Material Microstructure Effect-Based Simulation Model for the Surface Generation Process in Micro-milling

This paper presents a proposed model to simulate the sur-face generation process during micro-milling of multi-phase materials. The proposed model considers the effects of the following factors: the geometry of the cutting tool, the cut-ting parameters, and the workpiece material microstructure in terms of the variations of the minimum chip thickness for each phase within the material microstructure. In particular, the model can take into account the drastic changes of the minimum chip thickness at the phase boundaries that alter the machining conditions from a proper cutting to ploughing and from ploughing to cutting. Such alterations of the cut-ting mechanisms are considered as the main cause of mi-cro-burr formation. By applying the proposed model when processing multi-phase materials at micro scale, it is possible to estimate more accurately the resulting roughness owing to the dominance of the micro-burrs formation during the sur-face generation process in micro milling. The model was experimentally validated by machining AISI 1040 ferrite/pearlite steel under different cutting condi-tions. The results show that the proposed model accurately predicts the roughness of the machined surface by taking into account the effects of material multi-phase microstruc-ture. Also, the developed model successfully elucidates the mechanism of micro-burr formation at the phase boundaries, and quantitatively describes its contributions to the resulting surface roughness after micro-milling.