The mechanical properties of injection-molded components can be significantly improved by adding continuous fiber reinforcements. If continuous fibers are added only locally according to the occurring load paths, a component's lightweight potential can be maximized. Depending on the component's complexity as well as on the applied loads and their directions, topology optimization may show that the local continuous fibers should form a complex skeleton-like fiber structure.
Within the scope of this study, a novel robot-based manufacturing process - the 3D skeleton winding process (3DSW) - was designed, developed, and validated. The 3DSW process enables the manufacturing of three-dimensional reinforcement structures (fiber skeletons) to locally reinforce injection-molded components with continuous fibers. By using a component-specific winding tool attached to an industrial 6-axis robot, it is possible to automatically wind continuous fiber strands based on hybrid yarns around hard points or load introduction elements (e.g., aluminum inserts). Such hybrid fiber skeleton structures can be subsequently embedded in the final component geometry using injection molding.