Analysis of an are light mechanism and its application in sensing of the GTAW process - A theoretical model was developed that correlates arc light radiation with welding parameters

Sensing plays a key role in automating and controlling welding processes. I n recent decades, arc light sensing has been studied for arc length control , joint tracking and droplet transfer detection in arc welding. However, th e current technology relies on experimental data and lacks theoretical foun dation. To improve measurement accuracy, this work addresses the theoretica l foundation for arc light sensing. A theoretical model has been developed to correlate are light radiation to welding parameters. Distributions of di fferent radiant sources in the arc column are studied. It is found that the distributions of the ions of the shielding gas and the vapors of the base metal and tungsten are not even, while that of the shielding gas atoms is. This suggests the spectral lines associated with the shielding gas atoms ca n be used to improve the accuracy of arc light sensing. Hence, an arc light sensor has been developed to detect argon atom spectral lines in gas tungs ten are welding. The relationship between the argon lines and the welding p arameters has been derived from the theoretical model. Joint tracking exam pies showed the effectiveness of the developed method in improving accuracy .