing of different materials.Used in the processing of glass fiber reinforced materials, the amount of glass fiber can reach more than 50%, especially suitable for the processing of high filling materials, has a very broad market prospect.Because of its unique reciprocating structure, it can not well meet the requirements of construction pressure, so it is generally not suitable for direct extrusion molding of products.Usually used for molding processing, but also need to be equipped with a special molding extrusion machine.
