Technical Interpretation and Application Guide of Plastic Crusher Machine in Waste Plastic Recycling

Plastic crusher machine are the core pre-treatment equipment in the waste plastic recycling industry chain, directly determining the efficiency and quality of plastic recycling. This article provides practical technical references for practitioners from four dimensions: equipment structure, selection logic, scenario-based application, and operation & maintenance solutions, accurately addressing the crushing pain points in the recycling process.

1. Structure and Principle: Technical Support from "Crude Crushing" to "Precision Crushing"

Plastic crusher machine belong to shear-type crushing equipment. They crush waste plastics (such as PET bottles, plastic barrels, etc.) into compliant particles through the shearing action of moving knives and fixed knives combined with rotor extrusion.

Analysis of Core Components

    •Knife Set System:

The moving knives adopt an adjustable 3~8-claw layout, made of SKD11 high-carbon alloy tool steel (with a hardness of HRC58~62). The gap between the fixed and moving knives is strictly controlled at 0.2~0.4mm (out-of-control gaps will lead to uneven particle size or excessive knife wear). The knives support tungsten carbide coating repair or surfacing repair, and can be reused after wear, significantly reducing the cost of consumables.

    •Rotor Assembly:

It undergoes G2.5-level dynamic balance treatment, with a speed range of 300~800r/min (the low-speed design achieves "high torque and low entanglement", meeting the crushing needs of both soft PE films and hard PET bottles).

    •Filter Screen Device:

It is equipped with optional stainless steel filter screens with a diameter of 3~20mm, which can not only control the particle size of the discharged material but also separate residual liquid from the material (for example, when crushing gasoline bottles, residual gasoline can be efficiently recovered to achieve compliant disposal of hazardous waste).

    •Conveying System:

The input/output conveyor belts are suitable for feeding sizes of 500~3000mm, meeting the automatic feeding needs of waste plastics of different specifications.

2. Selection Strategy: A "Precision Formula" for Matching Recycling Scenarios

Selection must be closely linked to three core variables: material type, processing scale, and downstream processes. The following is the adaptation logic for key parameters:

3. Scenario-Based Application: "Customized Crushing Solutions" for Different Plastics

1. PET Bottle Recycling: Dual Control of Efficiency and Residual Liquid

For PET materials such as mineral water bottles, the shredder needs to complete the whole process of "bottle crushing → label separation → residual liquid removal":

    •A filter screen with a diameter of 8mm is selected to ensure particle dispersibility, facilitating subsequent cleaning;

    •A 6-claw knife set is configured to enhance shearing force, increasing crushing efficiency by 20%;

    •A built-in residual liquid separation filter screen recovers residual water in the bottle, reducing energy consumption in the subsequent drying process.

2. Hazardous Waste Plastics (e.g., Gasoline Bottles): Balancing Explosion Prevention and Resource Utilization

This scenario focuses on solving the problems of "explosion prevention + residual liquid recovery":

    •The equipment is treated with anti-static measures (such as body grounding and anti-static coating on knives);

    •The filter screen is integrated with a negative-pressure liquid extraction device, enabling a gasoline recovery rate of over 95% and achieving compliant disposal of hazardous waste.

3. PE/PP Films: Efficient Crushing with Anti-Entanglement

For easily entangled film materials, a spiral-edged knife set combined with a pressure roller feed port is adopted:

    •The spiral-edged knife set realizes "tearing + shearing" simultaneously, avoiding jamming of traditional knife sets;

    •The pressure roller forces feeding, increasing processing efficiency by 30%.

4. Operation & Maintenance and Troubleshooting: From "Shutdown Maintenance" to "Preventive Maintenance"

1. Knife Wear: A Two-Pronged Approach of Prevention and Repair

    •Prevention: Install a metal detector and a magnetic separator at the front end to remove foreign objects such as iron nails;

    •Repair: For slight wear, use plasma surfacing of tungsten carbide (surfacing layer ≥2mm); for severe wear, replace the knife set and perform dynamic balance correction.

2. Uneven Particle Size: Three-Step Rapid Troubleshooting

    •Check if the filter screen is clogged, and clean it with a high-pressure water gun and a brush every 8 hours;

    •Use a feeler gauge to detect the gap of the knife set and adjust it to a uniform range of 0.2~0.4mm;

    •Adjust the feeding distributor to ensure uniform material entry into the cavity.

3. Overload Protection: Active Defense of the Intelligent System

A torque sensor combined with PLC linkage is configured. When the load exceeds 120% of the rated torque, the equipment automatically reverses to discharge materials and restarts after 3 seconds, avoiding motor burnout and knife set deformation.

5. Technological Trends: Three Directions for Future Crushing

    •Intelligentization: Integrate machine vision to automatically identify materials and adjust knife set parameters;

    •Customization: Develop special models for medical waste plastics, agricultural films, etc. (e.g., medical plastic shredders have the integrated function of "high-temperature sterilization + crushing");

    •Environmental Friendliness: Equip with noise reduction enclosures and dust collection devices, with noise ≤75dB, meeting the requirements of VOCs control.

6.Selected Q&A: Directly Addressing Recycling Pain Points

    1.Q: What is the difference in the knife set when crushing PET bottles and PE films?

A: For PET bottles, multi-claw thick knives are selected (e.g., 6 claws, knife thickness ≥15mm); for PE films, spiral-edged knives are selected to prevent entanglement.

    2.Q: What is the purpose of the low-speed and high-torque design?

A: It reduces plastic thermal degradation, avoids entanglement of soft materials and jamming of hard materials, and improves crushing uniformity.

    3.Q: How to repair worn knives?

A: Slight wear can be repaired by coating (tungsten carbide), and severe wear can be repaired by surfacing, reducing maintenance costs.

    4.Q: Does the filter screen only function to control particle size?

A: No, it can also separate residual liquid (such as water and gasoline in bottles) to realize the simultaneous processing of materials and liquids.

The realization of the value of plastic crusher machine relies on the coordination of "precision selection + professional operation & maintenance + process adaptation". Under the trend of the circular economy, as the "front-end engine" of the recycling industry chain, it will continue to make breakthroughs in materials, intelligence, and environmental protection, providing core technical support for plastic resource utilization.