Control method for tracing a weld line in a welding apparatus

摘要

A control method in a welding apparatus for enabling a welding torch to trace a weld line with use of an oscillating process is disclosed. The welding torch is oscillated in left and right directions solidly crossing the weld line. Electric signals respectively detected when the welding torch moves in the left and right directions for a time interval of the right half of the oscillation are compared with each other so as to generate a first comparative signal, and electric signals detected similarly for a time interval of the left half thereof are compared with each other so as to generate a second comparative signal. The center of the oscillation is moved in such a direction that a difference between the first and second comparative signals becomes small.