CANNON FALLS, Minn., January 10, 2024 – Rotomolded fuel tanks made of acetal, produced via Gemstar Manufacturing’s Robomold® robotic rotomolding technology, have been identified as a highly viable alternative to fluorinated fuel tanks in the wake of an Environmental Protection Agency (EPA) decision to halt the production of fluorinated coatings for HDPE containers due to PFAS contamination. As a fluorination-free solution, Gemstar has commercialized several EPA-certified acetal fuel tanks made with its unique Robomold® robotic rotomolding process.

“Our innovative technology is a highly viable option that can fill the emerging needs of OEMs and molders who are struggling to fill production needs amidst disrupted supply chains,” said Kevin Lumberg, Channel Manager for Gemstar Manufacturing.

Gemstar’s exclusive Robomold® technology provides tighter tolerance control with precision-distributed heat and material control for consistent part repeatability and optimized strength-to-weight ratios. It also allows for unsurpassed design flexibility including the ability to layer different compounds and coatings into finished parts. Rotomolded acetal fuel tanks provide single-layer barrier protection that meets EPA requirements in comparison to injection molded HDPE tanks that require fluorination.

Nylon 6 has historically been the only material option to achieve a permeation barrier with a single-layer rotomolding process. However, nylon 6 is difficult to rotomold and yields a high scrap rate and poor cosmetic appearance. In comparison, acetal delivers a single-layer structure that achieves permeation requirements and provides good processability, low scrap rates, and favorable cosmetics.

Acetal has previously been used in injection molded fuel tanks but material suppliers have now developed new rotomolding grades that incorporate additive packages that raise the heat performance.

Robomold’s computer-controlled technology allows for precise control of multiple heating and cooling zones, customized material flow, optimized material use, increased product quality, and part traceability. It also offers instant cycle data collection, reduced cycle times, focused cycles for highly engineered resins, and the elimination of labor-intensive processes.

The core of the technology is a six-axis robot which delivers a greater degree of rotation than traditional rotational molding. Instead of using a heating oven, the robot tumbles the electrically heated mold which incorporates a multitude of separate heating zones. Direct heat applied to these zones enables plastic resin to reach its ideal processing temperature and permits manufacturers to create geometries that were previously unattainable.

Robomold® also delivers a range of sustainability advantages compared to conventional rotational molding. Robotic rotational molding reduces cycle time by 25-30% with little to no scrap compared to traditional rotomolding. Researchers at Queens University Belfast recently reported that Robomold’s electrical mold heating method takes significantly less time to heat the mold compared with a conventional oven, saving more than nine minutes (22%) with no appreciable difference in part quality.

As end-use requirements become more stringent, Robomold® robotic rotational molding is also finding greater use in custom applications. It is ideal for military, OEM, industrial, and commercial applications where precision and unsurpassed repeatability are required.

About Gemstar Manufacturing
Gemstar Manufacturing has been an engineering-based solutions provider of hard cases and custom OEM parts for 60 years. The company is a family-owned business supported internally by long-term employees. The firm’s history is rooted in custom manufacturing and the dedication of a customer-centric organization. Gemstar’s mission is “to test the limits of plastic manufacturing and exceed the expectations of customers.” Gemstar’s full-service manufacturing capabilities include industry-leading, vertically integrated manufacturing processes, a fully staffed engineering team, in-house tooling and testing, five-axis routing, and full-service finishing.