Investigation of the Effect of Vibration Amplitude on the Surface Integrity in High-speed Rotary Ultrasonic Elliptical Machining for Side Milling of Ti-6Al-4V

Abstract

The effect of vibration amplitude on machining surface integrity in high-speed rotary ultrasonic elliptical vibration milling Ti-6Al-4V is studied. Firstly, based on the kinematic characteristics of the tool-workpiece and the separation criteria of intermittent cutting condition during high-speed ultrasonic elliptical vibration milling, a chip thickness model and the tool dynamic cutting relief angle model with consideration of the tool-workpiece effectively cutting participation in milling are established. Aiming at investigating the effects of vibration amplitude on high-speed ultrasonic elliptical vibration milling, high-speed ultrasonic elliptical vibration side milling of titanium alloys experiments under minimum lubrication condition are conducted. The cutting forces, surface quality, residual stress, subsurface microstructure and machined surface microhardness during high-speed ultrasonic elliptical vibration milling under different amplitudes are investigated in detail. The experimental results show that the average radial cutting force during high-speed ultrasonic elliptical vibration milling shows a decreasing trend with increasing amplitudes. The vibration amplitude in high-speed ultrasonic elliptical vibration milling has a significant effect on the surface integrity of the workpiece. The surface roughness value of machined surface in high-speed ultrasonic elliptical vibration milling are increased with the increase of vibration amplitudes. The residual compressive stress value on the machined surface in high-speed ultrasonic elliptical vibration milling are increased with the increase of vibration amplitudes. Thickness of the deformed layer and grain refinement degree beneath the machined surface in high-speed ultrasonic elliptical vibration milling are increased with the increase of the vibration amplitudes. Hardening degree of machined surface in high-speed ultrasonic elliptical vibration milling are increased with the increase of vibration amplitudes.