Online Identification of Shearing and Plowing Constants in End Milling

Online methods for the identification of shearing and plowing cutting constants from forces in a single milling operation are presented. By virtue of the analytical nature of the milling force model in the frequency domain, the shearing and plowing constants are expressed, in a linear closed-form equation, in terms of cutter geometry, cutting depths and the Fourier coefficients of the milling forces. Two methods are presented to identify these cutting constants. The first method uses only the first harmonic components of the milling forces, and the second method utilizes the average forces as well as the ratio of the first harmonic forces. Limitations on the cutting conditions for each identification method are discussed. The accuracy and consistency of these two methods in extracting the shearing and plowing constants from a single set of force measurements are verified through simulation and milling experiments.