Characteristics of a novel elliptical ultrasonic vibration-assisted turning device

2D Ultrasonic Vibration-Assisted Turning (2D-UVAT) is a proven method to improve the traditional turning process. This process utilises bi-axial vibrations to enhance the smoothness of the machined surface and to suppress cutting temperature and cutting force. This study investigates the effects of employing a novel non-resonant vibration module, called the RNO vibrator, on the surface roughness, cutting temperature, and cutting force of aluminium alloy 6061-T6 machined using 2D-UVAT technique. The RNO vibrator operates by harnessing flexural hinges to disseminate and amplify the actuated vibrations originating from two orthogonal piezo actuator stacks. This vibrator was designed from a simple bar concept, expecting minimal adjustment on the tool post during installation. The experimental evaluation of the RNO vibrator's performance was conducted by varying key machining parameters, including spindle speed, depth of cut, feed rate, and vibrational frequency. The study reveals that the introduced RNO vibrator substantially enhances machining quality by diminishing surface roughness and cutting temperature, while concurrently reducing cutting forces. Under the given conditions, the machined workpieces had a surface roughness between 0.41 and 1.25 µm and a cutting temperature ranging from 153.36°C to 180.5°C, while the cutting force was low, typically between 35.3 N and 145.5 N. The vibrator works better at high frequency, particularly at 20 kHz. Eventually, the study suggests that the RNO vibrator has a promising performance as a vibration module for the 2D-UVAT process.