Contribution to Bead Width in Feedback Control of Cathode Torch Using Image Processing

In the industrial field, processing technology for joining metal materials is an indispensable technology. TIG arc welding has the advantages of welding without spatter and adaptability to any joint shape. TIG arc welding is widely applied in fields where high reliability and safety are required. TIG arc welding is technically challenging, and the number of welding technicians has been decreasing. In recent years, the introduction of robots and de-skilling in welding has been progressing, and it is needed to realize automatic welding without welding defects under various conditions. Automatic welding that can respond to various situations can be realized by grasping the current situation and controlling the welding process based on that information. Weld defects are caused by changes in heat input. Heat input is caused by changes in arc voltage. Arc voltage is caused by changes in the inter-electrodes distance. In this research, the bead width was calculated for feedback control of the cathode torch using image processing. In this method, images of the arc state during welding were processed and the inter-electrodes distance was measured. The cathode torch was driven using feedback control to keep the inter-electrode distance constant.