Study of the relationship between machine compliance and grinding forces in cylindrical grinding.

摘要

This work demonstrates a novel strategy for improving size and form control when grinding with abrasive wheels. A comprehensive math model is proposed to capture the relevant physics and is used in conjunction with in-process measurements to provide better workpiece quality. Key issues to the success of this approach include rigorous accounting of the many (nonlinear) sources of structural loop compliance and their interaction with the grinding force.;This work is particularly valuable in plunge and traverse grinding because any motion of the abrasive wheel translates directly into workpiece form errors. During a typical plunge grinding operation, the rapidly spinning abrasive wheel is advanced at constant rate into the slower workpiece. The literature documents many modeling attempts to predict the material removal as a function of these feeds and speeds. However, our novel experimental apparatus provides additional in-process information, most notably the grinding force, and clearly shows the inability of the traditional linear models to accurately predict workpiece size.;As will be shown, there are additional physics to consider as evidenced by the lag between grinding force and material removal. This lag is not fully predicted by existing models and is a key result of this research. The model presented here correctly predicts this apparent lag by including nonlinear phenomena such as the depth-dependent energy of material removal as well as nonlinear contact stiffness between workpiece and wheel.;The key contributions of this work are: 1) recognition of the errors of classical grinding efforts based on our results from a one-of-a-kind apparatus not available to other researchers; 2) inclusion of a physics-based description of the nonlinear relationship in material removal as a function of grinding parameters; 3) the prediction of workpiece size without off-line inspection; and 4) accurate simulation in the presence of ever-changing wheel condition, workpiece type, and grinding parameters.