What is the principle and structure of a single screw extruder, as a common extruder equipment used in the plastic processing industry? Below is an analysis of the principle of a single screw extruder from the conveying section, compression section, and metering section of the extruder.

A single screw extruder is generally divided into three effective lengths, determined by the diameter, pitch, and depth of the screw, each accounting for one-third of the total effective length.

The high-efficiency single screw extruder adopts a two-stage overall design, strengthening the plasticizing function, ensuring high-speed, high-performance, and stable extrusion. The special barrier comprehensive mixing design ensures the mixing effect of the material, and the high shear and low melting plasticizing temperature ensures the high-performance, low-temperature, and low-pressure metering extrusion of the material. Design concept and characteristics: High speed and high yield extrusion based on high flatness.

Principle of single screw extruder

After the feeding port, a thread starts to be called the conveying section. The material here is required not to be plasticized, but to be preheated and compressed for compaction. In the past, the old extrusion theory believed that the material here was a loose body. Later, it was proven that the material here is actually a solid plug, which means that after being squeezed, the material here is a solid body like a plug. Therefore, as long as the conveying task is completed, its function is complete.

Principle of a single screw extruder: When the second section is called the compression section, the volume of the screw groove gradually decreases from large to small, and the temperature needs to reach the degree of material plasticization. The compression generated here is from the conveying section three, where it is compressed to one, which is called the compression ratio of the screw -3:1. Some machines also have changes, and the material that completes plasticization enters the third section.

Principle of single screw extruder: The third section is the metering section where the material maintains the plasticizing temperature, only accurately and quantitatively conveying the melt material like a metering pump to supply the machine head. At this time, the temperature cannot be lower than the plasticizing temperature, usually slightly higher.

Single screw extruder is mainly used for extruding thermoplastic plastics such as soft and hard polyvinyl chloride, polyethylene, etc. It, in conjunction with corresponding auxiliary machines (including forming machine heads), can process various plastic products, such as films, pipes, plates, ribbons, etc., and can also be used for granulation.

The plastic extruder is designed reasonably, with high quality, good plasticization, low energy consumption, and adopts involute gear transmission. It has the characteristics of low noise, stable operation, large bearing capacity, and long service life.

Purpose of single screw extruder

Pipe extrusion: suitable for PP-R pipes, PE gas pipes, PEX cross-linked pipes, aluminum plastic composite pipes, ABS pipes, PVC pipes, HDPE silicon core pipes, and various co extruded composite pipes.

Plate and sheet extrusion: suitable for extrusion of profiles and plates such as PVC, PET, PS, PP, PC, etc. his

It extrudes various plastics such as silk, rods, etc. Extrusion of profiles: Adjusting the extruder speed and changing the structure of the extrusion screw can be applied to the production of various plastic profiles such as PVC and polyolefins. Modified granulation: suitable for blending, modifying, and enhancing granulation of various plastics.