Prediction of clamping deformation in vacuum fixture–workpiece system for low-rigidity thin-walled precision parts using finite element method

Abstract

In ultra-precision manufacturing, the prediction of workpiece deformation induced by loading of the fixture–workpiece system is critical for manufacturing workpieces with high-quality surfaces. However, the influence of any errors resulting from the differences between the surface profiles of the fixture and the workpiece on the clamping deformation is always neglected. This results in a low processing accuracy of low-rigidity workpieces. Moreover, the effects of different structural parameters of the workpiece and the vacuum fixture on the clamping deformation have not been thoroughly investigated. In this study, a comprehensive finite element analysis (FEA) model considering the surface profile error between the vacuum fixture and the low-rigidity flat parts was established to predict the clamping deformation under various clamping pressures in the vacuum fixture–workpiece system. Furthermore, the relationship between the clamping deformation, as well as the structural parameters of the flat parts and the vacuum fixture, was evaluated. A detailed comparison between the predictions and experimental results verified the accuracy of the proposed analytical method. Finally, based on the analysis results, the position angle of the vacuum fixture–workpiece system was optimized to reduce the clamping deformation caused by the differences between the surface profiles.