Analysis of the tool-chip contact length incorporating the effects of shear strain

In metal cutting, it has been acknowledged that the tool-chip contact length significantly affects many aspects of machining, such as chip formation, cutting temperatures, cutting forces, tool wear and tool life. As a result, it has great influence on finished surface quality and accuracy. A slip-line model of tool-chip contact length with two rake faces tool is simplified in this paper, and based on Dewhurst and Collins’s matrix technique for numerically solving slip-line problems and Powell’s algorithm of nonlinear optimization, the mathematical formulation of the tool-chip contact length is resolved. Because of the variation of the work material’s shear strain, it must be taken into account the effect of the shear strain on the tool-chip contact length. From the formulation of the tool-chip contact length, it can be seen that tool geometry, cutting conditions and the stress boundary conditions have great influence on the tool-chip contact length. In addition, the predicted ratio of tool-chip contact length L / t1 is in good agreement with theoretical and experimental results gained by other researchers.