Modelling and analysis of micro-grinding surface generation of hard brittle material machined by micro abrasive tools with helical chip pocket

Abstract

The abrasive particles on the surface of micro abrasive tool are very small and tightly distributed, which is prone to appear debris blockage and accelerate tool wear, so the service life and performance of existing micro abrasive tools have become one of the key factors restricting the engineering application of micro-grinding technology. Compared to ordinary cylindrical micro abrasive tools, the micro abrasive tool with micro helical chip pocket (MAT-HCP) presents excellent performance in facilitating debris discharge and improving wear resistance, but the existence of helical chip pocket will significantly affect grains distribution, grinding contact area and surface generated mechanism in the micro-grinding process. In this work, the micro-grinding surface topography model of hard brittle materials obtained with MAT-HCP is built by considering grain size and distribution, dynamic impact, helical chip pocket structures, transient chip thickness and hard brittle material removal mechanism. The micro- grinding experiments are carried out to analyze surface morphology characteristics and surface generated mechanism of sapphire material machined by MAT-HCP. The contrast of simulated and experimental results showed that the average predicted error of contour supported ductility domain ratio and surface roughness respectively can be confined to be 10 % and 5%, which indicates that this surface topography predicted model can succeed in capturing the micro-grinding surface characteristics of sapphire material fabricated by MAT-HCP. Moreover, experimental results disclosed that the increase of pitch length will make MAT-HCP harder to realize the plastic region machining for sapphire, and this novel micro abrasive tool is potential to obtain better surface quality at high feed velocity compared with ordinary micro abrasive tools. The research results are of great significance for extending the service life of micro abrasive tools and promoting engineering application of micro-grinding technology.