02 March 2021

What is Rotational (or Roto) Moulding?

Rotational Moulding (also known as rotomoulding) is a modern method of manufacturing extremely durable plastic products for today’s marketplace. Rotational moulding is often used for parts that require high-quality finishes, uniform wall thicknesses, high stability and one-piece construction.


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The rotational moulding process is a high-temperature, low-pressure plastic forming process that uses heat and biaxial rotation (i.e., rotation on two axes) to produce hollow, one-piece parts. The mould is placed in a large oven while it rotates on two axes at different speeds, which helps prevent powder from accumulating in one spot. The polyethylene melts and adheres evenly to the wall of the mould. Once the polyethylene is melted, the moulds are pulled out of the oven to cool. And once cool, the product (water tanks in our case) is then removed from the mould. It’s like a huge, spinning oven that cranks out tanks instead of baked dinners.

Advantages of Rotational Moulding

Rotational Moulding boasts a number of advantages over comparable moulding methods:

Consistent wall thickness:

the constant rotation of the mould coats the walls evenly during both the heating and cooling processes.

High durability:

parts are moulded as one solid piece, eliminating the need for joining techniques such as welding and joint fabrication which creates weak spots.

High stability:

the moulding material isn’t exposed to external pressure, increasing its stability and reducing the risk of defects in the finished part.

High strength:

rotational moulding creates thicker corners, reducing the risk of failure in these stress-concentration points.


the metal used for the rotomould tooling easily accommodates a variety of surface finishes.

The method of rotational moulding is so popular that it has become one of the fastest-growing sectors in the plastics industry in the last ten years. From residential to agricultural and industrial, Orion Australia, have our own onsite manufacturing facility that produces poly rainwater tanks using the rotational moulding process to ensure unparalleled quality, durability and lifespan! View our quality range of POLY WATER TANKS here.

LIKE TO KNOW MORE? Check out the following videos