Rotomold
A rotomold is a device used to make one-piece, hollow plastic parts. It is used in conjunction with a machine that heats molds on revolving axes and spindles. Rotomolding is a versatile process that can be used to make a vast number of shapes at a low cost. Through the rotational molding process, several pieces can be molded together as one, eliminating any assembly costs.
Many different types of plastics can be used to make rotomolded plastics, although most are made of polyethylene. Other plastics used in rotomolding include nylon, Polyvinyl chloride (PVC), and polypropylene. Various plastic products can be made through the use of a rotomold, including bottles, kayaks, hot tubs, trash bins, and helmets.
From start to finish, the rotomold process takes anywhere from 15 to 90 minutes. This process is a series of four steps or stages. In stage one, the plastic resin is loaded into metal molds. In the second step, the mold is heated on revolving axes and spindles. During stage three, the plastic is cooled with a fan. The last step involves simply removing the plastic part from the mold.