Rotational or rotomoulding is an extremely popular and well-used process for producing items that are usually hollow. It's most often used for very large articles which are usually made in small quantities. Items such as children's toys, garden furniture and road traffic bollards are manufactured by rotational moulding.  Rotomoulding uses polyethylene in powdered form which is introduced into the mould along with any additives such as pigments or finishers.

The mould is closed and then spun both vertically and horizontally and moved into an oven. As the powder starts to melt and the mould continues rotating, it's flung to the walls of the mould by centrifugal force where it forms a skin. After a fixed period, the mould is removed from the oven and allowed to cool carefully to avoid the product shrinking or warping.