Effect of topology-optimized support structures on the quality of Inconel 718 parts made by laser powder bed fusion additive manufacturing

AbstractSupport structures play a crucial role in laser powder bed fusion (LPBF) by ensuring geometric stability and mitigating distortion caused by residual stresses. Conventional gravity-driven supports often lead to excessive material usage and provide limited control over distortion. In this study, support structures designed using a residual-stress-aware topology optimization approach were fabricated and evaluated. Two support optimization design strategies are explored: gravity-only loading and combined gravity and residual stress loading. Arc-bridge specimens made from Inconel 718 via LPBF are employed to compare the performance of the optimized supports against conventional ones. Experimental and numerical comparisons are conducted in terms of distortion, residual stresses, microstructure, and microhardness. Compared with conventional supports, the optimized design achieves over 50% reduction in support material usage and more than 30% reduction in post-cutting distortion, while maintaining favorable refined microstructural features. This study demonstrates the practical advantages of employing residual-stress-aware topology optimization for improving LPBF part quality and manufacturing efficiency.