Plastic Pallet Manufacturing Process

As the core carrier of modern logistics and warehousing systems, the manufacturing process of plastic pallets directly affects the load bearing, durability and functionality of the product. Currently the mainstream manufacturing process includes injection moulding, blow moulding and rotational moulding technology each process corresponds to a different structure and use of the scene of the tray needs.

Injection Molding

Detailed flow description of the injection moulding process

1. Raw material preparation
   Plastic granules (e.g. PP, HDPE, etc.) need to be pre-dried to avoid moisture causing bubbles or defects. The material enters the barrel of the injection moulding machine through a hopper.
   
2. Melting and Plasticising
   The screw inside the barrel rotates and heats up the plastic granules to melt them into a homogeneous viscous flow state (temperature usually 180-300°C, depending on the material).
   
3. Injection Moulding
   The molten plastic is injected under high pressure (usually 50-200 MPa) through a nozzle into a closed mould cavity. The design of the mould needs to include gates, runners and other structures to guide the flow of the melt.
   
4. Pressurising and cooling
   Pressurising stage: Pressure is maintained for a short period of time to compensate for the shrinkage of the material and to ensure that the product is dense and free from shrinkage marks.
   Cooling phase: water or oil is circulated to cool the mould to solidify the plastic (time depends on the thickness of the product, usually from a few seconds to a few minutes).
   
5. Mould opening and ejection
   The mould is opened and the ejector mechanism pushes the moulded part out of the cavity. After the product is removed, it may be necessary to trim the sprue, burrs and other post-processing.

Why is Injection Moulding the Mainstream Method to Produce Plastic Pallets?

1. High efficiency and large-scale production
   Short injection moulding cycle time, the daily output of a single machine can be up to thousands of pieces, which is suitable for the logistics industry’s high volume demand for pallets.
   
2. Flexible structure design
   can produce complex structures (such as reinforcement, anti-skid pattern, stacking grooves) to optimise the load-bearing and functionality of the pallet.
   
3. High material utilisation
   The injection moulding process is virtually waste-free (runners and sprues can be recycled), reducing raw material costs.
   
4. High consistency and precision
   Moulding ensures dimensional stability of the product and meets the compatibility requirements of standardised logistics equipment (e.g. forklift trucks, shelves).
   
5. Cost Advantage
   Although the initial investment in moulds is high (tens to hundreds of thousands of yuan), the cost per piece is extremely low when diluted to mass production.

Blow Molding

Detailed Flow Description of Blow Moulding Process

1. Plastic Melting and Blank Extrusion: Plastic granules such as High Density Polyethylene (HDPE) are heated to a molten state, and formed into continuous hollow blanks through the extruder. 2.
2. Mould closure: the parison is placed in a pre-designed mould, which is closed and clamped to the parison.
3. Air blowing and expansion: Compressed air is injected into the parison through the air blowing tube to expand the parison and make it fit the inner wall of the mould to form the shape of the pallet.
4. Cooling: Cooling medium (e.g. water or air) is passed into the mould to make the plastic cool down and solidify rapidly to maintain the shape of the mould.
5. demoulding and trimming: open the mould, take out the moulded pallet and trim the excess edges and corners to complete the production.

Rotational Molding

Detailed flow description of the rotational moulding process

1. Loading: Plastic powder (such as polyethylene PE or polypropylene PP) is loaded into the mould.
2. Heating rotation: the mould is slowly rotated along two axes (horizontally and vertically) in a heating furnace, the temperature is usually between 200-400 ℃, so that the plastic powder is melted and uniformly adhered to the inner wall of the mould.
3. Cooling and curing: the mould enters the cooling zone (water or air cooling) and the plastic is gradually cured into shape.
4. demoulding: open the mould and take out the finished tray.

Process and pallet type

Summary

Through an in-depth analysis of injection molding, blow molding and rotational molding, we can better understand the technical core and application value of plastic pallet manufacturing. Injection molding has become the mainstream with its high efficiency and precision, while blow molding and rotational molding have their own strengths in specific fields. In the future, with the widespread application of environmentally friendly materials and intelligent technologies, plastic pallets will play a greater role in logistics and warehousing, while paying more attention to sustainability and efficiency.

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