Patent ID: 6791062
Filing Date: 2004-09-14
Classification: B23K

Abstract:
Method of positioning a welding torch and a welding wire of a welding device at the center of a desired path of a welding seam, in which the welding torch is positioned by means of a robot arm on a predetermined or programmed position between two seam edges of a workpiece, and an alignment process is run whereby the robot arm moves the welding torch in one direction until a short circuit occurs between the welding torch or the welding wire and one of the seam edges, and the welding torch is then displaced by the robot arm in the opposite direction until another short circuit occurs between the welding torch or the welding wire and the other one of the seam edges but no arc is ignited between the welding torch or welding wire and the workpiece when a short circuit occurs, after which a control system evaluates the displacement path in order to calculate the seam center on which the welding torch or welding wire is positioned by the robot arm, wherein the welding device uses a single current source having a power component supplying power for the welding process and the alignment process; by selecting a â€œFind positionâ€  function, the control system reduces the power output of the power component to the degree that a change in resistance is detected on the basis of the power applied to output terminals of the power component when a short circuit occurs and, to detect the short circuit, discharge capacitors between the output terminals are loaded by an output power of the power component with a low capacity so that ignition of an arc is prevented when a short circuit occurs.