Effect of Crystallography on Residual Stresses during Ultra-Precision Machining of Sapphire

Author(s): Aditya Nagaraj, Sangkee Min


Publication: CIRP Annals

Acknowledgment: NSF CMMI-2008563 NSF DMR-1720415 FANUC ALMT

Citation: CIRP Annals, Vol. 71, No.1, pp.101-104, April 26, 2022

Residual stresses play an important role in determining the quality of a machined surface during ultra-precision machining (UPM) of ceramics by initiating cracks at premature loads. In this study, the anisotropy in residual stresses resulting from UPM of two crystallographic planes of sapphire is investigated using micro-Raman spectroscopy. An analytical model is then used to improve our understanding of plastic deformation during UPM and its contribution to residual stress. Results show a strong dependence of residual stress magnitude on the slip and fracture systems activated during machining which are anisotropic based on the cutting direction.