Intelligent laser process control in the micro spot welding for copper

Micro welding of Copper by fundamental YAG laser is hard to process, because of its high reflectivity for near infrared laser and high thermal conductivity, In this research, we developed intelligent laser process control in micro welding of Copper sheet with 0.2mm thickness by means of laser beams combining AO Q-switched second harmonic YAG laser (SHG-YAG laser for short) with fundamental YAG laser. The objective of this study is to keep the size of melt zone and penetration depth constant in micro spot welding process by autonomic control. Reflected beam of fundamental YAG laser and vibration of specimen were measured during laser irradiation as the input signals of intelligent laser process control. The number of SHG-YAG laser pulse was controlled at 1ms intervals by neural network instructed by experimental data.