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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. [ABSTRACT FROM AUTHOR]

Giant magnetostrictive transducer can be widely used in active vibration control, micro-positioning mechanism, energy harvesting system, and ultrasonic machining. Hysteresis and coupling effects are present in transducer behavior. The accurate prediction of output characteristics is critical for a transducer. A dynamic characteristic model of a transducer is proposed, by providing a modeling methodology capable of characterizing the nonlinearities. To attain this objective, the output displacement, acceleration, and force are discussed, the effects of operating conditions on the performance of Terfenol-D are studied, and a magneto-mechanical model for the behavior of transducer is proposed. A prototype of the transducer is fabricated and tested to verify the proposed model. The output displacement, acceleration, and force have been theoretically and experimentally studied at different working conditions. The results show that, the displacement amplitude, acceleration amplitude, and force amplitude are about 49 μm, 1943 m/s2, and 20 N. The error between the model and experimental results are 3 μm, 57 m/s2, and 0.2 N. Calculation results and experimental results show a good agreement. [ABSTRACT FROM AUTHOR]

In this study, an ultrasonic-assisted electrochemical grinding (UAECG) system was designed to improve the low efficiency and tool wear in conventional grinding of hard and tough materials. In this system, multiple-field energy consisting of ultrasonic, electrochemical and mechanical grinding was used. The processing mechanism was investigated to determine the interaction mechanism between ultrasonic, grinding and electrochemical processing. The established theoretical model showed that the processing efficiency was affected by the ultrasonic amplitude, ultrasonic frequency, electrolyte conductivity and other parameters. In verifying the feasibility of UAECG machining and the effect of machining elements on machining, a series of corresponding machining experiments was conducted. Experiments showed that the machining efficiency can be improved by machining through the UAECG system. The material removal rate of W18Cr4V machining was 2.7 times higher than that of conventional grinding and 1.7 times higher than UAG. The processing efficiency of YT15 was increased by 3.2 times when the processing voltage increased from 2 to 6 V. The surface shape and roughness were also affected by these parameters. The surface roughness of the SiCp/Al workpiece reached the best level at 4 V as the machining voltage increased from 2 to 6 V. However, the surface roughness increased significantly when the voltage increased to 6 V. Thus, parameters such as machining voltage must be optimised for efficient and precise machining in practice. [ABSTRACT FROM AUTHOR]

To achieve high precision, stability, and good surface quality when producing micro-dimple arrays on cylindrical surfaces, we propose a new processing method known as radial ultrasonic rolling electrochemical micromachining (RUREMM) in this study. This method is based on the electrochemical micromachining (EMM) and ultrasonic machining principle. The relevant simulation model was created, and ANSYS researched the flow field characteristics of the electrolyte between the array electrodes and the workpiece. Micro-dimple arrays were created on a SS304 cylindrical surface with the consideration of the effects of the machining parameters, including ultrasonic amplitude and applied pulse voltage. Compared with the EMM, the average width of the micro-dimples is reduced by 24.5%, the aspect ratio of the dimple is increased by 108.0%, and the surface roughness of micro-dimples is decreased by 59.7%. In addition, the localization and the surface quality of micro-dimples by RUREMM can be improved when using appropriate machining parameters. [ABSTRACT FROM AUTHOR]

A study of polyvinylchloride-coated woven polyester fabric welding potential was conducted using continuous ultrasonic welding machines. The effect of cooling air, anvil wheel status, anvil wheel width, material surface contact, and welding gap on seam strength was studied. Three main welding parameters with different levels were selected based on 5 and 10 mm welding widths using old and new anvil wheels with and without cooling air. A lapped type of seam was applied under full factorial design. A microstructure was captured to examine the formation of welding joints, and seam tensile properties were determined. Comparative analysis of comparable welding parameters was analyzed for a gap against pressure and amplitude against power. The actual weld phenomenon was also analyzed based on the recorded machine parameters. The results showed that auxiliary parameters had a significant effect on seam strength. A microscopic image of a welded seam indicated that cooling air reduced the number and size of holes produced. Weld seam with controlled pressure or power provided higher seam strength than that of the controlled gap or amplitude. The actual phenomenon of welding parameters was important to evaluate weld seam quality, whereby the obtained results indicated good quality at lower power and pressure. [ABSTRACT FROM AUTHOR]

Ultrasonic vibration–assisted machining (VAM) is a process in which a tool or workpiece is vibrated using ultrasonic frequency small-amplitude vibrations to improve cutting performance, and an ultrasonic transducer usually generates these vibrations. This study investigates how two-dimensional vibrations are generated using axially polled piezoceramics. Modifying the wave propagation in geometric ways by creating a notch at the front mass, the longitudinal response excited by the axially polled piezoceramic discs can be converted into combined longitudinal and bending vibrations at the transducer front mass. Finite element analysis (FEA) software COMSOL is used to study wave propagation, and ANSYS is used to optimize the transducer's mechanical structure, while an equivalent circuit approach is used to analyze the electrical impedance spectra and confirm its resonance frequency. An experimental analysis of impedance response and amplitude of generated vibrations using the novel 2D ultrasonic transducer is conducted to validate the numerical and analytical results, which shows that resonance frequency results are in very good agreement with the theoretical model. Finally, the proposed design is validated by preliminary test results that demonstrate its performance and principles. [ABSTRACT FROM AUTHOR]

In this research, the effect of ultrasound time and dryer type (hot -air and infrared) on the drying time, effective moisture diffusivity coefficient and rehydration of wheat sprouts were investigated and drying kinetics were modeled. To apply ultrasound pre - treatment, the sprouts were placed inside the ultrasonic bath machine for 0, 5, 10, and 15 minutes, and after leaving the machine and removing extra moisture, the samples in thin layers were placed in the hot -air (with a temperature of 70°C) and infrared (power of 250 W) dryers. The results showed that sonication up to 5 minutes, causes an increase in moisture removal rate from the sprouts, an increase in the effective moisture diffusivity coefficient, and as a result, reduces the drying time. By increasing sonication time from zero to 5 min, the average drying time of sprouts in the hot -air and infrared dryers decreased from 126.7 min to 120.0 min, and from 25.7 min to 21.3 min, respectively. The average drying time of the samples in the hot -air dryer was 150.8 min and in the infrared dryer was 28.0 min. Also, the average effective moisture diffusivity coefficient calculated for the samples placed in the hot - air dryer was equal to 1.65×10 -10 m²S-1 and for the infrared dryer it was equal to 8.59×10-10m² s-1 . The time of ultrasound and drying treatment had significant effects on the rehydration of samples, and the value of this parameter was higher for samples dried in the hot -air dryer. In order to investigate the drying kinetics of wheat sprouts, mathematical models were fitted to the experimental data, and the Page model with two parameters (k and n) was chosen as the best model based on the highest accuracy. Generally, 5 minutes pre -treatment by ultrasound and then using an infrared dryer is the best condition for drying wheat sprouts. [ABSTRACT FROM AUTHOR]

In recent years, ultrasonic machining has been developing rapidly, and it is used in areas such as abrasive machining, cleaning, and welding. In this research, a magnetostrictive device with pure nickel conical core with cone angle of 30° was constructed. The observed sound pressure level was used as a measure of transducer performance. Also, the ability of the device to reduce the residual pesticide on cucumber surface due to cavitation was evaluated. The results showed that the sound pressure from simulation by JMAG-Designer software is almost the same as the sound pressure produced in the constructed transducer. To assess the performance of the device in removing residual pesticide from cucumber surface and evaluate the changes in peel texture of cucumber, the gas chromatography (GC) and scanning electron microscope (SEM) methods were used, respectively. The GC results showed that with 20 min treatment, the removal of pesticide based on height and chromatogram area was 75% and 83%, respectively. The SEM results showed that by increasing the treatment time, the stomatal pore area reduced from 144.74 μ m 2 (reference) to 30.56 μ m 2 (20 min treatment). These results are promising; hence, further research is suggested towards enhancing the device for commercial use in biomaterials processing operations such as cleaning and removing pesticides from fruits and vegetables. [ABSTRACT FROM AUTHOR]

In view of the defects of the new domestic T800 carbon fiber reinforced plastic (CFRP), such as lamellar tearing and fiber loss, which would be easily caused by large drilling force and torque during cutting, an experimental platform including a vertical ultrasonic machining center and force measurement system was constructed. Carbide twist drill, carbide candle stick drill and carbide dagger drill were used to compare the hole quality of T800 carbon fiber composite. Under the same technological parameters, the influences of three kinds of cutting tool structures on the cutting force, surface morphology of hole inlet and outlet, aperture deviation and surface roughness of T800 composite were compared with those of conventional drilling (CD). The ultrasonic vibration assisted drilling (UVAD) method was adopted to carry out feasibility experiments on optimum tool structure. The results show that the carbide dagger drill can effectively suppress the surface defects of T800 composite materials, but the entrance aperture accuracy is poor. The ultrasonic vibration assisted dagger drilling can further improve the quality of hole making, especially significantly improve the aperture accuracy by improving the drilling stability. [ABSTRACT FROM AUTHOR]

Machinability, along with its associated facets, is a critical parameter that ultimately determines the cost of machining. Its optimization, however, is inherently limited by the current technology. To surmount such limitations, novel alternative machining technologies, such as Ultrasonic Assisted Machining (UAM), have emerged. The present study introduces UAM, the technology's underlying principles, and general considerations for vibration application (harmonic waves, eigenfrequencies, resonance). The influence of ultrasonic application on the key parameters of conventional machining processes is studied and relevant research data are presented to support UAM benefits. Following, a comprehensive kinematic examination of vibration application to the milling process is conducted, accounting for various possible vibration modes. A detailed analysis of the requisite system components and their technical specifications is presented, followed by identifying common issues within such systems. Solutions for the identified limitations are proposed, acting as design guidelines for future technological advancements. Finally, based on the conducted research, conclusions are drawn and future directions for UAM are suggested. [ABSTRACT FROM AUTHOR]

As the core component of the rotary ultrasonic machining (RUM) system, the working frequency of the ultrasonic vibration unit and the actual tool vibration amplitude in RUM are important for the machining quality. The electrical characteristics of the ultrasonic vibration unit have a close correlation with both factors. Due to the difficulty in measuring the electrical characteristics of the ultrasonic vibration unit in the RUM system directly, the research on the effect of force load during machining on the variations of its electrical characteristics is relatively little. In this paper, the electrical characteristics of the ultrasonic vibration unit in a typical RUM system are investigated. Firstly, the relationship between electrical parameters and the resonant frequency of the ultrasonic vibration unit is investigated when different tools are clamped by the ultrasonic transducer. The ultrasonic vibration is designed to work in the local resonant state to adapt to various cutting tools. Then, rotary ultrasonic drilling experiments are conducted to study the effect of processing parameters on the electrical characteristics of the ultrasonic vibration unit. An experimental platform is designed where we can directly monitor the voltage signals and current signals of the ultrasonic vibration unit during the machining, and the variations of electrical parameters under different machining conditions are investigated. It is found that the variations of electrical parameters are significant under different ultrasonic voltages but not under different feed rates. [ABSTRACT FROM AUTHOR]

Thin-walled structures have many applications in the aerospace industry. An important feature of them is their high strength to weight. When milling the thin-walled part, the thickness decreases step by step by cutting, which causes the process to be complex and dependent on process parameters. In the present study, thin-walled aluminum structures are investigated using conventional and ultrasonic milling processes, and distortion, surface roughness, surface texture, and average thin-wall forces are also investigated. Therefore, 18 tests are performed on parts made of 7075T6 aluminum alloy using various feeds, spindle speeds, and machining modes. The results showed that the machining type and spindle speed had 47% and 33% effect on distortion, respectively. In addition, the results showed that by applying vibrations to the milling, the amount of distortion can be reduced by up to 30% and effectively optimized. This technique is suitable for manufacturing industries that require high dimensional accuracy. Also, the surface texture and burr formation are investigated. In particular, the surface roughness in ultrasonic milling decreased compared to conventional milling. [ABSTRACT FROM AUTHOR]

State of Charge and State of Health are critical indicators for evaluating the operational status of lithium-ion batteries. Accurate estimation of these parameters is essential for ensuring safe operation and optimizing charging-discharging performance. This study presents a novel method for estimating SOC and SOH based on ultrasonic characteristics. A pouch battery is selected as the experimental object, with ultrasonic waves extracted in real-time during battery operation. Acoustic parameters are obtained via signal processing to establish a training dataset for SOC estimation. Additionally, the impact of varying discharge rates on battery capacity degradation is analyzed to support battery aging experiments. During the aging experiments, real-time acoustic parameters are collected to develop a training dataset for SOH estimation. The results indicate a strong correlation between the acoustic parameters and the SOH. Moreover, the acoustic parameters serve as the characteristic parameters, and a hybrid-model combining the sparrow search algorithm and relevance vector machine is employed to accurately estimate the state parameters. The maximum relative error for the SOC estimation is 1.51 %, while the maximum absolute error for the SOH estimation is 0.79 %. The research results provide a new technical support for the non-destructive quantitative characterization of lithium-ion battery state parameters. • Combines ultrasonic and machine learning for SOC and SOH estimation. • Strong correlation found between ultrasonic parameters and SOH. • Novel tool enables non-destructive monitoring of LIB state parameters. [ABSTRACT FROM AUTHOR]

• Under the action of F p and F s , the L 1 and C 1 of the PT show a nonlinear trend, while C 0 remains nearly unchanged. • The zero-phase point of the transducer after LC matching and LCC matching has disappeared under the heavy load conditions. • After impedance matching using all four topologies, the RFT error of the transducer increases with the increase of F p. • Ls matching and LCL matching still provide good tuning matching under heavy load conditions. In power ultrasonic systems, impedance matching is a critical technique which enables electrical energy to be fully utilized by the transducer. However, the electrical parameters of the transducer will change when thermal-force loads are applied in the application scenario. Although the transducer can be operated at the optimum frequency point by using resonance frequency tracking (RFT), there is a certain tracking error when tracking the resonant frequency of the transducer in the loaded condition due to the impedance matching unit. To improve the RFT accuracy and the stability of the ultrasonic system, an ultrasonic system with RFT function was designed in this research. Then four commonly used matching topologies were introduced. Secondly, the electrical parameter drift patterns of the ultrasonic device were explored. Based on the patterns, the impedance characteristics of the transducer with four matching topologies after being loaded were revealed. Finally, the theory and experiments were combined to reveal the influence of matching topology and loading effect on the output characteristics of the transducer. The results showed that the Ls and LCL topologies have better resistance to load fluctuation. Meanwhile, after Ls and LCL matching, the phase-locked loop method still has good RFT performance under heavy load conditions. This study can guide the selection of the transducer's matching topology and RFT methods. [ABSTRACT FROM AUTHOR]

• High stability and fast response speed. • High drive capability. • High frequency tracking accuracy. • Good stability under load conditions. • Wide practical value. Power ultrasonic systems are facing challenge in amplitude control and electro-mechanical energy conversion efficiency due to their high power and low bandwidth. In this paper, a novel design method of LC matching parameters based on maximum current is proposed to achieve the high-power capacity and stable vibration of the ultrasonic transducers. The electrical model of the ultrasonic transducer under loading conditions is constructed by the joint surface dynamics model. The relationship between the equivalent parameters and the loading pressure, and the relationship between the dynamic branch current and the output amplitude are obtained. The mathematical model of ultrasonic transducer is established. A composite amplitude control algorithm based on frequency tracking and current control is proposed. The frequency tracking algorithm consists of fast frequency tracking and dynamic branch phase locking. The fast frequency tracking can quickly estimate the series resonant frequency at the beginning, and the dynamic branch phase locking continuously tracks the series resonant frequency. A constant current control algorithm composed of expert PI (Proportional Integral) and fuzzy PI is designed. According to the voltage, current and phase difference between the two ends of the ultrasonic transducer, the PI increment is calculated to adjust the duty cycle of the phase-shifted full-bridge to track the target current. The target current is calculated by the target amplitude, feedback data and the loading. The impedance matching experiment is carried out, and the output current can reach 2A under the impedance matching, and the amplitude of the transducer can reach 80 μm. The experiments under variable loads are carried out to attain the equivalence of the circuit parameters with the pressure and the dynamic branch current. The experiment of amplitude control is carried out, and the result of frequency tracking is 19680 Hz, and the absolute error with the series resonant frequency is 1 Hz. The absolute error between the output amplitude and the target amplitude can be controlled within 1um, and the relative error is lower than 6.7 %. [ABSTRACT FROM AUTHOR]

Fiber-reinforced ceramic matrix composites (CMCs) exhibit high hardness, brittleness, heterogeneity, and anisotropy. This study explores the material removal and damage formation mechanisms during ultrasonic vibration-assisted scratching of SiC f /SiC composites through experimental and micro-finite element simulations. The research reveals that high-frequency periodic indentation-separation of abrasive grain influences stress transfer and crack propagation, which are affected by the interfacial layer and fiber orientation. Crack deflection plays a crucial role in material removal and determines the amplitude of normal scratching force. Stress transfer interference primarily governs damage formation, with more severe damage occurring along the longitudinal and transverse fiber directions due to secondary stress concentration and crack deflection. In contrast, scratching along the perpendicular fiber direction requires higher normal forces due to residual adjacent phase materials, but results in more controlled material removal and less damage. The study provides insights into optimizing the ultrasonic vibration-assisted machining of CMCs to minimize damage. [ABSTRACT FROM AUTHOR]

Ultrasonic assisted high-speed machining (UAHSM) can be served as a thermomechanical surface sever plastic deformation (SSPD), because of the high-frequency impact load exerting to the sample together with thermomechanical loads due to shearing and plowing. Despite existing of few works which studied the impact of ultrasonic vibration on fatigue life assessment of difficult-to-cut material by experimental approach, they couldn't provide an in-depth analysis to identify the underlying mechanisms of fatigue due time-consuming and costly fatigue life tests. Hence, elucidating the role of ultrasonic vibration in UAHSM on variation of fatigue life needs further studies. In order to do so, in the present work, a hybrid predictive approach based using ANFIS-based machine learning model and micromechanical Navaro-Rios (NR) fatigue crack propagation model has been introduced to directly correlates the UAHSM's parameters to fatigue life. Here the former correlates feed rate, cutting velocity and vibration amplitude as process inputs, to surface integrity aspects (SIA) viz residual stress, roughness and grain size as output. Then, the modeled SIA are correlated to fatigue life using the former. The introduced hybrid model was then verified through series of UAHSM by examining the fatigue lives of milled Inconel 718 using four-point bending fatigue tests. Upon confirmation of the developed model, a comprehensive study was carried out to find how the process factors impact variation of SIA and subsequently fatigue. It was found from the results of developed models and confirmatory experiments that the role of ultrasonic vibration on improved fatigue life is mainly due to inducing compressive residual stress and more refined microstructure than the roughness. [ABSTRACT FROM AUTHOR]

• A 45 kHz ultrasonic vibration cutting device was specifically designed for straight-nosed diamond tools. • Ultrasonic vibration characteristics under consideration of Poisson's ratio are analyzed and experimentally verified. • The effect of ultrasonic motion on machining accuracy and tool wear was theoretically analyzed, considering the influence of Poisson's ratio. • Ultrasonic vibration decreases tool wear and allows higher feed rates in ultraprecision turning optical materials. This study proposes a novel ultra-precision machining technology that uses ultrasonic vibration and a straight-nosed diamond tool to improve the processing of the brittle optical material zinc selenide (ZnSe). This research addresses the challenges posed by Poisson's effect in ultrasonic vibration-assisted single-point diamond turning, which causes bending vibration along the depth of cut, resulting in lower machining efficiency and surface quality. This study analyses the relationship between one-dimensional ultrasonic vibrations at the diamond tool edge and induced bending vibrations using both theoretical and experimental methods. By investigating ultrasonic vibration dynamics in the feed direction and at the straight cutting edge, the results showed that ultrasonic vibration helps to improve the ductile-brittle transition ratio of the cutting area and surface quality. These improvements are accomplished by regulating the cutting position at the tool cutting edge, adjusting cutting parameters, and optimizing ultrasonic parameters. The machined surface roughness of ZnSe is reduced by approximately 30–46 % at higher feed rates under ultrasonic vibration with straight-nosed diamond tools. The findings demonstrate the potential of this novel technology to reduce tool wear and brittle fractures, resolving the challenge of ultra-precision machining for optical materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Time-dependent characterization of ultrasonic amplitude and ultrasonic frequency to showcase the efficacy of sapphire ultrasonic vibration-assisted flexible polishing. • Comprehensive examination of macro- and micro-level polishing forces to elucidate the dynamic behavior of C-plane sapphire workpieces. • Development of a methodology to elucidate the dynamic behavior of elastic tools, incorporating both static and dynamic force measurements. • Provision of a measurement-based parameter space oriented towards normal force, tailored for researchers and engineers in the field. Sapphire ultrasonic vibration-assisted flexible polishing (UVAFP) is a promising technique for comprehensively improving the surface integrity of machined parts. The technique was performed on an ultra-precision machine tool with the in-situ monitoring systems in this paper, which aims to provide a new perspective for understanding the material removal mechanisms in the sapphire UVAFP process. A Taguchi L 9 (43) orthogonal experiment was conducted to investigate the effects of feed distance, spindle speed, ultrasonic vibration (UV), and polishing time on the surface finish and material removal in the process. In addition, the effect of a polyurethane ball tool is not trivial. A single-factor experiment was conducted for exploring it. Based on a laser displacement measurement system and an acoustic emission sensor system, the characteristics of time-dependent ultrasonic amplitude and ultrasonic frequency for the sapphire UVAFP system were analyzed, with the effectiveness of UV demonstrated. Based on a three-component force measurement system, the characteristics of normal force and its relationship with process parameters and tool deformation were analyzed, with macro- and micro-level examined. In conclusion, this paper presents the characterization of UV and polishing force in the sapphire UVAFP process, providing novel insights into understanding the material removal mechanisms of sapphire and even more manufacturing problems. [ABSTRACT FROM AUTHOR]

The composite materials Si/AlC, crystal quartz, and ceramic glass are becoming an important part of the present society in many engineering and non-engineering fields. Conventional methods available for machining these materials have many flaws due to which their application on large scale is restricted. A non-conventional process known as ultrasonic machining (USM), can be implemented for machining of these materials effectively. Anyhow machining efficiency of USM greatly depends upon its horn design and therefore in the present study a horn based on a catenoidal profile with aluminum and titanium material for USM was designed and developed by using solid works and ANSYS. Modal and harmonic analysis was done on the horn for computation of various parameters of interest such as resonant frequency, amplitude vibration and equivalent stresses. After the computation of the results, they were analyzed and compared with those available in the literature in terms of stresses and magnification factor for their validation comparison with literature, it was found that an aluminum catenoidal horn shows higher magnification with the least stress magnitude as compared to horns avail-able in the literature and hence can be used in USM as a replacement for existing horns.

An ultrasonic sonar-based ranging technique is introduced for measuring full-field railroad crosstie (sleeper) deflections. Tie deflection measurements have numerous applications, such as detecting degrading ballast support conditions and evaluating sleeper or track stiffness. The proposed technique utilizes an array of air-coupled ultrasonic transducers oriented parallel to the tie, capable of "in-motion" contactless inspections. The transducers are used in pulse-echo mode, and the distance between the transducer and the tie surface is computed by tracking the time-of-flight of the reflected waveforms from the tie surface. An adaptive, reference-based cross-correlation operation is used to compute the relative tie deflections. Multiple measurements along the width of the tie allow the measurement of twisting deformations and longitudinal deflections (3D deflections). Computer vision-based image classification techniques are also utilized for demarcating tie boundaries and tracking the spatial location of measurements along the direction of train movement. Results from field tests, conducted at walking speed at a BNSF train yard in San Diego, CA, with a loaded train car are presented. The tie deflection accuracy and repeatability analyses indicate the potential of the technique to extract full-field tie deflections in a non-contact manner. Further developments are needed to enable measurements at higher speeds. [ABSTRACT FROM AUTHOR]

Piezoelectric actuators are characterized by high positioning accuracy, high stiffness and a fast response and are widely used in ultra-precision machining technologies such as fast tool servo technology and ultrasonic machining. The rapid response characteristics of piezoelectric actuators often determine the overall quality of machining. However, there has been little research on the fast response characteristics of piezoelectric actuators, and this knowledge gap will lead to low precision and poor quality of the final machining. The fast response characteristics of a piezoelectric actuator were studied in this work. Firstly, the piezoelectric actuator was divided into a no-load state and a load state according to the working state. A fast response analysis and output characteristic analysis were carried out, the corresponding dynamic model was established, and then the model was simulated. Finally, an experimental system was established to verify the dynamic model of the piezoelectric actuator's fast response by conducting an experiment in which the piezoelectric actuator bounces a steel ball. The experimental results verify the correctness of the model and show that the greater the cross-sectional area and height of the piezoelectric actuator, the higher the bouncing height of the ball, and the better the dynamic performance of the piezoelectric actuator. It is believed that this study has guiding significance for the application of the dynamic characteristics of piezoelectric actuators in the machining field. [ABSTRACT FROM AUTHOR]

Surface texturing is a potential approach to achieving excellent surface performance. To realize high precision and efficiency in micro-texturing fabrication, a surface texturing method utilizing an ultrasonic surface rolling process is proposed. Firstly, the feasibility and geometric controllability of micro-texture preparation using ultrasonic surface rolling process are analyzed. Then, a contact theory model of ultrasonic rolling texturing process is established, which can describe the geometric relationship of the micro-texturing generation region. Based on the elastic–plastic theory, simulations of single-pass and multi-pass ultrasonic rolling texturing processes are developed to elucidate the formation and strengthening mechanism of micro-textures, and further characterize the effects of ultrasonic rolling machining parameters on micro-textures. A series of validation tests of ultrasonic rolling texturing are implemented on AISI 5140 steel. Simulation and experimental results show that the ultrasonic surface rolling process can fabricate micro-groove arrays with the periodic distribution. The validity of the theoretical and finite element models is confirmed by the comparison results. It is demonstrated that the ultrasonic rolling texturing process is a feasible and efficient way to fabricate controllable micro-textures. [ABSTRACT FROM AUTHOR]

In rotary ultrasonic machining, contactless energy transfer (CET) converts power from an ultrasonic power supply to the ultrasonic transducers. Two-side compensation circuits improve the efficiency of this process, but the addition of secondary compensation causes problems such as dynamic imbalance. Load changes affect the performance of CET system (CETS) with compensation, and dynamic compensation is needed for good CETS performance, such as high transfer efficiency and output power. This article investigates the frequency characteristics of CETS without compensation under different loads. The effects of two-side compensation on CETS under load variations is studied for the dynamic compensation characteristic. The comparison of mathematical model and performance of CETS with dynamic compensation are investigated to propose the optimized dynamic compensation. The model of CETS with optimized dynamic compensation under load variations is developed. The CETS frequency characteristics with optimized dynamic compensation are studied. The experimental results basically agree with the calculated results. The CETS with optimized dynamic compensation at the series resonant frequency can produce high transfer efficiency, high output power, low input impedance range under load variations in the cutting process of RUM, and solves the problems caused by the secondary side compensation. [ABSTRACT FROM AUTHOR]

In order to further improve the cutting performance, the micro texture tool was applied to the elliptical ultrasonic assisted cutting processes, and the influences on cutting force, tool wear and surface quality were analyzed. Then the influence laws of tool surface micro texture angle and size on tool wear were analyzed. The results show that the micro texture tool may further improve the cutting performance while retaining the excellent performance of elliptical ultrasonic assisted cutting, and according to the experimental results, the change of micro texture angle and size will affect the wear resistance of the tool, when the micro texture is parallel to the main cutting edge and the width is as 70 µm, spacing is as 70 µm, the tool bond wear is the smallest. [ABSTRACT FROM AUTHOR]

In this study, the stability of water-emulsified diesel (WED) prepared by different methods have been analyzed. In first phase, the optimum condition of Hydrophilic-Lipophilic Balance (HLB) value of the surfactant used for the preparation of emulsified diesel with respect to its stability has been determined. Different resultant HLB values have been obtained by mixing two surfactants in different proportion. The highest emulsion stability (ES) is found for WED prepared with the surfactant mixture of HLB value 8 which is obtained by mixing 65.5% Span 80 and 34.5% Tween 80. In second phase, WEDs containing 10% water and 2% surfactant mixture with resultant HLB value 8 have been prepared using mechanical homogenization as well as ultrasonication methods. In third phase, the emulsions are prepared adding 10, 20, and 30% water and 2% surfactant mixture with resultant HLB value 8 using ultrasonication process. The emulsion mixture has been kept in a cooled water bath to minimize hot spot effect during ultrasonication process. The polydispersity index (PDI), water particle size and auto correlation factor (ACF) of all four prepared WEDs have been measured by nano particle analyzer which works on dynamic light scattering (DLS) technique. These properties of the WEDs have been analyzed to investigate their stability behavior of the emulsion. Experimental investigations have also been carried out on performance and emission characteristics of a single cylinder, four-stroke diesel engine using WED prepared by both methods containing 10% water. At full load, the brake thermal efficiency is found to be marginally higher using emulsified diesel prepared using ultrasonicator compared to base diesel. The NOx and smoke emissions have been found to be lower for both types of emulsified diesel than pure diesel. The experimental results show more favorable emulsification, performance and emission characteristics for the emulsified diesel prepared by ultrasonic machine than that prepared by mechanical homogenizer. The density, viscosity, and calorific value of the emulsions prepared by the two methods have also been measured and compared with that of neat diesel. [ABSTRACT FROM AUTHOR]

To improve the ultrasonic energy and realize far-field ultrasonic abrasive machining of complex surfaces, a spherical-array-focused ultrasonic abrasive machining system was established. By combining ultrasonic field simulation, detection and a single-factor experiment, the influences of the ultrasonic generator current, abrasive concentration, and particle size on the material removal properties and surface quality evolution of quartz glass were investigated. When the current was less than 0.4 A, the material removal showed plastic removal at the nanoscale. When the current was more than 0.5 A, the cavitation phenomenon formed micron-scale impact removal traces on the workpiece surface. The increase in abrasive concentration increased the impact density and material removal rate, while excessive abrasive concentration increased the impeding effect between abrasive particles and reduced the material removal rate. Moreover, the increase in abrasive particle concentration enhanced heterogeneous cavitation nucleation, promoted the removal of abrasive impact materials under the action of a cavitation jet, and inhibited the removal of direct surface cavitation. The abrasive particle size affects the heterogeneous cavitation nucleation and the acceleration of the cavitation jet on abrasive particles, which affects the material removal rate and surface quality. By controlling the energy of the focused ultrasound and abrasive parameters, the plastic or brittle domain removal of quartz glass can be achieved at the micro- and nanoscales. [ABSTRACT FROM AUTHOR]

This research is focused on the drilling of Nickel based super alloy with diamond metal core drill and identified the significant parameters of rotary ultrasonic machining that optimise the machining rate (MR) and surface quality. Four general parameters: workpiece material, workpiece thickness, tool material, and tool size; and four RUM parameters: tool rotational, feed rate, ultrasonic power rating, and abrasive grit size of the tool were tested against and surface quality of the cut. The results indicated that the maximum value of MR of 0.8931mm3/sec is acquired at higher level of tool rotation, feed rate, ultrasonic power and moderate level of abrasive grit size of diamond. The minimum surface roughness (Ra) 0.554 µm is observed at higher level of rotational rotation, Moderate value of feed rate, ultrasonic power and diamond abrasive grit size. In addition, for single-objective and multi-objective functions, the particle swarm optimization (PSO) approach is used to find the optimum values for process parameters. Furthermore, a scanning electron microscope is also utilized to check the machined surface after RUM. It is concluded that microcracks are observed on the machined surface. [ABSTRACT FROM AUTHOR]

Amorphous alloys are a new type of multi-functional advanced material with the properties of general metal materials and glass, which are also called metallic glasses. They have good comprehensive properties, such as a wide application range, low cost, and high reusability. Using reasonable process parameters, non-traditional machining can not only realize the machining of complex amorphous parts, but also avoid the crystallization and oxidation of amorphous alloys, realizing tasks that cannot be accomplished by traditional machining. Therefore, this review systematically summarizes the research status and development potential of amorphous alloys fabricated using non-traditional machining methods. First, we introduce the principles of laser machining, ultrasonic machining, electrical discharge machining, electrochemical machining, and other non-traditional machining methods for amorphous alloys. Subsequently, the influence of the machining parameters and other external conditions on the machining effect is summarized. The machining cost, machining efficiency, and environmental impact of these non-traditional machining methods were compared. Finally, non-traditional machining technology for amorphous alloys is summarized and discussed. • The processing principles of non-traditional machining methods are summarized. • The influences of processing parameters on the machining effect are reviewed. • Costs, effects, and pollution of non-traditional machining are compared. • The limitations or shortages of non-traditional machining methods are summarized. [ABSTRACT FROM AUTHOR]

To solve the problems of high cutting forces, severe tool wear, and poor surface integrity faced by advanced materials in aerospace manufacturing, multi-dimensional vibration machining (MDVM) is receiving unprecedented attention. MDVM utilizes workpiece and/or tool vibration excited in different directions to achieve high quality and efficient machining of aeronautical hard-to-cut materials. This paper covered typical MDVM hardware systems based on different vibration mechanisms, vibration application methods, and control methods, discussed the machining mechanisms such as friction reversal and contact-separation, and displayed the application effects in extending tool life, improving surface integrity, and manufacturing functional surfaces. The diversity of vibration mechanisms and the complexity of vibration modes of the MDVM system made it difficult to develop a unified design method for vibration systems and to demonstrate the machining mechanism under the coupling of different ultrasonic-induced effects. Therefore, it is an important development direction for future research to investigate the vibration and machining characteristics of MDVM systems and reveal the unified law. [ABSTRACT FROM AUTHOR]

Conventional surface grinding can be divided into up grinding and down grinding according to rotation direction of spindle. Nevertheless, the effects and differences of ultrasonic vibration on the two machining methods have been less reported. The influence of ultrasonic vibration amplitude on cutting force, surface roughness and surface topography were investigated in this paper by conducting tangential and radial ultrasonic vibration assisted down/up grinding comparison experiments on SiC. The results showed that the grinding force of down grinding was less than that of up grinding in conventional grinding, while the surface roughness was greater than that of up grinding. The grinding forces of both down grinding and up grinding were reduced to different ratios after applying different ultrasonic vibration, while the surface roughness increased. The grinding force of up grinding decreased and then increased with the increase of amplitude, while the grinding force of down grinding kept decreasing and the surface roughness decreased. The reasons for the differences in cutting forces and surface quality between the two grinding methods after the application of ultrasonic vibration are discussed. By observing the surface morphology, the percentage of ductile area on the machined surface decreases and then increases with the increase of amplitude. [ABSTRACT FROM AUTHOR]

Rotary ultrasonic machining (RUM) is an effective method of high-quality and high-efficiency machining for advanced composites. However, the machining mechanism and kinematic characteristics of ultrasonic machining of SiC particles-reinforced aluminum matrix (SiC p /Al) composites are yet unclear, limiting the applications of RUM in composites machining. In this study, a rotary ultrasonic vibration-assisted scratch (RUVAS) test was designed for the high-volume fraction of SiC p /Al composites. The kinematic and scratch force model of RUVAS was developed to describe the scratch process of SiC p /Al. Both RUVAS and conventional scratch (CS) tests were performed under various scratch speeds on SiC p /Al. The scratch trajectory was divided into three modes: continuous, semi-continuous, and intermittent. We observed the formation of different surface morphology under different modes. The scratch force difference between RUVAS and CS was insignificant when the scratch speed is high, which indicated that the effect of ultrasonic vibration diminished at a high speed when the ultrasonic frequency was fixed. When assisted by ultrasonic vibration, the scratch morphology of SiC p /Al indicated that the matrix has undergone significant plastic deformation. While the hard SiC particles tended to be ruptured and pressed into the plastic matrix, this mechanism can effectively suppress the initiation and propagation of cracks, which is beneficial to reducing the stress influence zone, healing the surface defects, and improving the surface integrity. The subsurface morphology indicates that the subsurface damage under CS and RUVAS mainly includes particle cracking, matrix tearing, and interface failure. Our experimental result shows that ultrasonic vibration can effectively reduce the subsurface damage of SiC p /Al composites, bringing insight into fundamental mechanisms of ultrasonic machining and providing guidance for the vibration-assisted processing of SiC p /Al composites. [ABSTRACT FROM AUTHOR]

Ultrahigh-temperature ceramic matrix composites are currently among the most promising high-temperature-resistant materials, owing to their high-temperature strength, high-toughness and excellent corrosion resistance; they are widely used in national defense and aerospace fields. However, it is a difficult material to machine, and high precision is difficult to achieve using traditional machining methods. Nontraditional machining methods are not constrained by material physical and mechanical properties, and good surface quality is easily obtained, which is an important direction in the field of ultrahigh-temperature ceramic matrix composites. This paper summarizes the recent nontraditional machining methods utilized in the fabrication of ultrahigh-temperature ceramic matrix composites. Firstly, various nontraditional machining methods for ultrahigh-temperature ceramic matrix composites based on borides, carbides and nitrides are reviewed, and the machining performances under different machining conditions are compared. Subsequently, the problems and challenges of ultrahigh-temperature ceramic matrix composite nontraditional machining are summarized and discussed. Lastly, the future development path of nontraditional machining methods for ultrahigh-temperature ceramic matrix composites is summarized and predicted. [ABSTRACT FROM AUTHOR]

The printability of artificial defects inside the additively manufactured laser powder bed fusion (LPBF) 316L stainless steel is investigated. The printing parameters of the LPBF process are optimized to produce artificial defects with reproducible sizes at desired positions while minimizing redundant porosity. The smallest obtained artificial defect is 90 μm in diameter. The accuracy of the geometry of the printed defect depends on both the height and the diameter in the input model. The effect of artificial defects on the very‐high‐cycle fatigue (VHCF) behavior of LPBF 316L stainless steel is also studied. The specimens printed with artificial defects in the center are tested under VHCF using an ultrasonic machine. Crack initiation is accompanied by the formation of a fine granular area (FGA), typical of VHCF. Despite the presence of relatively large artificial defects, FGA formation is observed around accidental natural printing defects closer to the surface, which can still be considered as internal. The causes for this occurrence are discussed. [ABSTRACT FROM AUTHOR]

Ceramic rock slab is a kind of new material with the advantages of high hardness, wear resistance, and high-temperature resistance, and it is widely used in industry and households. However, problems such as easy chipping and serious tool wearing occurred in conventional grinding (CG). To overcome these challenges, this work introduces rotary ultrasonic grinding (RUG) in processing ceramic rock slabs. Study the theoretical motion trajectory of single abrasive grain and the removal mechanism of hard and brittle materials in RUG, and analyzed the influence of amplitude on cutting force in finite element simulation of single abrasive grain. A comparative process experiment of RUG and CG was performed on the hole processing of ceramic rock slabs. The experimental results showed that compared with CG, the cutting force and chipping area of RUG were reduced by 40.4 and 14.3%, respectively. The cutting force and chipping area decreased with the increase of the spindle speed and increased with the increase of the feed speed. With the increase of ultrasonic amplitude, the cutting force and chipping area decreased gradually, and the tool wear rate decreased from 0.54 to 0.10%, which effectively suppresses the spalling of abrasive grains on the surface of the tool and extends the life of the tool. [ABSTRACT FROM AUTHOR]

The vibration characteristics of a giant magnetostrictive transducer play a significant role in the stability and processing effect of spinning ultrasonic machining. The output characterization of the giant magnetostrictive transducer is unstable subject to an powerful external load, which severely restricts the application of giant magnetostrictive transducer in industry. In this study, the effect of change of load force and electrical parameter in the different directions on the high-frequency (about 20 kHz) vibration output characteristics of the giant magnetostrictive transducer is investigated, through finite element analysis and static loading experimental. The result shows that the electrical parameter of a giant magnetostrictive transducer has a similar changing trend with the increasing of the axis and radial force load; The resonant frequency also increases with the increase of electrical parameter and load force; The amplitude attenuation of ultrasonic vibration will become extraordinary intense even almost to stop beat when the axis force load increase to 750 N and radial force load increase to 550 N; The gradient of resonant frequency in a radial direction is more significant than that in an axial direction. Based on the results of theoretical analysis and static loading experimental, the measures to reduce amplitude attenuation and improve output stability of amplitude under resonant frequency are proposed. The results can provide theoretical guidance for a magnetostrictive transducer used in the actual spinning ultrasonic vibration processings. [ABSTRACT FROM AUTHOR]

A non-contact ultrasonic abrasive machining approach provides a potential solution to overcome the challenges of machining efficiency in the high-precision polishing of optical components. Accurately modeling the material removal distribution (removal function (RF)) and surface morphology is very important in establishing this new computer-controlled deterministic polishing technique. However, it is a challenging task due to the absence of an in-depth understanding of the evolution mechanism of the material removal distribution and the knowledge of the evolution law of the microscopic surface morphology under the complex action of ultrasonic polishing while submerged in liquid. In this study, the formation of the RF and the surface morphology were modeled by investigating the cavitation density distribution and conducting experiments. The research results showed that the material removal caused by cavitation bubble explosions was uniformly distributed across the entire working surface and had a 0.25 mm edge influence range. The flow scour removal was mainly concentrated in the high-velocity flow zone around the machining area. The roughness of the machined surface increased linearly with an increase in the amplitude and gap. Increasing the particle concentration significantly improved the material removal rate, and the generated surface exhibited better removal uniformity and lower surface roughness. [ABSTRACT FROM AUTHOR]

Nomex honeycomb composites are used extensively in aerospace, automotive, and other industries due to their superior material properties. However, the tool wear during their machining can compromise the processing accuracy and the stability of the whole machining process, thus studies on the tool wear and strengthening method are urgently needed. This study presents a radial difference calculation method (RDC) to evaluate the tool wear of the disc cutter quantitatively in both conventional cutting and ultrasonic assisted cutting. The morphology of the tool wear process and its characteristics were analyzed. Two different heat treatments (salt bath quenching and vacuum quenching) were carried out to strengthen the tool performance. The research results demonstrated that ultrasonic vibration could significantly reduce the tool wear of the disc cutter, by up to 36%, after the same machining time. Salt bath quenching and vacuum quenching can both strengthen the tool performance. Particularly, after vacuum quenching treatment, the disc cutter's metallographic grains were refined, and the tool wear could be reduced by 64%, compared to the as-received disc cutter. The findings in this study could be instructive to obtain further understanding of the machining mechanism and to improve methods in ultrasonic assisted cutting of Nomex honeycomb composites. [ABSTRACT FROM AUTHOR]

This study investigated the applicability of using ultrasonic wave signals in detecting early fire damage in concrete. This study analyzed the reliability of using the linear (wave velocity) and nonlinear (coherence) parameters from ultrasonic pulse measurements and the applicability of machine learning in assessing the thermal damage of concrete cylinders. While machine learning has been used in some damage detections for concrete, its feasibility has not been fully investigated in classifying thermal damage. Data was collected from laboratory experiments using concrete specimens with three different water-to-binder ratios (0.54, 0.46, and 0.35). The specimens were subjected to different target temperatures (100 °C, 200 °C, 300 °C, 400 °C, and 600 °C) and another set of cylinders was subjected to room temperature (20 °C) to represent the normal temperature condition. It was observed that P-wave velocities increased by 0.1% to 10.44% when the concretes were heated to 100 °C, and then decreased continuously until 600 °C by 48.46% to 65.80%. Conversely, coherence showed a significant decrease after exposure to 100 °C but had fluctuating values in the range of 0.110 to 0.223 thereafter. In terms of classifying the thermal damage of concrete, machine learning yielded an accuracy of 76.0% while the use of P-wave velocity and coherence yielded accuracies of 30.26% and 32.31%, respectively. [ABSTRACT FROM AUTHOR]

The paper presents the fixtures with movably mounted turning and drilling cutting tools. The fixtures were developed on the principle of oscillating tooltip similar to the principle of the ultrasonic vibration-assisted machining process. However, presented fixtures do not need an electricity source and utilize mainly forced and self-excited oscillations. In general, the tool vibrations during the cutting process are recognized as a negative phenomenon as it causes a shortening of the tool life and worsens the roughness of the machined surfaces. However, a deeper understanding of the cutting process proposes possible positive effects of tool vibration in terms of chip shapes, flank wear, chip volume coefficient, and quality of the machined surface. Experimentally obtained dependence of mentioned quantities is provided in the paper. [ABSTRACT FROM AUTHOR]

This research focuses on the load characteristics of piezoelectric transducers in the process of longitudinal vibration ultrasonic welding. We are primarily interested in the impedance characteristics of the piezoelectric transducer during loading, which is studied by leveraging the equivalent circuit theory of piezoelectric transducers. Specifically, we propose a cross-value mapping method. This method can well map the load change in ultrasonic welding to the impedance change, aiming to obtain an equivalent model of impedance and load. The least-squares strategy is used for parameter identification during data fitting. Extensive simulations and physical experiments are conducted to verify the proposed model. As a result, we can empirically find that the result from our model agrees with the impedance characteristics from the real-life data measured by the impedance meter, indicating its potential for real practice in controller research and transducer design. [ABSTRACT FROM AUTHOR]

In the process of ultrasonic vibration cutting (UVC), the acoustic performance parameters of ultrasonic machining system change because of systems heating up and cutting loads. The changes of acoustic performance parameters will affect resonant frequency, impedance, and power match of the ultrasonic machining system, and stability of the amplitude of UVC system. It is hard to monitor the acoustic performance parameters online. Based on the analysis of the correlation mechanism between transducer temperature and acoustic performance parameters, the correlation models between transducer temperature and resonance frequency, static capacitance, and dynamic resistance of ultrasonic vibration machining system are established by curve regression analysis modeling method. The acoustic performance parameters of an ultrasonic vibration machining system are determined by transducer temperature using the correlation models. The effectiveness of the model is verified by experiments. It gives the information for the stability evaluation of the ultrasonic vibration machining process, the dynamic impedance matching of the ultrasonic machining system, and the power matching adjustment of the ultrasonic power supply. [ABSTRACT FROM AUTHOR]

The core of the ultrasonic machining system is the acoustic vibration component. Due to the inconsistency of the assembly conditions between the junction surfaces of the acoustic vibration component, the resonant frequency of the ultrasonic acoustic vibration component after the size adjustment of the ultrasonic horn is low, and the Impedance mismatch occurs in the ultrasonic system. In this paper, considering the influence of assembly conditions, the optimal assembly parameters were studied to reduce the junction surface's influence on the ultra-sonic horn's performance parameters. The paper analyzed the assembly structure, assembly parameters, and static and dynamic performance parameters of the acoustic vibration components and established a static and dynamic performance parameter measurement system. The assembly parameters of the ultrasonic acoustic vibration components were analyzed and determined. The static performance parameters of the ultrasonic acoustic components were measured and analyzed for the assembly parameters of the junction surface at the ultrasonic horn and the straight-edged knife. The optimal assembly parameters were preliminarily determined based on the analysis of the static performance parameters. The optimal assembly parameters of the junction surface of the ultrasonic horn and the straight-edged knife were determined through the measurement and analysis of the dynamic performance parameters of the two junction surfaces. The work is the basis for the adjustment of the ultrasonic horn. It also provides a basis for improving the working performance, manufacturing precision, and production efficiency of the ultrasonic horn while further popularizing the application of ultrasonic processing. [ABSTRACT FROM AUTHOR]

Zirconia (ZrO 2) ceramics, as advanced structural ceramics, are gradually used in manufacturing, aerospace and other fields due to their excellent properties. However, it is problematic to process the ZrO 2 ceramics by conventional machining. This study adopted the longitudinal-torsional coupled rotary ultrasonic machining to process the ZrO 2 ceramics. Firstly, the material removal mechanism was clarified in the view of a single abrasive particle. Then, the longitudinal-torsional coupled rotary ultrasonic machining experiment was conducted to explore the effect of processing parameters on the cutting force, hole surface roughness, surface morphology, and single abrasive particle wear with those in the conventional machining. It was found that the cutting force reduced with the spindle speed and ultrasonic power, growing with the feed rate. The hole surface roughness declined with spindle speed, enhanced with feed rate, and decreased first and then increased with ultrasonic power. Compared with the conventional machining, both the cutting force and surface roughness were significantly reduced in the longitudinal-torsional coupled rotary ultrasonic machining. The test results proved that the hole surface quality was improved, and the single abrasive particle wear was reduced in the longitudinal-torsional coupled rotary ultrasonic machining. This study's results are considered instrumental in the longitudinal-torsional coupled rotary ultrasonic machining processing of hard and brittle materials. [ABSTRACT FROM AUTHOR]

This paper is focused on the issue of preparing the cutting edge microgeometry of cutting inserts made of cubic boron nitride (CBN). The aim of this research was to investigate the possibilities of rotary ultrasonic machining (RUM) for preparing asymmetric cutting edge microgeometries of various shapes (chamfers, circular, and elliptical rounding and their combinations) on a CBN cutting tool. In this article, a new type of advanced cutting edge preparation method is presented. CBN is relatively resistant to the most often used (abrasive) methods of cutting-edge preparation, due to its very high hardness (which is a prerequisite property for machining difficult-to-cut materials). Such hard materials could be processed using advanced manufacturing methods, and rotary ultrasonic machining (RUM) is one such method. Experiments have shown that RUM can be used for machining CBN. However, high hardness is not the only challenge here. For cutting edge preparation, it is necessary to achieve an adequate accuracy of size and dimensions. The presented paper analyzes the suitability of the RUM process for processing CBN inserts. The results of the experiment showed that this method can be used for preparing asymmetric cutting edge microgeometries with various shapes. [ABSTRACT FROM AUTHOR]

Ultrasonic machining is a new technique, and one of the new and promising processes for machining metals, especially metal alloys with low machinability. In this paper, a set of laboratory studies is used to investigate the effect of using ultrasonic vibrations on the force required for drilling of the thin aluminum workpieces. For this perpuse, three aluminum workpieces with different thicknesses are drilled under three different rotation speeds, and four different advance rates. The results showed that in two aluminum workpieces, 1 and 1.5 mm, the use of ultrasonic vibrations generally reduced the axial force, but in the 2 mm workpiece, it is not possible to understand a meaningfull effect of adding ultrasonic vibrations. In other words, it can be said that adding ultrasonic vibrations with constant amplitude and frequency does not have the same effect on drilling in different conditions, and to reach the most efficient drilling, the characteristics of optimal vibration should be studied. [ABSTRACT FROM AUTHOR]

In this article, the effect of optimal selection of vibration and cutting parameters on cutting forces in the machining process with ultrasonic vibration assistance has been investigated and the results have been compared in two modes of conventional machining and of ultrasonic vibration assisted machining. In the investigation of the effect of ultrasonic vibration assistance on the machining process, analyzes have been carried out in different cutting speeds, and the effect of changing the cutting speed in relation to the tool's oscillation speed has been investigated. Finite element modeling and simulation has been done with DEFORM finite element software. The results show that the application of ultrasonic vibration in the machining process leads to the reduction of tangential and axial cutting and the reduction of heat resulting from the cutting process. By examining the results, it was found that in the machining process with ultrasonic vibration assistance, when the cutting speed is at least 30% lower than the vibration speed of the tool tip, the process has a favorable efficiency, and the favorable effects of applying ultrasonic vibration on the process include reducing shear forces, reducing the heat generated From cutting, reducing the friction coefficient between the tool and the workpiece, helping to improve the chip flow, etc. [ABSTRACT FROM AUTHOR]