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Dynamic Performance Analysis on Helical Milling Spindle Unit

Helical milling is a new holes processing technology, in which the special tool moves to the work piece with a helical path. Helical milling spindle unit is designed based on the helical milling machining principle. The dynamic performance of the unit has much effect on the workpiece surface quality. According to the whole transfer matrix method, the first four order critical speeds are obtained, and the effect of bearing span and stiffness on the critical speed is systematically studied. The result shows that the first order critical speed increases with the increase of bearing span and bearing stiffness.