Manufacturing process - Plastics

Injection moulding 

Granulated or powdered thermoplastic material is heated, melted and the forced under pressure into a mould. Once in the mould the material cools, forming a component that takes the shape of the mould cavity.

Rotational moulding

Rotational moulding is a process used mostly to create hollow items e.g. tennis balls etc. and uses plastics or polymers in which to do so. The plastic that is used is usually in the form of powder as it is easier to heat and saves space during transportation. The mould is heated so when the material is placed in the mould it is heated and therefore can flex into a variety of shapes.  The mould is slowly rotated so the heated plastic sticks to the outside of the walls (centripetal force) of the mould to create the hollow item. The precise amount of material which is usually plastic has to be weighed very precisely so that some parts of the item are not thicker than other parts. The mould continues to rotate during the heating phase so that the end result is not deformed in any way. Once in the mould the material cools, forming a component that takes the shape of the mould cavity.