Microscale contact state among polyurethane, abrasive particles, and the sapphire surface during the wheel polishing process

To investigate tool influence function (TIF) formation mechanism in sapphire polishing, this study adopts external and central polishing fluid supply, and selects polyurethane micro-asperity and peak-surfaces as typical polishing layers. Based on theoretical modeling and supplemented by qualitative experiments, it preliminarily analyzes the macro/micro contact states among the polishing layer, diamond particles and sapphire, establishes particle motion criteria, explores material removal mechanism and particle consumption path. For external supply, effective particles on peak surface that do not meet the movement conditions are consumed, while those meeting the conditions participate in material removal. The particles on micro asperity show zonal consumption/removal. The potential particles supplement from central supply enables front particles on peak surface to participate in material removal. External supply results in relatively low material removal and poor regularity of TIF for peak surface and micro asperity. In contrast, the peak surface with central supply has a relatively high material removal and good regularity of TIF. This study preliminarily reveals the potential mechanism of polishing fluid supply and polishing layer on TIF, providing a theoretical basis for the evolution of time-varying TIF in subsequent sapphire wheel polishing.