I. Overview of the extruder The extruder can be divided into continuous extrusion and discontinuous extrusion depending on the type of action. Plastic extruders are also a type of plastic machinery. The extruder divides the machine head into a bevel head and a right angle head according to the angle between the flow direction of the head and the center line of the screw. The outer casing of the machine head is fixed on the fuselage by bolts. The mold in the machine head has a core sitting and is fixed to the inlet port of the machine head with a nut. The front of the core seat is equipped with a core, a core and a core holder. The center has holes for the core wire. Second, the working principle of the extruder The single screw is generally divided into three sections in the effective length. The effective length of the three sections is determined according to the screw diameter and the pitch depth, and is generally divided into one third. The last thread of the material port is called the conveying section: the material is required to be plasticized here, but it must be preheated and compacted. In the past, the old extrusion theory believed that the material here was loose, and later proved that the material here is actually The solid plug, that is to say, the material here is a solid like a plug after being squeezed, so it is its function as long as the conveying task is completed. At this point, the volume of the groove gradually decreases from large to large, and the temperature is to reach the degree of plasticization of the material. Here, the compression is generated by the conveying section three, where it is compressed to one, which is called the compression ratio of the screw -3:1, and some machines There are also changes, the finished plasticized material enters the metering section, where the material maintains the plasticizing temperature, just as accurately as the metering pump, the melt material is delivered quantitatively to supply the machine head. At this time, the temperature cannot be lower than the plasticizing temperature. Slightly higher. Third, the application of the extruder The extruder is one of the types and it is necessary to grasp the operation points of the extruder and use the extruder correctly and reasonably. The use of screw extruders includes a series of links such as machine installation, adjustment, commissioning, operation, maintenance and repair. Its use has the commonality of general machines, mainly in the aspects of drive motors and gear shifting devices. However, the working system of the screw extruder is the extrusion system, but it has its own characteristics. When using the screw extruder, special attention should be paid to its characteristics. Two short, one long and long pitch screw plasticizing extrusion systems, engineering analysis software for the optimization design of vibration-induced plasticizing device, flat valve plus forming die and oblique valve plus forming die, internal cooling technology and double air vent Pressure cooling technology, multi-component weight loss metering feeding, on-line film thickness precision control system, computer centralized automatic control system and bus control technology. Fourth, the characteristics of the extruder The multi-layer composite technology utilizes materials with medium and high barrier properties to be combined with other packaging materials to combine the high barrier properties of barrier materials with the low cost or special mechanical and thermal properties of other materials to achieve specific functional requirements. The structural design of the co-extruded composite film is gradually required to systematically achieve the functions of integration, technology, cost, environmental protection, safety and secondary processing. The inner wall of the cooling water pipe attached to the extruder is easy to scale and the outside is easily corroded and rusted. Care should be taken during maintenance. Excessive scale will block the pipeline and will not reach the cooling effect. If the corrosion is serious, water leakage will occur. Therefore, descaling and anti-corrosion and cooling measures must be taken during maintenance. For the DC motor that drives the screw to rotate, it is important to check the brush wear and contact conditions. The insulation resistance value of the motor should be measured frequently if it is above the specified value. In addition, check the connection wires and other components for rust and take protective measures.