Transfer of Roundness Error from Center and Center Hole to Workpiece in Cylindrical Grinding and its Control

Summary In this study, firstly, the relationship among the roundness errors of the center, the center hole and the ground workpiece is investigated by applying Fourier analysis to their profilograms. The results obtained are as fellows: Among the many components of roundness error of workpiece, the oval and triangular ones are most predominant. The triangular component is mainly caused by that component of roundness error of the center hole. On the contrary, the oval component is caused not only by that of the center hole but also by some other factors, which force to oscillate the rotational axis of the workpiece at two cycles per revolution during grinding. Secondly, a special grinding method in which the wheelhead position is controlled accurately, synchronized with the rotation of the workpiece, is developed by utilizing a microcomputer and a stepping motor. This method is effective in reducing the oval component of roundness error down to one half.