Correlation between High Build Speed Process Parameters and Pore Characteristics of 316L Stainless Steel Manufactured by Powder Bed Fusion – Laser Beam

Low build speed is a challenge for wider industrial adoption of Powder Bed Fusion – Laser Beam (PBF-LB) as it is directly associated with higher production costs. The build speed can be efficiently increased by increasing processing parameters i.e. layer thickness, scan speed and hatch distance. However, higher build speeds come at the cost of increased porosity and surface roughness. This study investigates the impact of higher build speeds on pore characteristics by increasing layer thickness from 20 to 80 μm and hatch distance between 100 to 250 μm. Detailed pore characterization by light optical microscopy combined with image analysis and Synchrotron X-ray Computed Tomography (SXCT) on selected samples indicated that pore distribution and characteristics can be tailored by change in the process parameters. Highly anisotropic pore orientation and distribution could be achieved via control of hatch distance, scan speed and layer thickness, providing the possibility of engineered mechanical strength in certain orientation.