Prediction of workpiece deformation in a fixture system using the finite element method

Knowledge of workpiece deformations induced by loading in a fixture–workpiece system is important to ensure quality part production. Suitable methods for accurately predicting such deformations are essential to the design and operation of fixtures. In this regard, finite element modeling has been widely applied by researchers and practitioners. However, these studies generally neglect the role of compliance of the fixture body on workpiece deformation. Also lacking is knowledge of the effects of different finite element model parameters on workpiece deformation. This study uses finite element analysis (FEA) to model a fixture–workpiece system and to explore the influence of compliance of the fixture body on workpiece deformation. In addition, the effects of certain finite element model parameters on the prediction accuracy are also examined. Experimental verification of the workpiece deformations and locator reaction forces predicted by the FEA model shows agreement within 5% of the experimental data. For the fixture–workpiece system analyzed in this study, it was found that 98% of all system compliance is captured by modeling just the workpiece and fixture contact tips. The remainder of deformation occurred in the other fixture components. The accuracy and computational time tradeoffs are given for various fixture models.