URANAMI BEAD DETECTING METHOD IN PLASMA KEY HOLE WELDING AND GROOVE PROFILING METHOD

摘要

PURPOSE:To forms automatically good URANAMI bead by detecting the existance of the plasma arc which penetrate to the back face of the material to be welded and by detecting whether the URANAMI bead is formed or not. CONSTITUTION:The output signal of adder 19 becomes zero because of the output signal of photosensors 7a-7d becoming zero when plasma arc 4 does not penetrate the material 1 to be welded and the valve opening for plasma gas of welding torch 3 is made bigger by this signal. When the plasma arc 4 penetrates the material 1 to be welded, amplifier 16 is actuated by the output signal of the adder 19. In case of the center of the welding torch 3 and the groove center being coincided with this state the output signal of the comparator 15 becomes zero due to the output signal of the adder 13 and 14 being equal and the input signal of servo amplifier 17 becomes zero. A profile motor 18 is therefore not rotated and the welding torch 3 does not move to the right and left for the groove.