Numerical Analysis in Ultrasonic Elliptical Vibration Cutting (UEVC) Combined With Electrical Discharge Cutting (EDC) For Ti6Al4V

This paper reports the numerical analysis results of ultrasonic elliptical vibration cutting (UEVC) combined with the electrical discharge cutting (EDC), called UEVC+EDC. UEVC delivers decreasing cutting forces, repressing side-burrs, and lowering tool wear. EDC is a cutting technique using a pulsed spark to remove material using thermal energy. Difficult-to-cut materials, such as Ti-6Al-4V, can be cut effectively by combining these two techniques. A numerical study was performed using ABAQUS finite element analysis (FEA) software by investigating the von Mises stress, cutting forces, and temperature. Numerical analysis was carried out by modifying the ultrasonic vibration frequency, distance of the discharge pulse, discharge voltage, and discharge pulse radius. UEVC+EDC was compared numerically and experimentally with regular cutting (NC) and UEVC in terms of cutting force and tool temperature. The results showed that the UEVC+EDC method could improve the cutting condition by reducing the cutting force and von Mises stress and increasing the tool temperature.

Investigation on the Cutting Mechanism of Al/SiCp Composites in Ultrasonic Elliptical Vibration Machining

Aluminum (Al)-based silicon carbide (SiC) material composites are considered as difficult-to-machine materials because of the presence of hard reinforced SiC particles, which results in a greater cutting force and poor surface integrity during the machining process. This paper uses two finite element models to study the difference in the machining mechanism between ultrasonic elliptical vibration cutting (UEVC) and ordinary cutting (OC). Moreover, this paper mainly focuses on the influence of UEVC on cutting force, von Mises stress distribution, surface integrity, and chip formation. The models are validated by comparing chip shapes and machined surface features in OC machining Al/SiCp experience from the literature. Simulation results indicate that the cutting mechanism of Al/SiCp on UEVC is different from that of OC and has several good properties. At the same cutting parameters, high frequency vibration makes the cutting force of UEVC exhibit variable periodicity and reduces average cutting force. The instantaneous impact of tool and fast separation results in a more concentrated von Mises stress distribution, thereby resulting in the particles having a greater break degree than that obtained with OC. A comparison of the surface roughness values from the simulation result shows that UEVC obtains better surface integrity than OC does.

Experimental and Analytical of Ultrasonic Elliptical Vibration Cutting of Micro-pyramid Reflective Mold Based on Guided Wave Transmission

The ultrasonic elliptical vibration cutting (UEVC) technique has been found to be a promising technique for ultraprecision machining of microstructural functional surfaces. However, the current UEVC technique can’t achieve higher frequency ultrasonic cutting due to its rigid orthogonal vibration transmission. To further study the cutting mechanism and removal characteristics in high frequency UEVC of microstructural surface, the UEVC based on flexible guided wave transmission is proposed which can achieve 96.8 kHz. The influence of bending vibration of guided wave band on longitudinal vibration is elaborated with the model of the bending vibration dynamic model of the guided wave. The model of elliptical trajectory deflection of tool tip is established. Based on the theoretical modeling and finite element simulation, the residual height and material removal characteristics of elliptic trajectory with variable deflection angle are simulated and analyzed. The results show that when the deflection angle is between 10° and 70°, the tangential force is small and stable. Finally, the cutting experiments of micro-pyramid reflective mold in guided wave UEVC and conventional cutting (CC) are carried out. Compared with CC, high-frequency UEVC can obtain micro-pyramid elements with average roughness of 5.21 nm, that verifies the applicability of high-frequency UEVC in precision machining of microstructure.