Effect of Arc Polarity on the Quality of Deposition in GTAW Welding-Based Additive Manufacturing Process: A Preliminary Study

A Gas tungsten arc welding (GTAW)-based additive manufacturing has a potential for manufacturing metallic parts with better dimensional accuracy and dense structure. This paper discusses the issues in the GTAW-based metal deposition process for the positive and negative polarity of the welding electrode in the direct current circuit. The effect of direct current electrode positive (DCEP) and direct current electrode negative (DCEN) polarity on GTAW-based metal deposition process has been discussed. The experimental study has been done with a constant voltage source of ESAB Caddy 2200i welding machine and the metal beads were deposited on the substrate plate of mild steel. The results of these experiments showed that the metal deposited using DCEN polarity has a better dimensional accuracy over DCEP polarity due to its stability in arc formation and proper transmission of heat. The experimental investigation showed that the DCEP polarity causes the deterioration of the tungsten electrode after a few trials. The work done in this paper will help to distinguish between the use of DCEP polarity and DCEN polarity in GTAW-based additive manufacturing process for depositing the metal with better dimensional accuracy and better surface finish.