Product Code: ICAL09_701

Design of a Sensor-assisted Control of the Weld Filling Degree for the Manufacturing of Segments for Steam Turbine Cooling
Authors:
Uwe Reisgen, Rwth Aachen University; Aachen Germany
Simon Olschok, Rwth Aachen University, Isf; Aachen Germany
Stefan Longerich, Rwth Aachen University; Aachen Germany
Presented at ICALEO 2009

In order to increase the efficiency of combined cycle power plants up to 65%, special structures consisting of nickel base materials are joined with and without filler materi-als using the laser beam welding method. The particular joining geometry of these structures requires bridging of the air gap during welding. For this purpose, a closed-loop control has been designed which, dependent on weld speed, wire feed speed and joint geometry, allows to control the added filler material in a way that complete fusion and uniformly reinforced welded seams are achieved. The software LabView has been used for the realisation of the control. The joint geometry is optically measured via a light-section sensor, subsequently converted into analogue signals and, as a last step, evaluated. These data are used for the control of the oscillating mirror of the laser optic and also of the NC control of the applied CO2 laser. The design of this control is not limited to this particular task, it is, more-over, universally applicable. In this paper, the general set-up and design of the control are demonstrated, also the possibilities and the measuring range of the respective components are specified. The programming and alternative programming possibilities are introduced.