| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that, in a control method in which forward feeding and backward feeding of a wire are periodically alternated, and in which a welding output is made low during a period where the feed amount of the wire is small and the welding output is made high during a period where the feed amount of the wire is large, a short circuit state between a welding object and the welding wire is mainly mechanically opened during a period where the feed amount of the wire is small, but opening of a short circuit is not necessarily smoothly conducted, depending on a kind of disturbance, because the wire is fed forward by small and small and further a current is low although the feed amount of the wire is small. SOLUTION: The method for arc welding includes: a step of calculating a variation amount of a welding voltage per unit time for each predetermined sampling period to compare the calculated variation amount with a reference threshold value for detecting a constriction; and a step of determining detection of a constriction when the number of times, at which the variation amount of a welding voltage per unit time continuously exceeds the reference threshold value for detecting a constriction at each predetermined sampling period, reaches a predetermined number of times. COPYRIGHT: (C)2011,JPO&INPIT |
