Modeling study of milling force considering tool runout at different types of radial cutting depth

Abstract

Accurate force model during batch precision machining is the basis for optimizing milling parameters and maintaining process stability. Tool radial runout is inevitable and affects milling force, and milling parameters are also important factors affecting milling force. However, existing milling force models rarely consider the influence of tool runout under different types of radial cutting depth, resulting in unsatisfactory accuracy and limited practical application of the models. In this study, a model of the instantaneous undeformed chip thickness of tool considering the effect of tool radial runout is established in stages on the basis of the contact geometry of tool and workpiece. A prediction model for milling force at three types of radial cutting depth is obtained by combining the instantaneous stiffness model. In the model, the true tool radial runout value is calibrated by calculating milling force. The accuracy of the proposed model and the effects of milling parameters on milling force and true tool radial runout are investigated via milling experiments for three types of radial cutting depth. The experimental results show that the proposed milling force model has better accuracy than the models without considering tool runout and considering only tool static runout by comparing milling force curves, the values of R2, and the spectral characteristics of the three models. Milling parameters change the true tool radial runout. The results of this study can provide theoretical guidance for the selection of end milling parameters and theoretical support for maintaining the stability of milling forces in cutting operation.