ABOUT ROTATIONAL MOLDING
Rotational molding is a highly versatile manufacturing option that allows for numerous design possibilities. The process starts with a good quality design and a mold that is placed in a molding machine that has a loading, heating and cooling area. Several molds may be placed on one machine at the same time. 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 a vertical and horizontal axis. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during 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 entire process.
There are several advantages to roto molding over other molding process. One is with the proper design; parts that are assembled from several pieces can be molded as one part, taking out expensive assembly costs.
Another advantage is cost. Tooling is less expensive, because the parts are formed with head and rotation, rather than pressure. So molds don’t need to be engineered to withstand the high pressures of injection molding.