An analytical model for the prediction of force distribution of round insert considering edge effect and size effect

摘要

Turning operation is a fundamental machining method that is indispensable in aviation industry and automotive sectors, what is more, round insert is an important type of cutter due to its relatively massive engaged edge. Modeling of cutting force is important to forecast the machining process, what is more, to predict tool wear and surface quality of components. The cutting force distribution, often studied in milling and drilling operation, is necessary to be discussed in turning operation with round shape insert due to its complex and unique cutting geometry. In this paper, an analytical force prediction model for turning process is proposed based on the discretization of cutting edge and detailed geometric analysis with the consideration of edge effect and size effect, and applied to the force distribution of round insert. Firstly, a novel way is developed to divide the uncut chip area of round insert into many increments and the local parameters of each increment can be calculated by the classical oblique cutting theory. Secondly, shear flow stress of the workpiece at the primary shear zone is determined based on unequal division shear zone model and modified with the influence of size effect. The cutting force of each increment is predicted based on the oblique cutting theory with the consideration of edge effect. Then, an in-depth discussion of the distributions of local parameters is presented for each increment along the cutting edge of round insert, which indicates the characteristics of round insert. Finally, series of cutting experiments are performed on Inconel 718 and Ti6AI4V to verify the effectiveness of the developed model. The predicted results show good agreement with the measured ones, which proves the correctness and accuracy of the proposed analytical model. (C) 2018 Elsevier Ltd. All rights reserved.