What are the classifications of plastic extruders? The editor will give you an analysis: the plastic extruder is the main equipment on the plastic extrusion molding production line. The main function of the plastic extruder is to provide a plasticized molten material for plastic resin extrusion molding; to ensure that the production raw materials are uniformly mixed and fully plasticized within the temperature range required by the process; Provide molten material with uniform flow and stable pressure to make plastic extrusion molding production smooth and smooth.
Plastic extruders can be divided into twin-screw extruders and single-screw extruders. Below, let's take a look at the difference between the two extruders.
The difference between twin screw extruder and single screw extruder:
Single-screw machines and twin-screw machines: one is a screw and the other is two screws. It is driven by a motor, and the power varies with the screw. The power of the 50 cone double is about 20kW, and the power of 65 is about 37kW. The output is related to the material and the screw. The output of 50 cone pairs is about 100-150kg/h, and 65 cone pairs 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. At present, the single-screw extruder is the most widely used and is suitable for extrusion processing of general materials. The twin-screw extruder has less heat generated by friction, more uniform shearing of the material, greater conveying capacity of the screw, more stable extrusion volume, longer stay of material in the barrel, and uniform mixing.
The twin-screw extruder has the characteristics of forced extrusion, high quality, wide adaptability, long life, low shear rate, difficult to decompose materials, good mixing and plasticizing performance, direct powder molding, temperature automatic control, vacuum exhaust, etc. Device. It is suitable for the production of products such as tubes, plates and profiled materials.
The single screw extruder occupies an important position no matter as a plasticizing granulation machine or a molding processing machine. In recent years, the single screw extruder has made great progress. The single screw extruder for 3D printing consumables produced by Sanao has a screw diameter of 45mm and an output of 20t/h.
The main sign of the development of single-screw extruder lies in the development of its key part-screw. In recent years, people have conducted a large number of theoretical and experimental studies on the screw. So far, there have been nearly one hundred kinds of screws. The common ones are separation type, shear type, barrier type, split type and wave type.
From the perspective of the development of single screw, although the single screw extruder has been relatively perfect, with the continuous development of polymer materials and plastic products, more new types of special screw and special single screw extruder will emerge. Overall, single screw extruders are developing towards high speed, high efficiency and specialization.
The twin-screw extruder has good feeding characteristics, suitable for powder processing, and has better mixing, exhaust, reaction and self-cleaning functions than the single-screw extruder. It is characterized by poor thermal stability of plastics and blends. It also shows its superiority. In recent years, foreign twin-screw extruders have developed greatly. Various forms of twin-screw extruders have been serialized and commercialized. There are also many manufacturers. The general classifications are as follows:
(1) According to the relative positions of the two axes, there are parallel and tapered;
(2) According to the meshing procedure of two screws, there are meshing type and non-meshing type;
(3) According to the rotation direction of the two screws, there are the same direction and the different direction, and in the different direction, there are the points of inward and outward;
(4) According to the rotation speed of the screw, there are high speed and low speed;