Investigation of feature-based and space-filling tool path strategies for formability in incremental sheet metal forming

Incremental sheet metal forming (ISF) is a versatile dieless forming process for manufacturing complex sheet metal components. The toolpath is one of the most critical process parameters, significantly influencing the ISF formability. The conventional toolpath strategies, such as spiral and constant z-slice-based tool paths, do not prove helpful for complex asymmetries in part geometry. The approach to toolpath planning in ISF should consider both material behavior and design complexity. This work compares conventional toolpaths with two strategies, namely feature-based and space-filling fractal tool paths. Material thinning and geometric deviations are critical limitations for successful part development. All toolpath strategies were evaluated for material distribution, geometric accuracy, and fracture depth using four carefully designed components with gradually increasing asymmetry. As evident from the results obtained, the material deformation was sensitive to the choice of toolpath strategies. The feature-based tool path captures the part curvatures more uniformly, leading to homogeneous thickness distribution. At the same time, fractal-based strategies lead to lower overall geometric deviation in the region of curved profiles.