Machining, Measurement, and Control Laboratory

Machine Tools with an Enhanced Ball Screw Drive in Vertical Axis for Shaping of Micro Textures
D. Kono, T. Fujita, A. Matsubara, I. Yamaji

This study describes a three-axes machine tool equipped with a fine motion device in the Z (vertical) axis. The machine motion is basically provided by ordinary ball screw drives. The synchronization of the fine motion with the XY motion to control the depth of cut can produce micro textures on a workpiece surface. First, the closed loop control of the fine motion was tested, and the frequency response was evaluated. Second, in order to improve the response, a second order digital filter was installed in the FF controller. The bandwidth was improved to 130 Hz at the amplitude of 500 nm. Finally, the evaluation in actual machining was conducted. A sweep-sine wave was machined with a diamond bite by the control of the depth of cut. From the experimental result, it was verified that the system properly provided the depth of cut at less than 100 Hz.