Austrian KTM Technologies – specialised in mobility concepts, lightweight and performance technologies – have been developing the CONEXUS technology over the last years. CONEXUS is a coupling layer that allows to directly bond thermoset and thermoplastic components thanks to its specifically formulated chemical composition.
Applied to a thermoset laminate, the CONEXUS technology results in a surface with thermoplastic properties, allowing for direct overmoulding with thermoplastic elements such as ribs, fasteners, and local reinforcements in form of PA6, or even the possibility for ultrasonic welding.
Striving for a more sustainable solution to apply their new technology, KTM Technologies has collaborated with Swiss expert in sustainable lightweighting solutions, Bcomp. The brake cover of a motocross bike has been designed from the ground up to make full use of the best traits from both the thermoset and thermoplastic worlds. Bcomp’s technical ampliTex™ flax prepregs are used to create a lightweight yet stiff structure. The cured flax fibre composite part with the CONEXUS coupling layer, which is produced at the partner company ALBA tooling & Engineering GmbH, is then completed with reinforcement ribs, fasteners, and edge protection in the form of PA6 that is over-moulded in a special tool at KTM’s partner Altendorfer Spritzgusswerk GmbH.
Overmoulding the edges of the flax fibre composite elements protects them against potential interlaminar damage caused by impacts or flying debris while also providing a pleasing appearance. Compared to a traditional, injection moulded brake cover, this new version saves weight, shows reduced vibrations while it also significantly reduces the CO2 footprint thanks to the CO2 neutral flax fabrics. The coupling layer also gives the opportunity to separate the different materials at the end of product life and recycle the PA6.
Using Bcomp’s technical ampliTex™ fabrics rather than a standard carbon- and glass fibre hybrid layup, reduces the CO2 footprint of the thermoset components by roughly 82%. In the event of a crash or fatal impact on the brake cover, the flax fibres show a ductile fracture behaviour – completely opposite to the sharp shattering and splintering of carbon fibres that poses a risk to the track side safety personal as well as fellow riders with an increased risk for punctures. Significant safety improvements can also be observed at the production stage where flax fibres are pleasant to work with and don’t pose any risk to the worker’s health with zero toxic fibre dust.
The current version of the brake cover still relies on traditional epoxy resins for the thermoset and virgin PA6 for the thermoplastic elements. With the current advancements in the development of fully biobased epoxy resins and completely biobased PA6 already being available, KTM Technologies is looking at creating a fully biobased version of the brake cover. While some work will be necessary to adapt the formulation of the CONEXUS coupling layer to play nicely with the biobased resin and PA6, the potential for such a solution is significant. At the parts end-of-life the thermoset and thermoplastic components can easily be separated thanks to the CONEXUS foil. PA6 can be recycled and reused to produce new parts while the flax fibre composites with biobased matrix can be used as a source of renewable energy via highly efficient thermal energy recovery in state-of-the-art waste-to-energy cogeneration plants. In this case, KTM’s CONEXUS technology can be regarded as a key player, enabling a fully circular product.
Looking at the bigger picture, this brake cover serves as a demonstrator piece and perfectly showcases the technology and its market readiness, but the real break-through happens in the form of the ongoing technology transfer from race to road. What works perfectly on the small scale of the brake cover can well be transferred to other applications in the mobility market. With the possibility of adding local reinforcements, attachment points, and edge protection to thermoset composite parts in a highly efficient process might be paving the path for natural fibre bodyworks made from ampliTex™ in large-scale production.
Another possibility, provided by the co-cured coupling layer, are class-A body panels that can be manufactured with fixation elements directly on the back of the part via injection molding. With this material combination, the use of additional gluing steps is needless.
Mobility beyond existing solutions. Innovative lightweight construction. Applied technologies.
Three factors that KTM Technologies deals with every day, to develop reliable and safe solutions and innovative possibilities. Expanded with a deep understanding of the entire vehicle, the highly qualified employees at KTM Technologies solve challenges in many industries – from the first idea to serial production. As a specialist in concept development, KTM Technologies GmbH has specialised in mobility concepts, high-performance and lightweight technologies.
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https://www.ktm-technologies.com/en/home/
Bcomp & KTM Technologies finalists for JEC Innovation Awards
Image © KTM Technologies