Effect of double-excitation ultrasonic elliptical vibration turning trajectory on surface morphology

To explore the formation law and influence factors of three-dimensional geometry in axial turning surface, the turning experiment of 7075 aluminum alloy was carried out by using double excitation three-dimensional ultrasonic elliptical vibration method. Based on the theory of turning kinematics, the tool tip trajectory model of three-dimensional ultrasonic elliptical vibration turning (3D-UEVT) was established, and the related mechanism in surface residual height, surface topography formation characteristics, and turning transmission was given. Through single factor simulation and turning test, the influence of spindle speed, feed speed, amplitude, and phase difference on the surface microstructure and roughness of workpiece was analyzed contrastively. The results show that, compared with the traditional turning, the double excitation ellipse assisted turning can affect the surface topography and quality of the workpiece by causing the dynamic change of the cutting angle of the tool tip and the residual height of the material. Combined with the analysis of simulation and experimental results, it is found that the ideal microstructure and roughness can be obtained with low speed, slow feed, small amplitude, and small phase difference. Meanwhile, the tool workpiece separation characteristics, surface topography, roughness, and surface defect level can be effectively improved under the three-dimensional ultrasonic elliptical assisted vibration.