Development of a precision truing technique for a CBN grinding wheel of small diameter

摘要

In order to realize precision truing of a CBN grinding wheel of small diameter, a truing technique, in which the grinding wheel axial profile is an envelope formed by circular arcs, has been proposed. The truing equipment developed for the purpose of internal grinding consists of a rotary GC abrasive cup wheel or truer and a vertical guide which enables up-and-down motion of the truer. The rotating shaft of the truer is tilted downward so that the part of the truer section which contacts with the CBN grinding wheel traces a circular arc. A radial depth of cut is given to the grinding wheel at every descent of the truer and a straight-line envelope can be generated as the grinding wheel profile by shifting the truer in the transverse direction at periodic intervals. The truing method was applied to a vitrified CBN 120 grinding quill of5 mm diameter and it was confirmed that a wheel axial profile having a flatness of less than 0.5 micrometer can be obtained under the truing conditions which give a theoretical flatness of 0.26 micrometer.