Rotational Moulding Process
Rotational moulding (often referred to as Rotamoulding or Rotomoulding) is a process used for producing hollow plastic products. It differs from other processing methods in that the heating, melting, shaping, and cooling stages all occur after the polymer is placed in the mould, therefore no external pressure is applied during forming.
The process involves charging the hollow tool with a carefully predetermined quantity of resin powder and placing this into an oven which is then rotated slowly about two axes.
Resin heats up to the required temperature, fuses and adheres to the inner wall of the moulding tool, thereby taking its shape. Following a brief curing period, cold air (and sometimes water) is aimed at the mould which releases the plastic from the metal tool prior to remould.
Production cycle times vary depending on product size and wall thickness but can be as little as 10 minutes for a small, lightweight moulding.