부산대학교 도서관

The surface quality of three-dimensional products manufactured via laser powder bed fusion (L-PBF) depends on solidificationconditions, the staircase effect caused by layer-by-layer build-up processes, and the shape and size of un-melted particles. Although the surface quality can be slightly improved by optimizing process parameters such as layer thickness, laserpower, hatch spacing and scan speed, the effect is quite limited, and thus additional post-treatment processes are required fordramatic improvement. In the paper, the effects of layer thickness (30, 60 μm) and build angle (0°, 15°, 30°, 45°, 60°, 75°,90°) on the surface roughness of the Ti–6Al–4V alloy parts manufactured by L-PBF process were analyzed. In addition, inorder to investigate the effect of blasting conditions on the surface roughness, the specimens were post-treated by varioussizes of abrasives (#60, #80, #100, #120, #150), blasting angle (45°, 90°), and pressures (0.3, 0.4, 0.5 MPa), and the surfaceroughness of each specimen was measured and compared. The results indicate that the higher is the building angle and thinneris the layer thickness, the better is the surface quality; however, the difference tends to decrease via sandblasting, and theeffect depends on the process conditions. Sandblasting process improved the surface roughness up to 62% and 71% comparedas-built conditions for the layer thickness 30 μm and 60 μm for each. As a result, the surface roughness of minimum 5.0 μmand 3.8 μm for the layer thickness 60 μm and 30 μm was achieved in the case of building angle 90°.