The overall aesthetics of the finished product is assessed within the design brief, for instance, the parting line may not be critical for a product buried below ground level but will need to be masked for say, playground furniture. Where a complex shape dictates a multiple mould (i.e. more than two parts) the design may include a hinged or sliding arrangement for opening the mould in a defined sequence.

The factors affecting user friendliness, productivity, longevity of the mould, maintainability and product function and quality issues are given timely consideration in the product, material, moulding process and mould design. Rota Design considers the "overall system" and not just the individual elements in isolation.

shrinkage, expansion & contraction and dimensional variation

Shrinkage occurs within rotational moulding materials which has the advantage in assisting with removal of complex shaped components from the mould but gives the product designer tolerance problems especially at dimension sensitive locations such as abutments and joints. The other factor to be considered is that during the heating and cooling cycles the mould will expand and contract dependent upon the material being used.

Within the moulding process shrinkage variations occur as a result of ambient temperature fluctuations, process times and machine parameters. Rota Design is aware of these limitations and wherever possible turn a process disadvantage to an advantage by engineering out the problem as the product design evolves.