Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 55 10 2023 12 22 Effect of Build Orientation and Size on the Defects Rate of Stainless Steel 316L Parts Produced by Selective Laser Melting Process Effect of Build Orientation and Size on the Defects Rate of Stainless Steel 316L Parts Produced by Selective Laser Melting Process 1219 1232 5356 10.22060/mej.2024.22323.7630 FA Mohammad Ranjbarkohan Shahid Rajaee Teacher Training University Amjad Sazgar nuclear fuel cycle research school, nuclear science and technology research institute (NSTRI) 0000-0003-3868-2986 Ali Pourkamali Anaraki Shahid Rajaee Teacher Training University Journal Article 2023 07 05 The correct and optimal selection of selective laser melting process parameters prevents defects such as porosity, incomplete fusion holes, and cracks in the parts. This research focuses on the impact of zero, 45, and 90-degree build orientations, the effect of changing the size of the parts on mechanical properties such as tensile and shear strength, fracture strain, and the number of defects investigated. The built parts were subjected to tensile and shear tests. The fracture zone was investigated using Scanning Electron Microscopy, and existing defects were identified. Tensile test results indicated that larger samples have higher tensile strength than smaller ones. Moreover, samples produced in the zero-degree orientation exhibited higher tensile strength and lower fracture strain. Shear test results also showed that the shear stress strength for small and large samples produced in all orientations is almost the same, and the highest shear strain of failure is related to the samples produced at 45-degree orientation and independent of dimensions. Scanning Electron Microscopy results further demonstrated that the quantity and distribution of spherical holes and incomplete fusion holes in large samples at 90-degree are greater than the samples at other orientations. The correct and optimal selection of selective laser melting process parameters prevents defects such as porosity, incomplete fusion holes, and cracks in the parts. This research focuses on the impact of zero, 45, and 90-degree build orientations, the effect of changing the size of the parts on mechanical properties such as tensile and shear strength, fracture strain, and the number of defects investigated. The built parts were subjected to tensile and shear tests. The fracture zone was investigated using Scanning Electron Microscopy, and existing defects were identified. Tensile test results indicated that larger samples have higher tensile strength than smaller ones. Moreover, samples produced in the zero-degree orientation exhibited higher tensile strength and lower fracture strain. Shear test results also showed that the shear stress strength for small and large samples produced in all orientations is almost the same, and the highest shear strain of failure is related to the samples produced at 45-degree orientation and independent of dimensions. Scanning Electron Microscopy results further demonstrated that the quantity and distribution of spherical holes and incomplete fusion holes in large samples at 90-degree are greater than the samples at other orientations. https://mej.aut.ac.ir/article_5356_7ec0dbeee45813422897e04ad8424a5e.pdf