A model of micro-milling cutting forces based on micro-cutting experiments including tool eccentricity and deflection

In this study, a model of micro-milling cutting forces based on elementary cutting experiments is developed. Elementary cutting tests were used to identify the parameters of a new model that includes the uncut chip thickness and the effect of the cutting edge radius. This model assumes a straight cutting edge and a rigid cutting tool and is divided into two terms that represent the ploughing and shearing regimes. The complex shape of the cutting edge of the micro-end-mill is decomposed into linear elementary edges to which the force model can be applied. The uncut chip thickness during tool rotation includes the tool path deviation due to tool run-out and deflection. Micro-milling experiments were performed using a micro-end-mill with the same cutting edge geometry as the tool used in elementary cutting experiments on AISI 6F7 steel. Comparisons between the force model and the experimental results show a good correlation. This model can be extended to a ball-nose micro-end-mill to consider a wide range of operations and can be used to predict and avoid machining errors due to deflection and even tool breakage.