Structure principle and function of waste plastic granulator

1、 Structural composition

The plastic granulator uses the extruder as the core host and is equipped with auxiliary equipment for plastic granulation. The main structure is divided into three major systems:

1. Squeezing system

The high-strength corrosion-resistant alloy steel used for screws is the core component of plasticized plastics. The alloy steel or composite steel pipe selected for the barrel is used in conjunction with the screw to carry out processes such as crushing, softening, and melting. The bottom of the hopper is equipped with a cutting device for seasoning flow, and there are sight holes and measuring devices on the side. The head of the machine is precisely controlled by the mold core, mold sleeve, and pressure equalization ring to determine the thickness of the extrusion layer. The outer shell is fixed to the body, and the outer head is equipped with heating and temperature measuring devices.

2. Transmission system

Composed of an electric motor, reducer, and bearings, it provides stable driving torque and speed to the screw, ensuring a stable plasticization process.

3. Heating and cooling system

Electric heating (resistance or induction heating) is distributed in key parts such as the body, neck, and nose of the machine. The cooling system includes organic cylinder air/water cooling, screw center water cooling, and hopper cooling, with precise temperature control to prevent plastic decomposition or difficult shaping.

2、 Working principle

The plastic granulator converts waste plastic into recycled pellets through five steps:

1. Raw material processing

After sorting, washing, and drying the waste plastic, it is sent to the hopper and then rotated into the barrel by a screw.

2. Melt plasticization

The outer heating device of the barrel heats the plastic to a molten state, and the shearing and compression of the screw fully plasticizes, exhausts, and compacts the plastic.

3. Extrusion molding

Molten plastic is continuously extruded by a screw head under pressure, and the head converts rotational motion into parallel linear motion, forming a uniform tubular coating layer through the mold core and mold sleeve.

4. Cooling and shaping

The extruded strip material is immediately fed into the cooling device (water-cooled or air-cooled), and the rapid cooling or slow cooling process is selected according to the material characteristics to ensure the stability of the product shape.

5. Granulation packaging

The cooled strip is cut into uniform particles using a rolling blade, and the entire granulation process is completed.

3、 Functional Features

The plastic granulator has five core advantages:

1. Strong material adaptability

It can handle plastic waste such as PP, PE, and PVC, including films, woven bags, and bottles, and supports both dry and wet feeding.

2. Stable and reliable production

Equipped with a straightening device to solve the problem of wire core bending, a preheating device to dry the wire core and prevent air holes, a traction device and a meter to accurately control tension and length.

3. Energy saving

The power part uses a frequency converter to save motor energy consumption, and the heating part uses an electromagnetic heater, which saves 30% -70% electricity compared to traditional resistance heating, relying on insulation layers and direct heating to reduce heat loss.

4. Intelligent and convenient operation

Integrated monitoring system for temperature, pressure, and speed parameters, with fault diagnosis and interlock shutdown functions, and a touch screen operation interface to simplify the process.

5. Outstanding environmental benefits

Efficiently converting waste plastics into recycled particles, reducing environmental pollution, conserving primary plastic resources, and meeting the needs of circular economy development.