Thermoforming vs. Rotational Molding

Monday, November 30, 2020

Meeting your plastic part design specs requires understanding a wide swath of different plastic production options. Selecting an inefficient production method can result in lost revenue, delays, or inadequate results. Industrial Custom Products provides consumers with insight into production methods from rotomolding to thermoforming so that you can select the method that works for your project.


Rotational Molding

Rotomolding, or rotational molding, is a process that utilizes hollow molds, powder resins, heat, and steady rotation. The powder resin is heated until it melts and then the mold is carefully rotated until the liquid coats the entire interior. Once this is completed, the mold is cooled. This process produces a wide range of hollow products at a relatively low upfront cost. However, due to the requirements inherent in this process, the options for the types of materials that can be rotomolded is fairly limited.

Rotomolding is especially effective when utilized to form plastic storage tanks and other large-scale hollow containers. This method is ideal for these types of projects as the materials conducive to rotomolding are suitable for storing wastewaters, chemicals, fuels, oils and more. Combining high-quality, versatile materials with the rotomolding process yields multilayer, hollow parts that require zero welding and no subsequent joining.

These parts can also be branded with graphics, molds, labels, and more as the design is being processed. This simultaneous incorporation circumvents any issues that your design may have encountered with stickers or paints adhering to the exterior of the final product, and mitigates potential breakage of add-on inserts. Instead, these graphics inserts are introduced to the plastic inside the mold cavity during the melting and forming process. This ultimately produces sturdy, fully incorporated inserts and decorations.



By contrast, the thermoforming process involves sheets of thermoplastics that are heated, molded, vacuum formed, and then trimmed. The cost of thermoforming is often lower than that of rotomolding as the tooling tends to be less expensive and the cost of parts lower. Thanks to advanced machining, the thermoforming process can also handle larger items, tighter tolerances, and efficient production. Plus, thermoforming is suited to a wider range of potential production materials that can be selected to best support any design.

Both methods offer specialty plastics forming, but for larger projects or projects that would benefit from specialty or high-color materials, thermoforming generally offers more possibilities than rotomolding. Rotomolding is durable and fairly quick, but thermoforming is better suited for detail work or projects that require flexible tooling. If you’re not sure which methodology best supports your project needs, consulting with a plastic production professional can guide you toward the solution that suits your needs.


Get in Touch with Plastics Experts

If you’re looking for thermoforming support for your design concept or project, Industrial Custom Products has the thermoforming services you’re looking for. Contact us and speak with an engineer about your project at (612) 781-2255, or request a quote online. You will receive a prompt response.


(Rotomolding .gif credit: CC BY-SA 3.0, Link)