A novel finite element simulation approach for analyzing distortion and residual stress in ultrasonic-assisted milling

The cutting forces, residual stresses, and workpiece distortion in machining processes largely influence the quality of the end product. An advanced technique for the amelioration of these parameters is ultrasonic-assisted milling (UAM), which induces high-frequency vibrations onto the cutting tool to intermittently disrupt tool-workpiece contact, aiding in the removal of material more effectively. This study focuses on ultrasonic-assisted milling and its effects on cutting forces, workpiece distortion, tensile residual stress, and surface integrity via finite element simulation and experimental approaches. A numerical model was built in ABAQUS first and validated against experimental observations. In the experiments, aluminum 7075 was selected as the workpiece material, and various machining parameters including spindle speed, feed rate, and milling method were investigated. The results indicated that UAM reduced cutting forces up to 25%, workpiece distortion of 21.5%, and tensile residual stresses by 23% compared to conventional milling (CM). Microscopic investigations revealed better surface integrity in the UAM compared to CM, as trace scratches were less and there were fewer surface defects. The comparison between simulations and experimental findings also yielded good correlation with a deviation in output parameters within 11%. This finding demonstrates that ultrasonic-assisted milling is an effective method for improving dimensional accuracy and surface quality in the machining process.