What is a plastic granulator

        The main machine of the plastic granulator is an extruder, which consists of an extrusion system, a transmission system, and a heating and cooling system.

        1. The extrusion system includes a screw, barrel, hopper, head, and mold. Plastic is plasticized into a uniform melt through the extrusion system, and is continuously extruded from the head by the screw under the established pressure during this process.

                (1) Screw: It is the most important component of an extruder, which directly affects the application range and productivity of the extruder. It is made of high-strength and corrosion-resistant alloy steel.

                (2) Machine barrel: It is a metal cylinder, generally made of heat-resistant, high compressive strength, sturdy, wear-resistant, and corrosion-resistant alloy steel or composite steel pipes lined with alloy steel. The machine barrel is combined with the screw to achieve the crushing, softening, melting, plasticizing, exhaust, and compaction of plastic, and continuously and evenly transport the rubber material to the molding system. Generally, the length of the barrel is 15 to 30 times its diameter, based on the principle of fully heating and plasticizing the plastic.

                (3) Hopper: The bottom of the hopper is equipped with a cut-off device for adjusting and cutting off the material flow, and the side of the hopper is equipped with a sight hole and a calibration measuring device.

                (4) Head and mold: The head is composed of an alloy steel inner sleeve and a carbon steel outer sleeve, and a molding mold is installed inside the head. The function of the machine head is to transform the rotating plastic melt into parallel linear motion, evenly and smoothly guide it into the mold sleeve, and provide the necessary molding pressure to the plastic. Plastic is plasticized and compacted inside the machine barrel, and flows through a certain flow channel through the machine head neck into the machine head forming mold through a porous filter plate. The core mold sleeve is properly matched to form a continuously decreasing circular gap, allowing the plastic melt to form a continuous and dense tubular coating layer around the core wire. In order to ensure a reasonable plastic flow path in the machine head and eliminate dead corners of accumulated plastic, shunt sleeves are often installed. In order to eliminate pressure fluctuations during plastic extrusion, pressure equalizing rings are also installed. The machine head is also equipped with a mold correction and adjustment device to facilitate adjustment and correction of the concentricity of the mold core and mold sleeve.

        2.The function of the transmission system is to drive the screw and supply the torque and rotational speed required by the screw during the extrusion process. It is usually composed of an electric motor, a reducer, and bearings.

        3.Heating and cooling device Heating and cooling are necessary conditions for the plastic extrusion process to proceed.

                (1) Nowadays, extrusion machines usually use electric heating, which is divided into resistance heating and induction heating. The heating plates are installed in the body, neck, and head of the machine. The heating device heats the plastic inside the cylinder externally to achieve the temperature required for process operation.

                (2) The cooling device is set to ensure that the plastic is within the temperature range required by the process. Specifically, it is to eliminate excess heat generated by shear friction during screw rotation, in order to avoid the difficulty of plastic decomposition, charring, or shaping due to high temperatures. Machine barrel cooling is divided into two types: water cooling and air cooling. Generally, air cooling is more suitable for small and medium-sized extrusion machines, while for large machines, water cooling or a combination of the two forms of cooling are often used; Central water cooling is mainly used for screw cooling to increase the solid conveying rate of materials, stabilize the glue output, and improve product quality; But the cooling at the hopper is to strengthen the conveying effect of solid materials, prevent plastic particles from sticking and blocking the material outlet due to temperature rise, and to ensure the normal operation of the transmission part. www.jiashengsz.com