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 obtain high returns with lower investment. However, the high speed of the twin-screw speed brings a series of problems that need to be solved: if the material stays in the screw for a short time, it is easy to cause uneven mixing and plasticization of the material; excessive shear may cause the material to rise rapidly and thermally decompose; Extrusion stability problems occur; high-performance auxiliary machines and precision control systems are needed to match them; screw and barrel wear problems and reduction gear box design problems. Therefore, to provide solutions to the problems that may be brought about by high speed is one of the important directions of extruder screw manufacturers' technological innovation.
In terms of function, the twin-screw extruder is no longer limited to the molding and mixing of polymer materials, and its use has expanded to the fields of food, feed, explosives, building materials, packaging, pulp and ceramics. In addition, the "one-step direct extrusion process" that combines the mixing and pelletizing and extrusion molding processes into one is also very attractive.
Realizing the 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 relied on imports, and research on the localization of large-scale twin-screw pelletizing units is currently underway. Precision can increase the gold content of products, such as multi-layer composite co-extruded films. As an important means to realize precision extrusion, melt gear pump should be intensified for development and research.
Modular production can adapt to the special requirements of different users, shorten the research and development cycle of new products, and strive for a larger market share; while specialized production can arrange fixed-point production and even global procurement of various system module components of extrusion molding equipment. Ensuring the quality of the whole machine, reducing costs, and accelerating capital turnover are all very beneficial.
In addition to the technical transformation of the equipment itself, the advanced twin-screw extruder has generally adopted microcomputer control, the process parameters of the entire extrusion process such as melt pressure and temperature, the temperature of each section of the machine, the speed of the main screw and the feeding screw, the amount of feed, the ratio of various raw materials, the current and voltage of the motor and other parameters are monitored online and control, which is extremely beneficial to ensure the stability of the process conditions and improve the accuracy of the product.
