Path optimization strategies for wire-arc additive manufacturing of thin-walled parts

This paper presents a new methodology for manufacturing complex thin-walled parts using wire-arc additive manufacturing (WAAM). The work combines open-source slicing software with 3-axis CNC motion systems to establish the required parameters for WAAM. It also includes an adaptive path optimization strategy, which not only mitigates inefficient machining but also eliminates the need for excessive metal deposition to compensate for height deviations. The methodology effectively addresses challenges associated with key fundamental geometries - such as corners, intersections, and overhangs of up to 55° relative to the baseplate - during the path planning stage of WAAM. In addition, it further provides new insights into geometries involving the convergence and divergence of walls with variable inclination angles, which are crucial to produce customizable geometries with high strength-to-weight ratios. Validation of the proposed methodology was carried out through the fabrication of a pillar–beam connection prototype integrating all the fundamental geometries under investigation. The prototype was successfully produced, with geometric deviations from the original digital model remaining below 5%. Post-fabrication analyses also confirmed that the proposed methodology does not adversely affect the deposited material at either macroscopic or microscopic levels. Overall, the approach proved effective for producing functional and geometrically complex thin-walled parts by WAAM under conventional slicing software and 3-axis motion systems.