On rotary axes calibration using double ball bar, four-axis and five-axis machine tools

A method is proposed to measure the rotary axes errors of a five-axis machine tool or the C-axis of a four-axis machine tool using the magnetic double ball bar (DBB) as the measuring instrument. Five DBB tests are designed to measure axis motion errors and in conjunction with two ordinary circular DBB tests they allow the determination of the axis link errors. The exclusive motion of axis under test, using DBB (not expensive and more accessible) and the short time required are some of the characteristics of this method.