Surface morphology characterisation for parts produced by the high speed selective laser melting

Abstract

Additive Manufacturing (AM) systems are unique in terms of fast production and lead time to market. South Africa has built the AM Laser Powder Bed Fusion (LPBF) machine called Aeroswift with the world's largest build volume and highest speed. Surface roughness of LPBF parts depends on process-parameters. High surface roughness and deformations during processing limit the application of this technology for certain industrial applications that require high precision. This study characterises the surface roughness for self-supported parallelepipeds samples produced using the Aeroswift platform. Test artefact parallelepipeds were built with 0-90 degrees sloping angles with respect to the building direction. Surface roughness for the as-built samples was analysed using Mitutoyo SURFTEST SJ-210 system and Zeiss Smartzoom 5 digital microscope. It was found that roughness values were higher for the bottom surfaces (overhang part) compared to upward surfaces, as expected. This was attributed to the higher amount of attached partially melted powder particles that were observed on the downward surface. Absolute values of Ra and Rz versus scanning direction and slope angle were found and analysed.