<p>The industrial robot has emerged as one of the advanced automation methods for welding applications in various manufacturing industries. Due to its precise control and high repeatability, it is the most effective solution for achieving high structural integrity in welded parts. The present study focuses on the optimisation of process parameters for welding joints using an industrial ABB IRB 1520 robot-controlled Gas Metal Arc Welding (GMAW) for aluminium alloy. The study aims to improve the geometric and mechanical properties of welded joints by optimising the robotic welding parameters. The effects of three robotic GMAW parameters, such as wire feed rate, travel speed, and torch angle, were studied using an L27 Taguchi orthogonal array. The welding trials were conducted on beads-on-plate, and the final welded joints were produced in a butt configuration with optimised parameters. The output responses include Bead height (BH), Bead width (BW), and Depth of Penetration (DOP) obtained from 27 beads-on-plate experimental trials. The Analysis of Variance (ANOVA) results revealed that torch angle had the greatest effect on DOP (73.44%), wire feed rate on BW (83.44%), and travel speed on BH (53.59%). The developed first-order regression model was used to predict BW, BH, and DOP. The predicted value shows good agreement with the experimental values. The confirmation test revealed that the welded sample, selected based on the optimised parameters, achieved a tensile strength of 278&#xa0;MPa. Further, the confirmation test revealed the effectiveness of the optimised parameters in achieving greater depth of penetration, uniform bead width, and controlled bead height, all of which contribute to superior overall weld quality.</p> Graphical abstract