“…In this process, several input variables can affect the quality of the finished product, including continuous variables, such as laser power, scan speed and hatching distance, and discrete variables, e.g., the use of virgin/recycled powder and the layer thickness [29][30][31][32][33]. These input variables can affect a variety of quality characteristics of products, which will be called from now on output variables, including surface roughness, macro-hardness, porosity, tensile strength and dimensional accuracy [34,35]. A first problem is to determine which is the probability of occurrence of defects related to the selected output variables.…”