Tool Path Generation Modified by Predicting Workpiece Deformation Caused by Vise Clamping Using 3D Finite Element Method (FEM)

The manufacturing industry faces a labor shortage while needing to achieve high-mix and low-volume production at costs comparable to those of mass production. To enhance flexibility and value in production with limited human resources, increasing labor productivity by reducing production lead time is essential. Automated tool path generation is a promising solution; however, achieving high-precision machining involves not only simply preparing numerical control (NC) programs but also modifying NC programs through test cutting and reviewing machining conditions. One of the factors causing machining errors in cutting is the deformation of the workpiece due to the clamping in the vise. Such deformation can lead to dimensional errors after the workpiece is unclamped, even if it meets tolerances while still on the machine. This study proposes a tool path generation system that considers the deformation of the workpiece caused by the vise, with the purpose of realizing high-precision machining with high efficiency. In this study, a highly compatible computer-aided design model is generated in Standard Triangulated Language format, and the deformation of the workpiece due to clamping is predicted via the finite-element method. The tool path is then generated according to the prediction results to ensure that dimensional tolerances are satisfied after the workpiece is removed from the vise. A case study confirmed that the proposed system can generate numerical control programs that increase the dimensional accuracy of the product.