Surface morphology and grinding performance of metal-bonded diamond grinding wheels sharpened by microwave discharge

While microwave (MW) discharge technology has been developed to address the challenges inherent in sharpening metal-bonded diamond grinding wheels (MD-GW), the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation. This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge, with a focus on abrasive damage, grit protrusion height and uniformity, the number of effective abrasives, chip space, and bond morphology. The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments, using mechanical sharpening as the comparison group. The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods, albeit with minor graphitization and localized oxidative damage occurring. Furthermore, after being sharpened by the MW method, the grit protrusion height increased, demonstrating good uniformity, and simultaneously exhibiting a higher number of effective abrasives. Noticeable craters formed in proximity to the abrasives, augmenting chip space, but sputtering led to the formation of metal deposition layers on the abrasive surfaces. The MW-sharpened wheel exhibited superior grinding wear ratios, with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process progressed. These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner, resulting in improved grinding surface quality. The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW, with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.