Rotational Moulding – The Ideal Process For Manufacturing Hollow Plastic Products

Whatever industry you work in, there is a strong likelihood that plastic components play a part in the work you do. From oil and fuel tanks to cabs for tractors and JCBs, from pipes and ducts to medical equipment, plastic parts are everywhere. Companies are always on the lookout for more reliable and cost-efficient ways of mass-producing the components they need.

Rotational moulding is a particularly cost-effective process for manufacturing hollow plastic products. Because this process is so versatile and very little waste is produced, costs are low compared to other plastic manufacturing processes, such as blow moulding or injection moulding.

How the rotational moulding process works

Believe it or not, the process which is used to create such a versatile range of plastic products was originally developed for creating chocolate Easter eggs. Although the technology is far more sophisticated these days, the basic rotational moulding process remains the same.

In rotational moulding, polymer powder is slowly tumbled in a heated, enclosed mould. The powder melts, forming a coating over the internal surface of the mould. The mould is cooled, allowing the polymer coating to become solid. The mould is then opened, and an accurately shaped plastic part is extracted.

Rotational moulding is a highly versatile method for making a precise, stress and seam free plastic product at comparatively low cost. The process can produce complex shapes with controlled wall thickness in a variety of materials. It is particularly suitable for manufacturing hollow or partially hollow pieces.

By selecting from a range of different materials, articles with physical properties as varied as flexible gearstick gaiters or rigid commercial vehicle cab components can be made. Metal inserts such as threads and bushes can be moulded in, and moulded cavities filled with foam. Alternatively, threads may be part of the moulded shape itself. Mouldings may be CNC machined, drilled, sawn, routed, tapped or welded.

The appearance of the product can be enhanced by applying a surface texture or paint. The look and feel of other materials such as metal and leather can also be simulated. If more rigidity or insulation are part of the design, an inner foam layer can either be moulded integrally or injected into hollow sections after moulding.

Rotational moulding can produce a huge variety of plastic products

The uses for rotomoulding are extensive, stretching far beyond the basic enclosed box or tank for which the process is best known. Rotational moulding can produce components for machinery, furniture and fittings for aircraft, even products for the home or garden.

By choosing the correct polymer, tecni-form can produce articles with various physical properties: thus the result can range from extremely flexible – inflatable even – to very rigid and impact-resistant, such as a protective capping.

Although a moulding starts as an enclosed hollow shape, that does not limit the shape of the final product. For example, the original moulding can consist of two or more combined shapes which can then be separated to produce two or more separate products.

As rotational moulding is such an adaptable plastic manufacturing process, it can be used to create components for a wide range of industries. From the automotive industry to the world of advertising, from furniture to medical supplies, rotationally moulded plastic products are used in most market sectors.