Mechanisms of Material Removal in the Precision Production Grinding of Ceramics

Abstract

Grinding of ceramics is often treated as coarse grinding dominated by brittle fracture or fine grinding, at very low removal rates, dominated by plastic deformation. Through a set of experimental observations and analysis, it is shown that in grinding of ceramics the abrasive/work interaction can be treated similar to well known chip formation models. Such an approach permits the coexistence of ductile deformation and brittle fracture during the grinding of ceramics. When the grinding process is managed such that the brittle fracture is minimized, while maximizing the plastic deformation optimum results are achieved. In this regard it is conceivable to design ceramic grinding cycles, where the rough grinding cycle focuses on surface generation to achieve high material removal rate and productivity while minimizing brittle fracture and the finish grinding cycle focuses on surface generation which maximizes plastic deformation while still minimizing brittle fracture. While the above accounts for only one of four interactions in the grinding zone (viz) abrasive/work interaction, it is also necessary to address the other three interactions (viz) chip/bond, chip/work and bond/work interactions. The later considerations for ceramics grinding are identical to well established practices in metal grinding. When such grinding cycle optimization is carried out taking simultaneously into account the aspects of machine tool, grinding wheel, work material and operational factors, significant progress can be made in the grinding of ceramics. The results obtained through such systems approach are also described in this paper.