Rotational molding, also called rotomolding or rotocast, is a manufacturing process used in the plastics industry that has tremendous upside potential, yielding products with a wide range of consumer and industrial applications. Plastic components produced in this manner are used for sporting goods, toys and even in the transport of nuclear materials. The manufacturing process has evolved over the years into a highly efficient, cost-effective method for producing plastic-based goods.


Rotational Molding Basics

Rotational molding involves inserting plastics into a heated, hollow mold that rotates with the intention of creating components or complete products. This process varies depending on the equipment and plastic being used, but the basic process is the same. Once inserted in the rotational molding machine, plastic is heated to the point that it softens, causing it to disperse evenly into the mold. It is important that the speed of rotation is constant so that the plastic distributes evenly. After the plastic is applied to the mold, it is steadily cooled so that the new form can solidify and take on its intended shape.

Manufacturing Process

The production process is a relatively simple one, which is one of the reasons industrial manufacturers frequently use rotational molding. It also produces small amounts of waste that can often be reused or processed into a by-product. At a high level, the manufacturing process consists of four distinct phases, including loading the plastic, heating the plastic, cooling the plastic and removing the final product from the mold. A fifth possible phase is clean-up and maintenance, which is a standard best practice in most production facilities.

Given advances in technology and computer-aided manufacturing equipment, rotational molding has gained in popularity in the industrial sector. Process control and quality assurance has improved exponentially since the technology was first utilized in the 1940s. When manufactured properly, products created using rotational molding can meet high quality thresholds, resulting in fewer internal and external product failures and lower operating costs.

Equipment & Setup

There is a full spectrum of rotational molding machines on the market, but there are similar components to each type. These components include a mold or molds, cooling chamber, heating mechanism, oven and mold spindles. Molds are typically made from strong materials such as welded sheet steel, giving the machines a long useful life. Setting up this type of equipment for production can be labor and cost intensive at first. However, once the machine is in place, the setup consists of allocating the proper amount of plastic and keeping the molds free of debris while inspecting for maintenance issues.

Equipment used in the production process include:

  • Rock and Roll Machine
  • Carousel Machine
  • Shuttle Machine
  • Clamshell Machine

Applications & Products

The applications of rotational modeling are far reaching, including products that meet U.S. Food and Drug Administration requirements. Common products include furniture, road signs, storage tanks and road cones, just to name a few. Other specialized, highly sensitive applications include UN-approved containers for the transport of nuclear materials, lightweight components for the aerospace industry and anti-piracy ship protectors. As the technology continues to evolve, so too will the applications of rotational molding continue to grow, improving the lives of people all over the world.

Rotational molding has many distinct advantages, making it an ideal manufacturing process for everyday products as well as industrial components that require high levels of precision and reliability. It is a cost-effective and highly efficient way to meet production goals and enhance customer satisfaction.

Questions? Comments? Let us know in the comments section below.

Interested to learn more about plastic manufacturing? Download our free glossary of terms!


Leave a Reply

Your email address will not be published. Required fields are marked *