Röchling Automotive has made a breakthrough in structural lightweight design for automotive – the first plastic frunk that doubles as both storage space and a highly robust structural chassis component.

Manufactured by Röchling Automotive in Worms, Germany, the frunk makes its debut in the brand’s fully electric four-door high-performance sports car.

Plastic frunk from Röchling Automotive that acts as both storage space and a highly robust structural chassis component.

Manufactured in a single process step

Röchling Automotive developed an efficient hybrid-molding process for its production. The process combines thermoforming of organosheet from Envalior with injection molding in a single mold, enabling the production of a fully finished, rework-free component in a single manufacturing step.

“The manufacturing process we developed represents another key highlight of the application. Achieving uniform mold filling despite the complex geometry while simultaneously minimizing weld lines to ensure the part’s high mechanical performance was particularly challenging,” explained Matthias Schütte, Global Product Manager for Structural Lightweight at Röchling Automotive.

Precisely tailored fiber orientation

The polypropylene frunk is reinforced with Envalior’s multilayer organosheet featuring continuous fibers oriented at 0°/90° in the outer layers and +45°/-45° in the inner layers. This multiaxial laminate architecture is precisely tuned to the component’s direction-dependent mix of tensile, bending, and shear loads.

The 0°/90° fibers primarily improve crash performance, while the ±45° fibers ensure optimal vehicle dynamics under extreme lateral loading.

During highly dynamic driving maneuvers, off-road operation, or high-speed cornering, lateral forces can twist the front body structure – a deformation prevented by the frunk’s high torsional stiffness. Bolted to the strut brace at the upper flange and to the front-axle carrier at the bottom, the frunk acts as a vertical shear panel.

“We can produce customized multilayer organosheets in high-volume production with continuous fibers oriented not only at 0° and 90°, but at virtually any angle required. This allowed us to engineer a customized organosheet for the frunk whose fiber orientations follow the exact load paths within the component, making it precisely adapted to the load-specific requirements,” explained Dr. Klaus Vonberg, Sales & Project Manager Global Sales Tepex at Envalior.

Adding more features in frunks with hybrid molding

A key advantage of these multiaxially reinforced organosheets is their ability to withstand high forming degrees. The fabric layers are resistant to fiber shifting and remain intact even at component corners, ensuring a highly reproducible forming process and consistently high part quality.

“In the future, it may be possible to integrate features such as cool boxes, drawers, cargo nets, or holders for the charging cable directly into these frunks,” Matthias Schütte noted.

This is because the hybrid-molding process enables cost-efficient functional integration for high-volume production. At the same time, organo sheet materials reduce weight, as they can be significantly thinner than conventional injection-molded solutions.

Looking ahead, Röchling Automotive is already exploring the next generation of lightweight materials, including various natural-fiber-based alternatives for future applications.