There are usually two kinds of plastic machinery, one of which is the pullout machine and the other is the injection molding machine. The casting machine is to charge the molten plastic through a fixed shape at the outlet under the action of the screw, and to cut it after water cooling under the action of the tractor. It is mainly used for a large number of continuous production of all kinds of products with the same cross section, such as tube\ rod\ profile, etc., and can also be used for plastic modified granulation. The injection molding machine injects the molten plastic into the mold, and after cooling it is the product. The use is very extensive, depending on the plastic. The main engine of the plastic puller is the molding machine, which consists of a pressure charging system, a transmission system and a heating and cooling system. 1. The pressure charging system includes screw, cylinder, hopper, die, plastic and plastic is molded into uniform melt through the pressure charging system, and under the pressure established in this process, the screw is continuously ejected from the head of the machine. (1) Screw: it is the main component of the molding machine, which is directly related to the application range and productivity of the molding machine, and is made of high strength corrosion resistant alloy steel. (2) cylinder: it is a metal cylinder, which is generally made of composite steel pipe of heat resistance, high compressive strength, strong and wear resistant, corrosion resistant alloy steel or lined alloy steel. The cylinder is coordinated with the screw to realize the crushing, softening and melting of the plastic. Plastic, exhaust and compaction, and continuous and uniform delivery of rubber to the molding system. The length of the general cylinder is 15 times 30 times its diameter, so that the plastic can be fully heated and fully plasticized. (3) hopper: the bottom of the hopper is equipped with a truncation device to adjust and cut off the material flow, and the side of the hopper is equipped with a visual hole and a calibration metering device. (4) head and die: the head is composed of alloy steel inner sleeve and carbon steel coat, and the head is equipped with forming die. The function of the machine head is to change the rotating plastic melt into parallel straight line motion, uniformly and smoothly into the die sleeve, and to give the plastic the necessary molding pressure. Plastic in After the porous filter plate flows through the neck of the machine head to the die, the mold core die sleeve is properly matched to form the annular gap with the decreasing cross section, so that the plastic melt forms a continuous and dense tubular coating around the core wire. In order to ensure that the plastic flow channel in the head is reasonable and eliminate the dead angle of the accumulated plastic, a shunt sleeve is often arranged. In order to eliminate the pressure fluctuation when the plastic is thrown out, there is also a uniform pressure ring. The die correction and adjustment device is also installed on the die head, which is convenient to adjust and correct the concentric degree of the die core and die sleeve. According to the direction of material flow of the head and the angle between the center line of the screw, the molding machine divides the head into oblique angle machine. head (angle 120o) and right angle head. The housing of the head is bolted to the fuselage, the mold in the head has a die core sitting, and the nut is fixed to the inlet port of the head. The front of the die core seat is provided with a die core, and the center of the die core and the die core seat is perforated to pass through the core wire. The outside of the head is equipped with a heating device and a temperature measuring device. The drive system drives the screw. The torque and speed required for the screw to be taken out, usually composed of motor, reducer, bearing, etc. 3. The heating and cooling of the heating and cooling device is a necessary condition for the plastic ejection process. The main results are as follows: (1) at present, the molding machine usually uses electric heating, which is divided into resistance heating and induction heating. The heating sheet is installed in the fuselage, neck and head. The heating device is heated by the plastic in the external heating tube to reach the temperature required for the process operation.