STABILIZATION OF DRESSING PERFORMANCE OF ROTARY DIAMOND DRESSER BY MEANS OF ON-THE-MACHINE PROFILE CONDITIONING

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As a means to realize on-the-machine truing of rotary dresser for internal grinding machine, a dressing system in which the rotating speed of the dresser is very slow compared to that of the grinding wheel, is adopted, a journal bearing is used for the spindle in order to achieve a high stiffness of 40 N/μm. The contact point of dresser to the grinding wheel is detected by an AE sensor with an accuracy of 0.1μm. Dressing performance of two types of V-shaped rotary diamond dressers, a single-layered impregnated diamond dresser and a metal-bonded diamond dresser, are investigated. Internal plunge grinding of hardened steel was conducted and the effects of dresser type on the grinding performance were investigated. The following results are summarized.1)When a rotary dresser rotating with a very slow speed is applied to the grinding wheel with a small diameter, a part of grinding wheel surface in the widthwise direction may not contact the rotary dresser. This unevenness of dressing can be reduced by the use of a dresser on which the diamond grains are aligned with short intervals.2)The metal-bonded diamond dresser has the advantage that the intervals of diamond grains can be easily controlled, therefore, being available for the dresser of the grinding wheel with a small diameter.3)The metal-bonded diamond dresser can be trued with high profile accuracy by means of vitrified GC cup-wheel method.4)The metal-bonded diamond dresser brings about a grinding force more stable than that of the impregnated diamond dresser.5)The metal-bonded diamond dresser with small grain size increases the grinding force, decreases the finished surface roughness, and decreases the radial wheel wear. The optimum grain size of the dresser is around #270 for the grinding wheel of #140 mesh size.