Serving the UK & IE plastics industry

What Is A Rotational Moulding Machine And How Do They Work?

Rotational moulding (also known as rotomoulding) does not involve the use of a plasticising unit. Instead of injecting or extruding molten material under pressure, the process uses materials such as powdered polyethylene that are cast within a hollow tool.

Multi arm rotational moulding machine

A multi-arm rotational moulding machine with heating and cooling stations.

The tool is typically constructed from aluminium or sheet steel and is manually opened and closed to fill with powder and remove the finished part. The usual process is:

  • The tool interior is sprayed with a release agent that makes it simpler to remove the finished part.
  • The required amount of powder is placed within the tool, which is then closed.
  • The tool, which is attached to the arm of a rotational moulding machine, then turns the tool through two-axis within an oven. This melts and evenly disperses the material on the inner surface of the tool.
  • The machine’s arm then moves to a cooling station, where it continues to turn the mould through directed air or water jets.
  • Once solidified, the tool is opened and the part de-moulded.

Rotational moulding is a labour intensive and relatively slow process, so multiple tools are typically cycled through the various stages. To achieve this, the machine can have up to 4 separate arms. Shuttle machines move the tool in a linear manner through the stations, so only tend to have one or two arms, but swing and carosel designs can be more complex.

Visit here to contact the leading UK companies that can provide you with advice and quotes for your rotational moulding machine requirements.

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