Plastic extruders can be divided into single-screw extr […]
Plastic extruders can be divided into single-screw extruders, twin-screw extruders and multi-screw extruders according to the number of screws. At present, the single screw extruder is the most widely used, suitable for the extrusion processing of general materials. Due to the fact that the twin-screw extruder has less heat generated by friction, the shearing of the material is relatively uniform, the conveying capacity of the screw is large, the extrusion volume is relatively stable, the material stays in the barrel for a long time, and the mixing is uniform.
The conical twin-screw extruder has the characteristics of forced extrusion, high quality, wide adaptability, long life, low shear rate, materials that are not easy to decompose, good mixing and plasticizing performance, direct powder molding, etc., temperature automatic control, vacuum exhaust Gas and other devices. It is suitable for the production of pipes, plates, special-shaped materials and other products.
The main symbol of the development of single-screw extruder lies in the development of its key part-screw. In recent years, people have conducted a lot of theoretical and experimental research on screws, and there have been nearly a hundred types of screws, the common ones are separation type, shear type, barrier type, split type and wave type.
From the perspective of single-screw development, although single-screw extruders have been relatively perfect in recent years, with the continuous development of polymer materials and plastic products, more characteristic new-type screws and special single-screw extruders will emerge. In general, the single-screw extruder is developing in the direction of high speed, high efficiency and specialization.
The twin-screw extruder has good feeding characteristics and is suitable for powder processing. It has better mixing, venting, reaction and self-cleaning functions than the single-screw extruder. It is characterized by processing and blending plastics with poor thermal stability. The material time shows its superiority.