Laser polishing of metallic freeform surfaces

Abstract

Laser polishing represents a new surface finishing technique for free formed work pieces which offers shorter process times and lower costs in comparison to the predominantly used method of manual polishing. This new technique is based on remelting a thin surface layer by laser radiation. The surface tension of the melt pool induces a reallocation of material, thus creating a polished surface.When freeform surfaces are polished using this method, the angle of incidence is generally not perpendicular to the treated surface. The influence of this angle on the melt pool and the surface roughness thus obtained is investigated. By adjusting the laser power and the tool path geometries depending on the angle of incidence, adequate measures to compensate for the investigated influences are demonstrated.Additionally, this paper discusses the CAM process chain for laser polishing of freeform surfaces. The contour-aligned tool paths are generated on the basis of a CAD-model of the work piece using CAM software for five-axis milling applications. Afterwards, the tool-path data are processed in technology processor software. Comprising an application database, the software calculates all technology specific information according to the developed processing strategies. Data calculated by this software are then transferred to the 3D laser-polishing machine.Laser polishing represents a new surface finishing technique for free formed work pieces which offers shorter process times and lower costs in comparison to the predominantly used method of manual polishing. This new technique is based on remelting a thin surface layer by laser radiation. The surface tension of the melt pool induces a reallocation of material, thus creating a polished surface.When freeform surfaces are polished using this method, the angle of incidence is generally not perpendicular to the treated surface. The influence of this angle on the melt pool and the surface roughness thus obtained is investigated. By adjusting the laser power and the tool path geometries depending on the angle of incidence, adequate measures to compensate for the investigated influences are demonstrated.Additionally, this paper discusses the CAM process chain for laser polishing of freeform surfaces. The contour-aligned tool paths are generated on the basis of a CAD-model of the work piece using CAM software for ...