The Influence of Abrasive Grit Morphology on Wheel Topography and Grinding Performance

摘要

Understanding and controlling the topography of an abrasive, vitreous-bonded grinding wheel is important for optimising performance of the grinding process used to machine advanced aerospace materials. The dressing process plays a critical role in ensuring grinding wheel form and topography is achieved prior to grinding, however the mechanisms of roller dressing for advanced engineered grit morphologies is not well understood. In this investigation, the impact of different dressing parameters on the topography of two vitreous-bonded abrasive wheels with engineered grit morphologies and resulting grinding performance was assessed and compared to a grinding wheel with conventional ‘random’ grit morphology. Continuous dressing grinding cuts were performed under a range of dressing parameters (two different infeed rates and three speed ratios) to determine the impact of dressing condition on grit fracturing and influence of resulting varying wheel topographies, whilst controlling wheel breakdown (wheel self-sharpening during grinding cuts). Constant grinding parameters were used for all grinding cuts and power consumption was monitored during the process. The generated grinding wheel surface morphology was characterised by using a range of surface roughness/topography parameters. In line with previous studies for conventional grit morphologies, results for all three wheel morphologies studied show that under aggressive dressing conditions grinding power is reduced, but so is ground surface quality. Scanning Electron Microscopy imaging of abrasive wheel sections revealed changing grit fracture mechanisms under different dressing parameters. Significant variation in dressing response between conventional and engineered grit morphologies was also observed. This work aims to enhance the fundamental understanding of the relationship between wheel topography and grinding performance using experimental data, and could influence dressing strategies used in industry.