A large set of orthogonal metal-cutting tests has been conducted for Aluminum 2014-T6 using carbide and HSS tools over a wide range of cutting variables such as: spindle speed, fed and width of cut. The transient dynamic force behavior during the first few spindle revolutions after tool-workpiece contact was recorded and later analyzed in the time and frequency domains. Results show that, depending on the cutting conditions and in most of the tests carried out, the cutting and thrust forces reached their steady-state values in a number of spindle revolutions ranging from one and a half to two. This result indicates that the application of existing metal-cutting force models can not predict the actual behavior of the forces during transient cutting conditions. A new dynamic force model is proposed in which the instantaneous force and depth of cut as well as their first-order time derivatives are involved. This first-order linear differential equation is particularly important for advanced modeling for adaptive control purposes. Physical implications of these results are briefly discussed.
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