Numerical Investigation of Laser Path on Residual Stresses in the Laser Powder Bed Fusion Process

ABSTRACT Residual stress development in laser powder bed fusion (LPBF) manufacturing significantly affects part quality and dimensional accuracy. However, the influence of laser scanning strategies on thermal evolution and stress formation remains poorly understood for multi‐layer processing. An extended finite difference method framework was developed to enable comprehensive multi‐layer scanning path analysis with direct G‐code integration for Ti‐6Al‐4V components. Three scanning strategies were systematically investigated: simple bidirectional, alternating bidirectional with rotation, and alternating island scanning. While computational predictions initially suggested thermal management advantages for island‐based approaches, experimental validation from literature demonstrates that continuous scanning strategies with interlayer rotation remain superior for minimizing residual stresses. To accommodate component‐scale analysis, the computational grid was refined and model parameters were appropriately adjusted to suit the expanded computational domain. Two distinct heat source formulations were evaluated: a uniform heat distribution model across the laser beam radius and a Gaussian distribution model. The Gaussian volumetric heat source approach demonstrated superior agreement with experimental observations compared to the uniform distribution model. The comparative analysis of scanning strategies revealed both the promising capabilities and inherent constraints of computational modeling approaches in LPBF process optimization, underscoring the critical importance of experimental validation for making reliable scanning strategy decisions in industrial manufacturing contexts.