| Summary: | 博士 === 國立成功大學 === 機械工程學系碩博士班 === 90 === This paper presents a frequency domain force model for a general helical end mill including edge ploughing as well as chip shearing mechanisms. The differential local cutting forces are first formulated through differential geometry for a general helical cutting edge. The single flute and the multi-flute milling forces in the angular domain are subsequently composed through convolution integration and analyzed by Fourier analysis. In this frequency domain model, cutter geometry and the parameters of a general milling process are integrated into a unified framework with their roles clearly defined such that the Fourier coefficients of the total milling force can be obtained for any analytically definable helical cutter. From the Fourier analysis, it is shown in particular that in slot milling either the dynamic shearing force or the dynamic ploughing force components might vanish for any type of helical cutter depending on its flute number. By virtue of the analytical nature of the milling force model in the frequency domain, frequency domain force model can be further explored for the applications including the identification of specific cutting constants and cutter offset. Two on-line methods are presented to identify specific cutting constants. The first method uses only the first harmonic component of the milling forces and the second method utilizes the average forces as well as the first harmonic forces. Furthermore, the force model is applied for the prediction of chatter in milling. A 3D model is developed that includes the effect of helix angle. Numerical simulation and experimental results are presented to validate the presented force model and its applications.
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