Optimization of additively manufactured parts for direct screwing

Abstract The combination of additive manufacturing and direct screwing can reduce the limitations of the additive manufacturing such as long manufacturing times and high costs for expanding building spaces. Direct screwing allows components to be assembled into larger components and added to assemblies for functional integration. Therefore, large building spaces can be avoided and useful integration of additive components into serial production is possible. While guidelines for direct screwing of injection molded thermoplastic components are provided by the German Welding Society, there are no recommendations for additively manufactured components. Preliminary investigation at the Kunststofftechnik Paderborn have shown that recommendations for injection molded components cannot be applied to additively manufactured components. Since the layered manufacturing process additively manufactured components are anisotropic, the strength of the components depends on the build orientation. For the optimization, the geometry and the shape of additively manufactured screw domes are varied. To account for the anisotropy, the screw domes are built in three different orientations. The goal is to improve the strength of additively manufactured screw domes and to prevent delamination in critical orientations. The results show that a suitable shape optimization was found that improves the strength and neglects the occurrence of delamination.