How is the plastic granulator composed?

The main machine of theplastic granulator is the extruder, which consists of an extrusion system, transmission system, and heating and cooling system. plastic granulator has a very important role in the vigorous development of renewable resources, waste to treasure this aspect. This article will briefly introduce the composition of the plastic granulator.

Here is the list of contents

Extrusion system

Transmission system

Heating and cooling device

Extrusion system

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

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

Barrel: a metal cylinder, generally made of heat-resistant, high-pressure strength, strong wear-resistant, corrosion-resistant alloy steel or alloy steel lined with a composite steel pipe. The barrel cooperates with the screw to realize the crushing, softening, melting, plasticizing, exhausting, and compacting of plastics, and to continuously and evenly deliver the rubber to the molding system. The length of the barrel is generally 15-30 times its diameter so that the plastic can be fully heated and plasticized.

Hopper: The bottom of the hopper is equipped with a cut-off device to adjust and cut off the material flow, and the side of the hopper is equipped with a sight hole and a calibrated measuring device.

Head and mold: The head is composed of an alloy steel inner sleeve and carbon steel outer sleeve, and the head is equipped with a molding mold. The function of the head is to transform the rotating plastic melt into a parallel linear motion, which is evenly and smoothly introduced into the mold sleeve, and to give the plastic the necessary molding pressure. The plastic is plasticized and compacted in the barrel and flows through the neck of the head through a certain flow path through the porous filter plate into the head molding mold. The mold core and mold sleeve are properly matched to form a ring-shaped gap with decreasing cross-section so that the plastic melt forms a continuous dense tubular cladding layer around the core line. In order to ensure that the plastic flow channel in the head is reasonable and to eliminate the dead angle of the accumulated plastic, there is often a diversion sleeve placed, and to eliminate the pressure fluctuation of plastic extrusion, there is also a pressure equalization ring set. The head is also equipped with a die correction and adjustment device to facilitate the adjustment and correction of the concentricity of the die core and die sleeve.

Transmission system

The function of the drive system is to drive the screw and supply the torque and speed required by the screw in the extrusion process, usually consisting of an electric motor, reducer, bearings, etc.

Heating and cooling device

Heating and cooling are necessary for the plastic extrusion process to be able to proceed.

In 2013 extruders are usually heated electrically, divided into resistance heating and induction heating, with heating sheets installed in each part of the body, neck, and head. The heating unit heats the plastic inside the barrel from the outside to warm it up to the temperature required for the process operation.

The cooling device is installed to ensure that the plastic is in the temperature range required for the process. Specifically, it is to exclude the excess heat generated by the shear friction of the rotating screw in order to avoid the high temperature to make the plastic decompose, scorch or set the shape difficult. Barrel cooling is divided into two kinds of water-cooled and air-cooled, generally small and medium-sized extrusion machine using air-cooled is more appropriate, large is more water-cooled or a combination of the two forms of cooling. Screw cooling is mainly used in the center of water cooling, the purpose is to increase the rate of solid material delivery, stabilize the amount of rubber, while improving product quality; but the cooling at the hopper, is to strengthen the role of solid material delivery, to prevent the temperature of the plastic particles sticky blockage of the material mouth, the second is to ensure the normal work of the transmission part.

Nanjing Haisi Extrusion Equipment Co., Ltd. is a high-tech enterprise consisting of a team with many years of experience in R&D, design, manufacturing technology, sales, and service in the extruder industry. If you are interested in our products, welcome to contact us!