Pre-measured plastic resin is loaded into each mold, and then the molds are moved into the oven where they are slowly rotated on both the vertical and horizontal axis. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during the cooling cycle so the parts retain an even wall thickness. Once the parts are cooled, they are released from the mold. The rotational speed, heating and cooling times are all controlled throughout the process.
Rotational molding offers design advantages over other molding processes.
With proper design, parts that are assembled from several pieces can be molded as one part, eliminating expensive fabrication costs. The process also has a number of inherent design strengths, such as consistent wall thickness and strong outside corners that are virtually stress free. If additional strength is required, reinforcing ribs can be designed into the part. Rotational molding delivers the product the designer envisions. Designers can select the best material for their application, including materials that meet FDA requirements.