Precision Measurement of Multi-Degree-of-Freedom Spindle Errors Using Two-dimensional Slope Sensors

A measuring system consisting of three two-dimensional surface slope sensors is developed for spindle error and roundness measurement. The sensors, which are in the same XY-plane perpendicular to the spindle axis (Z), are placed around a cylindrical workpiece mounted in the spindle. The workpiece out-of-roundness and the X- and Y-directional components of the spindle radial error motion can be separated from each other using the radial direction outputs of sensors. On the other hand, the two-directional components of the spindle angular error motion can be obtained accurately from the angular direction outputs of sensors. Experiments of spindle error and roundness measurement were carried out.