Modeling of weld formation in variable groove narrow gap welding by rotating GMAW

As an effective welding method, rotating arc narrow gap MAG welding must ensure sidewall penetration, which is hard to realize when the groove is irregular in practical production. Therefore, it is significant to construct a weld form modeling for control weld penetration under the variable groove conditions. At first, the welding experiment system and the sensor system were set up. Arc sensing and visual sensing were applied to monitor the welding process, and effective algorithms were developed to extract the weld groove features. Three typical groove forms were considered and sufficient experiments were carried out to obtain enough experimental data. Furthermore, support vector machine is used to model the process. Welding current and the shortest distance between the arc center and the groove sidewall were used to predict the sidewall penetration. The verification results show that the model is effective under the condition that the height change of the groove is not more than 2 mm, the width change is not more than 2 mm, or the inclination angle of the bottom of the groove is not more than 10 degrees. The establishment of this model is very helpful to further control the formation of narrow gap welding.