With the shift toward high-mix, low-volume production, the proportion of process planning within the overall manufacturing lead time has increased. This issue is particularly critical in the medical field, where custom-made production of organically shaped components with complex curved surfaces is required, while the number of experienced workers responsible for process planning is decreasing. Typically, machining of models with complex curved surfaces is performed by milling processes, including 5-axis indexing machining and 5-axis simultaneous machining. However, cycle time can be reduced by incorporating additional machining processes, such as turning, alongside milling. Recently, the development of multitasking machine tools equipped with eccentric-axis turning functions has enabled greater machining flexibility and the potential for reduced machining time. Nevertheless, methods for tool path generation and numerical control (NC) program generation that effectively utilize eccentric-axis turning have not yet been sufficiently established. Therefore, in this study, an automated process planning and tool path generation method was proposed that applies eccentric-axis turning to the roughing stage for organically shaped components. In the proposed method, workpiece dimensions and product placement are determined based on shape analysis of a three-dimensional computer-aided design model in Standard Triangulated Language format, and an intermediate shape suitable for eccentric-axis turning is automatically extracted. Furthermore, for regions where material removal by turning is difficult, scanning machining that considers air cuts is applied, and tool paths for each process are generated. To verify the effectiveness of the proposed method, analytical evaluation and actual machining experiments were conducted using organically shaped components. The results confirm that the proposed method appropriately performs shape analysis and NC program generation, and that roughing using eccentric-axis turning is effective in reducing machining time for organically shaped components.

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