Prediction of Milling Force Coefficients From Orthogonal Cutting Data

The mechanistic and unified mechanics of cutting approaches to the prediction of forces in milling operations are briefly described and compared. The mechanistic approach is shown to depend on milling force coefficients determined from milling tests for each cutter geometry. By contrast the unified mechanics of cutting approach relies on an experimentally determined orthogonal cutting data base (i.e., shear angle, friction coefficient and shear stress), incorporating the tool geometrical variables, and milling models based on a generic oblique cutting analysis. It is shown that the milling force coefficients for all force components and cutter geometrical designs can be predicted from an orthogonal cutting data base and the generic oblique cutting analysis for use in the predictive mechanistic milling models. This method eliminates the need for the experimental calibration of each milling cutter geometry for the mechanistic approach to force prediction and can be applied to more complex cutter designs. This method of milling force coefficient prediction has been experimentally verified when milling Ti₆Al₄V titanium alloy for a range of chatter, eccentricity and run-out free cutting conditions and cutter geometrical specifications.