Ultrasonic Vibration-assisted Research Articles

Distortion analysis in axial ultrasonic assisted milling of Al 7075-T6

Dimensional distortion and instability in the milling process of aluminum alloy parts can significantly increase production costs and result in defective parts. Therefore, distortion mitigation has long been a central focus of aerospace industry researchers. This article aims to investigate the effect of axial ultrasonic-assisted milling on distortion. In this study, the machining parameters effect in conventional milling (CM) and ultrasonic assisted milling (UAM) were experimentally and statistically investigated on distortion and milling force, and the results were subjected to a comparative analysis. Experiments provided compelling evidence of the technical advantages offered by axial ultrasonic-assisted milling, demonstrating its efficacy in reducing both milling force and distortion when compared to conventional milling. Furthermore, our study established a direct relationship between milling force and distortion. Applying the axial ultrasonic-assisted vibration resulted in a notable 29% reduction in cutting force compared to conventional milling. Additionally, UAM exhibited a reduction in distortion by approximately 21%. These findings have significant implications, particularly in improving the flatness tolerance of the workpiece, thereby yielding components free from waves and warpages.

Research on Ultrasonic Vibration Assisted Grinding Technology of Quartz Fiber Reinforced Ceramic Matrix Composites

Ceramic matrix composites have good mechanical properties and high temperature resistance, but it is difficult to process. In order to solve the problems of fast tool wear and low machining efficiency in the dry grinding process, ultrasonic vibration assisted grinding technology of quartz fiber reinforced ceramic matrix composites is adopted in this paper. Grinding force, machining efficiency, tool wear and surface roughness are analyzed through the comparison experiment between the conventional grinding and the ultrasonic vibration assisted grinding. The influence of the ultrasonic vibration assistance and process parameters on machining quality and tool life is further obtained. According to the findings, when compared to traditional grinding, ultrasonic vibration grinding can lower the grinding force by 25% to 58% and the surface roughness by up to 16%. The tool life and machining efficiency can be significantly increased with the help of ultrasonic vibration.

Machining characteristics in ultrasonic vibration-assisted powder-mixed electrical discharge machining of TiN ceramics

This study aims to investigate the application and machining characteristics of brittle conductive ceramics using ultrasonic vibration-assisted powder-mixed electrical discharge machining (UV-PMEDM) technology. Titanium nitride (TiN) ceramics are widely used in aerospace, biomedicine, and electronics due to their excellent properties. However, the conventional mechanical machining methods of these materials result in severe tool wear, high costs, and low efficiency. Although electrical discharge machining (EDM) can overcome some limitations, it typically exhibits a low material removal rate and poor surface quality. This study utilizes the UV-PMEDM technology to process TiN ceramics. Single-factor experiments are conducted to analyze the effects of processing parameters, including ultrasonic amplitude, powder concentration, pulse-on time, and pulse-off time, on the material removal rate, surface roughness, and relative electrode wear rate, which indicate the EDM processing performance. With the assistance of ultrasonic vibration and mixed powders, the material removal rate of TiN ceramics using UV-PMEDM reaches 0.50 mm3/min, while maintaining a relative electrode wear rate below 1 % and surface roughness lower than 4.2 μm. The synergistic combination of ultrasonic vibration and mixed powders significantly enhances the processing efficiency and reduces surface roughness of TiN ceramics. These findings contribute to a better understanding of machining strategies for brittle conductive ceramics.

Effect of Ultrasonic Vibration on Tensile Mechanical Properties of Mg-Zn-Y Alloy

Ultrasonic vibration assisted (UVA) plastic forming technology has proven to be a highly effective processing method, particularly for materials that are challenging to deform. In this research, UVA tensile tests were carried out on Mg98.5Zn0.5Y1 alloy at different vibration frequencies and amplitudes. The experimental results indicate that, compared with conventional tensile tests, the yield strength and tensile strength of Mg98.5Zn0.5Y1 alloy exhibit a decrease. Furthermore, the application of ultrasonic vibration demonstrates an ability to enhance the material’s elongation and plasticity. In order to further predict the stress-strain relationship in the metal tensile process, a hybrid constitutive model coupling the frequency and amplitude of ultrasonic vibration was developed based on the modified Johnson Cook model. The calculated results of the constitutive equation are in good agreement with the experimental results, indicating that the established constitutive equation can accurately predict the trend of alloy stress change at different amplitudes and frequencies. It establishes a theoretical foundation for scrutinizing the deformation mechanisms of the alloy under ultrasonic vibration. Furthermore, Abaqus finite element analysis software was employed to simulate and analyze the UVA tensile process, elucidating the impact of ultrasonic vibration on stress distribution, strain patterns, and material flow in the tensile behavior of Mg98.5Zn0.5Y1 alloys.

Effect of Ultrasonic Vibration Assistance on Microstructure Evolution and Mechanical Properties in Laser-Welded AZ31B Magnesium Alloy

Given the susceptibility to weld porosity and poor weld formability in laser beam welding (LBW), this study delves into an examination of the impact of ultrasonic vibrations on microstructural morphologies and mechanical properties in AZ31B magnesium (Mg) alloy. A comparative analysis was conducted between ultrasonic vibration-assisted LBW and conventional LBW. The results established that the effective elimination of weld porosity, an outcome attributed to the combined effects of cavitation and acoustic streaming, resulted in a weld characterized by a visually seamless and structurally robust appearance. Furthermore, the incorporation of ultrasonic vibration assistance in the welding process yielded a finer microstructure as compared to the conventional LBW. Moreover, the lamellar structures of β-Mg17Al12 were transformed into particles and evenly distributed throughout the α-Mg matrix. In addition, the incorporation of 50% ultrasonic vibration assistance yielded notable improvements in tensile strength (259.6 MPa) and elongation (11.1%). These values represented enhancements of 4.8% and 35.4% as compared to joints fabricated by using conventional LBW.

Modelling of tribological behavior and wear for micro-textured surfaces of Ti2AlNb intermetallic compounds machined with multi-dimensional ultrasonic vibration assistance

Employing multi-dimensional ultrasonic vibration machining (MDUVM), Ti2AlNb intermetallic compounds were processed to generate highly consistent and uniformly arranged micro-texture surfaces. Compared to conventional machining (CM) surfaces, MDUVM surfaces exhibited a noticeable 10.9 % increase in hardness. Sphere-on-disk friction wear tests indicated a noteworthy 15 % reduction in both friction force and coefficient on MDUVM surfaces. The MDUVM surfaces improved contact pressure distribution, reduced oxidation, and facilitated smoother wear debris transition within the wear zone. As a result, the spread of wear into deeper layers was effectively inhibited. An Archard-based predictive model was developed to quantitatively predict wear behavior by incorporating surface micro-texture, confirming the significant influence of surface morphology on frictional wear, which was consistent with experimental findings.

Material removal mechanism of UD-C/C composites in ultrasonic-assisted vibration orthogonal cutting

Material removal mechanism of UD-C/C composites in ultrasonic-assisted vibration orthogonal cutting

Ultrasonic Vibration-assisted Electrochemical Discharge Machining of Quartz Wafer Micro-Hole Arrays

The micro-hole machining of quartz wafers depends on photolithography techniques akin to those used in semiconductor fabrication. These methods present challenges due to high equipment setup costs, large space requirements, and environmental pollution risks. This research applies ultrasonic vibration assistance in electrochemical discharge machining to create an array of micro-holes on quartz wafers. In the experiments, a self-prepared tungsten carbide micro-electrode array served as the tool electrode. This electrode was a 2 × 2 square array, with needles measuring 30 × 30 μm. A series of experiments was conducted to investigate the effects of various machining parameters, including working voltage, feed rate, duration time, duty factor, and ultrasonic power level, on the characteristics of the micro-hole array. The characteristics included average hole diameter and through-hole surface morphology. The experimental objective was to achieve a through-hole diameter of 80 μm with an accuracy of ±8 μm. During the electrochemical discharge machining, suitable ultrasonic vibrations can thin the insulating gas film coating on the electrode surface, resulting in a more uniform gas film. As the insulating gas film’s thickness decreased, so did the critical voltage needed for the electrochemical discharge machining, reducing the hole’s diameter expansion. The ultrasonic vibration assistance can enable the satisfaction of the dimensional accuracy requirement. The experimental results indicate that ultrasonic vibration assistance can effectively improve the processing capacity and reduce sample fragmentation. A working voltage of 44 V, feed rate of 1 μm/6 s, duration time of 30 μs, duty factor of 30%, and ultrasonic power level of 1 resulted in better inlet and outlet surface morphology without outlet fragmentation. Moreover, the average diameters of the inlet and outlet were roughly 80 μm while meeting the through-hole diameter of 80 μm with accuracy of ±8 μm.

Study of longitudinal-torsional ultrasonic-assisted vibration on micro-hole drilling Zr-based metallic glass

Study of longitudinal-torsional ultrasonic-assisted vibration on micro-hole drilling Zr-based metallic glass

An Experimental Study on Ultrasonic Vibration-Assisted Turning of Aluminum Alloy 6061 with Vegetable Oil-Based Nanofluid Minimum Quantity Lubrication

Minimum quantity lubrication (MQL) is a potential technology for reducing the consumption of cutting fluids in machining processes. However, there is a need for further improvement in its lubrication and cooling properties. Nanofluid MQL (NMQL) and ultrasonic vibration-assisted machining are both effective methods of enhancing MQL. To achieve an optimal result, this work presents a new method of combining nanofluid MQL with ultrasonic vibration assistance in a turning process. Comparative experimental studies were conducted for two types of turning processes of aluminum alloy 6061, including conventional turning (CT) and ultrasonic vibration-assisted turning (UVAT). For each turning process, five types of lubricating methods were applied, including dry, MQL, nanofluid MQL with graphene nanosheets (GN-MQL), nanofluid MQL with diamond nanoparticles (DN-MQL), and nanofluid MQL with a diamond/graphene hybrid (GN+DN-MQL). A specific cutting energy and areal surface roughness were adopted to evaluate the machinability. The results show that the new method can further improve the machining performance by reducing the specific cutting energy and areal surface roughness, compared with the NMQL turning process and UVAT process. The diamond nanoparticles are easy to embed on the workpiece surface under the UVAT process, which can increase the specific cutting energy and Sa as compared to the MQL method. The graphene nanosheets can produce the interlayer shear effect and be squeezed into the workpiece, thus reducing the specific cutting energy. The results provide a new way for the development of eco-friendly machining.

Study on the effects of ultrasonic assistance and external heat dissipation on friction stir welded 7075 aluminum alloy joints

In this paper, conventional friction stir welding (C-FSW), ultrasonic assisted friction stir welding (Ua-FSW) and heat pipe assisted friction stir welding (Ha-FSW) were performed on 4 mm thick 7075 aluminum alloy. The effects of the two different types of assisted technologies on C-FSW were qualitatively compared and analyzed. The microstructure of the joints in the NZ, HAZ and other regions were primarily characterized via SEM-EBSD and TEM, and the strength of the joints were evaluated via the room-temperature tensile properties and microhardness tests. The test results showed that both Ua-FSW and Ha-FSW effectively improved the weld forming, while the surface quality of the joints fabricated by Ha-FSW was better. The acoustic flow effect from ultrasound reduced the temperature gradient, and the heat pipe provided excellent heat dissipation, which well controlled the peak heat and the rate of heat loss throughout FSW, resulting in finer grain sizes after both the Ua-FSW and Ha-FSW processes. EBSD analysis showed that the assistance of two technologies provided a greater effect on TMAZ and HAZ, the stress field generated by ultrasonic vibration favored the formation of subgrains, the heat dissipation of the heat pipe also inhibited the recrystallization, and more subgrains were retained. The assistance of ultrasonic vibration and the heat pipe was mainly in the elongation, especially the joints prepared by the Ha-FSW showed an improvement in elongation by 16.7 % and 33.3 % compared to the Ua-FSW and C-FSW, respectively. This work provides insight into improving welding efficiency and joint performance through modified FSW processes.

In situ observation of melt pool evolution in ultrasonic vibration-assisted directed energy deposition

The presence of defects, such as pores, in materials processed using additive manufacturing represents a challenge during the manufacturing of many engineering components. Recently, ultrasonic vibration-assisted (UV-A) directed energy deposition (DED) has been shown to reduce porosity, promote grain refinement, and enhance mechanical performance in metal components. Whereas it is evident that the formation of such microstructural features is affected by the melt pool behavior, the specific mechanisms by which ultrasonic vibration (UV) influences the melt pool remain elusive. In the present investigation, UV was applied in situ to DED of 316L stainless steel single tracks and bulk parts. For the first time, high-speed video imaging and thermal imaging were implemented in situ to quantitatively correlate the application of UV to melt pool evolution in DED. Extensive imaging data were coupled with in-depth microstructural characterization to develop a statistically robust dataset describing the observed phenomena. Our findings show that UV increases the melt pool peak temperature and dimensions, while improving the wettability of injected particles with the melt pool surface and reducing particle residence time. Near the substrate, we observe that UV results in a 92% decrease in porosity, and a 54% decrease in dendritic arm spacing. The effect of UV on the melt pool is caused by the combined mechanisms of acoustic cavitation, ultrasound absorption, and acoustic streaming. Through in situ imaging we demonstrate quantitatively that these phenomena, acting simultaneously, effectively diminish with increasing build height and size due to acoustic attenuation, consequently decreasing the positive effect of implementing UV-A DED. Thus, this research provides valuable insight into the value of in situ imaging, as well as the effects of UV on DED melt pool dynamics, the stochastic interactions between the melt pool and incoming powder particles, and the limitations of build geometry on the UV-A DED technique.

Reducing the cutting tool wear in diamond turning of Zerodur glass-ceramic by the mechanical cleaning effect of ultrasonic vibration assistance

The effects and mechanisms of using ultrasonic vibration assistance (U.V.-assisted machining) combined with straight-nosed cutting tools on reducing the cutting tool wear in single-point diamond turning (SPDT) of Zerodur glass-ceramic are analysed and experimentally investigated. Aiming at the predominant abrasive wear in machining hard and brittle materials, analyses have shown that applying appropriate ultrasonic vibration to the cutting tool can induce considerable inertial acceleration to the wear particles residing on the tool-work interface for promoting their ejection from the contact area to reduce the abrasion. Meanwhile, the high thermal conductivity of diamond can prevent the possible excessive temperature elevation of the cutting tool surface that may result from the in-plane vibration components. To verify these, a longitudinal ultrasonic vibrator that works together with the Poisson's effect was designed for the SPDT processes with straight-nosed cutting tools. Machining tests on Zerodur optics have shown that the assistant ultrasonic vibration is able to decrease the tool flank wearland width by about 30 %, and the groove-like scratches on the tool flank wearland surface were reduced, which is consistent with the analytical deductions. Besides, no significant traces of structural change, element diffusion, and oxidation were found on the worn cutting tool surfaces under either the assisted or unassisted cutting conditions. The experiments have also shown that the enhanced durability of cutting tools has extended the cutting tool life for maintaining good machined surface quality, which is particularly beneficial to the ultra-precision machining of large-size optical parts.

Modelling of ultrasonic vibration-assisted forming considering the distribution of ultrasonic field with structure deformation

Ultrasonic vibration-assisted (UVA) forming is typically used to promote the forming quality of complex structures due to the acoustic-plastic effect. Ultrasonic vibration (UV) is always applied via the contact of tools with the structure surface; thus a distribution of ultrasonic field exists owing to the propagation and attenuation of ultrasonic waves, which may vary with structural deformation. This makes the prediction and control of ultrasonic effect extremely difficult in achieving high forming quality. To develop a new coupling model considering the interaction between ultrasonic field and deformation field, UVA tensile experiments of superalloy sheet were performed first. The experimental results demonstrated that UV had a local effect on the tensile specimen, resulting in non-uniform distribution of temperature, strain and dislocation density. During the modelling, the intensity of ultrasonic field was quantified by acoustic energy density, which can be calculated using vibration velocity. A dislocation-based constitutive relation was also established, in which ultrasonic-related functions were introduced to reflect the effect of ultrasonic field on structural deformation. Then, a sequential coupling modelling method was proposed. Through the cyclic calculation of ultrasonic field and deformation field, the simulation of UVA forming considering the distribution of ultrasonic field with structure deformation was realised. With the coupling model, the non-uniform distribution of deformation accompanied by a non-uniform ultrasonic field during UVA forming was revealed. When applied to a complex W-bending process, the targeted softening effect on the W-bending specimen was precisely predicted. The coupling model is expected to lay a foundation for the optimisation and control of the UVA forming process.

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.

Sonocapillary and wetting mechanism during ultrasonic brazing porous Si3N4 ceramics in air

In this work, porous Si3N4 ceramics are directly brazed in air using ZnAl filler with the assistance of ultrasonic vibration. The results show that good wetting of ceramic is realized within 10 s at low temperature of 450 °C. Under ultrasonic, high pressure of 7.5 MPa occurs near the entrance of ceramic micro-hole, which helps to overcome the energy barrier (1.09–2.18 MPa) to initiate sonocapillary. The capillary action of the filler is rapid, and then the infiltrated filler tightly bonds with the ceramic. The microstructure analysis reveals that Al element of the filler and O element that pre-dissolved in the filler are the main wetting elements, and the bonding interface is amorphous. It is the high temperature (1500 K) and pressure (4.87 × 108 MPa) caused by the collapse of the cavitation bubbles that cause the rapid wetting of the ceramics, which is proved by simulation. Ultrasonic power higher than Mode II produces joint stronger than the ceramic substrate, showing the potential of ultrasonic brazing.

Sensors-based discharge data acquisition and response measurement in ultrasonic assisted micro-EDM drilling

Micro-electrical discharge machining (μEDM) suffers from the problem of low material removal rate (MRR) and poor surface finish, especially when there are recurring abnormal sparks. Such sparks are mainly due to the accumulation of unflushed debris in the discharge zone resulting in a frequent arcing phenomenon. Vibration assistance to μEDM has proven contributions to the MRR and surface finish enhancement, but the intrinsic information on discharge pulse modification due to the vibration is unclear. The present work proposes a pulse categorization strategy to understand the nature of discharge pulses during the conventional and ultrasonic vibration assisted μEDM. The discharge pulses were acquired at a sufficiently high sampling rate using NI LABVIEW-based data acquisition through an in-house developed pulse discrimination system (PDS). The developed PDS is simultaneously used to estimate the real-time discharge energies of individual pulses and their histograms with the machining progress. The acquired information from the developed PDS is used to justify the variations in discharge energy, discharge frequency, surface roughness and accuracy with increasing machining depth. Vibration assistance to the μEDM process was found beneficial, with an 18% increase in the discharge energy, and a 7.14% reduction in the percentage error in depth. The surface roughness at high-energy settings reduces from 3.2 μm to 0.45 μm because of ultrasonic vibration assistance.

Numerical prediction of surface morphology and roughness in rotary ultrasonic face grinding SiO2f/SiO2 composite

The SiO2f/SiO2 ceramic matrix composite has been applied to fabricate high-performance radar radome because of its good wave transmission and mechanical property. The machined surface morphology and roughness of SiO2f/SiO2 ceramic matrix composite have an important impact on the service performance of radome products. This paper presented a numerical model to predict surface morphology for grinding of SiO2f/SiO2 composite. The prediction model was based on finite element method (FEM). Both conventional face grinding (CFG) and rotary ultrasonic face grinding (RUFG) of SiO2f/SiO2 composite were FEM simulated by integrating the microstructure of SiO2f/SiO2, the constitutive as well as failure mechanism of fiber/matrix, and the coupling grinding effect of multiple abrasive grits. The machined surface morphology was predicted by extracting node coordinates on simulated ground surface. The numerical prediction results were quantitatively validated using experimental results of ground surface roughness Sa. The application of the proposed prediction model not only elucidated the influence law of fiber orientations and machining parameters on ground surface quality but also revealed the different shear failure modes of SiO2 fiber during grinding process. The ground surface of SiO2f/SiO2 was deteriorated by uncut-off debonding fibers and fiber peeling pits. Ultrasonic-assisted vibration was beneficial to improve ground surface quality by force reduction and hammering effect caused by intermittent machining. However, the key prerequisite for the ultrasonic hammering effect to exert its process advantage was that the ultrasonic hammering energy could effectively fracture fibers on the ground surface rather than being absorbed by crack propagation at the fiber–matrix interface.

Ultrasonic vibration assisted double disc chemo-magnetorheological finishing of silicon wafer: Experimental investigations and optimization for surface roughness

To polish the surface of silicon wafers, the impact of ultrasonic vibration assistance on the double disc chemo-magnetorheological finishing was investigated. The in-house setup was fabricated to provide vibrations to the workpiece during the polishing in the longitudinal direction. The central composite design (CCD) approach was adopted in experiment planning to understand the influence of process parameters (like magnets rotation, abrasive concentration, and ultrasonic power) on the surface roughness ([Formula: see text]). A 3D optical profilometer was employed to check the surface roughness of the polished wafers. The individual and interaction of significant process factors affecting were determined using the analysis of variance (ANOVA) technique. A regression equation based on response surface methodology was developed. The process parameters were optimized using a genetic algorithm to maximize the change in surface roughness before and after polishing. The experiment performed at an optimized set resulted in an average surface finish of 3.4 nm. A 3D surface plots and scanning electron microscopy (SEM) were used to understand the changes on the surfaces of unpolished and polished samples at the optimized parameters.

Edge chipping damage in lithium silicate glass-ceramics induced by conventional and ultrasonic vibration-assisted diamond machining.

Diamond machining of lithium silicate glass-ceramics (LS) induces extensive edge chipping damage, detrimentally affecting LS restoration functionality and long-term performance. This study approached novel ultrasonic vibration-assisted machining of pre-crystallized and crystallized LS materials to investigate induced edge chipping damage in comparison with conventional machining. The vibration-assisted diamond machining was conducted using a five-axis ultrasonic high-speed grinding/machining machine at different vibration amplitudes while conventional machining was performed using the same machine without vibration assistance. LS microstructural characterization and phase development were performed using scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. Machining-induced edge chipping depths, areas and morphology were also characterized using the SEM and Java-based imaging software. All machining-induced edge chipping damages resulted from brittle fractures. The damage scales, however, depended on the material microstructures; mechanical properties associated with the fracture toughness, critical strain energy release rates, brittleness indices, and machinability indices; and ultrasonic vibration amplitudes. Pre-crystallized LS with more glass matrix and lithium metasilicate crystals yielded respective 1.8 and 1.6 times greater damage depths and specific damage areas than crystallized LS with less glass matrix and tri-crystal phases in conventional machining. Ultrasonic machining at optimized amplitudes diminished such damages by over 50 % in pre-crystallized LS and up to 13 % in crystallized LS. This research highlights that ultrasonic vibration assistance at optimized conditions may advance current dental CAD/CAM machining techniques by significant suppression of edge chipping damage in pre-crystallized LS.