Investigation of material flow behaviour and chip formation mechanism during grinding of glass-ceramics by nanoscratch

Abstract

Abstract Material flow analysis is important for revealing the mechanisms of chip formation and material removal in ductile regime machining of glass-ceramics. However, the analysis is limited by a lack of elastic–plastic stress field modelling of the scratch process. Therefore, this paper proposes an analytical stress field model of material flow for glass-ceramics to reveal the material removal mechanism at a microscale. This model includes the grit tip radius and nominal rake angle, which have a significant effect on material flow. Theoretical analysis results show that the material flow direction and chip formation depend on the relative grit sharpness. With greater relative grit sharpness, more material flows upwards and a chip is easily formed owing to the smaller effective rake angle, whereas less relative grit sharpness results in a larger effective rake angle such that all the material flows downwards and no chip is formed. To validate the proposed model, a taper nanoscratch experiment was conducted. The experimental and theoretical results are in good agreement. These findings of material flow behaviour can help predict chip formation and achieve the ductile regime grinding of glass-ceramics.