Patent ID: 6201206
Filing Date: 2001-03-13
Classification: B23K

Abstract:
A method of detecting wear amount of welding gun electrodes in a welding robot having a welding gun attached to an end of its robot arm for holding an object to be welded with a fixed-side electrode and a moving-side electrode opposite to the fixed-side electrode and moving driven by a gun-axis servomotor to hold with pressure the object to be welded, said method comprising the steps of:fixing a plate-shaped jig between the fixed-side electrode and the moving-side electrode;controlling, before either of the electrodes is worn, the robot such that the end of the arm moves by an external force only in the direction moving-side electrode moves, then moving the moving-side electrode toward the jig, and after the moving-side electrode comes into contact with the jig, pressing the moving-side electrode against the jig with a constant force such that the end of the arm moves in a direction opposite to the direction in which the moving-side electrode moves with a counterforce;acquiring a position of the robot and a position of the gun axis servomotor in a predetermined coordinate system as reference positions respectively when the jig is held between the moving-side electrode and the fixed-side electrode;acquiring thereafter a position of the robot and a position of the gun-axis servomotor in the coordinate system in a similar manner; andcalculating a wear amount of the fixed-side electrode and a wear amount of the moving-side electrode from a difference between the present position of the robot and the reference position of the robot and a difference between the present position of the gun axis servomotor and the reference position of the gun axis servomotor, respectively.