Working Principle And Structural Function Of Extruder

Some people ask about electric heating: What is the principle of the extruder and the role of each structure? Today, Nanjing COLOWE Chemical Machinery Co., Ltd. to explain the extruder, first introduce the principle of extruder.

The polymer is fused and tamped, and the mold shell is directed by constant current source, temperature control and rotating table speed, according to which the commercial melt state of the mold shell is generated. However, the extruder is not the same as the single screw extrusion mechanism, the principle is not the same, and the processing technology standards for its manipulation are not the same.

The whole process of plastic extrusion is to use the extruder extruder screw to transport the plastic, tamp it, and further melt the plastic in a completely symmetrical melting situation, extrusion from the die under working pressure, after forming machinery and equipment setting, refrigeration to make the required products.

Therefore, the extruder is the main equipment for plastic extrusion, which determines the quality and production of the extruder products. The key of the extruder is composed of the extruder screw, the barrel, the heating and cooling system, the transmission device and the control device. In which extruder screw is an important role of extruder components, it shoulders the transportation of raw materials, compaction, melting, homogenization, compaction, and pumping out the whole extrusion process of the key role.

Typical single-screw extruder The extruder is a three-stage, respectively feeding, reducing and extrusion section.

1. Feeding section: the feeding of extrusion is generally made of granular material. The feeding device is a device that ensures continuous feeding to the extruder barrel, which is like a Brinell funnel, with conical and square cones, also known as a hopper. The bottom end of the feed hole is connected with the barrel, and the point is provided with a disconnecting device, which can adjust and disconnect the feed flow. There is a cooling barrel clamp around the feeding hole, which is used to avoid the heat conduction from the high temperature of the material to the hopper, and prevent the plastic in the hopper from rising temperature and becoming sticky, resulting in uneven feeding and blocking the flow of the material. The side of the hopper is provided with a laminated glass viewing hole and a calibration metering verification device. Some hoppers also have heating and drying vacuum pump pressure relief devices to avoid plastic digestion and absorption of water from the air, and contain stirring devices to overcome the "railway bridge" condition caused by powdered plastic and automatic feeding devices that can perform quantitative analysis at regular intervals.

2, the reduction section: the barrel is also called the barrel, which is a metal material cylinder that is stressed by heat. The melting and reduction of raw materials are all carried out in the barrel. The operating temperature of extrusion forming is generally 180~290℃, and the pressure in the cylinder reaches 60MPa. The heating and cooling device heating is generally divided into three to four sections outside the barrel, and the common resistor or inductor electric heater is also used for far-heat radiation. The purpose of refrigeration is to avoid overtemperature of plastics or to cool plastics quickly when parking to prevent the dissolution of plastics. Refrigeration is generally cooled by air or water cooling. The barrel must bear high pressure, and it is required to have sufficient compressive strength and bending stiffness, and the inner cavity is smooth. The barrel is generally used and the inch wear and corrosion resistant plastic friction make the plastic overtemperature, in addition, the outer temperature of the extruder screw is slightly lower than the barrel, avoiding the adhesion of raw materials on it, which is conducive to the transportation of raw materials.

3, extrusion section: extruder screw with thrust bearing suspended in the middle of the barrel, in line with the barrel axis, without significant error. The gap between the extruder screw and the barrel is not large, so that the plastic suffers from strong cutting effect and melts and pushes forward.