Process-aware hybrid slicing for Wire Arc Additive Manufacturing of mixed-feature components under fixed process conditions

Wire Arc Additive Manufacturing (WAAM) is increasingly being investigated for fabricating large-scale metallic components. However, despite its potential, WAAM is still mainly applied to medium-complexity geometries. A major limitation is the lack of slicing and path-planning strategies capable of automatically accommodating heterogeneous cross-sections, small features, and substantial variations in wall thickness within the same component and within the same sliced layer, without requiring local changes to the process parameters. Fixed single-strategy approaches are inadequate because thin-wall and bulk regions require different path-generation logics and bead-growth behaviours. This work therefore proposes a process-aware hybrid slicing methodology for robotic WAAM. Within each sliced layer, the method automatically identifies regions requiring thin-wall or multi-pass bulk deposition while maintaining a single predetermined and experimentally characterised process-parameter set. Thin regions use Medial Axis Transform (MAT)-based centreline deposition, while wider regions use boundary and infill paths. A layer-growth synchronisation strategy is also introduced to compensate for the different effective bead heights produced by the two deposition regimes, reducing progressive height mismatch across the component. The proposed framework is assessed on representative mixed-feature layer geometries and demonstrated experimentally on an ER4043 aluminium component containing both thin-wall and bulk regions. The results demonstrate advantages over the standardised single-strategy path-planning baseline by enabling geometric adaptation without changing the selected process parameters. This is relevant for qualification-oriented applications, where parameter changes may affect heat input, thermal history, microstructure, and mechanical properties. Overall, the methodology enables process-aware planning of variable-thickness WAAM components under predetermined process conditions.