Control system for reducing weld spatter during the welding process by using high-speed visual sensing

Robotic welding has been the biggest use in many industry. It is important to control weld robots without weld spatter for small size target. To prevent flying weld spatter, the precursory phenomenon of weld spatter must be detected, and power source of robotic welding must be controlled to reduce before weld spatter occurs. This study aimed to propose a control system to prevent the occurrence of flying weld spatter during laser or gas tungsten arc (GTA) welding process in real-time. Because the strategy involves detecting the precursory phenomenon at high-speed, we simplified the recognition system as much as possible. The system consists of a lighting system to illuminate the weld pool, a high-speed camera and an FPGA board. The control algorithm of this system used image data information for a histogram. We analyzed the images from the high-speed camera during welding. Our analysis found that, just before the weld spatter is generated, very bright pixels temporarily and abnormally increased as the precursory phenomenon. According to the proposed system, it is possible to prevent the occurrence of weld spattering in real time during the welding process. This integration of visual feedback in a robotic welding system enhances the quality of the weld work.