MARCH 2019

Think you know everything about rotomoulding? Here are 10 things you may not know about rotamoulding:

Variety of Polymers

A variety of polymers may be used but the most common is Linear Low Density Polyethylene (LLDPE)


Aluminium Cast

Moulds are made of either formed sheet steel or cast aluminium


Slow Process

The process is slow compared to injection moulding, blow moulding and extrusion moulding


Bigger Size

Much bigger products are able to be made using rotational moulding than the other plastic moulding processes



A properly functioning breather is critical as there is a lot of airflow out of the mould during the heating cycle and a similar amount of airflow into the mould during cooling cycle


Cooling Process

The cooling process is more important and takes as long as the cooking process


Baking Process

The correct baking process is critical as an under cooked product has porosity (air bubbles in the plastic) and weakness in the walls and over cooking creates a brittleness


Mould Size

The polyethylene shrinks 3% during the cooling process! This means that the moulds are made slightly bigger than the final product needs to be



Graphics are able to be added to the mould before a cooking cycle which then become embedded in the product for the life of the product



Following the de-moulding process, the product requires trimming along the part-line to remove any excess material that might have formed