Investigation and prediction of surface integrity induced by milling of hot forged and heat treated AA7075

This study examines the influence of cutting parameters on surface integrity, focusing on residual stress and surface roughness, in hot-forged and T6 heat-treated AA7075 components post-milling. Using the Taguchi L9 DOE method, orthogonal cutting milling experiments were performed, with residual stress measured via nondestructive X-ray diffraction (XRD). The analysis indicated that lower cutting speeds reduce residual stress, with down milling causing compressive and up milling causing tensile stresses. A proposed model showed a significant correlation between cutting force and residual stress—higher cutting forces increased residual stress. Surface roughness assessment revealed that feed rate greatly impacts residual stress, with lower feed rates reducing roughness. These insights will aid in developing a regression model for predicting outcomes in future experiments, enhancing the understanding and control of surface integrity in milling AA7075 components.