Effect of layer thickness on internal pore and mechanical properties of hybrid additive manufactured 18Ni-300 maraging steel

Additive manufacturing (AM) offers advantages such as design freedom, flexible processes, and significantly reduced production steps, making it faster and more cost-effective for small-scale manufacturing. However, at large-scale process levels, energy efficiency often decreases. In particular, hybrid 3D metal printers combining 3D printing and milling processes require additional time due to the milling stage. The goal of this study is to optimize parameters considering the AM time of parts, and an optimal layer thickness was selected to minimize the AM time. Additionally, the feasibility of milling based on the angle configuration of the parts is investigated. In this study, the fabricated specimens were analyzed for relative density, microstructure, hardness, tensile testing, wear resistance, and surface roughness. The optimal parameter conditions were found to be a layer thickness of 50 mu m and an energy density of 70 J/mm3, which demonstrated the highest relative density of 99.9% and excellent mechanical strength. Furthermore, the milling results showed interference with the milling tool, limiting milling to the range of 0 to 30 degrees. These findings will be crucial indicators for selecting layer thickness according to the characteristics of various parts, optimizing manufacturing time, and ensuring quality.