The objective of this research is to investigate an on-machine estimation method to achieve efficient and fast estimation of the fixturing force and workpiece deformation. The estimation enables us to visualize workholding states and improves machining accuracies of thin-walled parts. In this research, a systematic estimation method of workholding states which combines fixturing simulation and locally measured strain is proposed and evaluated. The proposed on-machine estimation method is evaluated in different workholding conditions (clamping sequences and fixturing forces). Estimated fixturing force and workpiece deformation for a clamped thin-walled workpiece were compared to the results from the engineering experiments. From the comparison, it becomes clear that the proposed method has the feasibility to detect improper workholding states such as insufficient fixturing force or excessive deformation.

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