Rotational Moulding has a broad niche with regard to economies of scale. The factors of design costs, tooling costs, production volumes, unit costs, design functionality, tooling maintenance and, increasingly, environmental costs, all have to be taken into account.
Unlike other polyethylene moulding processes, Rotational Moulding does not involve pressure loading. Consequently the mould tools can use more cost-effective materials such as sheet steel and aluminium. Furthermore, Rotational Moulding tools are simpler to construct, as they require only a female element, and this can significantly reduce project lead times. The tooling is also easier to modify and maintain; designs can be “tweaked” during the lifetime of the tooling.
It takes high volumes before lower unit costs balance the high tooling costs of other methods of plastic manufacturing. Material costs and energy costs are equivalent; however, Rotational Moulding cannot be fully automated, so labour costs have to be incorporated into unit costs.
The larger the product, the higher the tooling cost difference will be, making Rotational Moulding the most cost-effective method of manufacture for all but small size, high volume items.
Rotational Moulding is also quick to set up, making small batch production possible to match variable demand. This helps reduce stockholding and potential redundancy of stock.
Few processes use materials as cost-effectively or with as little environmental impact as Rotational Moulding. The vast majority of Rotationally Moulded products use thermoplastics such as polyethylene or polypropylene, which can be recycled and re-used, so enhancing your environmental policy.