Laser polishing: a review of a constantly growing technology in the surface finishing of components made by additive manufacturing

Additive manufacturing is a vanguard production technology that has contributed greatly to speed up replacing on the market of complex-shaped components. A delicate and unavoidable phase of additive technology is that relating to the post-processing of the components, especially the finishing process. Post-processing needs to be automated and made scalable so that the technology can actually be adopted also for mass production. In this respect, an emerging post-processing technology suitable for surface finishing, not in contact and easily automatable, is the one that involves the use of laser sources, known by the name of laser polishing. Laser polishing is spreading, in fact, more and more strongly, in the field of manufacturing as a valid alternative to conventional technologies for the surface finishing of metallic components obtained by additive processes. Laser polishing is widely considered very suitable to improving the surface finish of metal components. When compared with the conventional finishing technologies, laser polishing has many benefits in terms of costs and process times especially if automated, through the use of CNC systems and scanning heads. In this manuscript, the knowledge of this technology is deepened through a review of the relevant literature that highlights the aspects of the interaction of the laser beam with the metal alloys most frequently used in 3D printing, without neglecting the importance of the thermo-mechanical properties that derive from it. The analysis conducted on the technology of laser polishing aims therefore at evaluating the potential applications in industrial engineering, mainly with regard to the surfaces quality achievable as a result of the polishing of metal components fabricated by additive manufacturing.