Rotational moulding is a manufacturing method which allows to obtain hollow products in one technological operation. The process's characteristics is that the melting, forming and cooling of the polymer takes place in a mould and no external pressure is applied. The molten material is evenly distributed over the walls of the mould cavity due to the rotation of the mould around two perpendicular axes. Rotational speeds are relatively low, therefore rotational moulding should not be confused with centrifugal casting. The external shape of the mould corresponds to that of the mould cavity.

Rotomoulding is a cyclical process and consists of four stages: loading, heating, cooling and unloading. Plastic, most often powdered, is introduced by an operator in the right amount into the moulding cavity. After the mould is closed (for this purpose, quick-release clamps are most often used), the heating phase begins and the mould rotation begins. When the mould cavity reaches the appropriate temperature, the polymer liquefies and begins to stick to its walls. The method of heating depends on the type of machine. The heat sources can be exhaust gases or hot air, the movement of which is increased by the fan. The next step is cooling, in which the rotary motion continues and the molten polymer solidifies. This phase can only take place from the outside. This results in extending the process time and minimising the unsymmetrical nature of cooling, which reduces product distortions. The method of cooling influences the structure of the material. Rapid cooling (with a stream of water sprayed on the moulds) increases the hardness of the product while reducing its stiffness. Slow cooling (with air) will increase the strength and stiffness of the cast at the expense of reducing impact toughness. When the solidified material reaches the temperature at which it maintains a constant shape, it is unloaded. The mould is opened and the cast is removed. Then another portion of the material is introduced into the mould and the cycle is repeated.

ADVANTAGES OF ROTOMOULDING:

• Manufacture of products of various sizes and complex shapes
• Low manufacture costs of the product compared to other technologies
• Low mould costs compared to other technologies
• Manufacture of products in short batches
• Very quick and easy colour change
• The possibility of embedding threaded inserts and other metal parts in the product.
• Manufacture of multi-layer products
• No internal stress
• No material loss during manufacture.
• Manufacture of products in one block, not filled inside.
• Fast production start-up time.

Meeting the expectations of our customers, ROTOSPACE uses only materials with the highest quality parameters in the production process. Therefore, we carefully select the suppliers of plastics.

We are sure that the success on the rotomoulding market is due primarily to over 20 years of experience of our staff and an uncompromising approach to product quality.

Extensive competences in the field of engineering, design, production and logistics make ROTOSPACE a trusted partner from concept to project implementation.