Impact of machine factors on the surface quality of parts fabricated by selective laser melting

Abstract

In the growing additive manufacturing (AM) industry, there are growing demands for better as-built surface quality of parts fabricated by selective laser melting (SLM) process, especially for the aerospace, medical and tooling industrial sectors. The surface of SLM parts is relatively bad due to the inherent layer-by-layer processing method. Currently, the surface roughness of SLM components, depending upon the material used, ranging from Ra values of 5 to 50 μm. To enhance the as-build surface quality, various approaches, such as modifying printing process parameters, optimizing support designs and upgrading laser hardware have been explored by a variety of groups. In this study, we investigated the machine factors on the as-build surface quality of parts in the SLM process. Results showed the surface quality of as-build 1.2709 tool steel parts, with a layer thickness of 30 μm, is largely affected by its distance to the laser centre and with little impact from the gas flow direction and recoating direction. The present study demonstrated the possibility of enhancing the as-build surface quality of SLM parts through better planning of machine settings without changing key processing parameters.