Effect of selective laser melting layout on the quality of stainless steel parts

摘要

Purpose - Selective laser melting (SLM) is increasingly used for the manufacture of end-use metal tools and parts, requiring the careful identification of a range of appropriate process parameters and conditions to achieve desirable properties and quality. Process conditions such as the relation between layout of parts and internal gas flow within the SLM platform can influence the consolidation of metal powers and therefore the quality and properties of the final parts. The purpose of this paper is to investigate the effect of part layout on quality and mechanical properties of cylindrical 316L stainless steel parts manufactured by SLM. Design/methodology/approach - The cylindrical 316L stainless steel parts were manufactured in two directions, one perpendicular to the gas flow direction and one parallel to it. The investigation first focuses on visual inspection and porosity measurements to compare the quality factors such as delamination and porosity of the parts. A mechanical test procedure including tensile, compressive, and shear-punch is used to assess the mechanical properties of the SLM specimens. Cross sectional analyses are carried out to better understand of material response under mechanical tests. Findings - The results show that the part layout and gas flow condition have a negligible influence on porosity formation, however they notably affect the thermal stress and bonding strength between particles which consequently influences the mechanical properties of final parts. The manufacturing of parts perpendicular to gas flow seems to be more advantageous rather than parallel to gas flow. Originality/value - This is the first work investigating the effects of the SLM layout on the quality and mechanical properties of stainless steel specimens. The results can be used in quality control purposes and for quality improvement of SLM parts.