2020 Volume 38 Issue 3 Pages 147-156
In this paper, in order to predict the occurrence of excessive penetration and burn-through that occur in groove MAG welding, we observed the molten pool with cameras, and considered parameters correlating with the occurrence of the excessive penetration and burn-through. In the case of groove MAG welding using a robot, excessive penetration and burn-through that occur due to the effects of disturbances such as gap between base materials caused by heat distortion and member accuracy are obstacles to improvement of welding quality and production efficiency. So, we constructed a simultaneous observation system for the top and bottom side of the molten pool using two cameras. Molten pool width (W) and reduction of molten surface height (R) are extracted as feature quantities, and compared with the state of the bottom side of the molten pool. Although the decrease of W and R was confirmed, they alone were not enough to predict the occurrence of burn-through. Therefore, W+R was set as a new parameter (P) in consideration of the molten pool cross-sectional shape change. As a result, the decrease of P was confirmed before the occurrence of burn-through, and it was shown that P is an effective parameter for predicting the generation of burn-through.
