Study of microcutting fundamentals for peripheral and end cutting edges in micro-end-milling

Abstract

In the micro-end-milling of surfaces, thin walls, and micro channels, etc, both peripheral and end cutting edges of micro end mills are engaged in cutting. However, the microcutting fundamentals for end cutting edges have not been well studied, even though those for peripheral cutting edges have been studied widely. Key micromilling variable analyses show that the order of significance is the axial depth of cut (ap), feed per tooth (fz), and radial depth of cut (ae). It means that the microcutting mechanisms of the end cutting edge need to be studied and compared with that of the peripheral cutting edge in order to understand micro-end-milling mechanisms more thoroughly. Simulations using the finite element method (FEM) show that the minimum undeformed chip thickness (MUCT) is different for peripheral and end cutting edges, even though the cutting edge radius remains unchanged. The results of those simulations have been experimentally validated. It shows that the MUCT of the end cutting edge is larger than that of the peripheral cutting edge. That means the MUCT is not only the size of a certain proportion of the cutting edge radius, as mentioned in previous studies, but also has a close relationship with the location of the cutting edge. Therefore, ap could be several times larger than fz according to the relationship between MUCT and the micromilling parameters. It creates a solid basis for the selection and quantization of micro-end-milling parameters in the fabrication of complicated geometries as thin walls and micro channels.