Classification of auxiliary equipment for plastic extruders

Plastic extruders are divided into twin-screw extruders and single-screw extruders.
The difference between the two extruders:
Single-screw machines and twin-screw machines: one is one screw, the other is two screws. Both are driven by one motor. The power varies depending on the screw. The power of 50 cone twin is about 20kW, and that of 65 is about 37kW. The output is related to the material and the screw. The output of 50 cone twin is about 100-150kg/h, and that of 65 cone twin is about 200-280kg/h. The output of a single screw is only half.
Extruders can be divided into single-screw, twin-screw and multi-screw extruders according to the number of screws. Today, single-screw extruders are the most widely used and are suitable for extrusion processing of general materials. Twin-screw extruders have the characteristics of less heat generated by friction, more uniform shearing of the material, larger screw conveying capacity, more stable extrusion volume, longer material retention in the barrel, and uniform mixing.
SJSZ series conical twin-screw extruder has the characteristics of forced extrusion, high quality, wide adaptability, long life, low shear rate, material is not easy to decompose, good mixing and plasticizing performance, direct powder molding, etc., temperature automatic control, vacuum exhaust and other devices. It is suitable for the production of products such as pipes, plates, and special-shaped materials.
Single-screw extruders occupy an important position as both plasticizing and granulating machinery and molding processing machinery. In recent years, single-screw extruders have made great progress. The large-scale single-screw extruder for granulation produced in Germany has a screw diameter of 700mm and an output of 36t/h.
The main sign of the development of single-screw extruders lies in the development of its key parts-the screw. In recent years, people have conducted a lot of theoretical and experimental research on screws. There are nearly 100 types of screws now, including separation type, shear type, barrier type, diversion type and wavy type.
From the perspective of single-screw development, although single-screw extruders are relatively complete, with the continuous development of polymer materials and plastic products, more characteristic new screws and special single-screw extruders will emerge. Generally speaking, single-screw extruders are developing towards high speed, high efficiency and specialization.
Twin-screw extruders have good feeding characteristics and are suitable for powder processing. They have better mixing, exhaust, reaction and self-cleaning functions than single-screw extruders. They are more superior when processing plastics and blends with poor thermal stability. In recent years, foreign twin-screw extruders have made great progress. Various forms of twin-screw extruders have been serialized and commercialized, and there are many manufacturers. They are roughly classified as follows:
⑴ According to the relative position of the two axes, there are parallel and conical types;
⑵ According to the meshing process of the two screws, there are meshing types and non-meshing types;
⑶ According to the rotation direction of the two screws, there are same direction and different direction, and in different direction, there are inward and outward;
⑷ According to the rotation speed of the screw, there are high speed and low speed;
⑸ According to the structure of the screw and the barrel, there are integral and combined types.
On the basis of twin-screw extruders, in order to make it easier to process blends with poor thermal stability, some manufacturers have developed multi-screw extruders such as planetary extruders.