Rotational Moudling | Crompton Mouldings

What is Rotational Moulding?

Rotational moulding, roto-moulding or rota-moulding is the process of hollow plastic moulding, multiple materials can be used but the most commonly used material is polyethylene. This is a relatively cost-effective process for a large range of plastic products, small to large from lawn mower wheels to boat containers.

Charging

Cooling

Heating

Demolding

How's it Made?

A hollow tool manufactured from sheet steel, cast aluminium or CNC machined aluminium depending on the product design and complexity is charged with a specific volume of plastic powder, each individual tool has its own powder weight depending on the size of the product and wall thickness, wall thickness can be determined by upping or lowering the volume of powder used.

Once charged the tool will enter an oven at a predetermined temperature and will begin rotating on a vertical & horizontal plate, this process adheres the inner lining of the tool with molten plastic and begins to form said product from the outside in, creating a hollow cast.

After a set time the tool will leave the oven and enter its cooling station, continuing to spin on a vertical & horizontal plate the molten plastic inside the tool will begin to cool this process shrinks the product pulling it away from the tool wall and is now ready to be emptied.

Advantages of Rotational Moulding

Wall Thickness

Wall thickness can be easily modified for each product by increasing or decreasing the shot weight which is poured into the tool.

Low Tooling Costs

Compared to other moulding processes such as injection moulding, rotational mould tools are relatively inexpensive.

Durability

Products achieve a uniformed wall thickness throughout the process which eliminates the risk of weakened areas which can cause failure in application.

Size

There are few limitations on size ranging from a cup size shape to a shipping container.

Other Processes

Rotational moulding can include graphics, steel inserts, foam for buoyancy or rigidity and may other engineering forms can be assembled to produce a complex product part.