## 1 Introduction  
Metal-additive manufacturing (MAM) has established itself as a new manufacturing method for light, complex and customized parts in the automotive, aerospace and medical sectors due to its design freedom and short throughput time. As one of the most common industrial AM techniques, laser powder bed fusion (LPBF) is an MAM technology based on the powder-bed-fusion (PBF) process. In this process, a thin layer of powder, in this case metal powder, is spread onto the build platform by a recoater arm, and then selectively melted by a laser, whereupon it fuses with surrounding powder particles as well as the previous layer and builds up on the part. After the layer is finished, the platform movesdownwards, is recoated again and the process is repeated [1] (as seen in Figure 1). The process and its outcomes such as printing time, part quality and material properties depend on printing parameters such as laser power, scan speed, scan spacing, layer thickness and laser spot size [2]. Since the parts are built on a base plate, which is attached to the platform, post-processing steps are necessary to remove the built part from the base plate, e.g., with wire EDM [3]. Further post-processing might include a heat treatment to strengthen the mechanical properties and for the removal of residual stresses that might induce warpages and distortion in the parts, or a surface treatment such as polishing or cutting, to reduce surface roughness and to improve the overall surface finish [4]. The part quality of AM parts, regarding surface roughness and mechanical properties, is still a challenging issue to be addressed since the as-built quality is still not comparable to those produced by conventional subtractive manufacturing methods [5]. Therefore, post processing is often necessary, which diminishes the advantage of shorter production time and the design freedom offered [6; 7]. [PERSON] et al. [8] investigated the correlation of different process parameters, such as scan speed, layer thickness and build direction, with surface roughness and microhardness (HB) of iron-based LPBF-manufactured parts. It was found that the build direction and layer thickness have a noticeable correlation with the mechanical properties such as bending strength and elongation with no effect on tensile strength. [PERSON] et al. [9] examined the effect of laser energy density E, which is influenced by laser power, scan speed and hatch spacing, on the relative density and surface roughness (microstructure) of LPBF-fabricated parts. A total of 32 cuboids with different sets of the above-mentioned parameters were printed and investigated, resulting in a range of investigated energy densities of 48-208 J/mm\({}^{3}\). It was found that energy density has a significant effect on surface roughness and can be divided into four different value ranges, which affect the outcome. In particular, these are the \"insufficient melting zone\" (E \(<\) 75 J/mm\({}^{3}\)), the \"partially balling zone\" (75 J/mm\({}^{3}\) \(<\) E \(<\) 120 J/mm\({}^{3}\)), the \"successful fabricating zone\" (120 J/mm\({}^{3}\) \(<\) E \(<\) 170 J/mm\({}^{3}\)) and the \"excessive melting zone\" (E \(>\) 180 J/mm\({}^{3}\)). In a following paper, [PERSON] et al. [10] enlarged their study on surface morphology by concentrating on varying laser power (100-500 W) and scan speed (600-1600 mm/s) and keeping hatch spacing constant at 0.08 \(\upmu\)m. As a result, they added another zone between the \"successful fabricating zone\" and the \"excessive melting zone\", the \"smooth forming zone\", and specified the parameter values for each zone, such as laser power (150 W) and scan speed (800 mm/s) for the \"successful fabricating zone\". [PERSON] et al. [11] also looked into the effect of laser energy density on surface roughness and microhardness (HV) of selective laser-melted 30 CrMnSiA steel parts by modifying the laser power and exposure time. The  
Figure 1: Visualization of the LPBF Technology.