The difference between twin-screw plastic granulator and single-screw plastic granulator

Plastic extruders can be divided into single-screw granulators, twin-screw granulators and multi-screw extruders according to the number of extruder screws.

At present, the single-screw granulator is the most widely used and is suitable for the extrusion production and processing of general materials. The twin-screw granulator generates less heat due to friction, the shear of the material is relatively uniform, the extruder screw has a large conveying capacity, the extrusion volume is relatively stable, the material stays in the barrel for a long time, and the mixture is even.

The twin-screw granulator has the characteristics of forced extrusion, high quality, wide adaptability, long life, low shear rate, difficult material decomposition, good plasticizing performance of the mixed rubber, direct molding of pellets, automatic temperature control, and vacuum exhaust. Pipes and other devices. It is suitable for the production and manufacturing of tubes, plates, special-shaped materials and other products. The twin-screw granulator occupies an important position both as a plasticizing plastic processing machine and a molding processing machine. In recent years, the twin-screw granulator has developed greatly.

At present, the large and medium-sized single-screw granulators for plastic processing produced in Germany have an extruder screw diameter of 700mm and an output of 36t/h. An important indicator of the development trend of single-screw granulator lies in the development trend of its important component, the extruder screw. In recent years, we have conducted a lot of theoretical and experimental research on extruder screws. So far, there are nearly a hundred types of extruder screws. The common ones are separation type, shear type, natural barrier type, separation type and corrugated type etc. ​

Judging from the development trend of single-screw granulators, although single-screw granulators have been relatively perfect in recent years, with the continuous development trend of fiber materials and plastic products, new extruder screws with more characteristics will continue to emerge. and special single-screw granulator. Generally speaking, single-screw granulators are developing in the direction of high speed, efficiency and specialization. The twin-screw granulator has good feeding characteristics and is suitable for the production and processing of pellets. It has better mixing, exhaust, reaction and self-cleaning functions than the single-screw granulator. It is characterized by the production and processing of plastics and plastics with poor heat resistance. It shows its superiority even more when blending materials.

In recent years, overseas twin-screw extruders have been developing rapidly. Various types of twin-screw granulators have become common and technologically advanced, and are produced by many manufacturers. They can be roughly classified as follows:

(1) According to the relative positions of the two center lines, they can be divided into parallel surfaces and conical shapes;

(2) According to the meshing procedure of the two extruder screws, there are meshing type and non-meshing type;

(3) According to the rotation direction of the two extruder screws, they can be divided into the same direction and different directions, and the different directions can be divided into inward and outward;

(4) According to the rotation speed of the extruder screw, there are high speed and low speed gears;

(5) According to the structure of the extruder screw and barrel, they are divided into integration and composition.