A geometry-driven interlayer surface correction framework for adaptive-width wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) enables rapid fabrication of large-scale metal components, yet cumulative interlayer height variation remains a critical barrier to dimensional accuracy and print stability. While existing interlayer control strategies have shown promise, they are often restricted to simple, stack-aligned geometries or thin-walled structures. This paper presents a geometry-driven surface correction framework that stabilises interlayer height in complex, non-stack-aligned toolpaths with varying bead width by decoupling toolpath planning from height stabilisation. The framework utilised interlayer laser line scanning to capture the as-built surface profile, where reconstruction using Delaunay triangulation enables computing of localised, segment-wise height deviation. A regression-based inverse process model maps these deviations into updated process parameters for the subsequent layer. The proposed method was experimentally validated using a Cold Metal Transfer (CMT)-based WAAM system to fabricate three structures, two 50mm-tall and 80mm-tall, in nickel-aluminum bronze, with variable bead widths and continuously shifting contours. Results demonstrated controlled cumulative error buildup; interlayer standard deviation reduced by over 67% of open-loop despite initial start-stop abnormalities. Tensile testing indicates lower-bound tensile strengths comparable to conventional constant-height builds. The proposed framework provides a practical, hardware flexible solution for enhancing the reliability and dimensional consistency of WAAM for complex industrial prototyping.