Product Code: ICA10_1705

Laser Polishing of Metallic Freeform Surfaces
Authors:
Roman Ostholt, Rwth Aachen University; Aachen Germany
Edgar Willenborg, Fraunhofer Ilt; Aachen Germany
Konrad Wissenbach, Fraunhofer Ilt; Aachen Germany
Presented at ICALEO 2010

Laser polishing represents a new surface finishing technique for sculptured work pieces which offers shorter process times and lower costs in comparison to the predominantly used manual polishing. The technique is based on remelting a thin surface layer by laser radiation. The surface tension of the melt pool induces a reallocation of material from the peaks to the valleys, 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. By adjusting the laser power and the line spacing depending on the angle of incidence, adequate measures to compensate the investigated influences are demonstrated.
Additionally, the 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 a CAM software for 5-axis milling applications. Afterwards, the tool-path data are processed in post-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.