Prediction of tool-chip interface friction and chip-groove effects in machining with restricted contact grooved tools using the universal slip-line model

This paper presents a new predictive model for the tool-chip interface friction and the chip groove effects in machining with restricted contact grooved tools. This model is derived from the recently established universal slip-line model for machining with restricted contact tools. Four important machining parameters including cutting forces, chip thickness ratio, chip back-flow angle, and chip up-curl radius are predicted in this model on the basis of (1) the rigid-plastic universal slip-line model, (2) a maximum value principle for determining the stress state of the plastic region in machining processes, (3) Dewhurst and Collins' matrix technique for numerically solving slip-line problems, and (4) numerical algorithms for solving non-linear equations. An analysis of the effect of tool geometry parameters, e.g., groove width and backwall height, on machining parameters is presented in this paper. A new methodology for predicting the actual tool-chip friction is also developed and presented in the paper with a case study demonstrating a unique solution. This methodology gives a range of solutions for combinations of tool geometry parameters.