Influence of additive manufacturing technology of topologically optimized products from photopolymer resins on the anisotropy of their mechanical properties

This article discusses the problem of ensuring strength and minimum mass in the design of products manufactured using additive technologies. The authors investigated the possibility of using topological optimization in computer-aided design systems to create an optimized model with the necessary strength at a minimum weight. As part of the work, the topological optimization of the bracket, the production of its samples by additive manufacturing methods and strength tests were carried out. The optimal values were found via finite element analysis using the SolidWorks and ANSYS software. The calculation results show that the optimized model retains about 20 % of the original mass and has the necessary mechanical characteristics. In particular, the excess safety margin is reduced by 2.5 times, which is acceptable for this bracket. The subsequent verification of the models is carried out through destruction tests of the products manufactured using additive technologies, i.e. the method of filament deposition and stereolithography. To account for the anisotropy of the material, a series of samples oriented at different angles to the direction of construction was made. The tests were carried out on a test bench for simultaneous biaxial stretching, which corresponds to the design loads on the bracket. An increase in the tensile load on the sample was carried out before its destruction. In the course of the work, the presence of anisotropy of mechanical properties was revealed, and optimization results in various software packages were studied. The results of strength tests allow us to draw two conclusions. Firstly, due to the anisotropy of the material, the strength properties significantly depend on the orientation of the bracket during additive manufacturing. Secondly, the bracket, optimized by means of the SolidWorks software package, generally showed the best strength properties for various orientations during manufacturing. Also, which is quite expected, the samples obtained by stereolithography showed less anisotropy than the samples obtained by the method of filament deposition. In conclusion, it is noted that the use of additive technologies to create optimized forms requires considering printing technologies and anisotropy of properties, as well as the choice of appropriate software.