Development of Ultrasonic Vibration-Assisted Magnetic Compound Fluid (MCF) Polishing Technology

This study investigates the development of an ultrasonic vibration-assisted magnetic compound fluid (MCF) polishing technology for final polishing. The fabrication of an experimental apparatus entails an ultrasonic polishing unit, and the experimental investigation of its performance in surface polishing is described. In addition, ultrasonic vibration-assisted MCF polishing under different applied methods of ultrasonic vibration is studied. The experimental results indicate that applying ultrasonic vibration to the workpiece improves the surface roughness and material removal rate when the ultrasonic vibrations are changed. In addition, across the range of polishing conditions employed in this study, the precision surface roughness and high material removal rate can be easily obtained on the acrylic plate by applying an elliptical vibration to the ultrasonic vibration.

Piezoelectric Hysteresis Modeling of Hybrid Driven Three-Dimensional Elliptical Vibration Aided Cutting System Based on an Improved Flower Pollination Algorithm

Three-dimensional elliptical vibration assisted cutting technology has been widely used in the past few years. The piezoelectric stack drive structure is an important part of the three-dimensional elliptical vibration aided cutting system. Its piezoelectric hysteresis characteristics affects the final output of the elliptical trajectory. Aiming at this problem, a piezoelectric hysteresis modeling method based on a generalized Bouc–Wen model is presented in this paper. An improved flower pollination algorithm (IFPASO) was used to identify Bouc–Wen model parameters. Standard test result shows that IFPASO has better algorithm performance. The model identification effect experiment proved that the Bouc–Wen model obtained by IFPASO identification, the highest modeling accuracy of the three axial subsystems, can reach 98.86%. Therefore, the model can describe the piezoelectric hysteresis characteristics of the three axial subsystems of the 3D-EVC system effectively and has higher modeling accuracy and fitting accuracy.

Cutting Force Prediction Model for Elliptical Vibration Cutting SiCp/Al Based on Three-Phase Friction Theory

The friction behavior in the tool-chip interface is an essential issue in aluminum matrix composite material (AMCM) turning operations. Compared with conventional cutting, the elliptical vibration (EVC) cutting AMCM has attractive advantages, such as low friction, small cutting forces, etc. However, the friction mechanism of the EVC cutting AMCM is still inadequate, especially the model for cutting forces analyzing and predicting, which hinders the application of EVC in the processing of AMCM. In this paper, a cutting force prediction model for EVC cutting SiCp/Al is established, which is based on the three-phase friction (TPF) theory. The friction components are evaluated and predicted at the tool-chip interface (TCI), tool-particle interface (TPI) and tool-matrix (TMI), respectively. In addition, the tool-chip contact length and SiC particle volume fraction were defined strictly and the coefficient of friction was predicted. Based on the Johnson-Cook constitutive model, the experiment was conducted on SiCp/Al. The cutting speed and tool-chip contact length were used as input parameters of the friction model, and the dynamic changes of cutting force and stress distribution were analyzed. The results shown that when cutting speed reaches 574 m/min, the tool-chip contact length decreases to 0.378 mm. When the cutting speed exceeds 658 m/min, the cutting force decreases to a minimum of 214.9 N and remains stable. In addition, compared with conventional cutting, the proposed prediction model can effectively reduce the cutting force.

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.

Analytical Compliance Equations of Generalized Elliptical-Arc-Beam Spherical Flexure Hinges for 3D Elliptical Vibration-Assisted Cutting Mechanisms

Elliptical vibration-assisted cutting technology has been widely applied in complicated functional micro-structured surface texturing. Elliptical-arc-beam spherical flexure hinges have promising applications in the design of 3D elliptical vibration-assisted cutting mechanisms due to their high motion accuracy and large motion ranges. Analytical compliance matrix formulation of flexure hinges is the basis for achieving high-precision positioning performance of these mechanisms, but few studies focus on this topic. In this paper, analytical compliance equations of spatial elliptic-arc-beam spherical flexure hinges are derived, offering a convenient tool for analysis at early stages of mechanism design. The mechanical model of a generalized flexure hinge is firstly established based on Castigliano's Second Theorem. By introducing the eccentric angle as the integral variable, the compliance matrix of the elliptical-arc-beam spherical flexure hinge is formulated. Finite element analysis is carried out to verify the accuracy of the derived analytical compliance matrix. The compliance factors calculated by the analytical equations agree well with those solved in the finite element analysis for the maximum error; average relative error and relative standard deviation are 8.25%, 1.83% and 1.78%, respectively. This work lays the foundations for the design and modeling of 3D elliptical vibration-assisted cutting mechanisms based on elliptical-arc-beam spherical flexure hinges.

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.