Detailed introduction





Innovative Technology Trends in Twin Screw Market

High speed, high efficiency and energy saving have been the main theme of continuous improvement of international plastic machinery in recent years. High speed and high output allow investors to get high returns with low input. However, the high speed of the screw brings a series of problems to be solved: for example, the short residence time of the material in the screw is easy to cause uneven mixing and plasticization of the material; Over-high shear may cause rapid heating and thermal decomposition of the material; Extrusion stability problems may occur; High-performance auxiliary equipment and precision control system are required to match it. Wear of screw and barrel and design of reduction transmission box, etc. Therefore, providing solutions to the problems that may be caused by high-speed is one of the important directions of technological innovation for twin-screw suppliers.
The new type of double introduced by the German company Belstoff (Berstorff).ScrewExtruder-ZEUTX series, performance is distinguished by an excellent screw diameter/productivity ratio. Screw design maximum speed up to 1200rpm, torque, extrusion capacity between 100~3500 kg/h. Can be carried out at the same time the material mixing, reaction, exhaust and other processes. The modular design of the barrel and screw can meet various special process requirements and has excellent process flexibility. It is also equipped with ZSEF side feeder, which can realize high solid particle conveying rate. The pelletizer can match different production rates and material processing.
In order to meet the needs of high speed and high yield, the extruder has many improvements. Equipped with a cartridge heater, the temperature rise of the extruder can be completed in a very short time, and the maximum heating temperature can reach 450 ℃; The cooling channel design truly realizes reverse flow cooling and optimizes the cooling system. Equipped with "bow clamping device", the time to replace the barrel can be faster than the traditional bolt connection type; The barrel adopts a patented high-frequency quenching and hardening process, giving it excellent wear resistance, this eliminates the need for expensive wear-resistant bushings; in addition, it is equipped with the company's advanced process control system.
In terms of function, the twin-screw extruder is no longer limited to the molding and mixing of polymer materials, and its use has been extended to the fields of food, feed, building materials, packaging, pulp and ceramics. In addition, the "one-step direct extrusion process" that combines the kneading granulation and extrusion molding processes is also very attractive.
WPC (Wood Plastic Composite) has been used for outdoor applications such as deck planking and fencing for quite some time, especially in the United States. The Cincinnati Company developed the Fiberex series specifically and continuously optimized it for WPC molding. The fourth generation Fiberex has an extended, wear-resistant processing unit, which can fully meet the different requirements of customers and achieve high output. At last year's NPE exhibition, Cincinnati company demonstrated the whole Fiberex pilot production line. the production line was equipped with a Fiberex T58 extrusion machine with a production capacity of 200 kg/h(440 lb/h), which was used to form PP compound with 75% wood flour filling. The production line manufactures a profile for the furniture industry with a wall thickness of 2.5mm and an extrusion speed of 2 m/min.
Large-scale and precision
The realization of large-scale extrusion molding equipment can reduce production costs, especially for large twin-screw pelletizing units, film blowing units, and pipe groups. In China, large-scale equipment has long been dependent on imports, and research on the localization of large-scale twin-screw granulating units is being carried out. Precision can improve the gold content of the product, such as multi-layer composite co-extruded film. Melt gear pump as an important means to achieve precision extrusion should increase efforts to develop research. Internationally renowned suppliers have a large number of mature technologies in the development of large extruders.
In order to meet the needs of different customers, JSW provides twin screw extruders with different specifications from TEX30 to TEX400. Its largest twin-screw extruder TEX400 has a barrel diameter of 443mm, a total length of 35m and a total weight of 320 tons.
Yanbu National Petroleum recently ordered a large twin-screw ZSK320 extruder from W & P, including motor, granulator and water cooling system, with a total value of more than 20 million euros. According to different polymer varieties and viscosity, the output of 25-50 tons per hour.
Cincinnati Extrusion Co., Ltd. in Vienna, Austria shipped to a customer in the United States in 2006 a to date the world's largest non-rotating parallel twin-screw extrusion machine. The output of this 30t giant machine can reach 2000 kg/h, which is an ideal equipment for high-speed production of PVC sheets.
Domestic research institutes have also done a lot of work in the research and development of melt gear pumps. Beijing University of Chemical Technology has developed several series of melt gear pump products.
Krauss-Maffei company 36D series twin screw extruder specially designed for PVC processing
Modularity and specialization
Modular production can adapt to the special requirements of different users, shorten the development cycle of new products, and strive for a larger market share; and specialized production can arrange fixed-point production or even global procurement of various system module components of extrusion molding equipment, which is very beneficial to ensure the quality of the whole machine, reduce costs and accelerate capital turnover.
Manufacturers will significantly reduce the cost of raw materials for PVC pipes by increasing the amount of filler. The engineering challenge is to ensure process stability and product quality. Krauss-Maffei 36D series parallel twin-screw extruders are designed for ideal PVC processing. They achieve the unity of high output and high mechanical properties of products, in addition, these extruders can provide high-quality pipes with stable quality.
In terms of processing high-filling formula, it is also feasible to process PVC sewage pipes by using 36D twin-screw extruder developed by Krauss-Maffei Company, with a filling amount of up to 65 parts (about 40%) of CaCO3. High-filled pipes with a diameter of 50 to 500mm are mainly used to transport sewage.
In order to make the processing of highly filled formulations easier, the extruder is equipped with a special material feeding, weighing and metering system. The PVC dry blend and CaCO3 are conveyed from the storage silo to the hopper of the weighing and metering device by means of a spiral feeding screw. A mixer and an agitator are installed in the hopper to prevent bridging. In addition, all surfaces of the metering device in contact with the material have a special coating to prevent the flow of material from being blocked. From the metering device, the material is conveyed to the feeding device located at the feeding port of the extruder under the action of the agitator and a special twin-screw feeder.
Intelligent and networked
In addition to the technical transformation of the equipment itself, the advanced twin-screw extruder has generally adopted microcomputer control. The on-line monitoring and control of the process parameters of the whole extrusion process, such as melt pressure and temperature, body temperature of each section, rotation speed of the main screw and feeding screw, feeding amount, ratio of various raw materials, current and voltage of the motor, are extremely beneficial to ensure the stability of the process conditions and improve the accuracy of the product.