Modeling and analysis of factors of size effect in micro-cutting: The tool geometry and the depth of cutting

Based on the finite element approach and the strain gradient (SG) theory, this paper produced a study on factors of size effect and minimum cutting thickness phenomenon in the micro-cutting process. Mechanisms of micro-cutting focusing on its characteristics that include size effect, tool edge radius and minimum cutting thickness has been studied. A new constitutive relationship based on SG theory is formulated to model the size effect of material properties at micro-scale. The new constitutive was implanted into the FEM, and size effect was investigated. From the result of simulation, it is indicated that size effect in micro-cutting could be well formulated by SG theory. The curve of material properties is approached to curve of JC with the depth cutting increased; when the rake angle is increased, the size effect is more obvious. The tool edge radius has a significant influence on the size effect. Result show that the cause of the minimum chip thickness is the tool edge radius.