Introduction of Plastic Granulator

The host machine of the plastic granulator is an extruder, which consists of an extrusion system, a transmission system and a heating and cooling system. Vigorously develop renewable resources and turn waste into treasure.

Extrusion system

The extrusion system includes a hopper and die. The plastic is plasticized into a uniform melt through the extrusion system, and under the pressure established in this process, the screw is continuously extruded by the die.

Screw

It is the most important part of the extruder, which is directly related to the application range and productivity of the extruder. It is made of high-strength and corrosion-resistant alloy steel.

Barrel

It is a metal cylinder, which is generally made of alloy steel with high heat resistance, high compressive strength, strong wear resistance and corrosion resistance or composite steel pipe lined with alloy steel. The barrel cooperates with the screw to realize the pulverization, softening, melting, plasticizing, exhausting and compacting of the plastic, and continuously and uniformly convey the rubber material to the molding system. Generally, the length of the barrel is 15 to 30 times than its diameter, so that the plastic can be fully heated and fully plasticized.

Hopper: The bottom of the hopper is equipped with a cutting device to adjust and cut off the material flow, and the side of the hopper is equipped with a viewing hole and a calibration metering device.

Die and mold: The die is composed of an alloy steel inner sleeve and a carbon steel outer sleeve, and a forming mold is installed in the die. The function of the die is to convert the rotating plastic melt into parallel linear motion, evenly and smoothly introduce it into the mold sleeve, and give the plastic the necessary molding pressure. The plastic is plasticized and compacted in the barrel, and flows into the die forming die through the neck of the die along a certain flow channel through the porous filter plate. A continuous and dense tubular cladding layer is formed around the core wire. In order to ensure a reasonable plastic flow channel in the machine head and eliminate the dead angle of accumulated plastic, a shunt sleeve is often installed. In order to eliminate the pressure fluctuation during plastic extrusion, a pressure equalizing ring is also installed. The die is also equipped with a mold correction and adjustment device, which is convenient for adjusting and correcting the concentricity of the mold core and the mold sleeve.

Transmission system

The function of the transmission system is to drive the screw and supply the torque and rotation speed required by the screw during the extrusion process. It is usually composed of a motor, a reducer and a bearing. 

Heating and cooling device

Heating and cooling are necessary conditions for the plastic extrusion process to be carried out.

In 2013, the extruder usually uses electric heating, which is divided into resistance heating and induction heating. The heating sheet is installed in the body, neck and head of each part. The heating device heats the plastic in the cylinder externally to heat it up to the temperature required for the process operation.

The cooling device is set up to ensure that the plastic is in the temperature range required by the process. Specifically, it is to remove the excess heat generated by the shear friction of the screw rotation, so as to avoid the plastic decomposition, scorch or difficulty in shaping due to excessive temperature. Barrel cooling is divided into water cooling and air cooling. Generally, air cooling is more suitable for small and medium-sized extruders, and water cooling or a combination of the two forms is used for large extruders. The screw cooling mainly adopts central water cooling, in order to increase the solid conveying rate of materials to stabilize the glue output and improve product quality at the same time; but the cooling at the hopper is to strengthen the conveying effect of solid materials, prevent the plastic pellets from sticking and block the material port due to heating, and to ensure the normal operation of the transmission part.