Rotational molding, or rotomolding, is a cost-effective way to produce large parts. Plastic resins are loaded into a mold that is heated as it is rotated slowly on both the vertical and the horizontal axis. This simultaneous heating and rotationdistributes the material on the inner surfaces of the mold and fuses it.
Rotomolding is a four-phase process, which comprises loading, heating, cooling, and unloading the mold. In the first stage the pre-measured plastic resin is loaded into the mold. (Polyethylenes and plastisols are the most common of the many materials used in rotomolding resins.) Several molds may be loaded on a given machine at the same time.
The charged molds are then closed and moved into the oven, where they slowly rotate on two axes. As the heat penetrates the molds, the melting resin adheres to the mold’s inner surface until it is thoroughly fused, evenly coating the entire surface.
During the cooling phase, the mold continues to be rotated to maintain evenwalls as air, water spray, or a combination of the two gradually cools the mold. The mold is then opened , the finished part removed, and the mold is ready for its next cycle.