Experimental and statistical investigation of mechanical properties and surface roughness in additive manufacturing with selective laser melting of AlSi10Mg alloy

In metal-based additive manufacturing, laser power, scanning speed, hatching distance and layer thickness are important manufacturing parameters. These parameters are very important in terms of microstructure, mechanical properties and surface quality of the final product. For this reason, it is very important choosing these parameters correctly in the production process. One of the common approaches used to optimize these parameters is volumetric energy density. In this study, product quality improvement in additive manufacturing of AlSi10Mg alloy was focused, and test pieces were produced at different volumetric energy densities. The parts were manufactured according to the Taguchi L9 orthogonal array experimental design. Three different laser powers (250–300–350 W), three different scanning speeds (900–1000–1100 mm/s), three different hatching distances (0.17–0.19–0.21 mm) and constant layer thickness values were used as manufacturing parameters. The performance properties of the manufactured parts were investigated in terms of mechanical properties and surface roughness. As a result of the study, it was observed that the mechanical properties of the samples produced at very high and very low volumetric energy densities decreased and the surface roughness increased. Maximum mechanical properties within the produced samples were obtained at 55.82 J/mm3 volumetric energy density, and minimum surface roughness was obtained at 54.46 J/mm3 volumetric energy density. For mechanical properties and surface roughness, multiple response optimization was performed with Taguchi-based Grey relational analysis method. According to the experimental results, optimum manufacturing parameters for additive manufacturing of AlSi10Mg alloy; it was obtained as 350 W laser power, 1100 mm/s scanning speed, 0.19 mm hatching distance and 55.82 J/mm3 volumetric energy density, which is the interaction of these parameters. The mechanical properties and surface roughness obtained graphically were supported by fracture surface images and microstructure studies. With multiple response optimization, 30.15% improvement was achieved in performance indicators. In addition, it has been demonstrated that volumetric energy density can be used as an important evaluation tool in determining product quality.