Damage assessment in ceramic grinding

Grinding helps to shape and finish workpieces, but also induces damage, especially in ceramics. In this research a model for the mechanism of grinding damage is proposed. Finite Element Modeling was conducted to study the temperature and stresses during ceramic grinding for process estimation and mechanism study. Grinding temperature, forces and residual stress were measured; surface and subsurface cracks were examined using optical microscopy and scanning electron microscopy. A non-destructive technique, post-grind acoustic emission (AE), was studied for damage assessment. The mechanism of post-grind AE was explored and the correlation between post-grind AE and grinding parameters was investigated. Grinding damage was also correlated with edge chipping, and the relationships between edge chipping, grinding parameters and the retained strength of workpieces were investigated. Through this study, the damage mechanism was verified and the criteria for grinding with minimum damage to the workpiece were established. In addition, the grindability of ceramics, including silicon nitride, aluminum oxide, zirconia and ferrite, was studied and grindability formula were put forward.