Rotational Molding

Rotational Molding begins with the melting of a plastic resin in a closed mold. Unlike most other plastic processes, no pressure is involved. The three-stage process includes loading the resin in the mold, heating and fusion of the resin and cooling and unloading the mold. After the charged mold is moved into an oven, the mold is rotated on two axes at low speed. As heat penetrates the mold, the resin adheres to the mold's inner surface until it is completely fused. The mold is then cooled by air or water spray or a combination of both while still rotating, lowering the temperature in a gradual manner. The mold is opened, finished part removed and mold recharged for the next cycle. Cycle times vary from 7 to 60 minutes, depending on part size, material and wall thickness.