A slip-line solution to metal machining using a cutting tool with a step-type chip-breaker

Abstract

Chip-breakers play a predominant role in the effective control of chip-flow and chip-breaking, especially at high cutting speeds, for the easy and safe disposal of chips, as well as for protecting the surface-integrity of the workpiece. In the present paper, a theoretical analysis of metal machining using an orthogonal cutting tool has been carried out, using the slip-line field technique for a parallel step-type chip-breaker, assuming constant friction at the chip–tool interface. Friction at the interface of the chip and the chip-breaker is neglected. The cutting forces, radius of curvature of the chip, chip-breaking force, contact length, chip-reduction coefficient, stress-distribution at the chip–tool interface and other associated parameters are computed. Analysis predicts the condition when the effect of chip-forming starts for a chip-breaker. The conditions for under-breaking and over-breaking of the chips are determined from the analysis for mild steel. Some comparisons with experimental data, as available in the literature, are found to be satisfactory