Material removal mechanism of FCC single-crystalline materials at nano-scales: Chip removal & ploughing

Abstract

In machining operations, investigating the transformation between chip removal and ploughing is crucial to understand the material removal mechanism, which is also the basis for analyzing the machining process, such as calculating cutting force and predicting minimum uncut chip thickness (MUCT). In this study, an analytical model was proposed to predict the chip thickness and ploughing width for FCC crystal materials under arbitrary crystal orientations in nano-machining. The molecular dynamics (MD) simulation methods and the nano-scratching experiments were conducted to verify the theoretical model under two representative crystal orientations. The results indicate that the crystal orientation determines the transformation between chip removal and ploughing. Moreover, according to surface crystal orientation, machining direction, tool radius, and uncut chip thickness, the chip thickness and ploughing width can be calculated in nano-machining. The model can be applied to the nano-machining process of FCC crystals that achieve the plastic deformation by the (110){111} slip system, where tool size and uncut chip thickness are at the nanoscale.