Abstract: The eccentricity of cutter may induce great variation of milling force. In order to identify the geometry of eccentricity, regularities of milling force varying with eccentricity are studied. Milling force on single edge is mathematically expressed as functions of the rotation angle and the sequence number of cutter edge. By mathematically deducing, the peak milling force of each cutter edge is found to be a discrete sine function of only the sequence number, its mean part be the nominal force without cutter eccentricity, and the variable part be the increment force induced by eccentricity, moreover, the increment force be same with spindle rotation in frequency, its initial phase be dependent on the angle of eccentricity, and its amplitude be in direct proportion to both the distance of eccentricity and axial milling depth, but irrelevant to feed per tooth. Based on these findings, a kind of data fitting method is present to estimate the distance and angle of eccentricity, which is mainly to fit peak milling forces of every cutter edge with sine function. This method is simple, and needs only one milling test. The results of milling experiment agree with above findings, and show that this estimation method is validate. This study reveals the eccentricity-relate characteristics of peak milling force, and presents a simple method of estimating the geometry of eccentricity. Study results can be used in identifying the state of milling process.

Key words: Characteristics, Cutter eccentricity, Fit, Geometry estimation, Peak milling force