About Fluence and Process Parameters on Maraging Steel Processed by Selective Laser Melting: Do They Convey the Same Information?

In this paper the influence of process parameters and fluence on mechanical properties of maraging steel in Selective Laser Melting (SLM) is studied. The results of the present work show that there exists a steady region of process parameters where fluence conveys all the information required to describe and predict density and tensile properties. We also show that in this region of the parameters, the choice of process parameters can be carried out considering other optimality criteria such as productivity, rather than maximization of density. To pursue this objective, a V-Alphabetical optimal design with fixed fluence levels was specifically designed for the experimentation. The used fluence levels and the corresponding process parameter combinations were tested on an industrial SLM system. To compare the informative content of fluence and the process parameters, two regression equation were estimated from experimental results for part density and tensile properties. The comparison of the regression models showed that the predictive ability of fluence and process parameters in the steady region is the same, however fluence allowed to obtain a higher precision. In conclusion, based on the experimental conditions studied, new process parameters are suggested using a productivity-based criteria.