Rotational moulding is done by assembling metal moulds into a rotational mould system. The plastic powder is added and rotated while heating the moulds. A layer of plastic builds up, resulting in a constant wall thickness and a hollow centre.
Rotational Moulding – Plastic powder is loaded into a heated metal mould which then tumbles around forming a hollow shape with a constant wall thickness.
The tooling is relatively inexpensive because only the outside of the shape is required.
This is a low-pressure process and therefore mould and running costs are reduced greatly.
Typical applications – water and chemical tanks, recreational boats Kayaks and canoes, dog houses, road bollards, planters and large toys.
Quality – The surface takes on the dimensions and texture of the mould. The mouldings have a wall constant wall thickness that is stress-free. Shrinkage is only 3%. Warping may occur on large flat areas, it is best to compensate by adding some cross support sections.
Production ideas – Because of the hands-on process and large size production is slower than the likes of injection moulding, this however allows relatively short production runs. Set up time and costs are relatively low.
Products size – 10cm /10 m /3. Mouldings can be done individually or in a gang mould for multiples.
Materials – Polyethene (PE) is the most commonly used material. Polyamide (PA), Polypropylene (PP), Polyvinyl Chloride (PVA) and Ethylene Acetate (EVA) can also be used.