The PP woven bag plastic granulator is mainly composed of several key parts, which cooperate with each other to complete the transformation from waste PP woven bags to plastic granules.
Its main engine is an extruder, which consists of three systems: extrusion, transmission, and heating and cooling.
In the extrusion system, the screw is the core component, generally made of high-strength corrosion-resistant alloy steel like 38CrMoA1A or bimetallic material. Its function is to push the plastic material forward and plasticize it. The barrel cooperates with the screw to realize a series of operations such as crushing, softening, and melting of plastics.
The compactor cutter is used for compacting PP materials, featuring rotating blades at the bottom to meter the feeding volume to the screw.
A die head and die transform the rotating plastic melt into parallel linear motion, which is uniformly introduced into the die sleeve and subjected to die head pressure.
The transmission system consists of a motor, reducer, and bearing, which together provide the required high torque and speed for the screw.
The heating and cooling device ensures plastic is extruded within the proper temperature range. Typically, electric heating is used for heating, while water or air cooling maintains thermal stability.
During operation, the waste PP woven bags are sorted, crushed and washed to remove impurities and moisture. Then, the clean material enters the compactor through the conveyor belt and falls onto the screw. The rotation of the screw pushes the material towards the die. In this process, due to the decrease of the thread depth and the resistance of the filter screen and the die, the material is compressed and the pressure is increased. At the same time, the heat generated by external heating and internal friction of the material raises the temperature of the plastic, and it changes from glassy state to high elastic state and then to viscous state, thus completing plasticization. The plasticized PP material is extruded from the machine head at constant pressure, quantitatively and uniformly under the action of screw thrust, cooled and shaped by a cooling water tank, and finally cut into pellets by a granulator to complete the whole granulation process.
The washed PP woven bag materials are usually processed using a two-stage extrusion pelletizing method.
The first extruder is equipped with a net-free laser filter, while the sub-extruder uses a common plate structure.
This configuration is particularly beneficial for customers in regions with high labor costs, as it helps reduce manual workload and operational costs.
For the granulation stage, the vertical water-ring granulation method is typically recommended.
This method helps ensure optimal saturation and granule quality, and is suitable when the MFI (Melt Flow Index) value ranges from 1 to 20.
Thanks to the powerful overall machine control system, we can achieve online operation of the entire production line. All parameters of the machines can be set on a single control screen, with precise control, visualization and intelligent empowerment for the recycling business.
RETECH is a creative company focusing on the technology R&D of Plastic recycling machinery solutions.
