Rotational Molding


Rotational Molding is a high-temperature, low-pressure, plastic forming process for producing usually hollow parts. It starts with a high quality mold that is placed in a rotaional molding machine that has a loading, heating and cooling area.

Pre-measured plastic resin is loaded into each mold. They are then moved into the oven where they are slowly rotated on both the vertical and horizontal axis. The rotational speed, heating and cooling times are computer controlled throughout the process. As the resin melts it coats every surface of the hot mold. During the cooling cycle the mold continues to rotate so the parts retain an even wall thickness. As the parts are cooled they release from the mold.

With IRM’s specialized Rock and Roll machine, which uses 3-3.5m BTU Natural gas burners for heat, we can electronically monitor and control the entire process. The single arm rotates (or rolls) the mold continuously 360 degrees and at the same time rocks the mold up to 45° above or below the horizontal line. The computer controls the speed of the rock and roll to any setting for even and/or varying wall thickness as required. The cooling process is electronically controlled utilizing atomized mist and forced cool air, gradually lowering the temperature to optimize the final physical properties of the finished part.

Our state of the art Rock and Roll machine, which is the largest in North America, is capable of molding parts of various shapes and sizes up to 28’ in a vertical line by 14’ in diameter. Complementing this machine, we have a “Rotoline DC2.50 XT” for smaller parts.