Ultrasonic Elliptical Vibration Research Articles

Evolution mechanism of microstructure and microhardness of Ti–6Al–4V alloy during ultrasonic elliptical vibration assisted ultra-precise cutting

The ultra-precision Ti–6Al–4V alloy parts are growing used in medical and aerospace industries, and which always work in the extreme working conditions such as high temperature, high pressure, and variable load. Thus, the requirements for machining accuracy and surface quality of parts are getting higher and higher. The ultrasonic elliptical vibration assisted cutting (UEVC) technology has been proved to be an effective method for the ultra-precision machining of Ti–6Al–4V alloy. However, in the UEVC process, the evolution mechanism of microstructure and microhardness, which directly affect the service performance and life, is unrevealed. In this paper, the comprehensive investigations of microstructural plastic deformation, grain refinement, phase transformation and microhardness of machined surface layer under conventional cutting (CC) and UEVC processes are carried out. The experimental results indicated that, due to the effects of UEVC technology, the plastic deformation area show obvious compression deformation, the depth of plastic deformation is less than 10 μm, there is no obvious phase transformation on the machined surface layer material, and the hardening rate of machined surface is more than 20%. These findings show the UEVC technology has a unique influence on the microstructure and microhardness of Ti–6Al–4V alloy, which have important implications for the cutting parameter design of ultra-precision Ti–6Al–4V alloy parts.

Ultrasonic elliptical vibration micro-cutting mechanism of CoCrFeNiAlX short fiber reinforced aluminum-based composite

This study explores the precision micro-machining of CoCrFeNiAlX short fiber-reinforced 7A09 aluminum matrix composites, focusing on the interplay between machining parameters and composite properties. The investigation scrutinizes the influence of vibrational amplitude, oscillation frequency, penetration depth, fiber orientation, and aluminum concentration on machining dynamics. Findings reveal that enhancing the X-axis vibrational amplitude to 80 μm is associated with a decrease in machining force, which then rises after reaching a threshold. In contrast, maintaining the Y-axis amplitude below 90 μm significantly increases the machining force. Higher amplitudes and frequencies were observed to reduce machining forces by up to 57% at an ultrasonic frequency of 15 kHz. Employing ultrasonically assisted vibration cutting (UEVC) culminated in a substantial 72% decrease in machining forces when fibers were optimally oriented at 45°. The study also identifies a direct correlation between the cutting temperature and both the vibrational amplitude and penetration depth, with the Y-axis amplitude having a more significant impact, causing a 55% variation in temperature. An increase in frequency initially lowers the cutting temperature, with the lowest temperature of 92 °C achieved at 5 kHz, while the peak temperature occurs at a machining depth of 60 μm. Temperature profiles indicate an initial rise with increased fiber orientation, followed by a decline. A slight increase in aluminum concentration marginally raises the cutting temperature. Furthermore, UEVC is found to produce a parabolic residual stress distribution, where amplitude and penetration depth determine the peak stress levels, and higher frequencies contribute to stress reduction. Fiber orientation also affects residual stress, with proper alignment reducing compressive stress and misalignment increasing it. The lowest point of residual compressive stress is detected in the Al0.6 fiber composite, while the peak is observed in the Al1 composites.

Research on tool wear and surface quality in laser-assisted ultrasonic elliptical vibration cutting of cemented carbide

The Laser-ultrasonic elliptical vibration cutting (LA-UEVC) method was introduced for machining challenging cemented carbide. The machining parameters were estimated through numerical simulation, and the cutting forces, the tool wear and the workpiece surface quality were analyzed and investigated. Compared to precision cutting, during LA-UEVC of cemented carbide, the main cutting force and the cutting radial thrust force were reduced by 44.3% and 31.2%, respectively. Moreover, the tool wear decreased, which led to an increase in tool life by 118.8%, and a maximum reduction of 89.7% of Workpiece surface roughness was received. The impact of laser power and cutting parameters on surface roughness was analyzed through orthogonal experiments, and a surface roughness prediction model was established using a quadratic regression model.

Generation mechanism of the surface morphology on tilted ultrasonic elliptical vibration cutting TC4 titanium alloy

TC4 titanium alloy is utilized in aerospace and a wide range of other applications due to its high strength and corrosion resistance, but its poor thermal conductivity and high ductility introduce challenges in machining. In this paper, firstly, a mathematical model of workpiece surface morphology under tilted ultrasonic elliptical vibration cutting (TUEVC) was established based on the tip trajectory and material removal mechanism, and the variation of workpiece surface morphology was investigated at different tool tilt angles θ, and it was found that the tilt θ in a certain range could significantly reduce the surface residual height compared with that of ordinary ultrasonic elliptical vibration cutting (UEVC). Second, the TUEVC experiment of TC4 titanium alloy was carried out to comparatively analyze the changes in the surface morphology, surface profile, and surface roughness of the workpiece under different tilt θ, the effect of each machining parameter (cutting speed, feed, and ultrasonic amplitude) on surface roughness was explored. The experimental results indicate that as the tilt θ changes from 0° to 90° throughout the process, the workpiece surface morphology flatness decreases and then increases. When the tilt angle θ is 45°, workpiece cutting surface roughness is minimized (Sa = 0.157), compared with the ordinary ultrasonic elliptical vibration cutting roughness is reduced by 47.6 % maximum. Both the surface morphology flatness and the surface roughness of the workpiece are at their smallest, whereas the theoretical profile curve and cutting surface profile curve are at their most consistent. Under the same machining parameters, TUEVC can reduce the surface roughness more effectively compared with UEVC, this technique reduces surface roughness by 16 %, 23 %, and 26 % at maximum for different cutting speeds, feeds, and ultrasonic amplitudes, respectively.

Design, modeling and experiment of a novel ultrasonic elliptical vibration generator

Design, modeling and experiment of a novel ultrasonic elliptical vibration generator

Experimental Study on the Roundness of Deep Holes in 7075 Aluminum Alloy Parts by Two-Dimensional Ultrasonic Elliptical Vibration Boring.

The 7075 aluminum alloy deep hole pipe finds extensive applications in the aerospace industry due to its remarkable attributes, such as high strength, exceptional wear resistance, and favorable mechanical properties. However, traditional boring processes for 7075 aluminum alloy deep hole pipes tend to generate elevated cutting forces, potentially leading to deformation issues in these deep holes. In response to these challenges, this study introduces a novel approach involving the use of a two-dimensional ultrasonic elliptical vibration tool. This tool features a single excitation asymmetric structure and aims to enhance the deep hole machining process in 7075 aluminum alloy. The research methodology involved several key steps. First, theoretical analysis and simulation were performed to study the motion trajectory of the cutting edge of the tool. Second, practical experiments were conducted comparing two-dimensional ultrasonic elliptical vibration boring with conventional boring for 7075 aluminum alloy deep hole pipes. The results demonstrate that, in contrast to conventional boring, two-dimensional ultrasonic vibration boring could achieve a maximum reduction of 54.1% and an average reduction of 50.4% in the roundness value of the deep holes. The impact of machining parameters on deep hole roundness is assessed through experimental analysis, leading to the determination of optimal processing parameters. In summary, this experimental research has a certain reference significance for the application of 7075 aluminum alloy deep hole parts in the aerospace field.

Undeformed chip thickness with composite ultrasonic vibration-assisted face grinding of silicon carbide: Modeling, computation and analysis

In order to achieve high efficiency and low damage processing of hard and brittle materials, composite ultrasonic vibration-assisted face grinding (CUVAFG) has been proposed by comprehensively combining the high efficiency of axial ultrasonic vibration grinding (UVAG) and the low damage of elliptic ultrasonic vibration grinding (EVAG). However, the three-dimensional ultrasonic vibration brings about a more complicated machining mechanism than the previous ultrasonic vibration-assisted grinding methodology. Hence, in order to explore the grinding mechanism in deep, this paper first developed a new model of undeformed chip thickness for CUVAFG from the perspectives of the kinematic mechanism and elastic-plastic deformation mechanism. Then the influences of different processing parameters on interference rate and undeformed chip thickness were further confirmed. Finally, CUVAFG experiments of silicon carbide (SiC) ceramics were conducted to study the relationship between the undeformed chip thickness and the resultant grinding forces, specific grinding energy, ground surface morphology and roughness, and subsurface damage. It is found from the experimental results that the critical chip thickness of brittle-ductile transition in CUVAFG is between 0.31 and 0.35 μm. As the undeformed chip thickness is less than the critical value, the grinding forces and the specific grinding energy increases with the undeformed chip thickness, but the ground surface roughness decreases with improved surface morphology and shallow subsurface damage. After exceeding the critical value, the grinding force remains unchanged, the specific grinding energy decreases, and ground surface roughness increases with deteriorated surface morphology and deepened subsurface damage. For the purpose of good machining surface integrity, it is essential to guarantee that the undeformed chip thickness is less than the critical value. The computational and experimental results have demonstrated the contribution of the developed undeformed chip thickness model to understanding the grinding performance of hard and brittle material by CUVAFG.

Insight into surface formation mechanism during ultrasonic elliptical vibration cutting of tungsten alloy by scratching experiment and molecular dynamics

Insight into surface formation mechanism during ultrasonic elliptical vibration cutting of tungsten alloy by scratching experiment and molecular dynamics

Compensating varying size effect in diamond cutting of SiCp/Al by ultrasonic elliptical vibration

The heterogeneous mechanical properties of individual phases in SiCp/Al result in significant varying size effect (SE) existed in its deformation process. And modulating the varying SE is crucial for improving the machined surface finish of SiCp/Al in mechanical machining. In this study, we elucidate the mechanisms governing the varying SE in conventional cutting and ultrasonic elliptical vibration-assisted cutting (UEVC) of SiCp/Al using diamond tools by theoretical analysis, numerical simulations and experiments. Specifically, the impact of cutting tool-workpiece contact states in UEVC on the fundamental cutting behavior of SiCp/Al, in terms of microscopic deformation modes and their correlations with machining force variation, machined surface morphology and chip profile, is evaluated. Subsequently, ultrasonic elliptical vibration-assisted diamond turning of SiCp/Al is performed to achieve a surface roughness of 20 nm accompanied with significantly suppressed tool wear. Finally, the compensation effect on the varying SE in SiCp/Al cutting by ultrasonic elliptical vibration of cutting tool is discovered, which leads to decreased brittle fracture and improved surface integrity. The research findings provide a theoretical support for understanding the machining mechanisms of UEVC of SiCp/Al, as well as proposing new perspectives for improving the machinability of SiCp/Al composite accompanied by suppressed varying SE.

Investigation of ultrasonic mechanism and development of tool wear model in ultrasonic elliptic vibration assisted cutting of stainless steel

By analyzing the kinematics and dynamics of ultrasonic vibration under various conditions, the tool wear mechanism in Ultrasonic Elliptic Vibration-Assisted Cutting (UEVAC) were investigated. Two distinct mechanisms for mitigating tool wear emerge: In non-separated UEVAC, the pivotal factor is the reduction of material yield stress through the acoustic softening effect. Conversely, in separated UEVAC, tool wear reduction is attributed to the decrease in average contact stress via stress superposition and the hammer effect. These findings highlight the effectiveness of aligning ultrasonic energy field action times and intensity to reduce stainless steel tool wear rates in non-separated UEVAC. Furthermore, the proposed tool wear model demonstrates robust reliability for separated UEVAC processes.

Wear study of CBN tools in laser ultrasonic composite cutting of cemented carbide

The laser ultrasonic composite cutting (LUCC) process was proposed by combining laser heating-assisted cutting (LHAC) and elliptical ultrasonic vibration cutting (UVC). In the process of cutting experiment, cubic boron nitride (CBN) is selected as the tool’s material. The wear morphology and wear appearance of the tools were observed by super depth-of-field microscopy and scanning electron microscopy (SEM) to research the wear characteristics and wear mechanism of CBN tools during LUCC of cemented carbide. Compared with conventional cutting (CC), UVC and LHAC, during LUCC of cemented carbide with CBN tools the tool wear are significantly reduced by 45.11%, 28.92%, and 17.39% respectively, the cutting force are decreased by 61%, 44%, and 46% respectively, and the surface roughness are lowered by 77%, 55%, and 62% respectively, therefore the tool life is obviously lengthened. Moreover, the tool flank wears model of during LUCC of cemented carbide was established and verified by the tool flank face wear test. The results show that when the CBN tool is used for LUCC of cemented carbide, the wear band on the tool’s rake face is basically parallel to the cutting edge and is in the shape of a long strip, and the wear band on the tool’s flank face shows a triangular-shaped wear band accompanied by shallow pits and grooves; In the process of the LUCC of cemented carbide, the main causes of CBN tool wear include adhesive wear, oxidation wear and abrasive wear are the main causes of CBN tool wear during LUCC of cemented carbide; The faster the cutting speed, the bigger the error among the experimental value with the calculated value, and the wear of tool’s flank face during LUCC of cemented carbide gradually increased.

Surface/subsurface formation mechanism of tungsten during ultrasonic elliptical vibration cutting

The ultrasonic elliptical vibration cutting (UEVC) has been proved to be a valid method to improve surface quality and reduce subsurface damage of tungsten. However, it is still a huge challenge to elucidate the surface/subsurface formation mechanism of tungsten during UEVC. Hence, molecular dynamics simulations were employed to reveal the formation mechanism of surface/subsurface during UEVC of tungsten from the atomic level, and the effects of ultrasonic amplitude and frequency on the surface/subsurface formation were explored. The results showed that compared with general cutting (GC), the improved surface quality was attributed to the smaller actual cutting depth and more amorphous tungsten in chips caused by cyclic loading-unloading during UEVC. Moreover, the reversing friction direction facilitated the formation of surface chips during UEVC as well. The thermal-activated dislocations caused by high transient cutting temperature could result in the wide distribution of subsurface dislocations, and the dislocations were usually expanded by the way of crystal plane slip to suppress generation of long slip plane, which could reduce the subsurface damage of tungsten during UEVC. In comparison with ultrasonic amplitude in cutting depth direction, elevated ultrasonic amplitude in cutting speed direction or ultrasonic frequency could reduce depth of subsurface damage layer, surface roughness, and dislocation density, which derived from the small transient cutting force and stress as well as high strain rate. This study provides a new insight into the surface/subsurface formation mechanism of tungsten during UEVC, which can offer a theoretical basis on the selection of ultrasonic parameters for achieving high surface/subsurface quality for tungsten and other materials machined by UEVC.

Effect of longitudinal-bending elliptical ultrasonic vibration assistance on electrosurgical cutting and hemostasis

Electrosurgical devices are widely used for tissue cutting and hemostasis in minimally invasive surgery (MIS) for their high precision and low trauma. However, tissue adhesion and the resulting thermal injury can cause infection and impede the wound-healing process. This paper proposes a longitudinal-bending elliptical ultrasonic vibration-assisted (EUV-A) electrosurgical cutting system that incorporates an ultrasonic vibration in the direction of the cut by introducing an elliptical motion of the surgical tip. Compared with a solely longitudinal ultrasonic vibration-assisted (UV-A) electrosurgical device, the EUV-A electrode contacts the tissue intermittently, thus allowing for a cooler cut and preventing tissue accumulation. The experimental results reveal that the EUV-A electrode demonstrates better performance than the UV-A electrode for both anti-adhesion and thermal injury through in vitro experiments in porcine samples. The tissue removal mechanism of EUV-A electrosurgical cutting is modeled to investigate its anti-adhesion effect. In addition, lower adhesion, lower temperature, and faster cutting are demonstrated through in vivo experiments in rabbit samples. Results show that the EUV-A electrode causes lower thermal injury, indicative of faster postoperative healing. Finally, efficacy of the hemostatic effect of the EUV-A electrode is demonstrated in vivo for vessels up to 3.5 mm (equivalent to that of electrocautery). The study reveals that the EUV-A electrosurgical cutting system can achieve safe tissue incision and hemostasis.

Cutting Chatter in Ultrasonic Elliptical Vibration Cutting and Its Influence on Surface Roughness and Tool Wear

Ultrasonic elliptical vibration cutting has a wide range of applications in the field of precision cutting of difficult-to-machine metal materials. However, due to its intermittent cutting characteristics and the weak rigidity of the horn, cutting chatter is prone to occur during its cutting process, which has an important impact on cutting surface quality and tool wear. In this paper, the rigid/viscoplastic rod model is used to simulate the horn in the ultrasonic elliptical vibration cutting device, and the influence factors of the amplitude-frequency response of the horn are analyzed. The influence of cutting speed and cutting depth on cutting chatter was studied by ultrasonic elliptical vibration cutting experiment of tungsten heavy alloy, and the influence of cutting chatter on cutting surface morphology and diamond tool wear was studied. The research shows that cutting speed will change the excitation frequency of the horn, and reasonable cutting speed can inhibit the occurrence of cutting chatter and avoid resonance of the horn. The cutting depth will affect the excitation amplitude and amplify the vibration amplitude when chatter or resonance occurs. The experimental results show that in ultrasonic elliptical vibration cutting of heavy tungsten alloy, chatter suppression can significantly improve the quality of the cutting surface and reduce the wear of diamond tools.

Microstructure evolution mechanism of tungsten induced by ultrasonic elliptical vibration cutting at atomic/nano scale

Ultrasonic elliptical vibration cutting (UEVC) technology has been utilized for ultra-precision machining of difficult-to-machine metal materials such as tungsten. Nevertheless, the microstructure evolution mechanism of tungsten under the synergistic effect of ultrasonic and mechanical loads remains unclear, particularly at the atomic/nano scale. Additionally, the plastic deformation mechanism of tungsten differs from that of other metallic materials due to its low dislocation mobility (brittle at room temperature). Hence, the molecular dynamics simulation of UEVC for single crystal tungsten was established to study its mechanisms in plastic deformation and microstructure evolution under stress induction in this study. The results indicated that the main plastic deformation mechanisms including dislocation slip, amorphous phase transformation and nanocrystal were found during the tungsten removal, and accompanied by some extent of lattice distortion. The instantaneous shear stress of UEVC reached 16.88 GPa. Compared with common cutting (CC), the formation of nanocrystals mainly occurred in UEVC because the instantaneous shear stress exceeded the critical shear stress of multiple slip systems during cutting. Similarly, the high dislocation density and high plastic deformation degree of the machined zone in UEVC were also attributed to the high shear stress. The dynamic recrystallization of tungsten induced by UEVC was realized from dislocation slip to the formation of dense dislocation walls, followed by the formation of sub-grain boundaries, and finally to the formation of nanocrystals.

Tool–workpiece separation characteristic and surface generation in ultrasonic assisted milling

Ultrasonic assisted machining is an eco-friendly surface texture fabrication method with low machining cost, high-accuracy precision, and efficiency. This study analyzes the surface texture formation in feed direction ultrasonic vibration assisted milling (FUVAM) and elliptical ultrasonic vibration assisted milling (EUVAM). The trajectories of the single and adjacent tool tips in FUVAM are analyzed. Furthermore, the tool–workpiece separation mechanism in EUVAM is discussed. Moreover, a 3D surface topography model of EUVAM is applied to study the influences of machining parameters on the ultrasonic machining topography. The experiments of conventional milling (CM) and EUVAM are carried out and different types of surface textures are successfully fabricated on Ti-6Al-4V using EUVAM. The results of the response surface indicate that the surface roughness shows an increasing trend with higher spindle speed, but decreases with improved feed speed and cutting depth. Compared with CM, the chips generated in EUVAM have the characteristics of small width and low bending degree. This work is expected to provide some guidance for the selection of machining and vibration parameters during ultrasonic assisted milling.

Analytical modelling and experimental study of surface roughness in ultrasonic elliptical vibration assisted ultra-precision cutting of Ti-6Al-4 V alloy

Analytical modelling and experimental study of surface roughness in ultrasonic elliptical vibration assisted ultra-precision cutting of Ti-6Al-4 V alloy

Study on Removal Mechanism of Ultrasonic Elliptical Vibration Cutting of Tungsten Heavy Alloy

Study on Removal Mechanism of Ultrasonic Elliptical Vibration Cutting of Tungsten Heavy Alloy

Study of the 3D Topography Modelling and Control Method for Blazed Gratings Induced by Ultrasonic Elliptical Vibration Cutting

Study of the 3D Topography Modelling and Control Method for Blazed Gratings Induced by Ultrasonic Elliptical Vibration Cutting

Study on tool wear mechanism of single-crystal diamond in ultrasonic vibration elliptical cutting of tungsten heavy alloy

Tungsten heavy alloy has been widely used in the nuclear industry, military, and other fields due to its excellent material properties. In this paper, the wear of single crystal diamond tool and its influence on surface roughness were studied by ultrasonic elliptical vibration cutting experiment of tungsten heavy alloy and compared with conventional cutting. The experimental results show that under ultrasonic elliptical vibration cutting, the flank wear of a single crystal diamond cutter is reduced by 74.5%, and the retreat of the cutting edge is reduced by 70.6%. After the cutting experiment, the elements on the cutting surface, chip surface, and diamond tool adhesion were detected and analyzed by Raman spectroscopy and X-ray photoelectron spectroscopy. The results show that compared with conventional cutting, ultrasonic elliptical vibration cutting can effectively inhibit the graphitization of single-crystal diamond tools and avoid chemical wear. This is an essential reason why single-crystal diamond tools can be used for tungsten heavy alloy processing under ultrasonic elliptical vibration cutting.