Rotation moulding:
Rotation moulding is a process mainly to create hollow shaped products such as balls. The machine works by having 3 separate arms that rotate around a central point, these stop at different stages, otherwise known as processing points. Moulds are attached to these arms and are rotated throughout the moulding process. The only times in which they are not being rotated is the first stage (where the moulds are filled with the plastic granules) and the final stage (where the product is removed).

The stages of Rotational moulding:
1- The first stage of rotational moulding is simply filling the mould with thermoplastic granules/pellets
2- The second stage would consist of transferring the mould into an oven chamber where the plastic is heated to mould to the shape of the cavity
3- The machine then rotates with heat, after this the mould is put in to a cooling chamber where it is cooled by cold air or jets of cold water.
4- The final stage is when the product has been cooled; it is removed from the mould as a complete product.

Extrusion moulding:
This product can be compared to toothpaste being squeezed from the tube. It is a continuous process that can be used to create solid and hollow products that have the same cross section throughout. It cannot create a shape with an alternating cross section as the die is one solid shape.

The stages of Extrusion moulding:
1- Thermoplastic granules are put into a hopper which are then fed through the machine by a rotating screw that runs throughout the whole machine, this runs through the heating area, where when the plastic granules run through it, are melted down into liquid.
2- The plastic granules are given a plasticiser after being heated, which adds a flow property making it easier to flow through the die
3- As the plastic flows through the mould; it is cooled by water coolers so that it comes out the other side as a hard, solid shape.