Experimental Optimization of Bead Geometry in WAAM for Single-layer Deposition

Introduction: Wire Arc Additive Manufacturing is increasingly used for producing medium- and large-scale metallic components due to its high deposition rate and efficient material usage. Despite these advantages, achieving consistent bead geometry and defect-free deposition depends strongly on the selection of process parameters. The present study aims to examine and optimize key input parameters that affect the formation of a single-layer weld bead in the WAAM process. Methods: Single-layer weld beads were fabricated using SS316L stainless steel MIG filler wire. The main process variables considered were shielding gas flow rate, open-circuit voltage, and welding speed. The quality of the deposited bead was evaluated in terms of height-to-width ratio and microhardness. Experiments were designed using a Taguchi L9 (3⁴) orthogonal array, and the results were analyzed with Minitab 17 and ANOVA F-test to determine the influence of each parameter and identify suitable operating conditions. Results: The experimental results indicate that variations in SGFR, OCV, and WS have a noticeable effect on bead geometry and hardness. Certain parameter combinations resulted in improved bead shape with a more uniform height-to-width ratio, along with better hardness values. The analysis also highlighted the relative significance of each parameter in controlling the deposition characteristics. Discussion: The study shows that proper adjustment of process parameters is essential for maintaining bead stability and achieving desirable mechanical properties. The interaction between heat input and material deposition plays a key role in defining bead shape and hardness. The outcomes provide useful guidance for selecting process conditions in WAAM applications to improve build quality and consistency. Conclusion: The investigation demonstrates that optimizing the shielding gas flow rate, opencircuit voltage, and welding speed improves weld-bead characteristics in WAAM. The Taguchi method proved effective in identifying suitable parameter settings, supporting better control of the deposition process and enhancing overall performance.