Empirical Strength Comparison of 3D Printed Beams and Proposal of a Joining Method for Large Parts

Several challenges arise when considering the application of 3D-printed parts to robotics. First, there is less discussion on bending strength. Second, variations in bending strength occur depending on the type of 3D printer used. Third, the fabrication of large-scale parts remains difficult. In this study, to address the first challenge, we conducted three- point bending tests on specimens with dimensions deviating from standardized specifications, revealing discrepancies in material properties and emphasizing the importance of filament crystallization. For the second challenge, we fabricated identical test specimens under the same conditions using two different 3D printers. We performed three-point bending tests, thereby elucidating the variability in bending strength attributable to the printer type. To address the third challenge, we proposed a joining method involving the mating and adhesion of square- pyramidal convex/concave parts and demonstrated its effective- ness through three-point bending tests.