| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve an arc start performance by accurately detecting a wire tip grain size upon weld finish in consumable electrode arc welding.SOLUTION: When a weld start signal St changes to Low, a feeding motor is stopped to perform an anti-stick control for switching over a weld voltage setting signal to an anti-stick voltage setting value, so that welding is finished by extinguishing an arc with a grain formed at a wire tip. An integral value is detected, for time lengths Tb or weld currents Iw over a burning period of times t54 to t7, the period from release of the last normal short circuit generated during a period of the anti-stick control of times t5 to t8 until the extinguishment of the arc, to detect a grain size at the wire tip from these values. On the basis of the detected grain size at the wire tip, a parameter upon an arc start is optimized. In this way, constantly favorable arc start performances can be obtained even when variation occurs in the grain size at the wire tip.</p> |
