Rotational molding and thermoforming are two manufacturing processes that can create plastic products. Compared to injection molding, both offer cost-effective tooling; however, there are some important differences to consider when choosing the best process for your project.

Does your application require ruggedness with reinforced corners and support for complex, enclosed geometries? Then rotational molding provides key advantages. Keep reading to learn more and contact Gregstrom for Made in USA rotomolding services.

1. Seamless, Hollow One-Piece Construction

Thermoforming requires secondary seams to create enclosed or fully hollow parts. By contrast, rotational molding produces fully enclosed, hollow parts in a single cycle without weld lines, pinch-offs, or joints. Because there aren’t any seams, rotomolded parts are free from failure points that are prone to leaking, splitting, or environmental stress cracking.

2. Virtually Stress-Free Molded Parts

Thermoforming stretches plastic sheets, which introduces significant residual stresses in the material. By contrast, rotational molding is a low-pressure process where polymer chains naturally relax as the mold cools. As a result, rotomolded parts are virtually free from molded-in stresses and can resist blunt impacts.

3. Reinforced Corners

Thermoformed sheets stretch and become thinner as depth increases, but rotomolding deposits extra material into outer radii and corners as the mold rotates. This creates thick, reinforced edges where parts experience impact and abrasive wear. The result is a plastic part with balanced strength that can stand up to tough field conditions.

4. Design Versatility and Part Consolidation

Rotational molding readily accommodates interior undercuts, molded-in inserts, graphic transfers, dual-wall insulation, and threaded fittings in a single operation. This eliminates extensive secondary operations for reduced costs and faster assembly times. By contrast, thermoforming may require secondary operations to attached hardware or integrate functional fittings.

Partner with Gregstrom for Rotational Molding

Thermoforming is a good choice for trays and parts with shallow open covers, but rotational molding offers advantages for strong, hollow, and impact-resistant plastic products like plastic boats and storage tanks. Gregstrom Corporation has decades of rotomolding experience and can produce parts that withstand tough field conditions.

Contact us to discuss your project.