Process	Rotation moulding
	A plastic moulding process carried out in four steps, especially suitable for hollow parts, parts with low residual stress (no stress corrosion) and thick walled parts. Parts with negative slip-angles (undercuts) can be made as well. First, the required amount of plastic material is poured into the mould which is then closed. While rotating around two axes the mould is first heated to the melting-point of the plastic and then cooled again. Finally the mould is opened and the finished part is removed. No finishing operations, like removal of runners, are required. Mainly for small production volumes.
Danish Name	Rotationsstøbning
Category	Mass conserving processes, Shaping plastics
Materials	LDPE HDPE PVC
Typical products	Boat fender Street bollard Inspection well
Competing processes	Blow moulding
References	Nordisk Wavin A/S Dan Hill Plast A/S
Price notes	Moulds are normally made from metal, but compared to injection moulding are tooling costs much lower. However cycling times are higher.
Photo	Thomas Nissen (Computer graphics)
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