Modeling the Minimum Chip Thickness in Orthogonal Micro-cutting Based on Plastic Strain Gradient

In micro-cutting, the uncut chip thickness is comparable or even less than the tool edge radius and as a result a chip will not be generated if the uncut chip thickness is less than a critical value, viz., the minimum chip thickness. Knowledge of the minimum chip thickness plays a key role of the selection of appropriate machining conditions and optimization the micro-cutting processes. An analytical model is developed to predict the minimum chip based on the strain gradient plasticity theory in this paper, and the model accounts for the effect of material property in micro-scale such as the shear modulus, intrinsic length scale, fracture toughness and the Burgers vector. Predicted results are validated by experimental data obtained from the orthogonal micro-cutting experiments.