Structuring by laser remelting as a method for waviness reduction on additive manufactured parts

Abstract

The surface roughness of parts manufactured by laser powder bed fusion (LPBF) is often not sufficient for the intended application. Therefore, surface finishing is necessary. Conventional finishing techniques have many disadvantages like accessibility of complex geometries, high time and cost consumption and a negative environmental impact due to the use of abrasives. As a solution laser polishing is investigated. In this study it was found that surface roughness of LPBF parts up to a spatial wavelength of 0.5 mm can be reduced by ∼96% with laser polishing, while waviness can only be reduced by ∼55%. To further reduce waviness, structuring by laser remelting (WaveShape) is investigated. The basic idea is to structure the inverse of the initial structure and thus to “de-structure” the waviness. A structured profile of a laser polished LPBF surface is “de-structured” with a variation of process parameters. The results show the potential of a waviness reduction of 85%.