| CPC B23K 11/25 (2013.01) [B23K 11/11 (2013.01); G01N 29/07 (2013.01); G01N 29/4427 (2013.01); G01N 2291/2672 (2013.01)] | 16 Claims |

|
1. A control system, comprising:
a detector transmitting an ultrasonic wave toward a weld zone formed by resistance spot welding and detecting a reflected wave, a plurality of members joined at the weld zone, the reflected wave including a plurality of peaks of intensities based on surfaces of the plurality of members;
a processing device receiving a detection result of the reflected wave, determining whether or not a peak of the plurality of peaks based on a surface where the plurality of members are joined is present, and calculating a diameter of the weld zone based on a result of the determining; and
a control device controlling a welding device performing resistance spot welding,
the control device receiving the diameter,
in a case where the diameter is within a first range, the control device modifies a setting value for a next resistance spot welding and causes the welding device to perform the next resistance spot welding, the first range being not more than a first threshold and not less than a second threshold, and
in a case where the diameter is within a second range, the control device does not cause the welding device to perform the next resistance spot welding, the second range being not more than the second threshold.
|