The Rotational Molding process is simple in concept. Heat is used to melt and fuse a plastic resin in a closed mold. Rotational Molding does differ from other processes as it is all heat transfer and centrifugal force driven, no pressure is involved. The three-stage process includes loading the resin into the mold, heating/fusion of the resin and cooling and unloading the mold.

The mold is opened and a pre-weighed amount of resin is poured into the mold cavity. The pre-weighed amount of resin will determine the nominal wall thickness that the product will have. More Resin = Thicker Walls, Less Resin = Thinner Walls. The mold is then closed and is ready to move onto Stage 2.

At this time, the mold is moved into the oven chamber where the mold is generally 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.

Once the Oven Cycle has completed, the mold is then moved to the cooling chamber where it is cooled by air and/or water spray while still rotating, lowering the temperature in a gradual manner. This process solidifies the plastic into its hardened state. The mold is then moved out of the cooling chamber and opened. The finished molded part is removed from the mold and the mold is recharged so it can begin Stage 1 again.