Multi-Response Process-Thickness-Property Optimization of Thin-Walled AlSi10Mg Alloy Fabricated by Laser Powder Bed Fusion

Laser powder bed fusion (LPBF) of AlSi10Mg alloy is highly sensitive to processing conditions, particularly when thin-walled components are fabricated. This study investigates the combined effects of wall thickness, laser power, scan speed, and hatch distance on the mechanical performance of LPBF-fabricated AlSi10Mg. A Box–Behnken design (BBD) based on response surface methodology was employed using 27 experimental runs. Wall thickness was varied from 1 to 3 mm, laser power from 320 to 380 W, scan speed from 730 to 1070 mm/s, and hatch distance from 80 to 130 μm. Relative density (RD), ultimate tensile strength (UTS), yield strength (YS), elongation at fracture, and hardness were evaluated as response variables. The statistical analysis showed that wall thickness and scan speed were the most influential factors for tensile properties, whereas the effects on RD, elongation, and hardness involved additional interaction and nonlinear terms. Among the developed models, the predictive performance is quite adequate along with comparatively higher fitted R2 values; however, only the RDrelative density model performance is limited by giving a negative predicted R2. Optimization of the four mechanical responses, excluding relative density, identified an exploratory candidate at 3.0 mm wall thickness, 320 W laser power, 1070 mm/s scan speed, and approximately 100.46 μm hatch distance. The corresponding predicted UTS, YS, elongation, and hardness were 354.7 MPa, 193.8 MPa, 13.54%, and 112.6 HV, respectively, with a composite desirability of 0.892. The results demonstrate the importance of considering component wall thickness together with LPBF process parameters when optimizing the overall mechanical performance of thin-walled AlSi10Mg components.