Once the parts are cooled, they are released from the mold. The rotational speed, heating, and cooling times are all controlled throughout the molding process.

the Association of Rotational Molders International, says that rotational molding offers design advantages over other molding processes because parts that are assembled from several pieces can be molded as one part, eliminating expensive fabrication costs. There is consistent wall thickness and strong outside corners that are virtually stress free, and if additional strength is required, reinforcing ribs can be designed into the part.

Additives to help make the part weather resistant, flame retardant, or static free can be specified. colors  added to the mixture are even through OUT the material so scratches do not turn white AS WHAT HAPPENS WITH MOST OTHER PRODUCTS THAT HAVE A FINISH ON THEM. Inserts, threads, handles, minor undercuts, flat surfaces that eliminate draft angles, or fine surface detail can all be part of the design. Designers also have the option of multi-wall molding that can be either hollow or foam-filled.

Compared to injection and blow molding, rotational molding can easily produce large and small parts in a cost-effective manner. Tooling is less expensive because there's no internal core to manufacture, which also means minor changes can easily be made to an existing mold. And because parts are formed with heat and rotation, rather than pressure, molds don't need to be engineered to withstand the high pressure of injection molding.
CONCLUSION: THE CUSTOMER GETS A BETTER LONGER LIFE, MORE MAINTENCE FREE PRODUCT AT ABOUT 1/3 THE COST OF PRODUCTS DONE BY OLDER PROCESSES.