Abstract
It is necessary to manage not only in-process but also pre-process and post-process for improvement of the welding quality. In this paper, the fault condition sensing technique is proposed by the waveform monitoring and the waveform analysis of the physical quantity in the welding process. The waveform monitoring is applying control chart method in quality control. The waveform analysis such as running average process, differential characteristics, integral characteristics and time subtraction of data are particularly effective for monitoring a laser welding system. Application of the technique to the laser-half-penetration-spot-welding for thin stainless steel sheets is discussed. This monitoring system was verified by the welding examination with pulse gating mode Nd:YAG laser welding system. Welding conditions as follows; peak power is 4kW, pulse width is 30ms, processing speed is 1.5m/min, and assist gas is Argon. These successful results were very promising.
