Disclaimer of Quality Pages Are Missing from the Original Document. Pages 35 and 102 Missing from Original the Attritious and Fracture Wear of Grinding Wheels Thesis Supervisor Wear of Grinding Wheels

THE ATTRITIOUS AND FRACTURE WEAR OF GRINDING WHEELS by Stephen Malkin Submitted to the Department of Mechanical Engineering February 1968, in partial fulfillment of the requirements for the degree of Doctor of Science A detailed investigation is made of the nature and extent-of grinding wheel wear in finish grinding. The wear is broadly classified as either attritious or fracture wear. Attritious wear results in the dulling of the tips of the abrasive grain by rubbing against the workpiece surface. Fracture wear is the removal of abrasive particles from the wheel either by fracturing within the grain (grain fracture) or fracturing at the bond (bond fracture). Most of the wear is found to consist of grain and bond fracture particles. The rate at which fracture wear occurs is directly related to the grinding forces. The attritious wear, although contributing insignificantly to the total, is the most important form of wear. The dulling of the grains by attrition, measured by the area of the wear flats, uniquely determines the grinding forces for a particular workpiece material and for given grinding conditions. Both the horizontal and vertical grinding force components increase linearly with the wear flat area. (For steel this is true only up to a critical wear flat area where burning occurs.) This linear variation between grinding force and wear flat area is explained by considering the force as the sum of a cutting force due to chip formation and a sliding force due to rubbing between the wear flats and the workpiece. Related investigations are also made of wheel dressing, surface finish, workpiece burn, and grinding temperatures. Thesis Supervisor: Nathan H. Cook Professor of Mechanical Engineering