Influences of processing parameters on metal-bonded diamond wheel wear when grinding a sapphire wafer

Abstract

Wear processes on a metal-bonded diamond grinding wheel during surface grinding of monocrystal sapphire were investigated. Through a single-factor grinding experiment, the grinding depth of the workpiece, wear from the grinding wheel, and surface roughness of the workpiece were measured and surface morphologies of the processed surface, the grinding wheel, and diamond abrasives were observed. Moreover, the mechanism of action for influences of wear of the grinding wheel on surface quality of workpiece was investigated based on a complex model of roughness when grinding in plastic and brittle modes. The results indicate that: (1) The wear process of the grinding wheel consists of four stages, i.e. slow-speed wear, high-speed wear, slow-speed wear, and stable wear; (2) With the increase of the grinding depth, the probability of plastic material removal increases by using abrasives, while workpiece surface roughness first decreases then increases; (3) Wear forms of diamond abrasives mainly include wear land at the tip and crushing of abrasives. During the grinding of sapphire wafers using a metal-bonded diamond grinding wheel, wear from the grinding wheel rises with the increase of the grinding depth. When the grinding depth is 240 μm, the surface quality of the workpiece deteriorates, so the grinding wheel needs to be dressed to restore its grinding capacity and precision.