That is, the powder or paste material is first injected into the mold, and through the heating of the mold and the vertical and horizontal rolling rotation, the material can be evenly filled with the mold cavity and melted by its own gravity and centrifugal force. After cooling, the mold is demolded. Get hollow products. Because the rotational speed of rotomolding is not high, the equipment is relatively simple, the product has almost no internal stress, and it is not easy to deform and dent. At first, it was mainly used for PVC paste plastic to produce small products such as toys, balls, bottles and cans. Recently, it has also been widely used in large products. The resins used include polyamide, polyethylene, modified polystyrene polycarbonate, etc.

A molding method similar to rotary casting, the difference is that the material used is not a liquid, but a sintered dry powder. The process is to put the powder into the mold and make it rotate around two mutually perpendicular axes. After being heated and uniformly fused on the inner wall of the mold, the hollow product can be obtained from the mold after cooling.

Also called rotational molding or rotary molding. The powdered plastic (such as LLDPE) is added into the closed mold, the mold is heated while rotating, the plastic is melted and evenly attached to the surface of the mold cavity, and after the mold is cooled, a plastic hollow product with the same shape as the mold cavity can be obtained, such as a boat , boxes, barrels, pots, cans, etc. It usually consists of basic steps such as feeding, molding, heating, cooling, demolding, and mold cleaning. This method has the advantages of low product shrinkage, easy control of product wall thickness and low mold cost, but low production efficiency.