Welded portion inspection method

摘要

A welded portion inspection method highly accurately identifies emitted light from a molten portion during inspection laser light irradiation, enabling highly reliable inspection. When transitioning from a first irradiation step S21 of welding laser light L1 irradiation to a second irradiation step S23 of inspection laser light L5 irradiation, the welding laser light L1 irradiation is interrupted and then the welding laser light L1 is switched to the inspection laser light L5. In an inspection step S25 of inspecting a welded portion, two points in time at which the emitted light intensity is equal to or less than a certain threshold value are extracted from an intensity waveform of the emitted light L2, L6 as an inspection start point in time A and an inspection end point in time B. The interval between the inspection start point in time A to the inspection end point in time B is estimated as being a irradiation period of the inspection laser light L5. The welded state is inspected based on the intensity waveform of the emitted light in the irradiation period.