Study on the grinding mechanism of self-sharpening agglomerated diamond wheels for hard and brittle materials

Abstract

Agglomerated diamond (AD) wheels, which integrate the advantages of fine-grained abrasives with enhanced wear resistance, were employed to overcome the wear limitations of conventional fine-grained wheels in precision grinding of hard and brittle materials. The grinding mechanism of AD wheels was systematically investigated through theoretical modeling and numerical analysis, using single-crystal diamond (SCD) wheels for comparative evaluation. The thickest chip models were established for both the AD wheel and the SCD wheel, followed by numerical simulations and experimental validation involving the grinding of fused quartz. The results demonstrated that the AD wheel features a higher density of protruding abrasives, reduced abrasive spacing, and more uniform abrasive heights, leading to thinner chip formation. Significant variations in undeformed chip thickness among quasi-equal-height micro-edges on a single active AD abrasive resulted in their functional differentiation into primary and non-primary working micro-edges. From 30 to 90 grinding passes, the surface roughness (Ra) of the workpiece processed with the SCD wheel increased by 56.1 %, whereas that of the workpiece processed with the AD wheel decreased by 10.2 %. Throughout the grinding process, the AD wheel consistently maintained superior surface quality and stability. The micro-fracture of AD abrasives during grinding enables sharp non-primary working micro-edges to replace dulled primary working micro-edges, with this renewal continuing as new primary working micro-edges degrade. This self-sharpening mechanism ensures the processing stability of AD wheels and highlights the significant potential of ultrafine abrasives for further applications in precision grinding.