Rotomolding

Rotomolding, also known as rotational moulding, rotomoulding, and plastic rotational molding, is a plastic formation process in which a mold is used to shape raw plastic material into a useable product.

The demand for shaped plastic products throughout industry, commerce and in consumer products contexts is very high. Because so many different plastic shapes are demanded from so many industries for use in so many different applications, a wide variety of plastic formation processes is necessary to accommodate them.

Rotomolding is a process used to create hollow plastic products. Plastic tanks, plastic flamingos and plastic construction cones are all on the list of potential rotationally molded plastics.

Rotational molding is used to create large products in limited quantities as well as small products in abundant quantities. The process is prized for its aptitude for generating plastic formations of uniform quality and precise wall width.

All kinds of plastic materials can be rotationally molded: PVC, nylon, high and low density polyethylene, PET, polycarbonate and many other thermoplastic varieties can be easily and effectively formed by rotational molding.

It can be used to create stock shapes for use in standardized applications, or specialized molds can be custom made to suit the needs of customers.

Rotomolded 550 Gallon Tank
Rotomolding – Sherman Roto Tank

The rotomolding process involves heating a plastic material beyond its melting point in order to give it a shape. In this way, it is not unlike other thermoplastic forming methods like extrusion and injection molding.

The difference is that in rotomolding, the mold moves and the molten plastic coats the mold as it rotates. The process begins with a collection of raw plastic material in a half mold. Once the mold is full, its other half attached and the mold is sealed.

It is then heated, causing the plastic material to exceed its melting point. Once sufficiently heated, the mold is rotated. Depending on the equipment variety, the mold can be rotated biaxially or in a single direction. Different equipment is chosen to form different kinds of shapes.

Once the molten plastic has coated the entire interior surface of the mold, the mold ceases its rotation and is cooled by an external water jet cooling system or by other methods.

The cooled plastic is then ejected from the mold, keeping the mold’s shape. Depending on the shape, the newly rotationally molded plastic product can be prepared for shipment to customers, or it can be sent for additional processing like cutting and surface treatment.

Rotomolding Informational Video