Rotational moulding is a very competitive alternative to blow moulding, thermoforming and injection moulding for the manufacture of hollow plastic parts. It offers designers the chance to produce stress-free articles, with uniform wall thickness and complex shapes. Typical moulded parts include bulk containers, tanks, canoes, toys, medical equipment, automotive parts and ducts. There are many advantages associated with rotational moulding. Firstly, the moulds are relatively simple and cheap, because the process is low pressure, unlike injection moulding. The wall thickness of parts is more uniform and it is possible to alter the wall thickness without changing the mould. Complex parts with undercuts ad intricate contours can be manufactured relatively easily. There is also very little waste as the required weight of plastic to produce the part is placed inside the mould.