| 摘要 |
PURPOSE:To form good beads having uniform height at all times by controlling a welding current by detecting arc light penetrated to the back of a material to be welded and at the same time, controlling the controlled welding current to form surface beads of specified height. CONSTITUTION:The amount of arc light and the amount of radiant light from a preceding electrode welding wire 4 are detected by a photocell 5 provided on a backing strap 2, converted to a voltage value, added by an adder 7, and the differential voltage between the set voltage value of a back bead width setting device 8 is obtained by a comparator 9. This differential voltage is inputted to a welding current controller 10, and the welding current of a welding wire 4 is controlled to make the differential voltage to zero and back beads of specified shape are formed. This controlled welding current value is detected by a welding current detector 12, and compared with the set value of a surface bead height setting device 12'. The welding speed is controlled by a welding speed controller 17, the welding speed of succeeding electrode is controlled by a succeeding current controller 19 and the wire projection length is controlled by wire projection length controllers 20, 20' to make the differential voltage to zero. |
