Effect of Printing Strategies on Mechanical Properties of Tool Steel in Laser Powder Bed Fusion Process

The selection of printing strategies in the LPBF process is pivotal, as it significantly impacts residual stress, which in turn affects the mechanical properties and density of the material. Recognizing the importance of optimizing printing strategies to enhance the final residual stress characteristics, this study investigates the effects of different printing strategies on as-manufactured H13 tool steel. Specifically, the research focuses on evaluating the tensile properties, micro-hardness, and density of the LPBF-manufactured samples. Two distinct printing strategies-bidirectional and chess scanning-were employed, with each strategy incorporating four different rotational orientations per layer (0 degrees, 45 degrees, 67 degrees, and 90 degrees). The aim is to understand how these variations influence porosity formation and the resultant mechanical properties of the tool steel, thereby providing insights into optimal printing parameters for improved material performance. Results showed that minimum porosity, maximum relative density, maximum mechanical strength, and maximum hardness were obtainable with the bidirectional printing strategies at rotation angles of 45 degrees and 67 degrees. The chess strategy exhibited more significant manufacturing defects, including extensive cracking and voids, particularly at 45 degrees and 67 degrees, leading to inferior mechanical properties and higher porosity compared to the bidirectional strategy.