RSM-based optimization of robotic TIG welding parameters for copper rotor bars: Multi-property validation for special purpose machine development

Abstract

One of the major bottlenecks in submersible pump manufacturing is the manual welding of rotor copper bars, which leads to inconsistent weld quality, reduced production throughput, and potential health and safety risks for operators. Currently, conventional carbon arc welding is widely used for this operation because of its simplicity and low operating cost; however, it provides limited arc stability, generates excessive heat input, and results in significant variability in joint integrity. This study examines the feasibility of employing a tungsten inert gas (TIG) welding process as a more precise and reliable alternative for rotor copper bar welding. A six-axis robotic TIG welding platform was utilized to conduct systematic experimental trials aimed at identifying and optimizing the critical process parameters that influence weld quality. Optimization was performed using response surface methodology and analysis of variance (ANOVA) to establish statistically significant relationships among the process variables. Test samples fabricated under optimized conditions were evaluated through mechanical testing, macro- microstructural characterization, and electrical conductivity measurements to validate weld integrity and process repeatability. The findings demonstrate that robotic TIG welding provides superior arc control, improved joint performance, and enhanced consistency compared to the conventional process. These outcomes establish the foundation for developing a low-cost, application-specific special-purpose welding system tailored for rotor copper bar fabrication. Overall, this study not only confirms the technical viability of robotic TIG welding for copper but also contributes to improved productivity, stronger quality assurance, and enhanced operator safety in rotor manufacturing.