In principle, rotational casting is a simple process consisting of four stages:
The casting mould is opened and a pre-weighed amount of plastic powder is placed in the casting mould. The powder may be treated in advance 3to the desired colour, or pigment may be mixed dry in the powder prior to filling it into the mould.
The casting mould is closed, normally by means of quick clamps. Thereafter it is rotated biaxially around two normal axes in a heated environment. The rotational speed is relatively low, less than 20 rpm. The powder is rotated while being heated and melts gradually.
When the powder has melted, the mould is cooled while still rotating and the product hardens.
When the plastic has cooled and hardened, the casting mould is opened and the product removed. By then, the plastic article has obtained the same shape as the mould. New powder is then placed in the mould and the process repeated.