This work investigates the effects of various processing parameters (laser power, scanning speed, hatch distance and beam offset) on the resultant inclined up-facing surface roughness of AlSi10Mg alloys produced by laser powder bed fusion (LPBF). A two-step approach, orthogonal test followed by the Doehlert matrix design (DMD) test is used to efficiently optimize the up-facing surface and contour parameters. The former method aims to determine the significance of variables while the latter one facilitates a rapid optimization. The results show that the interaction and interdependency among the parameters are of great significance to the obtainable surface roughness. Using a rational design of experiments, the optimized up-facing surface roughness of Ra of 5.4 μm is achieved. This is attributed to the elimination of the laser partition track and the reduction in irregularities at the edges of the parts. This work demonstrates an effective approach of experimental processing parameter optimization to improve the surface finish of LPBF parts.

With the upgrade of additive manufacturing (AM) equipment, pure copper and various Cu-based alloys with almost full density have been successfully produced, maintaining their excellent thermal and electrical conductivity and good mechanical properties at high temperatures as well. In this paper, a model with a series of inclined surface structures was designed and fabricated to investigate the structural design on the formability of CuCrZr alloy produced by laser powder bed fusion (LPBF). The typical structure dimensions of the as-built samples were measured and compared with their corresponding dimensions and the inclined angle (α) and the relative angle (γ) between the inclined surface and recoating directions. The results demonstrate that the inclined structures with α < 50° were fabricated either with varying buckling deformation and powder adhesion or in failure for severe distortion. The differences (L_d) between the typical structure dimensions and their models increase with the decreasing of α. It has been observed that L_d reaches 1 mm when α is 20° and drastically reduces to around 200 μm when α is above 50°. When α < 50°, L_d is generally increasing with a rising γ value from 0° to 180°, significantly affecting the dimensional accuracy.