Modeling the chip-work contact force for chip breaking in orthogonal machining with a flat-faced tool

The present tendency towards increased automation of metal cutting operations has resulted in a need to develop a model for the chip breaking process. Conventional cutting force models do not have any provision for the study of chip breaking since they assume a continuous mode of chip formation, where the contact action of the free-end of the chip is ignored in all analyses. The new cutting force model proposed in this work incorporates the contact force developed due to the free-end of the chip touching the workpiece, and is applicable to the study of two-dimensional chip breaking in orthogonal machining. Orthogonal cutting tests were performed to obtain twodimensional chip breaking. The experimentally measured cutting forces show a good correlation with the estimated cutting forces using the model. Results show that the forces acting on the chip vary within a chip breaking cycle and help identify the chip breaking event.