| Summary: | 博士 === 國立成功大學 === 機械工程學系碩博士班 === 92 === This paper presents analytical force models for a general helical serrated end mill with sinusoidal and square edges profile in both the angle and frequency domains. Based on the numerical chip load model, Chip load distribution is analyzed with respect to tool geometric parameters. The proposed chip load model describes the influence of flute geometry, number of cutter flutes, flute helix angle, wavelength of sinusoidal edge, cutter radius. Sinusoidal-edge chip thickness is N times that of a regular end mill, if the ratio of wave amplitude to the feed per tooth hs is large, that value of hs required to satiable is dependent on the number of the flute and the ratio of the radial depth of cut to the cutter diameter hr. Square-edge chip thickness is N/2 times that of a regular end mill by chip load of cutting edges. They are shown that under normal feed conditions that there exist only one and two cutting point at any axial position for an N-flute roughing end mill with its chip thickness N and N/2 times that of a regular end mill, while the effective axial depth of cut are only 1/Nth and 2Nth that of a regular end mill. Based on the chip load model, the analytical force model is subsequently established through convolution integration of the elemental cutting function with the cutting edge geometry function in the angular domain, followed by Fourier analysis to obtain the frequency domain force model. Distinctive features of the chip load distribution, vibration energy, surface rounghness and cutting energy for a roughing end mill are illustrated and compared with a regular end mill in the frequency as well as in the angular domain. Numerical simulation and experimental results are carried out to demonstrate the force characteristics and verify the force model.
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