Abstract

Laser Powder Bed Fusion (LPBF) is widely employed for manufacturing complex metallic components; however, process-induced distortion, residual stress, and thermal accumulation remain major challenges affecting dimensional accuracy and structural integrity. In the present study, a three-dimensional thermo-structural finite element model was developed to investigate the combined influence of component orientation and base plate material on the thermo-mechanical behavior of LPBF-fabricated Inconel 718 components. In addition, an integrated optimization methodology combining response normalization, a weighted sum performance index, and radar chart analysis was adopted to realize the optimal combination of the process variables by a simultaneous consideration of distortion, residual stress, and temperature. Accordingly, five part orientations and five different base plate materials were examined under identical processing conditions through 25 simulation cases. The obtained results revealed that component orientation represents the dominant factor controlling distortion and residual stress development, whereas both orientation and base plate material significantly affect component temperature. The inclined orientations generated the highest distortion levels, while the vertical configuration exhibited the highest residual stresses. In contrast, the horizontal orientation along the X-direction demonstrated the most balanced thermo-mechanical performance. Furthermore, AlSi10Mg base plate material provided the lowest thermal accumulation due to its high thermal conductivity. The integrated optimization analysis based on radar chart assessment and performance index evaluation identified the Horizontal-X/Ti-6Al-4V and Horizontal-X/AlSi10Mg configurations as the most favorable LPBF conditions. These findings provide practical guidelines for selecting build orientation and base plate material to reduce thermo-mechanical defects, thereby improving the dimensional accuracy and manufacturing reliability of LPBF-fabricated Inconel 718 components.

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