Mechanism study on adiabatic shear fracture induced isolated segment formation during high-speed machining

Abstract

The adiabatic shear fracture is an inevitable fracture phenomenon in high-speed machining with the further increase of cutting speed, leading to isolated segment formation. A quick-stop device is designed and applied in high-speed machining process to obtain chip roots. On the basis of chip morphology examinations, the occurrence mechanism of adiabatic shear fracture is investigated and the multi-stage physical model is proposed. The experimental results show that the serrated chip is formed due to the occurrence of adiabatic shear, while the isolated segments are generated due to the adiabatic shear fracture. The adiabatic shear fracture induced isolated segment formation in high-speed machining is a periodic process. The energy convergence and release effect in adiabatic shear band plays a significant role in the late stage of adiabatic shear fracture.