Optimization of surface roughness in WAAM-fabricated ER70S-6 steel components

This study proposes a cost-effective and practically applicable process optimization strategy for improving surface quality in WAAM using ER70S-6 solid wire. A Taguchi L9 orthogonal array was employed to systematically investigate the effects of three process parameters, travel speed, current, and voltage on the areal surface roughness of deposited walls. Interpass temperatures were monitored using an infrared thermal camera to evaluate thermal accumulation. The results revealed that a parameter combination of 20  cm/min travel speed, 130 A current, and 19  V voltage, coupled with a stabilized interpass temperature of approximately 250 °C, significantly reduced thermal buildup and enhanced surface morphology, yielding a minimum S_a of 187  μm. The optimized parameters were further validated through the fabrication of a geometric structure. The findings confirmed that interpass dwell time contributes to improved local surface flatness and verified the stability and feasibility of the selected parameters. This work not only demonstrates a practical pathway to surface improvement in low-alloy WAAM components but also provides a useful reference for surface quality control and thermal management strategies in WAAM processes.