Authors:
N. C. Stache
J. Dieckelmann
Institute of Imaging and Computer Vision, RWTH Aachen University, 52056 Aachen, Germany

J. Gedicke
A. Olowinsky
Fraunhofer Institute for Laser Technology, Steinbachstr. 15, 52074 Aachen, Germany

T. Aach
Institute of Imaging and Computer Vision, RWTH Aachen University, 52056 Aachen, Germany

In most laser welding applications the welding result is highly sensitive to the weld position. The initial determination of process parameters therefore requires time-consuming adjustments to be made. When manufacturing individual parts with low quantities, this is a significant cost driver. State-of-the-art computer-aided design/computer-aided manufacturing systems ease the creation of weld seams significantly, but position deviations resulting, e.g., from workpiece tolerances or displacement must still be compensated. Seam tracking systems are rather complicated to handle during process qualification as they require adjustment to a start position and are subject to be misguided by disturbances in the material. Besides, it is difficult to apply seam tracking to scanner-based microwelding operations, which are considered in this paper. Therefore, the authors developed a system that enables the user to position welds easily and accurately by marking the intended weld position in a calibrated live image of the workpiece, which serves as reference. Thereby, positioning errors are compensated. When executing the welding process it is also possible to observe it in the live image and to assess the geometrical properties of the weld surface immediately. Moreover, the paper describes how this idea is extended to a system for creating more complex weld paths and concludes with an approach for automated image-based path generation by extracting the joint geometry from the workpiece image.