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AbstractPlant-based food consumption has increased substantially owing to its positive effects on human and global health. However, ensuring the quality and safety of plant-based foods remains a challenge. Diagnostic ultrasonic technology is widely used for rapid and nondestructive determination owing to its ability to penetrate optically opaque materials, strong directivity, rapid detection capabilities, low equipment costs, and ease of operation. This review provides a comprehensive understanding of diagnostic ultrasonic technology by summarizing the principles of food characterization, factors that influence detection accuracy and methods to mitigate their impact, composition of ultrasonic machine systems, and application of diagnostic ultrasound for monitoring plant-based foods. The detection principle of ultrasonic technology is based on empirical equations that establish a relationship between the ultrasonic and physicochemical indicators of food. To improve the detection accuracy, a compensation mechanism for the temperature and pressure should be established, measurement distances should be set in the far-field region, and liquid samples should be degassed. Furthermore, the sample platform design and the choice of detection mode depend on the nature of the food. Combining ultrasonic technology with machine learning techniques presents promising prospects for real-time process monitoring in the food and beverage industries. [ABSTRACT FROM AUTHOR]

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

This review article presents the current status of various micromachining techniques used to create microfeatures in alumina ceramic. Alumina has emerged as an advanced substrate in various radio-frequency communication and automotive packaging applications due to its superior electrical resistivity, lower dielectric loss, higher wear resistance, and dimensional stability at high temperatures. However, creating complex-shaped microfeatures in alumina is challenging due to its hard and brittle nature. Traditional contact-based methods fail to create microsized shapes in alumina; thus, the researchers are exploring novel machining methods, like abrasive, thermal, chemical, and hybrid micromachining processes. This review article comprehensively summarizes various micromachining methods used to create microfeatures in alumina ceramics. The mechanism, unique features, pros/cons, novelty, and applications of ultrasonic machining, laser ablation, electrochemical discharge machining, abrasive-jet machining, etc., are presented. The associated processing challenges in various alumina micromachining and the potential remedies to produce high-quality alumina microparts for microelectronics applications are discussed. [ABSTRACT FROM AUTHOR]

The material removal in the ultrasonic machining process is due to the fracture of the workpiece material. The fracture is due to energy transfer by vibrating abrasive particles. The vibration energy is induced by a tool oscillating at a frequency of more than 20 kHz. The vibrating particles not only impact the workpiece surface but also impact the oscillating tool, and it leads to the fracture of the tool, which is of interest to understand to guarantee efficient machining with accuracy and precision. In the current investigation, the tool wear during the ultrasonic machining of Inconel 718 super alloy is attempted. An acoustic emission sensor is integrated with the machining setup, and signal information is extracted in the time and time-frequency domains. The features and process parameters are input to a support vector regression model to estimate tool wear. The model developed for tool wear prediction yields an accuracy of 96.13% compared to the model developed with only process parameters, which delivers an accuracy of 84.89%. The developed model can be beneficial for the real-time monitoring of tool wear during the ultrasonic machining process for industrial and remote applications. [ABSTRACT FROM AUTHOR]

The increase in demand for aerospace parts leads to a need for effective and efficient machining methods to enhance the machinability of titanium alloys. This research investigates the effect of ultrasonic-assisted turning (UAT) on aerospace titanium alloy Ti-6Al-4V by varying cutting parameters. Ultrasonic turning experiments were conducted to investigate the reduction in cutting forces and tool wear at different cutting parameters with wear and surface roughness analysis. Consequently, a finite element model is used to simulate the ultrasonic turning of titanium to have a better understanding of the effect of UAT on stresses and temperature profiles in the process and help explain the results found experimentally. Separation time between the tool and chip was found to be inversely proportional to the cutting speed and the depth of cut with a reduction in cutting forces and surface roughness of up to 42.5% and 61.4%, respectively, for low cutting speed and depth of cut. Tool wear is also shown to decrease in the ultrasonic machining where adhesion-diffusion wear is reduced on the rake face due to separation in the tool-chip interface. The chip temperature was found to increase while the tool temperature is found to decrease with the motion of the tool. [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]

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]

The traditional machining process is not suitable for machine brittle material like glass, ceramics and hard alloys. To machine such kinds of materials, the non-traditional machining process is used. In today's modern industry, ultrasonic machining is used for machine hard and brittle materials. Operation conditions of USM very high frequency (18 to 46 kHz) and tool vibration gives around 6-μm amplitude. Cutting tools have an amplitude of around 5–90 μm for achieving good machining quality. In the USM process, horn transfers the vibration force from the transducer to the cutting tool end. Novel horn design gives the magnification factor (MF) for vibration amplitude. In this paper, the horn is invented for the USM process with the help of ANSYS and finite element analysis (FEA) to manage the necessary performance for the industry. First of all, the horn profile is designed by using the differential equations for getting a 3D model. The shape of mode and frequencies is found out by modal analysis performance. Similarly, design feasibility is verified by balanced retaliation performance analysis to found out the magnification factor with the help of a novel horn. Finally, the design of the novel horn is compared with the suggestive horn. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) is prone to surface damage such as delamination, uncut fibers and tear during the process of hole-making in aerospace field. Helical milling greatly improves the exit damage of CFRP holes, but the entrance damage will further deteriorate. To further diminish hole entrance damage and enhance hole machining quality, this paper proposed a longitudinal torsional ultrasonic assisted helical milling method to investigate the formation mechanism of hole entrance damage based on a cutting fracture mechanism with a fiber angle of 0° to 180°. The differences of hole entrance damage between longitudinal torsional ultrasonic helical milling (LTUHM) and traditional helical milling (THM) were analysed by a series of comparative experiments. The results showed that longitudinal torsional ultrasonic machining significantly reduced the damage of CFRP holes compared to THM. The delamination damage factor and uncut fibers factor of the hole entrance are reduced to 24.92% and 20.28%, respectively, and the fiber fracture surface is flatter under LTUHM. The study provides a production guide for efficient hole-making of CFRP. [ABSTRACT FROM AUTHOR]

In ultrasonic vibration-assisted drilling (UVAD), the processing stability is strongly influenced by the ultrasonic vibration system's vibrational characteristics. The effect of tool parameters on UVAD's vibrational characteristic was experimentally studied and theoretically analyzed in this paper. Firstly, a measurement experiment was designed to assess the above effect in three various tools under different loads. The relationship between the ultrasonic power and amplitude was used to indirectly monitor the ultrasonic amplitude variation, which was corroborated by the UVAD test results. The ultrasonic amplitude and power were mainly controlled by the stiffness coefficient, while the damping coefficient effect could be ignored. Furthermore, the tool vibration frequency exhibited an increasing trend with the load value. Finally, the effects of the stiffness coefficient and damping coefficient on the vibrational characteristics were theoretically substantiated. The results of this study are considered instrumental in selecting tool and process parameters in ultrasonic machining. [ABSTRACT FROM AUTHOR]

Carbon-carbon composites (C/C composites) is typical high temperature resistant material. Therefore it is applied in solid rocket motor (SRM) throat mostly. Because the throat is mostly single piece and mini-batch, which is not suitable for mold forming. Usually, numerical control machining is still the main method. Due to high strength and heterogeneous composites, the machining damage defects are obvious and quality is poor. Thus, from the perspective of C/C composites ablation resistance, rotary ultrasonic machining technology effect on C/C composites surface defects and damage is investigated. Moreover, the influence of ultrasonic vibration on fiber cutting angle and machined surface morphology is analyzed. Meanwhile, based on comparative experiment, fiber pull-out length and surface porosity are presented as characterization parameters. The results show that ultrasonic vibration not only improves fiber cutting angle effectively, but also reduces pores and cracks on machined surfaces. Moreover, it reduces fiber pull-out length by 10%–50% numerically when along fiber milling. When fiber is perpendicular to the cutting direction, the pull-out length becomes shorter. The above study provides a theoretical basis for subsequent machined damage influence on ablation resistance of C/C throat. [ABSTRACT FROM AUTHOR]

In this study, bioethanol was produced from Eichhornia crassipes (EC) plant and tested in diesel engine in order to understand the potential of this fuel. The blending of Eichhornia Crassipes bioethanol with diesel is done with the help of ultrasonic machine. For acquiring data, Kirloskar made single cylinder diesel engine of 3.5 kW rating was employed for experimentation. Bioethanol obtained from EC plant was blended in various proportions with petro-diesel and biodiesel. The properties of bioethanol produced from EC plant was measured based on ASTM standards. The experimental results revealed that 10% blend (90% petro-diesel and 10% bioethanol) was a clear stand out in terms of engine parameters such as enhanced brake power and appreciable brake thermal efficiency. Also the emission levels such as CO and unburned HC was comparatively lesser than other blends except for NOx which eventually depends on the engine construction. [ABSTRACT FROM AUTHOR]

In recent years, demand of titanium alloy (Ti6Al4V) in various industries especially aerospace industries drastically increased. Several exceptional properties of titanium alloy that contribute to its popularity include high compressive and tensile strength, fracture toughness oxidation resistance and high strength-to-weight ratio. However, due to these superior properties, titanium alloys are categorized as hard-to-machine materials. The drilling process is accounted for roughly 40%−60% of material removal processes of an aeronautical product. Drilling processes for titanium alloys are categorized into conventional method (twist drilling) and unconventional method (rotary ultrasonic machining [RUM] drilling, laser drilling and electron discharge machining [EDM] drilling). This research aims to identify mechanisms and limitations of each drilling method applicable on titanium alloys. In addition, processing parameters affecting performance measures of each drilling method are discussed. The main problem associated with conventional twist drilling is extreme processing temperature, resulting in rapid tool wear and extensive burrs formation. These issues cause the cost for titanium alloy drilling to be relatively high as compared with twist drilling of other materials. To minimize these issues, researchers have developed several unconventional drilling methods, aiming to minimize issues found in conventional twist drilling. [ABSTRACT FROM AUTHOR]

In the present work, machining of boron carbide (B4C) has been performed using ultrasonic machining (USM) with the same material as abrasive particles. A comparative assessment of machining of B4C with that of glass and brass has also been carried out by drilling microholes using USM. The experimentation has been conducted according to Taguchi L9 orthogonal array. The effect of feed rate, slurry concentration, and grit size has been evaluated on the performance measures such as material removal rate, overcut, circularity error, taper angle and tool wear rate. Additionally, overall evaluation criteria (OEC) has been formulated to evaluate the combined performance measures. After ANOVA feed rate became the most significant parameters affecting OEC for all the materials. The machining of B4C has been found to be possible but lacks in the machining rate in comparison with that of glass and brass. Least tool wear rate has been found in case of glass whereas minimum overcut, circularity error and taper angle have been observed for brass. The quality of the drilled holes in B4C is better as minimal surface chipping and burr formation has been observed. [ABSTRACT FROM AUTHOR]

Rotary ultrasonic machining (RUM) is a hybrid machining process that combines the material removal mechanisms of grinding and ultrasonic machining. RUM has been applied to hole-making for a wide range of materials. It is known that ultrasonic vibration amplitude has significant effects on cutting force, torque, and surface finish in RUM. One experimental observation that has been reported in the literature multiple times states that different tools show different vibration amplitudes on the same ultrasonic power level. However, no analyses can be found in the literature to explain this observation. The existence of this knowledge gap makes it difficult to explain some experimentally obtained trends or to conduct more realistic physics-based modeling work. The objectives of this research are to understand the effects of tool natural frequency on ultrasonic vibration amplitude in RUM, to provide an explanation to the observation and verification of measurement methods, and also to guide tool design and selection in RUM. Ultrasonic vibration amplitudes of tools are measured by three methods and compared. It is found that tool natural frequency significantly affects ultrasonic vibration amplitude. The tool with its natural frequency closest to that of the ultrasonic power supply (20 kHz) generates the highest ultrasonic vibration amplitude on every ultrasonic power level tested. [ABSTRACT FROM AUTHOR]

Electrochemical discharge machining (ECDM) is one of the non-traditional processes which employs physical and chemical phenomena to remove the material from the non-conductive workpiece. Moreover, some technical augmentations have been added to the mentioned process to achieve a more efficient machining method. Typically, ECDM includes numerous electric discharges, but study on a single discharge, with/without application of external augmentation, leads to understanding the complicated nature of the ECDM process and the effect of technical augmentation. In this research, the ECDM process is studied in the mode of single discharge. Also, ultrasonic vibration, as a technical augmentation, is added to the process (UAECDM) and related effects are studied. For this purpose, special configuration and equipment are used to apply ultrasonic vibration and generate only single discharge. Material removal and tool wear are two important characteristics of drilling process which can be considered to determine the machining efficiency. The current signal is used to determine the current variation and discharge(s) condition. Results showed that the application of ultrasonic vibration changed the current signal pattern to increase discharge numbers in constant condition. Also, ultrasonic vibration increased the material removal up to 35%, while tool wear reduced between 3% and 14%. [ABSTRACT FROM PUBLISHER]

Developing tools for ultrasonic machining processes is one of the most challenging tasks, because the shape of the machined surface of the workpiece is a replica of the tool surface. In this research, using reverse engineering (RE), the tool has been designed and fabricated for the ultrasonic machining (USM) process. Zirconia is a very hard and brittle bio-ceramic material and is highly biocompatible. Nowadays, zirconia material is used for producing the acetabular cup for hip joint. In this research work, an attempt has been made to apply the RE for developing the CAD model of a USM tool from the existing hemispherical shape cavity on a zirconia workpiece. Experimental analysis has been undertaken for generating the hemispherical shape cavity on zirconia bio-ceramics with the help of these developed tools. Through a number of graphical plots, comparisons of diametrical deviation and circularity error have been made using RE and without RE. Comparisons have also been made for justifying the accuracy of the tool development by RE with respect to the initial existing hemispherical shape cavity and developed tool for USM. [ABSTRACT FROM AUTHOR]

Macor ceramic has been well recognized as a classic engineering material that possesses wide industrial usage owing to its excellent and versatile properties. However, its fruitful and productive processing is still unanswered. The present article attempts to experimentally investigate the influence of numerous process variables on machining characteristics in rotary ultrasonic machining of macor ceramic. The impact of different input factors, namely spindle speed, feed rate, coolant pressure, and ultrasonic power, has been evaluated on the process responses of interest, i.e., surface roughness (SR) and chipping thickness (CT). The experiments are designed by utilizing response surface methodology (RSM) through a central composite rotatable design. The variance analysis test was performed with a view to observe the significance of the considered parameters. Microstructure analysis of the machined samples revealed and confirmed the presence of dominating brittle fracture that caused the removal of material along with a slight plastic deformation of the work surface. The multi-response optimization of machining responses was carried out by utilizing the desirability approach. At optimized parametric setting, the obtained experimental values for SR and CT were found to be 0.523 µm and 0.156 mm, respectively. [ABSTRACT FROM AUTHOR]

Ultrasonic vibration is assumed to be stable or unchangeable during the process of rotary ultrasonic machining (RUM) on brittle materials, neglecting the effects of different processing parameters. However, no experimental evidence has been reported to validate this assumption. In this study, the effect of thermomechanical load on the stability of ultrasonic amplitude during RUM was investigated by theoretical analysis and experimental procedures on quartz glass and sapphire. It was shown that the instability of ultrasonic amplitude during the machining process is mainly attributed to variation of resonant frequency under the implementation of thermomechanical load. The thermal effects of ultrasonic vibration decrease the resonant frequency of the ultrasonic machine, while mechanical loading during the machining process increases the resonant frequency. Furthermore, a higher feed rate or a harder material leads to a higher resonant frequency change. The variation of ultrasonic power can be used to review the validity of difference-neglected assumption when different values of processing variables, materials, or even machine tools are used during modeling. The results of this study should be well considered for future references when designing an ultrasonic machine. [ABSTRACT FROM PUBLISHER]

Alumina ceramic is well documented as a much-demanded advanced ceramic in the present competitive structure of manufacturing and industrial applications owing to its excellent and superior properties. The current article aimed to experimentally investigate the influence of several process variables, namely: spindle speed, feed rate, coolant pressure, and ultrasonic power, on considered machining characteristics of interest, i.e., chipping size and material removal rate in the rotary ultrasonic machining of alumina ceramic. Response surface methodology has been employed in the form of a central composite rotatable design to design the experiments. Variance analysis testing has also been performed with a view to observing the consequence of the considered parameters. The microstructure of machined rod samples was evaluated and analyzed using a scanning electron microscope. This analysis has revealed and confirmed the presence of plastic deformation that caused removal of material along with brittle fractures in rotary ultrasonic machining of alumina ceramic. The validity and competence of the developed mathematical model have been verified with test results. The multi-response optimization of machining responses (material removal rate and chipping size) has also been attempted by employing a desirability approach, and at an optimized parametric setting the obtained experimental values for material removal rate and chipping size were 0.4166 mm3/s and 0.5134 mm, respectively, with a combined desirability index value of 0.849. [ABSTRACT FROM AUTHOR]

The use of calcined egg and cockle shell as heterogeneous solid catalysts for a transesterification reaction to produce biodiesel from food processing waste has been investigated in this work. The CaO catalysts were obtained from the calcination of egg and cockle shell and were characterized by surface analysis, X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The experiments employed stirring and ultrasonic agitation, which proved to be a time-efficient approach for biodiesel production from food processing waste oil. A response surface methodology (RSM) was used to evaluate the effects of the process variables methanol to oil molar ratio, catalyst concentration, and reaction time on biodiesel production. The optimal % fatty acid methyl ester values obtained when using egg and cockle shells as catalysts were found to be 94.7% and 94.4% when the methanol to oil molar ratios were 9.3:1 and 8.5:1, egg and cockle shell catalyst mass fraction percentages were 3.8% and 3.5%, and reaction times were 47 and 44 min, respectively. The study has shown that ultrasonic agitation might be employed in a practical pilot reactor for biodiesel production. [ABSTRACT FROM PUBLISHER]

Zirconia (ZrO2) is a highly biocompatible ceramic material providing fracture strength properties that allow application as dental implants in biomedical engineering. In this present research, experimental analysis has been made for generating stepped hole on zirconia bioceramics with desired quality using ultrasonic machining (USM) process. Four independent controllable input process parameters are abrasive grain diameter, power rating, concentration of abrasive slurry, and tool feed rate. Material removal rate (MRR), overcut of larger diameter (OLD) hole, and overcut of smaller diameter (OSD) hole of stepped hole are considered as the responses. Response surface methodology (RSM) is used for modeling the performance of USM process. Multiobjective optimization has been performed to maximize the MRR and minimize the OLD hole and OSD hole of stepped holes. All the responses are improved at the optimal parametric condition and verified by confirmation test. The present research opens up the application feasibility of USM process for stepped hole generation on bioceramics and its utilization in biomedical field. [ABSTRACT FROM AUTHOR]

WC–Co composite material is highly demanded in manufacturing industries, because of its unique properties such as excellent hardness with toughness, higher mechanical strength, and good dimensional stability. The present investigation is aimed at studying the impact of different experimental conditions (by varying cobalt content, thickness of work piece, tool profile, tool material, abrasive grit size, and power rating) on responses of interest (material removal rate and tool wear rate) in ultrasonic drilling of WC–Co composite material. The experiments have been planned by using Taguchi's L-36 orthogonal array and grey relation analysis has been applied for optimization of multiple responses. Analysis of variance is also employed to find the significant factors. Significant effects are observed for process variables such as cobalt content, abrasive grain size, and power level. Tools with higher hardness delivered better machining performance. [ABSTRACT FROM PUBLISHER]

SiCp/Al composites have been widely used in many fields such as aerospace, automobile, advanced weapon system, etc. But this kind of material, especially with high volume fraction, is difficult to machine due to the reinforced particles existing in matrix, which has limited its further application. Rotary ultrasonic machining (RUM) has many excellent features and it has never been used to machine SiCp/Al composites. In order to improve the machinability and application of SiCp/Al composites, the rotary ultrasonic face grinding experiments of SiCp/Al composites reinforced with 45% volume SiC particles were carried out to investigate cutting force, surface quality, tool wear, and abrasive chip shapes. The experimental results indicate that ultrasonic vibration could reduce cutting force, surface roughness, surface defects, and increase plastic removal ratio. The cutting force could be lowered by an average of 13.86% and the surface roughness could be lowered by an average of 11.53%. The examined results of tool wear patterns suggest that tool wear is mainly caused by grain breakage and grain fall-off. Grinding wheel blockage and grinding burn were not observed in machining process. [ABSTRACT FROM PUBLISHER]

This study has focused on the evaluation of the influence of different input variables (cobalt content, thickness of workpiece, tool profile, tool material, size of abrasive grains, and power rating) on the hole quality (dimensional and form accuracy) obtained in ultrasonic machining of WC-Co composite material. Taguchi's approach has been employed for planning the experiments and optimization of the experimental results. Three measures of hole quality (hole oversize, out of roundness, and conicity) have been investigated under controlled experimental conditions. The experimental results showed that abrasive grit size and power rating were most influential for the hole quality. Hole quality has been found to be improved at higher cobalt content, whereas it is found to be degraded with the use of coarse grit size. [ABSTRACT FROM AUTHOR]

The present study aimed to establish an exact comprehension of the subsurface damage patterns generated during rotary ultrasonic machining (RUM) of glassBK7process. First, the subsurface damage of the specimens produced with and without ultrasonic using three different diamond tools was compared and characterized by means of the bonded interface sectioning technique. Then, the RUM scratching tests were conducted on the polished specimen surfaces with two diamond tools to investigate the subsurface damage formation mechanisms involved in formal RUM process. The damage characteristics of the RUM scratches were investigated with respect to the kinematics principles of the abrasives and the dynamic fracture theory of the brittle material. As a result, three types of RUM-induced subsurface damage were identified: pulverization, chipping and cracking. The pulverization layer characterized by finer debris was just populated near the top surface of the RUM specimen without extending into the interior material. The finer debris should emerge simultaneously, resulting from the increased strain rate and the decreased dynamic fracture toughness of the material, both of which were aroused by the inertia loading of the abrasive when reaching the vertex of its sinusoidal trajectory. [ABSTRACT FROM PUBLISHER]

Ultrasonic machining (USM) is a mechanical material removal process used to erode holes and cavities in hard or brittle workpieces by using shaped tools, high-frequency mechanical motion, and an abrasive slurry. The fundamental principles of stationary ultrasonic machining, the material removal mechanisms involved, proposed models for estimation of machining rate, the effect of operating parameters on material removal rate, tool wear rate, and workpiece surface finish, research work reported on rotary mode USM, hybrid USM, process capabilities of USM have been extensively reviewed in this article. The limitations of USM, gaps observed from the literature review, and the directions for future research have also been presented. Overall, this article presents a comprehensive review of USM process for advancement of the process through fundamental insights into the process. [ABSTRACT FROM PUBLISHER]

Ultrasonic machining (USM) on ceramics is highly demanded in the present industry because of its wide and potential uses in various fields in modern industries. Experiments based on central composite second-order rotatable design have been conducted on ultrasonic drilling of hexagonal shaped hole on high alumina ceramic. RSM was employed for developing empirical models. Analysis on machining characteristics of ultrasonic drilling operation was made based on the developed models. In this study, abrasive grit size, slurry concentration, power rating, tool feed rate, and slurry flow rate are considered as USM process parameters. The process performances on workpiece material with respect to material removal rate (MRR) and surface roughness are evaluated by using analysis of variance (ANOVA). The optimum parametric combination of USM process parameters for maximum MRR and minimum value of surface roughness have been obtained through multiobjective optimization. [ABSTRACT FROM AUTHOR]

The optimum selection of process parameters is essential for advanced machining processes, as these processes incur high initial investment, tooling cost, and operating and maintenance costs. This article presents optimization aspects of an important advanced machining process known as ultrasonic machining (USM). The objective considered is maximization of material removal rate (MRR) subjected to the constraint of surface roughness. The process variables considered for optimization are amplitude of ultrasonic vibration, frequency of ultrasonic vibration, mean diameter of abrasive particles, volumetric concentration of abrasive particles, and static feed force. The optimization is carried out using three nontraditional optimization algorithms, namely, artificial bee colony (ABC), harmony search (HS), and particle swarm optimization (PSO). An application example is presented and solved to illustrate the effectiveness of the presented algorithms. The results of the presented algorithms are compared with the previously published results obtained by using genetic algorithm (GA). [ABSTRACT FROM AUTHOR]