Four-point method of roundness and spindle error measurements

A new method of roundness and spindle error motion measurement is presented in this paper. Roundness error of the workpiece and radial error motion of the spindle are measured simultaneously by using 4 probes mounted with certain angle arrangement. This method gives high accuracy for all harmonics which is difficult for three point method. Based on error analysis a methodology for selecting optimal parameters is given. Both computer simulation and experiment justify the high accuracy of proposed method.