A systematic finite element-based methodology for predicting cutting forces in micro-milling of Al2024-T3 incorporating tool runout and chip flow direction

Micro-end milling is crucial for the manufacture of miniature parts with complex geometries. This study presents a systematic finite element (FE)-based methodology for predicting cutting forces in micro-milling of Al2024-T3 by integrating numerically extracted shearing and ploughing force constants with tool runout and chip flow direction within a unified framework. The force constants are identified from two-dimensional (2D) orthogonal micro-cutting FE simulations incorporating an energy-based ductile fracture model, thereby reducing reliance on extensive experimental trials. These constants are subsequently implemented in a comprehensive force model that accounts for runout and chip flow direction, the latter evaluated using Stabler’s rule while maintaining computational efficiency. The FE model predictions show good agreement with experimental results, with deviations of approximately 3% for cutting forces and below 10% for feed forces. Tool runout is found to significantly influence force distribution between flutes, increasing the force ratio (Formula presented) /(Formula presented) up to 2.8 at higher offsets without altering the flute passing frequency. As the locating angle increases, load distribution improves and force imbalance decreases. Moreover, higher feed rates and axial depths of cut lead to increased force amplitudes due to greater chip load and tool engagement, while up- and down-milling exhibit comparable force levels because of nearly symmetric cutting conditions.