Mechanistic modelling of the micro end milling operation

The presented research work has been done during the development of a mechanistic model to predict micromilling cutting forces. The aim of such a prediction is to be able to estimate the tool deflection and the real tool-path during the micromilling process. The first step to achieve a robust model is to develop a procedure to identify the specific cutting force coefficients. Beginning with the conventional end-milling cutting force model, based on six coefficients (three specific cutting force coefficients and three edge coefficients), several modifications are proposed to adapt it to the prediction of the micromilling cutting force. A variety of end mill shapes (cylindrical, ball, and bull-nose) are considered in the geometric part of the model. The paper presents these modifications and their experimental validation by the micromilling of tool steel (H13 hardened up to 60 HRC) using two-flute carbide micro end mills with diameters from 0.1 to 0.4 mm. Finally, the consistency between the simulated and measured cutting force is shown as the main conclusion. Weak points suitable for further research are also exposed.