A plastic granulator is a machine that can transform waste plastic into plastic granules. It can gradually crush and melt waste plastics, and then press and granulate them to become new plastic granules. These granules can greatly reduce the use of raw materials when producing plastic products again, thereby reducing costs and improving efficiency. Plastic granulators are mainly used for the production and processing of waste plastic film (industrial packaging film, agricultural film, greenhouse film, wine packaging, handbags, etc.), packaging bags, agricultural convenience bags, pots, buckets, plastic bottles, office furniture, daily necessities, etc., suitable for most common waste plastics.
1. Types and Uses of Plastic Granulators
Depending on different usage requirements and process flows, the types of plastic granulators also vary. For example, common ones include single-screw granulators, twin-screw granulators, and vertical granulators. Each type of granulator has different functions and application ranges, and users can choose and purchase according to their actual needs.
Single-Screw Granulator
The single-screw granulator is a commonly used granulator model. It uses a single screw to advance, suitable for the production of small batches of plastic waste and small and medium-sized enterprises. Due to its simple structure, low cost, and easy maintenance, the single-screw granulator has been widely used.
Twin-Screw Granulator
The twin-screw granulator is a new type of granulator developed based on the single-screw granulator. It employs a twin-screw engine, and compared to the single-screw granulator, the twin-screw granulator has significantly improved production capacity, granulation efficiency, and product quality.
Vertical Granulator
The vertical granulator is a special model of granulator. It features a vertical structure design, which results in a small footprint, reduced floor space, and high production efficiency. The vertical granulator is suitable for smaller production sites or enterprises that need to perform precise granulation.
Plasma Granulator
The plasma granulator is a relatively new type of granulator. It utilizes physical plasma state technology for advanced powder preparation. The powder produced by the plasma granulator has extremely high purity and uniformity, making it widely applicable in fields such as material science, catalyst preparation, biomedicine, and more.
2. How to Choose a Plastic Granulator Based on Raw Materials
Choosing the appropriate plastic granulator requires considering factors such as the type of raw material, particle size, and density to meet different production requirements.
2.1 Understand the Raw Material, Determine the Type of Plastic for Granulation
First, determine the type of plastic for granulation. Common plastics include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), etc. Each type of plastic has different physical and chemical properties, so the chosen granulator needs to be able to accommodate the specific processing requirements of the plastic. It's also important to understand the physical properties of the raw material, such as density, melt flow index (MFI), moisture content, and particle size distribution.
Polyethylene (PE): Polyethylene is a common type of plastic that can be processed by an extrusion granulator. The extruder heats the polyethylene raw material to a molten state, then extrudes it through a die, and finally cuts it into granules using a cutting device.
Polypropylene (PP): Polypropylene is also a common type of plastic. Similar to polyethylene, it is suitable for processing with an extrusion granulator.
Polyvinyl Chloride (PVC): PVC plastic is usually processed using an extrusion granulator. Due to its relatively high processing temperature, a high-temperature resistant extruder is required.
Polystyrene (PS): PS plastic can be processed by an extrusion granulator or a pelletizer, depending on the production scale and process requirements.
Polycarbonate (PC): The granulation of PC plastic usually uses an extrusion granulator. High-temperature and high-pressure resistant equipment is needed.
Nylon (PA): The granulation of nylon plastic is suitable for an extrusion granulator or pelletizer, and the choice of suitable equipment should consider its wear resistance and processing temperature.
Polyester (PET): The granulation of PET plastic usually uses an extrusion granulator. Consideration should be given to the drying treatment of the raw material and the wear resistance of the extruder.
2.2 Consider Processing Requirements to Determine the Output Capacity of the Plastic Granulator Needed
Determine the desired output capacity, measured in kilograms per hour (kg/hr) or pounds per hour (lbs/hr). Some granulators have high capacities, suitable for large-scale production, while other machines may be better suited for small-scale or laboratory-scale production.
Single Screw Extruder Granulator: Generally suitable for smaller production volumes, with capacities usually ranging from several tens to several hundred kilograms per hour. The production speed is slower, but for some special plastic raw materials, the single screw extruder may be the more appropriate choice.
Twin Screw Extruder Granulator: Has a higher capacity than single screw extruders, typically ranging from several hundred kilograms to over a ton per hour. Twin screw extruders are suitable for large batch production and are a common choice for processing special materials or when higher production speeds are required.
Pelletizer: Pelletizers have relatively high capacities, generally ranging from several hundred kilograms to several tons per hour. Since pelletizers can perform extrusion and cutting simultaneously, they are highly efficient and suitable for large-scale production.
Water Ring Granulator: Has a large capacity, generally ranging from several tens to several hundred tons per hour. Water ring granulators are suitable for high output, high-speed production environments, and are commonly used for producing common plastic pellets such as polypropylene and polyethylene.
Additionally, the final particle size and shape requirements need to be assessed. Some applications may require uniform pellets, while others may accept irregular flake-like particles.
Lastly, consideration should also be given to the density and strength of the pellets to ensure they meet the requirements of the final product.
2.3 Material Handling and Feeding
2.3.1 Assess in what form the raw materials will be fed into the machine
The feeding methods for plastic granulators are generally divided into three types: bulk, packaged, and roll feeding, each differing in the way materials are conveyed and supplied.
Bulk Feeding: Bulk feeding refers to directly loading the plastic raw materials into the feed inlet of the granulator in bulk form. This method is suitable for small granules that are easy to flow, such as plastic pellets or granular materials. The advantage of bulk feeding is its simplicity and suitability for continuous production, but it may cause dusting for some sensitive plastic materials.
Packaged Feeding: Packaged feeding involves packing the plastic raw materials in bags, buckets, or other containers before loading them into the feed inlet of the granulator. This method is suitable for larger granules that are easy to pack and handle, such as pelletized materials or scrap. The advantage of packaged feeding is that it can effectively control the flow and scattering of materials, reducing dust and pollution, but the operation is relatively complex, requiring manual unpacking and pouring of the materials into the granulator
Roll Feeding: Roll feeding means conveying the plastic raw materials to the feed inlet of the granulator in roll form. This method is suitable for rolled materials such as plastic films or strips, and usually requires the use of a roll unwinding machine or roll unwinding device. The advantage of roll feeding is that it enables continuous feeding, suitable for high-speed production, but it demands high requirements for roll unwinding equipment and the operation is complex.
2.3.2 Consider whether additional equipment is needed for effective feeding
The feeding methods for plastic granulators include automatic feeding systems, hoppers or silos, preprocessing equipment, and material conveying pipelines.
Automatic Feeding Systems
Automatic feeding systems can achieve automatic transport and supply of raw materials, improving production efficiency and reducing labor costs. Common automatic feeding systems include:
- Conveyor Belts: Transport plastic raw materials from the storage hopper to the granulator's feed inlet.
- Screw Conveyors: Deliver raw materials to the granulator by rotating a screw.
- Vacuum Loaders: Use vacuum pressure to draw and convey raw materials to the granulator.
- Vibratory Feeders: Deliver plastic granules to the granulator uniformly through vibration.
Hoppers or Silos
In some cases, plastic raw materials may need to be stored in hoppers or silos before being conveyed to the granulator via manual or automatic feeding systems. Hoppers or silos can be used to temporarily store raw materials, ensuring the stability and continuity of the supply.
Preprocessing Equipment
Some special plastic raw materials may require preprocessing before granulating, such as using crushers to break down waste or large chunks of plastic into particles of a suitable size for processing.
Material Conveying Pipelines
To ensure the smooth transportation of raw materials from storage to the granulator, material conveying pipelines may need to be installed, equipped with corresponding valves and control systems for regulation and control.
3. Precautions for Using Plastic Granulators
The following precautions should be taken when using plastic granulators to ensure production safety, improve production efficiency, and protect the lifespan of the equipment.
Safety Operations: Operators must be familiar with the equipment’s operation manual and safety procedures, and strictly follow the operating rules. When using plastic granulators, protective gear such as safety helmets, goggles, gloves, etc., should be worn to prevent accidental injuries.
Equipment Inspection: Before each use, a comprehensive inspection of the granulator should be conducted to ensure that all parts are functioning normally, well-lubricated, and free of abnormal sounds and odors. Regularly check the equipment's electrical and hydraulic systems to ensure their safety and stability.
Raw Material Handling: Plastic raw materials should be of high quality and meet production requirements, and they should be appropriately processed, such as by drying, screening, etc. Different types of plastic raw materials need to be processed with the appropriate settings according to their characteristics to ensure a smooth granulation process.
Feed Control: Control the amount and speed of raw material feeding to avoid equipment blockage or instability due to excess or insufficient supply. For automatic feeding systems, regularly check the pipelines and conveying devices to ensure they are unobstructed.
Discharge Treatment: Waste gases, wastewater, and residues produced during the granulation process should be properly treated to avoid environmental pollution. For waste containing harmful substances, it should be classified, packaged, and handled according to relevant regulations.
Regular Maintenance: Regularly clean and maintain the granulator to remove accumulated debris and residues, keeping the equipment clean. Regularly replace wear parts, such as cutting tools, filters, etc., to ensure the normal operation of the equipment.
Training and Education: Provide professional training and education to operators to improve their operating skills and safety awareness, reducing the likelihood of operational errors and accidents.
4. Maintenance and Care of Plastic Granulators
Maintenance and care are crucial for ensuring the long-term stable operation and extending the lifespan of plastic granulators.
Regular Cleaning: After each use, the granulator should be thoroughly cleaned, including both interior and exterior surfaces. During cleaning, care should be taken to remove debris, residue, and dust to avoid affecting the normal operation of the equipment.
Lubrication Maintenance: Regularly check the granulator's lubrication system to ensure there is a sufficient supply of lubricant and that it is functioning properly. Lubrication points include bearings, gears, and drive chains, where lubricating oil should be added timely and excess grease should be removed.
Cutter Maintenance: The cutters are critical processing components of the granulator. Regularly inspect the wear on the cutters and replace them when they are significantly worn. When replacing cutters, ensure that they are of reliable quality and are correctly installed and adjusted to guarantee cutting effectiveness and processing quality.
Screen Cleaning: The screen is an important part used for separating and sieving particles. Clean the screen regularly to ensure it is free from blockages. Careful handling is necessary during cleaning to prevent the screen from becoming deformed or damaged.
Electrical System Inspection: Regularly inspect the granulator's electrical system, including the motor, switches, and wiring terminals, to ensure good electrical connections and to prevent leakage or short circuits. For automatic control systems, check the normal operating status of sensors, controllers, and other equipment.
Safety Protection Inspection: Regularly inspect the safety protection devices of the granulator, such as safety doors and protective covers, to ensure they are intact. If any safety protection devices are found to be damaged or malfunctioning, they should be repaired or replaced promptly to ensure the safety of operators.
Regular Maintenance Plan: Establish a regular maintenance plan that specifies the maintenance intervals and content to ensure that all maintenance work is carried out on schedule. For commonly used wear parts and critical components, consider setting up a more frequent maintenance schedule to ensure the stability and reliability of the equipment.
