Optimization and analysis of porosity and roughness in selective laser melting 316L parts

Abstract

Purpose: The investigations have been carried out on 316L stainless steel parts fabricated by Selective Laser Melting (SLM) technique. The study aimed to determine the effect of SLM parameters on porosity, hardness, and structure of 316L stainless steel. Design/methodology/approach: The analyses were conducted on 316L stainless steel parts by using AM125 SLM machine by Renishaw. The effects of the different manufacturing process parameters as power output, laser distance between the point’s melted metal powder during additive manufacturing as well as the orientation of the model relative to the laser beam and substrate on porosity, hardness, microstructure and roughness were analysed and optimised. Findings: The surface quality parts using 316L steel with the assumed parameters of the experiment depends on the process parameters used during the SLM technique as well as the orientation of formed walls of the model relative to the substrate and thus the laser beam. The lowest roughness of 316L SLM parts oriented perpendicularly to the substrate was found when 100 W and 20 μm the distance point was utilised. The lowest roughness for part oriented at 60° relatives to the substrate was observed when 125 W and the point distance 50 μm was employed. Practical implications: Stainless steel is one of the most popular materials used for selective laser sintering (SLM) processing to produce nearly fully dense components from 3D CAD models. Reduction of porosity is one of the critical research issues within the additive manufacturing technique SLM, since one of the major cost factors is the post-processing. Originality/value: This manuscript can serve as an aid in understanding the importance of technological parameters on quality and porosity of manufactured AM parts made by SLM technique.