Rotational Molding

Why Rotational Molding?

Rotational molding is one of many plastic processes specifically known for producing extremely durable parts with a very long lifespan. Many materials can be roto-molded but polyethylene is the most commonly used material. Requirements for this process includes a mold or tool, which can be built by a number of methods, including casting, machining or fabricating a mold. Design for rotomolding is essential to successful part production. Granger Plastics Company is an authority in rotational molding with specialized experience with large, complex products, complete offering of secondary services including, trim, assembly, foam filling, packaging, drop shipping, material conversion from less durable materials to polyethlene and more. The rotomolding experts at Granger Plastics can help you determine if the rotational molding process is right to produce your part or project.

Rotomolding Process

Rotational Molding is an extremely specialized and unique process. Heat is used to melt and fuse plastic resin in a closed mold. Unlike most other plastic molding processes, no pressure is involved. The four-stage process includes loading the resin in the mold, heating and fusing the resin, cooling and finally unloading the part from the mold. After the charged mold is moved into an oven, the mold is rotated simply upon a rotating two axes arm at a low speed. As heat penetrates the mold, the resin adheres to the mold's inner surface until it is completely fused. The mold is then cooled by air or water spray or a combination of both, while still rotating, thus lowering the temperature in a gradual manner. The mold is opened, finished part removed and the mold is recharged for the next cycle. A variety of materials are available. The most widely used is polyethylene. Other potential materials include plastisols, nylon, fluoropolymers, polycarbonate, polypropylene, polyurethane, and elastomers. With the Rotational Molding process, parts can be molded economically in a variety of shapes and sizes, many of them would be impossible to produce by any other process.

Granger Plastics Rotational Molding

The Granger Plastics Company is a full service custom rotational molder that excels at molding parts of all sizes, shapes and for many applications. With wall thicknesses that range from .250 inches to 1" and greater Granger is able to manufacture parts with many capacities. A variety of materials are available to suit particular needs including prime virgin material, recycled and reprocessed materials as well as FDA approved food grade materials. Assembly services are also available for custom orders. Offering excellence in design services for businesses partnering with Granger Plastics, this rotational molder is known worldwide for manufacturing extremely durable products that have incredibly long life expectancies and are capable of handling the abuse and punishment of everyday use for years and years to come.

Custom Rotational Molding

Granger Plastics Company, American rotational molding leader, is available for complete custom manufacturing services including costing, design, mold making, manufacturing, assembly, order fulfillment and warehousing. Contact Granger about your rotational molding project today and let our experience guide you to excellence.

Click below for additional Rotational Moulding Information:


Rotomolding Picture Gallery

Click on any of the thumbnail images to the right to see the image in the larger gallery view. To learn about Rotomolded Products and capabilities, please see the Granger Plastics Products & Capabilities.

Product gallery
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  2. Rotational Molding, Roto-Molding, Plastic Roto Molding, Rotocasting, rotomolding, Rotational Moulding,
  3. Rotational Molding, Roto-Molding, Plastic Roto Molding, Rotocasting, rotomolding, Rotational Moulding,
  4. Rotational Molding, Roto-Molding, Plastic Roto Molding, Rotocasting, rotomolding, Rotational Moulding,

Rotomolding Videos

Watch in the videos below to learn more about the rotational moulding process. Learn more about the capabilites, durability and the manufacturing process of Rotational Molding. Additional Rotational Molding videos can be found at

About Granger Plastics Rotomoulding Video

Granger Plastics Rotational Molding

Rotomolded Tornado Shelter Door FEMA 320/FEMA 361 testing

See the industry leading Granger ISS Storm Shelter go thru FEMA 320 and FEMA 361 testing using the SAME DOOR! How is that for Rotational Molding strength and durability!

Rotational Moulding Links

Granger Plastics Rotational Molding Information

For more information on Granger Plastics Rotational Molding: Click Below

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Granger Plastics Company Rotomoulding Information






  • Rotomolding Tooling being built, Rotational Molding Tooling

    Rotational Molding Tooling

    Rotationally molded items require a mold or a tool to produce. While prototypes can be easily mapped out using a variety of processes, production projects must have tooling designed and produced to materialize. Tooling varies greatly in cost and time to produce before manufacturing can begin. Contact Granger Plastics for a complete quote including tooling costs.

  • Rotomolding Design, Rotational Molding Design

    Rotomolding Design

    Design for rotational molding requires knowledge of the process and its many variables. The nature of this application requires certain design elements to be implemented in order to produce the most reliable parts. Granger Plastics Company leads the industry in groundbreaking innovation in rotomolding design.

Rotational Molding Info

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