| 摘要 |
PURPOSE:To shorten a welding operation time by intermittently lighting on a surface of a steel plate to be welded by pulses, obtaining a signal which shows whether the surface is plated or not according to the difference in output between a photodetector before the lighting and the photodetector in the lighting, and changing welding conditions according to said signal. CONSTITUTION:A projector 3 projects light upon a surface of a steel material at a specified slanting angle at prescribed intervals of time according to prescribed pulses. Signals of a photodetector before and in the projection are extracted respectively to obtain the difference between both the signals, and on the basis of a signal which corresponds to the difference, a discriminator discriminates whether the surface of the steel material 1 is plated or not. According to the output signal of the discriminator, welding conditions of the weld zone are changed. Thus, individual sampling is performed to find the difference between the both, ahd consequently the signal for the discrimination is obtained to eliminate the influence of disturbing light generated irregularly by another welding device. |
