The arrival of the Promens businesses has also seen the introduction of a new technology into the RPC Group portfolio.
Rotational Moulding is ideal for the production of complex and hollow plastic parts for the vehicle, construction, agriculture and industrial bulk containers (IBCs) markets.
The process comprises a four-stage process. Plastic powder is first sealed into the tool, which is fixed on a machine arm. The arm then starts to move the tool in a slow bi-axial rotation. This means that one rotary movement takes place around the axis of the machine arm and another around the mould carrier plate on which the tool is mounted. At the same time, the arm moves the tool into the heating chamber, where the powder melts and creates a layer of plastic on the inner surface.
The arm continues to rotate and moves to a cooling station where the tools are cooled down by air or an air/water mixture. Once the plastic is solidified and the formed plastic part created, the rotational movement stops and the machine arm moves to the next station, where the mould is opened and the part removed. The mould is then recharged and the process starts again.
Rotational moulding offers a continuous circle of recharging, heating, cooling and demoulding using just one machine. The roto machine can itself contain several arms, each with several moulds.
Many roto-moulded plastic products also require additional parts such as inserts and flanges, which can often be of metals, including brass, steel and aluminium. Providing the melting point of these materials is above that of the plastic, these can be directly moulded into the part during the process so that after cooling, they form a permanent connection.
Rotational Moulding offers cost-effective manufacturing of products from 300 to 30,000 units per year. It is ideal for the production of complex and hollow parts, with tooling relatively inexpensive compared to blow moulding and injection moulding options. The process offers excellent design flexibility and multi-functionality including the integration of items such as components, fixings, flanges and connectors, as well as fast realisation from concept to finished part. It ensures an even wall thickness with no seams or welding, and multilayer products can also be produced.
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