The literature review task defined in milestone 1 was prepared jointly by the BME Polymer Technology Department and X-Plast colleagues. The professional experience of the development team with numerous international patents greatly contributes to the achievement of the objectives of the milestone, so by focusing on the patent research of the selected gear type in the early stages of the work, a detailed mapping of the current state of science relevant to the topic was possible. This facilitated the accurate and efficient execution of the relevant international literature review. In addition, various polymer composite materials were developed, which we can use in injection molding and 3D printing processes for the production of gear parts. We have also prepared hybrid composites containing high-performance carbon fiber and boron nitride with different compositions, which combine the advantageous properties of the individual additives (high strength, good thermal conductivity, wear resistance, etc.). In the case of the raw material developed for 3D printing, we also developed an extrusion production method to maximize the length of the reinforcing fibers, thus improving the efficiency of the composites. In the work phase, we also prepared the tasks for the next milestone, examining possible outcomes and obstacles.

In the 2nd phase, components were selected using metal-to-plastic and lightweight design principles. The possibility of using an all-polymer or metal-polymer hybrid design was also investigated for these components. Meeting several often conflicting requirements in product design is a significant challenge. The main load directions were identified during the topological optimization, and the preliminary rib structure was determined. Prototypes made of different materials, 3D printed, and test bench measurements on these prototypes played a key role in the simulation-assisted development process. In parallel with the measurements, kinematic-dynamic and homogeneous isotropic strength simulations were used to optimize the geometry of the selected outer casing and compared with the test bench results. The measured data was evaluated by further design iterations, considering both the injection molding and the machining manufacturing technology limitations for the central metal core. In this step, so-called coupled finite element simulations were run taking into account the fiber orientation derived from the Moldflow simulation results of the Department of Polymer Engineering of the Budapest University of Technology and Economics. During this step, the developed geometric variables were parameterized with an anisotropic material model with different properties in each direction as a function of the fiber orientation. Using this state-of-the-art method, it is possible to map the fabricated parts in a virtual development environment (like a digital twin) and thus investigate the behavior of the part according to the intended loads. In addition to the development of the geometry, the potential and limitations of the application of different specific fabrication techniques were investigated. We analyzed processes and their combinations that are not yet available on the market for mass production, such as T-RTM (Thermoplastic Resin Transfer Molding) technology, the embedding o