Rotational moulding is a technique which is used to produce small to large hollow plastic components. Firstly, a hollow mould tool is produced, with interior dimensions that reflect the required design. The material (often in a powder format) is then placed inside the mould, where it is heated and becomes molten. The mould is then slowly rotated on two axis, allowing the molten material to coat the entirety of the inside of the mould. Once the interior of the mould is thoroughly coated, it is then cooled, allowing the material to solidify. Upon completion of the cooling process, the solidified component is retrieved by opening the mould.
Unlike other moulding methods, rotational moulding does not rely upon pressure in order to force the material into the mould cavity. This means that the corresponding tooling costs for rotational moulding are cheaper than other moulding methods, as the mould tool does not have to withstand the introduction of pressure. Rotational moulding usually uses polyethylene material to produce parts, although polypropylene and PVC are also occasionally used.
