Factor analysis of selective laser melting process parameters and geometrical characteristics of synthesized single tracks

Purpose - Properties of the parts manufactured by selective laser melting (SLM) depend strongly on the each single laser-melted track and each single layer, as well as the strength of the connections between them. The purpose of this paper to establish links between the principal SLM parameters (laser power density, scanning speed, layer thickness), properties of the powder and geometrical characteristics of single tracks. This study will provide a theoretical and technical basis for production of parts from metal powders. Design/methodology/approach - This paper discusses the SLM parameters affecting on geometrical characteristics of the synthesized single tracks. Granulomorphometric characteristics of powders were studied in detail. A Greco-Latin square design was used to control geometrical characteristics of the tracks. Analysis of variance (ANOVA) permitted to establish a statistically significant influence of the SLM process parameters on geometry of the single laser-melted track. Findings - The behavior of individual tracks and their geometric characteristics depend on the process parameters, and physical-chemical and granulomorphometrical properties of the powder. Each powder shows peculiar behavior in the process of single track formation. For stainless steel grade 904L powders with different particle size it was found that the most influencing parameter is the laser power (the following values were applied: 25, 37.5, 50W), and then, in order of decreasing importance, are the powder layer thickness (60, 90, 120 gm), the scanning speed (0.05, 0.10, 0.15 m/s), and, finally, the particle size. Originality/value - The proposed hierarchy of the process parameters is a new systematic study presented by the authors, developed for selective laser melting. Obtained data can be used in surface structuring and micro-manufacturing characterized by a small number of layers within a part and, thus, sensible to the geometric dimensions and shape of the individual tracks.