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With the Extruder application area continues to expand and advance technology The market for extruders still maintained a certain upward trend, but the price of domestic extruders fell sharply. The sloppy and vicious price wars of some manufacturers have affected the overall image and market competitiveness of domestic plastic machinery and hindered the development of the plastics processing industry.
Experts believe that the future market of extrusion machine mainframes and production lines will develop in the direction of high technology content and low price. From the point of view of molding equipment, the domestic mainframe is basically a conical twin-screw extruder and a single-screw extruder, with mature technology and large market sales. However, the general specifications of this product have exceeded demand and can only be maintained at around 50%-60% of the peak market. In the future, the domestic mainframe market should focus on the development of parallel and reverse twin-screw extruders to meet the needs of large-scale extrusion. Parallel co-rotating twin-screw extruders should be developed to the sixth and seventh generations of high-speed large aspect ratios. The single-screw extruder is developing in the direction of super large, ultra-miniature, large aspect ratio, high output and high displacement. The screw barrel structure adapted to the special processing needs has become the focus of research and development. In fact, the single-screw extruder is a low-energy, low-cost model. As long as the process is reasonable and the structure design is reasonable, the efficiency of the twin-screw extruder can also be achieved. According to reports, the plastic extrusion machines used in the United States are mainly single-screw extruders. High-tech single-screw extruders have gradually replaced twin-screw extruders in certain areas.
Special single-screw extruder
Recently, with the development of the market, various manufacturers at home and abroad have launched various special single-screw extruders to meet The special needs of the market. The following is a special introduction to the research and development of several special injectors in China.
The development of portable extruder is successful
The diameter of the screw is only 12 mm, the weight of the whole machine is less than 2.5 kg, and the working speed of the screw is 800-1200 rpm. Divided, continuous or intermittent work can be achieved. In addition, due to the large wall slip, the bridge is easy, the processed material is equipped with a specially designed forced feeding device, and a special multi-channel exhaust device is designed for the portable operation of the injector, which fully guarantees the discharge of the injector. the amount. gas. In addition, the machine also has the characteristics of deep groove, large pitch, electric and pneumatic driving modes, cleaning and maintenance.
The machine was originally designed to process a special low-density, low-viscosity material that can be used in the extrusion of various low-viscosity materials. Such as hot melt adhesives, low molecular weight resins, various paraffin waxes, fuels, pigments, cosmetics, and the like.
The research and development of micro-extruders has many unimaginable difficulties in the design and processing of general-purpose equipment. According to reports, the key to the development of the equipment lies in the solution of the feeding, exhaust and low-temperature extruder transportation problems.
Commercialization of Disc Extruder
Many domestic manufacturers have completed grinding discs The development of the ejector has realized the commercial production of the disc ejector.
It is difficult to process high fillers in conventional single or twin screw extruders. When glass fiber reinforced mixing is carried out using a twin-screw extruder, if the glass fiber content exceeds 45%, processing is difficult. In the processing of magnetic materials, the content of magnetic powder is usually as high as 60% to 70%, and sometimes even more than 90%. It is almost impossible to machine and granulate magnetic materials with ordinary extruders.
According to the needs of domestic magnetic materials and other high-fill materials, some domestic manufacturers and research institutes have independently designed wheel sprayers. Typical examples are Beijing Fengji and Beijing University of Chemical Technology.
The disc extruder can adjust the disc combination to suit the extrusion process of glass fiber reinforced, magnetic plastic, conductive materials, new ceramics and other high-fill materials. .
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