An analysis of the sensitivity of cutting force coefficients and their influence on the variability of stability diagrams

Abstract

Process forces are an integral characteristic for the evaluation of machining operations, which can be calculated using, for instance, empirical models. An adequate prediction is essential, especially as it provides input data for subsequent models, e.g., for stability analysis of milling processes. However, the calibration of force model coefficients is not unambiguous and may have multiple local optima, which can significantly affect the accuracy of the approximation of the cutting forces. In this context, the selection of experiments used for calibration is crucial to obtain adequate results. In this paper, a systematic analysis of the selection of the required calibration experiments and the influence of the resulting parametrization of the coefficients on the predicted milling forces and the stability limit was conducted.Based on the results, designs of calibration experiments could be identified, with which the influence of varying undeformed chip thicknesses could be represented adequately. By applying these force model parameterizations for stability analysis, an improvement in the prediction of stability limits was achieved.