Control device, control system, welding system, control method, method for manufacturing joined body, and storage medium

A control method for controlling a welding device performing resistance spot welding, comprising:

• 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;
• determining whether or not a peak of the plurality of peaks based on a surface where the plurality of members are joined is present;
• calculating a diameter of the weld zone based on a result of the determining;
• in a case where the diameter is within a first range, modifying a setting value for a next resistance spot welding and causing 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, not causing the welding device to perform the next resistance spot welding, the second range being not more than the second threshold.

A method for manufacturing a joined body, the joined body including a plurality of members, the plurality of members overlapping in a first direction and joined at a weld zone formed by resistance spot welding,

• the method comprising:
• 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;
• determining whether or not a peak of the plurality of peaks based on a surface where the plurality of members are joined is present;
• calculating a diameter of the weld zone based on a result of the determining;
• in a case where the diameter is within a first range, performing a next resistance spot welding after modifying a setting value of the next resistance spot welding for manufacturing another joined body, 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, not performing the next resistance spot welding to manufacture the other of the joined bodies, the second range being not more than the second threshold.

A non-transitory computer-readable storage medium storing a program,

• the program:
• causing a detector to transmit an ultrasonic wave toward a weld zone formed by resistance spot welding and detect 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;
• causing a processing device to receive a detection result of the reflected wave, determine whether or not a peak of the plurality of peaks based on a surface where the plurality of members are joined is present, and calculate a diameter of the weld zone based on a result of the determining;
• and
• causing a computer to receive the diameter,
• in a case where the diameter is within a first range, the computer modifies a setting value for a next resistance spot welding and causes a 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 computer does not cause the welding device to perform the next resistance spot welding, the second range being not more than the second threshold.