An innovative method to model run-out phenomena in micro-milling by using cutting force signal

This work deals with the modeling of micro-milling processes by considering the phenomena generated by the transition from conventional size to the micro-scale machining. The concomitant effects of different cutting regimes, and the deviation of the cutting edges from their theoretical trajectories due to tool run-out, are important aspects to be considered during the process modeling. Several models are available in literature to describe how ploughing and shearing regimes influence cutting forces and how the tool run-out impacts on the actual chip thickness. In a previous authors research, a comprehensive model was published achieving a good agreement with the experimental data, but its calibration requires the measurement of the width of the micro-milled slots. This practice is time consuming and subjected to experimental errors, while a calibration of the model based only on the elaboration of the cutting force signal appears a promising strategy. Starting from the mathematical description of the geometrical model, a new equation to compute the tool run-out parameters was found. The parameters depend on eight variables that must be calculated from tool geometry, material composition, cutting parameters and the cutting force signal. An experimental procedure was developed to compare the prediction achieved by the new method and the conventional technique.