Construction of a predictive model for residual stresses in micro-milling of 7075 aluminum alloy

This manuscript delineates a predictive model for evaluation of residual stress phenomena in micro-machining operations, predicated upon the symbiotic dynamics of strain, strain rate, and thermal conditions. The objective is to scrutinize the ramifications of variable parameters such as machining velocity, axial depth of cut, and cutting tool’s rake angle on the resultant machining forces and induced residual stresses. By analyzing the interplay between the shear forces, frictional stresses, and the material deformation forces during micro-machining, alongside the correlation between shear velocity and material displacement, as well as thermal contributions in both primary and secondary deformation regions involving the substrate, removed material, and the cutting implement, the residual stresses are deduced employing the Johnson-Cook material behavior model, manifesting predominantly as compressive residual stresses within the work material. The veracity of the analytical model for residual stress is corroborated with the maximum relative discrepancies for principal cutting force and residual stress at 16.8% and 6.53%, respectively, both falling under the 15% threshold, thus affirming the model’s precision. Empirical findings underscore the axial depth of cut as the most influential parameter on machining forces, with theoretical escalations of 183.84% and 145.67% in the orthogonal X and Y directions accordingly, as the depth of cut augments from 10 to 25 μm. Conversely, the machining velocity predominantly affects the thermal profile and residual stress levels; a surge in machining velocity from 400 to 800 mm/min correlates with a theoretical amplification in thermal generation by 227.52%, while concurrently registering a decrement in residual stress magnitude by 7.08%.