They appear in frescoes in ancient Egypt: spoked wheels. Their basic shape has not changed. They can be found on bicycles, cars and in industry. In sports, spoked wheels made of lightweight fiber-plastic composites are widespread. Until now, their production has been associated with high costs, making them unattractive for many applications. The situation is different with a new process developed by researchers in Kaiserslautern: It enables automated production tailored to customer requirements. The Kaiserslautern researchers are marketing their technology in the newly founded start-up Evolime.

It takes a lot of time to build spoked wheels from fiber-reinforced plastic composites, or FRP for short. "The process involves numerous steps, and much of it can only be done by hand," says Dr. Marcel Bücker, who has been working with fiber-reinforced plastic composites for a long time. "In addition, a lot of the expensive material has to be used, as a large amount of waste is produced," continues Bücker.

However, the process developed by Bücker and his colleagues Dr. Thomas Robbert, Valentin Hörtdörfer and Frank Belyea at the Institute for Composite Materials at the Technical University of Kaiserslautern is different. "Compared to conventional processes, we can produce the wheels much more efficiently with our three-stage process," explains Robbert. The process is also waste-free and therefore has a very good environmental balance.

"At its core, it is a so-called wet winding process in which fibers are automatically wound onto small molded parts and simultaneously formed into wheel structures," explains Bücker. First, the engineers use a 3D printer to produce molds made of biodegradable plastic. The exact shape is determined by a computer program. They are then used in the production of the wheels and are wrapped with a fiber tape on a rotating tool plate. "This continues until the desired thickness for the spokes is achieved. The still soft tape is then formed into spokes," continues Bücker. In a final step, another fiber tape is wrapped around the spokes to create a complete wheel. Once the plastic has hardened, the molded parts are removed. The spoked wheel is finished.

The special feature: Depending on customer requirements, the size of the wheel or the number of spokes, for example, can be adjusted as required. In many cases, this can be done at the touch of a button using specially developed software. This means that individual solutions can be realized for customers very quickly. The strong digital integration enables the start-up to achieve short delivery times for a wide range of components, opening up access to industries for which low weight and high performance are crucial. Applications include mechanical and plant engineering, such as high-performance grinding wheels or gearwheels for wind turbine gearboxes. Mobility applications such as bicycle wheels or car rims also offer good potential uses.

The Kaiserslautern researchers are marketing their idea in their newly founded start-up Evolime. The development to market maturity is being funded by the Federal Ministry for Economic Affairs and Energy and the European Social Fund as part of an Exist research transfer called CompoSpoke. In addition, the start-up office at TU Kaiserslautern and Kaiserslautern University of Applied Sciences is on hand to advise them. as