Effects of tool edge radius and rake angle on ductile machining process of CaF₂

The submicron level orthogonal cutting process of CaF₂ has been investigated by the finite element approach, and the effects of tool edge radius on cutting force, cutting stress and chip formation were investigated. T results indicate that increasing the tool edge radius causes a significant increase in thrust force and a decrease in chip thickness. A hydrostatic pressure (~2 GPa) is generated in the cutting region. The volume of the material under high pressure increases with the edge radius. The effects of tool rake angle on cutting stress and chip formation were also investigated. The results indicate that increasing the tool rake angle causes a significant increase in stress and a decrease in chip thickness. The simulation results from the present study show the optimal tool rake angle to the ultra-precision cutting of CaF₂ is -20°. The simulation results from the present study can be applied for optimising tool geometry design in CaF₂ machining.