A novel mechanistic-analytical force model for slot milling based on the decomposition into cutting and ploughing actions

Accurate prediction of cutting forces is essential for optimizing milling operations, improving tool life, and enabling reliable force-based monitoring and control strategies. This study presents a mechanistic–analytical model based on the decomposition of the resultant forces into their fundamental mechanical components, with explicit consideration of the minimum uncut chip thickness that defines the ploughing region. In addition, the model accounts for the in-process friction coefficient, enabling the evaluation of frictional contributions under real machining conditions. A dedicated methodology for model calibration is introduced, based on slot milling tests conducted with a single-insert tool configuration and a rotary dynamometer. This setup simplifies the interpretation of cutting force signals and enables accurate identification of model constants. Once calibrated, the model is applied to predict force signals in conventional multi-insert slot milling, successfully distinguishing between ploughing and cutting effects. The approach is validated through milling experiments on Ti-48Al-2Cr-2Nb, a titanium aluminide widely recognized as a difficult-to-machine material. Tests were carried out under varying depths of cut and feed rates, encompassing a wide range of chip geometries. The proposed model demonstrates high predictive accuracy, particularly for the tangential force component, with coefficients of determination exceeding 0.95. This enhanced force modeling framework provides a robust foundation for process planning, real-time monitoring, and adaptive control in high-performance milling applications involving challenging materials.