A SLIP-LINE SOLUTION TO METAL MACHINING USING A CUTTING-TOOL WITH A STEP-TYPE CHIP-BREAKER

Chip-breakers play a predominant role in the effective control of chip -flow and chip-breaking, especially at high cutting speeds, for the ea sy and safe disposal of chips, as well as for protecting the surface-i ntegrity of the workpiece. In the present paper, a theoretical analysi s of metal machining using an orthogonal cutting tool has been carried out, using the slip-line field technique for a parallel step-type chi p-breaker, assuming constant friction at the chip-tool interface. Fric tion at the interface of the chip and the chip-breaker is neglected. T he cutting forces, radius of curvature of the chip, chip-breaking forc e, 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-breaki ng of the chips are determined from the analysis for mild steel. Some comparisons with experimental data, as available in the literature, ar e found to be satisfactory. (C) 1998 Elsevier Science S.A. All rights reserved.