Laser polishing of extrusion additively manufactured 316L stainless steel

The surface quality of metal parts produced by additive manufacturing methods often exhibits
poorer surface roughness compared to conventionally manufactured part. Laser polishing
process is a very promising technique for achieving a smoother metal surface without the
requirement for direct contact between a tool and the surface of the part. The procedure is
based on the concepts of surface re-melting and quick solidification of the laser-molten layer.
In this study, 316L stainless steel produced by extrusion additive manufacturing was polished
using a nanosecond pulse laser under various processing conditions to improve its surface
roughness. Experiments were conducted to examine the impact of laser scanning speed, laser
pulse repetition rate, overlap percentage, and argon gas shield on the roughness and
morphology of the polished surface. The results show that applying suitable polishing
conditions can improve the roughness of laser-polished surfaces by up to 55%. Furthermore,
argon gas shielding can help to mitigate oxidation during laser polishing. The findings of this
study provide specific laser polishing conditions for post-processing extrusion additive
manufacturing, where surface roughness is a critical concern, to smooth the rough 3D-printed
surfaces.