Mainland Products, Inc.

Custom Molds for the Plastic Industry


Mainland Products, Inc.
2161 Maple Privado
Ontario, CA 91761
(909) 923-4353


Rotational Molding Process

At Mainland Products, we use the most up-to-date rotational molding technology available to custom create molds in virtually any size and shape—no matter how complex the design. Another major plus to this method of mold manufacturing is the wide variety of materials, performance characteristics, colors, surface textures and finishes we can offer. Rotational molding is much more economical and more precise than the alternative molding methods (i.e. conventional injection or blow molding).

A Three-Stage Process

After each unique mold has made its way through the design, model, female reverse pattern, and foundry or casting processes, it is custom framed and ready for the rotational molding machine. (See Services for more details on these processes.)

Rotational molding is a simple, three-stage, no-pressure plastic molding process: heat, cool, unload/reload.

• HEAT •

Heat is used while the mold slowly rotates on two planes. As the heat penetrates the mold, the plastic resin uniformly coats itself into the interior of the mold.

• COOL •

The cooling process starts immediately after the resin is completely fused to the mold. The temperature is gradually lowered by using cool air, water spray or a combination of both while the part continues to rotate.


Finally, the finished part is removed and the mold is recharged for the next cycle.