Post-processing

One major issue of laser powder bed fusion (L-PBF) technology is the poor surface quality and the irregular surface roughness of its as-built parts. This is primarily induced by partially melted powders, staircase effects, balling, spatters, melt-pool instability, and support removal. Surface irregularities can deteriorate material performance under static and cyclic loading, corrosion, wear and scratch resistance; they can also impart concerns on geometrical tolerances as well as reflective and aesthetic features of the additive manufactured part. Furthermore, due to the complex thermal history, the L-PBF material regularly exhibits directional properties, anisotropic microstructural features, often combined with internal porosity and undesirable tensile residual stresses. The synergistic effects of these undesirable features can adversely affect the as-built material’s functionality under different in-service conditions. Various post treatments have been employed to mitigate these issues and efficiently enhance the performance of additive manufactured parts. This chapter provides an overview on the most commonly used post-processing techniques designed to improve the surface quality, promote microstructural homogeneity, release undesired residual stresses and reduce if not eliminate the internal porosity of as-built L-PBF parts.