Method of multi-layer welding

Abstract

A method of multi-layer welding in which the welding operation is performed according to a path of welding defined by interpolating a plurality of instructed points by a suitable line, the method being characterized by storing in a memory device the coordinates actually passed by a welding torch in the welding operation of the first layer at the instructed points and determining the welding path of the second and succeeding layers by adding a predetermined amount of shift to the actual detected coordinates stored in the memory device at the instructed points and interpolating the shifted coordinates by a suitable line. According to another aspect of the present invention, therefor provided is a method for controlling the locus of operation in the second and succeeding layers in a multi-layer welding operation by a teach/playback type robot including an arithmetic control mechanism the method being characterized by teaching an arcuate locus of operation of the first layer; utilizing as a parameter a shift width corresponding to the arcuate bead to be formed in the second and succeeding layers through an external input member; determining the direction of shift of the second and succeeding layers by calculating the inner product of the directional vector of a welding torch according to the teaching data of the first layer and a directional vector from a point on the arcuate locus of operation to the center of the arc; and calculating the locus of operation of the second or a succeeding layer from the shift direction and width by the arithmetic control mechanism.