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This study explores those composite materials are difficult to machinate because of their variability, heat sensitivity, and high abrasiveness. This leads to damages to the material and extremely high tool wear and damage to the tool. A thorough overview of advanced machining techniques for composite materials is presented in this article. There is an emphasis on glass and carbon fiber reinforced polymeric composites and long fiber reinforced metal matrix composites in the area of fiber-reinforced composites. Particulate composites cannot be machined in the same way as metal matrix composites, though conventional machining processes due to their advanced properties. As per the previous research we concluded that advance machining process is used to cut hard material such as ceramics, composites, Titanium, etc. It is the opposite of traditional machining when a wedge-shaped tool is used to remove material in the form of chips by causing friction coefficient. These techniques have been used in a number of ways to remove material. One approach is to produce stresses via various methods but not with a well-directed wedge-shaped instrument in the material. Some of the techniques like ultrasonic machining, water jet machining, and abrasive jet machining, to name a few of them. The thermal effect may also be used to dissolve or evaporate the materials. Successful and cheap, advanced machining techniques are finding application in sectors.

Fibre metal laminates are one of the most popular structural materials for the automotive and aviation industry. Fibre metal laminates comprise alternating laminae/sheets of metallic alloys and fibre-reinforced polymer matrix. The amalgamated stackup imparts superior mechanical properties of high tensile/ shear strength, excellent stiffness-to-weight ratio, fatigue resistance, impact strength, apart from being lightweight. For obtaining the desired shape and size of components from these laminated materials, forming and machining are vital processes. Due to the contrasting machinability of the monolithic metals and alloys, as compared to that of the fibre-reinforced polymer matrix materials, machining is very challenging. Conventional machining processes like drilling and milling are known to cause delamination in the laminates, heat affected zones at the edges of the monolithic metallic layers and accelerated tool wear. To overcome the challenges of conventional machining, non-conventional machining processes like abrasive water jet machining, laserjet machining, electric discharge machining, and ultrasonic machining are being employed with great success. In this review article, the non-conventional machining processes for fibre-metal laminates, the parameters affecting the machining have been covered.

A novel triaxis static force sensor that uses lead zirconate titanate (PZT) ceramic rings is proposed. The actuator ring is driven at the resonance frequency of the thickness vibration mode to generate ultrasonic waves in the detector rings. The electric potential between the top and bottom surfaces of the detector ring due to the direct piezoelectric effect is measured. The sensing mechanism is based on the variation of the compliance coefficient with the applied force. The bolt-clamped Langevin transducer is the most widely used ultrasonic actuator in ultrasonic machining. The proposed design composed of two PZT ceramic rings imparts triaxis static force sensing capability to the Langevin transducer without the use of external components. The statics model, relationship between stress and the compliance coefficient, and decoupling matrix were derived to estimate the forces on the tool tip based on the voltages at the electrodes on the detector ring. The mean differences between the calculated and experimental results in terms of ${F} _{\textbf {x}}$ , ${F} _{\textbf {y}}$ , and ${F} _{\textbf {z}}$ were 1.92%, 2.54%, and 4.26%, respectively, the full range of ±150 N. The experiments were conducted using different weights and a multiaxis force reference sensor.

Micro-structure on metal surface can be created with high precision and good surface quality by ultrasonic-assisted electrochemical micromachining (USEMM). One of the prevalent material removal mechanisms in ultrasonic machining (UM) is cavitation erosion. However, the mechanism of material erosion is not clear and worth investigating. This study of the mechanical and chemical effects of the ultrasonic vibration on the 6061 aluminum alloy is targeted to reveal the material processing mechanism in USEMM. Based on the built model, the velocity of micro-jet produced near the workpiece surface by ultrasonic cavitation reaches up to 350 m/s when bubble collapses computed by software MATLAB. The impact of micro-jet produces plastic micro-pits on the metal surface and the convex peak around the edge of the pits, which is verified in ABAQUS software. The metallographic microscope and curves of the electrochemical polarization behavior results indicate a significant grain refinement and a marked increase of anodic dissolution current, as well as a weaker resistance than the original workpiece in NaNO3 electrolyte during UM. The current-time curve during machining demonstrates the passive layer forms on the metal surface and then breaks down at the time of less than 0.0066s in USEMM. Micrographs of scanning electron microscope (SEM) of the machined surface in different stages show that many uniform and flat pits are formed in USEMM, compared with the local uneven pits in EMM.

This work reports an ultrasonic horn design and development for improving the performance of ultrasonic machining process in terms of better material removal rate for the same input conditions. The suitable operating frequency range (20 kHz-25 kHz) of the horn is analyzed with the help of finite element approach using the Ansys and for modelling Creo software is used. Typically, the machining tool vibrates around 10-20 μm, but for effective machining requires the more magnitude or intensity (80-200 μm) of vibration within this frequency range. Performance of ultrasonic horn mainly depends on the geometrical aspects and type of material used. In this work, we focus on the ultrasonic horn with an innovative design compared to earlier reported works to obtain the maximum magnification factor within permissible stress limits. The standard criteria “stresses below the permissible limit and mode shapes at different resonance frequencies (modal analysis)” are considered while designing the horn for avoiding the tool and horn failures during machining. The optimum numbers of elements are identified to mitigate computational time based on the optimum mesh criteria. In this study, we have analysed the equivalent stresses, magnification factor (ratio of output to input amplitude) of the horn by harmonic response analysis, which can be used to arrive at the effective machining processes. Finally, the magnification factor is increased within the safe stress limit using our innovative horn design. Newly, designed horn’s performance is compared and validated with the earlier reported literature at a similar input parameters or loading conditions.

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 use...

Machining-induced edge chipping damage represents a common challenge in ceramic applications. This paper reports on responses of zirconia materials with porous and dense microstructures to edge chipping damage induced in conventional and ultrasonic vibration-assisted diamond machining. The machining-induced damage was evaluated using optical and scanning electron microscopies. The results show that edge chipping damage produced in these processes was associated with brittle fracture and depends on the material microstructure and the vibration amplitude. Pre-sintered porous zirconia with a high brittleness index yielded significantly larger edge chipping damage than sintered dense zirconia with a low index in these processes. Ultrasonic machining at an optimal vibration amplitude minimized the scale of brittle fracture at the micro level, and thus significantly diminished edge chipping damage in zirconia materials with distinct microstructures. The investigation underpins the transition from conventional to ultrasonic vibration-assisted machining for manufacturing of ceramics to achieve better product quality.

Ultrasonic machining is a processing method typically practiced for processing the highly brittle/hard materials. The proposed research work is attempted at exploring the influence of varying input conditions namely; cobalt %, power rating, thickness of work, different tools, tool geometry, and abrasive size on the infiltration rate in ultrasonic drilling of WC–Co composite through neural modelling. The design of experiments methodology has been practiced for scheming out the experiments. The significant process variables have been acknowledged using variance analysis test which has revealed the abrasive size, power rating, and tool profile as the most influential factors for the infiltration rate. An artificial neural network (ANN) model is suggested to analyze the infiltration rate in USM with striking parameters. Multiple layer feed frontward neural architecture is restrained through error-back propagation-based training algorithm. Predicted results show the effectiveness of the proposed neural structure with maximum error of 6%. The optimized parametric combination for infiltration rate has been revealed as; cobalt- 6%, work thickness- 3 mm, tool- hollow, tool material- nimonic-80A alloy, abrasive size- 200, and power rating- 80%. Microstructure analysis revealed that good edge quality with no appearance of cracks or burr/chipping on the edge of the drilled holes which further ensured the quality level of hole drilling through attempted work.

The ultrasonic transducer employing helical slots to generate longitudinal-torsional (L&T) ultrasonic vibration is popular in the field of hard and brittle material machining. However, the design approach for this type of L&T ultrasonic transducer is not well established. An improved design model combining equivalent circuit theory and material parameter equivalent method based on stiffness variation was proposed in this study. The structure parameters of the transducer can be obtained according to given resonance frequency and nodal position. The model can further predict electrical characteristics and mechanical responses under specific excitation. For the preliminary verification of this theoretical model and the optimization of the transducer, finite element analyses were carried out to investigate the influences of slot structure parameters on dynamic performances in terms of resonance frequency, frequency separation, and amplitude of L&T vibration. After that, a prototype was manufactured according to the design results, and the measurements of impedance curve and vibration amplitude were conducted. The experimental results indicate that this prototype resonates at 24,920 Hz with an effective electromechanical coupling coefficient of 0.19. Meanwhile, the vibration amplitude in longitudinal direction is 8.1 μm and that in tangential direction is 5.6 μm under 70-V sinusoidal voltage excitation, which are consistent with the theoretical design and simulation results. Furthermore, machining tests demonstrate that surface roughness reduction and surface quality improvement can be gained by adopting this L&T ultrasonic transducer, compared to using the longitudinal vibration transducer. The proposed design approach was validated and this study can provide guidelines for the design of L&T ultrasonic transducer for rotary ultrasonic machining (RUM).

Carbon fiber–reinforced plastic (CFRP) composites are extensively being applied in manufacturing sectors because of their extraordinary characteristics. However, CFRP composites often require some extra machining processes to improve the dimensional accuracy and component integrity of CFRP composites in manufacturing industries. The ultrasonic machining (USM) process progressively has been examined due to its greater ability in machining difficult to cut, brittle, and hard materials such as CFRP composites and due to its relatively low machining cost. Furthermore, USM shows to be a promising process with better surface quality, lower cutting force, less or no fiber fracture, laminate delamination, and lower tool wear rate. Recently, USM has been extensively investigated by many researchers for the machining of CFRP composites. This paper explores the literature and presents a comprehensive review of the advances in USM of CFRP composites by classifying the studies reported in two perspectives. First, the review summarizes most of the reported studies starting from 2011 to 2020 based on the applied USM process, equipment/system/platform used to carry out experiments, considered process parameters and output variables, and challenges investigated or gap filled. Then, the reported studies are summarized considering the type of USM process variant, CFRP composite, adopted process parameters on machining characteristics, and their respective results and conclusions. The aim is to present the current research status in USM of CFRP composites and thus provide guidance and foundation for future research.

There are many parameters affecting the amount of removed rust on the steel surface during ultrasonic cleaning. This article presents the experimental study results to determine the value range of some paratmeters of machining process to ensure the amount of removed rust on the steel surface with great value. Tests were performed in two different detergent solution media of without using acid and using acid. The reasonable value ranges of machine power, machining time, distance from steel plate to ultrasonic transducer (called machining distance) and detergent solution concentration have been determined. From the results achieved in this paper, the development direction for the next studies has also been proposed.

Ultrasonic steel surface cleaning technology is increasingly playing an important role in many different fields. The determination of the influence of the machining parameters on the amount of removed rust on the steel surface is important in the selection of these parameters to increase the machining productivity. In this study, we conducted tests to determine the influence of machining parameters on the amount of removed rust on the steel surface. Tests were performed according to Box-Behnken matrix in two cases: Acids are used or not used in cleaning solutions. In the absence of the use of acids, the selected parameters were the input parameters of the test including machine power, cleaning time and the distance from the steel surface to the ultrasonic head (referred to as the machining distance). Four parameters have been selected as the input parameters when using acids in the detergent solution, including machine power, machining distance, solution concentration and machining time. Finally, orientation for the next research has also been proposed in this paper.

Rotary ultrasonic machining (RUM) has been proven to be a suitable technology for micro-nano precision manufacturing for hard and brittle ceramics/composite materials. However, the working frequency of the ultrasonic transducer in current RUM is in range from 20 kHz to 30 kHz. Moreover, the tool is tightened by an elastic chuck, which is in low clamping precision, high radial run-out, and unstable ultrasonic energy transmission. In this paper, we developed a novel heat shrinkable RUM ultrasonic transducer with 60 kHz frequency by equivalent circuit and finite element method (FEM). An analytical electromechanical equivalent circuit model was deduced to obtain the initial structure dimensions of the ultrasonic transducer. Three flange mounting structures were proposed to optimize and improve the energy transmission at the working resonant frequency. The influence of the proposed flanges on the resonant frequency of three transducers was analyzed and presented. The designed transducers were manufactured and tested in experiment. It shows that resonant frequencies of these three transducers with step, circular, and plate flange are 62.2 kHz, 61.46 kHz, and 61.4 kHz, and vibration amplitudes in 90 V driving voltage are $1.33\mu \text{m}$ , $4.74\mu \text{m}$ , $5.33\mu \text{m}$ , respectively. The working resonant frequencies by experimental measurement are consistent with the calculation result of the equivalent circuit and FEM. Moreover, the plate flange transducer shows the optimal amplitude capability with enough ultrasonic energy in micro-nano precision manufacturing.

Ceramics are solid compounds largely consisting of inorganic and non-metallic components bound by strong ionic and/or covalent bonds. Advanced ceramics such as Zirconia, Silicon carbide, Alumina and Silicon Nitride, find extensive applications in the field of aerospace, military and defence industry due to their enhanced mechanical and physical properties such as excellent refractoriness, high compressive strength, chemical inertness and hardness. While such properties are highly desirable in extreme environments, the inherent high brittleness and low shear strength poses a significant challenge to their machinability. Machining of ceramics is also plagued by surface damage, excessive tool wear, and edge chipping when machined using conventional techniques; non-conventional techniques such as Electric Discharge Machining (EDM) and Abrasive Water Jet machining are characterized by poor surface finish and excessive occurrence of pits, respectively. Achieving dimensional accuracy and minimizing collateral damage such as surface cracks are the key challenges in the machining of ceramics. In this review work, the machining parameters significantly influencing the machining of ceramics using non-conventional processes such as, Ultrasonic machining and Laser machining have been discussed. In contact type of non-conventional machining, feed rate significantly affects the surface finish while in the non-contact type laser scan speed seems to be deciding input parameter in machining ceramics. Rotary Ultrasonic Machining and Laser Assisted Machining (LAM) seem to be the most popular techniques for machining of ceramics, mainly due to better metal removal rate and almost defect-free surface compared to the conventional machining processes.

Ultrasonic machining is among the non-conventional machining technique which is used to machine very hard and brittle material with help of abrasives. The ultrasonic horn is the most important part of USM which amplifies the vibration available at the transducer end to attain a required amplification factor. In the present research paper, an attempt has been made to develop a new variant of ultrasonic horn which could result in maximum magnification factor with minimum induced stresses. A comparative analysis has been made among eight different horn shapes using Modal & Harmonic Analysis in commercially available finite element package i.e. ANSYS and a new design profile i.e. a hybrid horn has been presented to attain maximum amplification factor with a reduction in the equivalent stresses.

The frequency measurement and controlling were difficult in Ultrasonic Machining (USM) process. It was used to remove hard and brittle materials due to the high frequency of vibrations and abrasive slurry. In the present study was introduced an electric network analyzer was used to measure high frequency during the ultrasonic machining of Eglin steel. The controlled frequency was achieved by coupler and splitter. The machining accuracy was confirmed through tool vibrations. The vibrating frequency was sensed by an electric network analyzer based on the power rating, Material Subtraction Rate (MSR), and Hole Depth (HD). The experimental objective was to find the maximum material subtraction rate, holes depth, and its corresponding optimal frequency was found through the Taguchi technique and its effect was confirmed by variance test analysis.

The combination of nickel and chromium has provides better substance properties. In addition to that, the Silicon Carbide (SiC) particulates (weight percentage of 1.50) were mixed to the base alloys to enhance the further substance properties. The tensile strength and density of the composite was increased. The chemical composition was validated through Energy Dispersive Spectroscopy (EDS) test. The chrome composite was drilled by ultrasonic vibrations. The voltage, slurry concentration and abrasive grit size was chosen for control factors. The Material Removal Rate (MRR) was determined through the combinations of control factors. Taguchi approach was used to optimize the ultrasonic machining factors. The factors effects have been discussed through variance test and Pareto chart.

This paper describes the results of investigation on the rotary ultrasonic machining (RUM) of the float glass with the primary objective of analyzing and remedying the edge chipping defects. The present research is conducted to ascertain the effect of various process variables viz. feed rate, ultrasonic power on edge chipping size, through an efficient statistical method, response surface methodology (RSM). In addition, optimal parametric settings have also been proposed to reduce the edge chipping defects for the benefit of practitioners. It is found that both feed rate and ultrasonic power significantly affect the edge chipping behaviour of float glass under RUM. Edge chipping size (ECS) initially decreases with increase in ultrasonic until 60% beyond which it increases for a specific feed rate. It is further observed that feed rate has direct correlation with the size of edge chipping. Statistical analysis of the measured data through ANOVA suggests that the feed rate has major contribution on edge chipping.

With an increase in demand for materials that are lightweight, thermally stable, and can sustain higher temperatures, ceramic matrix composites or CMC’s turned out to be potential candidates however, the major challenge with these materials was the manufacturing aspect and so, there was a demand for machining methods which could easily machine these materials without having much tool wear, provide higher material removal rate (MRR), and produce low surface roughness. Conventional machining (CM) processes like milling, grinding, drilling, and so on were turning out to be disadvantageous as the hardness of these materials is high and it results in excessive tool wear, high surface roughness, and low MRR. Recent researches in unconventional machining processes such as laser machining, plasma machining, electric discharge machining, and abrasive water jet machining, etc. are showing positive results when compared with CM. The current work presents a review of the unconventional machining process of these difficult to machine materials. The unconventional machining processes considered here are the laser-assisted machining process, rotatory ultrasonic machining process, and abrasive water jet machining process. Furthermore, it also discusses how these machining processes are better than conventional machining processes and it compares their MRR, surface roughness (SR), change in the properties, and also discusses the effect of these machining processes on the same parameters.

Heterogeneous material properties and complex cellular hexagonal thin-walled lightweight structure of Nomex honeycomb composites (NHCs) pose significant challenges to achieve high quality processing in terms of low machinability, specialized cutting tools design, precision and influence of processing parameters on surface quality and cutting force. Surface defects have substantial impact on the functional performance and service life of sandwich structural components of NHCs used in aerospace, defense and automotive industries. In this paper, series of single factor and four-factors 4-levels orthogonal experiments were performed to study the effects of processing parameters on rotary ultrasonic machining (RUM) characteristics in terms of cutting force and surface quality by ultrasonic circular saw blade (UCSB) and ultrasonic circular knife (UCK) cutting tools. Furthermore, comparison of NHCs core workpiece cutting on RUM machine tool with ultrasonic vibration (UV) and without UV was conducted by both UCK and UCSB cutting tools. Experimental results proved that the cutting force increases with increase in feed rate and cutting depth whereas, it shows inverse relation with spindle speed and vibration amplitude. Cutting width has greater influence on cutting force among all processing parameters. UCK cutting tool generates less number of burr but length of burr is long and some tearing defects exists whereas, UCSB cutting tool produces large number of burr with very short burr length, no tearing defects and no uncut fibers. Moreover, NHCs core workpiece cutting on RUM machine tool with UV gives better surface quality and lower cutting force compared to without UV. The present study can be used as basis for comprehensive understanding of NHCs processing mechanism, cutting tools design and processing parameters optimization.

When processing difficult-to-cut materials, conventional turning (CT) typically suffers from the problems of large cutting force, difficult chip removal, and serious tool wear, resulting in deteriorated processing quality, reduced processing efficiency, and increased processing costs. In addition, special-purpose machine tools used for ultrasonic machining exhibit disadvantages, such as narrow application scope, high manufacturing cost, and poor universality; thus, they are not conducive to being popular in actual production and processing. Accordingly, this study analyzed the characteristics of ultrasonic wave, the mechanism of ultrasonic vibration-assisted turning (UAT), and the formation of a machined surface in UAT. Moreover, the machining system of UAT was established. This system applied an ultrasonic wave vibration device to an engine lathe to meet the requirements of vibration cutting in actual production. Simultaneously, Inconel 718, a typical and widely used difficult-to-cut material, was selected for the experimental study. The machining effect of UAT was analyzed in detail, including surface roughness, surface topography, and chip shape. Results indicated that ultrasonic amplitude, cutting speed, depth of cut, and feed rate exert considerable influences on the machining effect. UAT can achieve this effect, which is difficult to realize via CT, under the condition of a reasonable selection of technological parameters. This research can provide theoretical support and experimental basis for the development and practical application of UAT.

In this study, the potential to monitor the high-technology nailing of carbon fiber reinforced thermoplastic material (CFRTP) under ultrasonic vibration was investigated by acoustic emission (AE) method. AE signals were detected by a piezoelectric AE sensor during high-technology nailing under ultrasonic vibration. This paper describes some experimental results on AE signal characteristics and observation of the high-technology nailing. In order to investigate the effects of machining condition, we focused on RMS voltage, which is dependent on the energy parameter of the AE signal. It was found that the AE method is a useful method of monitoring high-technology nailing.

In present study, a trending hybrid drilling process i.e. rotary ultrasonic machining has been used for the float glass drilling. A majorly silica based Float glass has extensively used in various engineering applications. However, hole quality associated with pre and post tempering is a major concern affecting the service span of the glass and must be minimized or avoided. Hence, first time the effect of tempering has been investigated on machined damage region. This article presents a rotary ultrasonic drilling (RUD) process to improved hole quality by reducing-edge chipping size i.e. radial chip distance (RCD). The float glass specimens have been drilled using RUD and conventional drilling (CD), and further put in a tempering oven as per industrial standards. The results showed that RUD gives better hole quality in comparison to CD. After tempering process, it is reported that average RCD is increased by 42.58% in RUD holes, whereas 43.93% of RCD is increased for CD holes. It stated that tempering having a significant impact on RCD. Also reported that RUD technique is recommendable, as before and after tempering the RCD is approx. 36.92% lesser than CD process. Clearly indicates that RCD has reduced for RUD holes that directly reduce the monetary loss.

Cutting force is the predominant output variable in rotary ultrasonic machining (RUM). It dictates other output variables, such as tool wear, cutting temperature, edge chipping, etc. It is desirable to develop a mechanistic model to predict cutting force and reveal the underlying cutting tool-workpiece interaction in RUM. Numerous researchers have developed theoretical approaches to predict cutting force in RUM; nevertheless, the combined effects of material removal on cutting force model have not been investigated. RUM has been used for machining rocks in several recent experimental investigations. However, there are no reports on cutting force model for RUM of rocks. This work bridges the gap and reports an improved mechanistic cutting force model. The model is derived based on the ductile mode removal and brittle fracture mode removal of rock under the indentation of a single abrasive particle. The cutting force model for RUM of rocks is then developed by aggregating the effects of all active abrasive particles bonded to the tool end face. Based on this model, the relationships between input variables (tool rotation speed, feedrate, ultrasonic vibration amplitude, abrasive size, abrasive concentration, and tool size) and cutting force are predicted. Experiments have been conducted and the experimental results agree well with the model predicted trends.

Ceramic matrix composites of type C/SiC have great potential because of their excellent properties such as high specific strength, high specific rigidity, high-temperature endurance, and superior wear resistance. However, the machining of C/SiC is still challenging to achieve desired efficiency and quality due to their heterogeneous, anisotropic, and varying thermal properties. Rotary ultrasonic machining (RUM) is considered as a highly feasible technology for advanced materials. Cutting force prediction in RUM can help to optimize input variables and reduce processing defects in composite materials. In this research, a mathematical axial cutting force model has been developed based on the indentation fracture theory of material removal mechanism considering penetration trajectory and energy conservation theorem for rotary ultrasonic face milling (RUFM) of C/SiC composites and validated through designed sets of experiments. Experimental results were found to be in good agreement with theoretically simulated results having less than 15% error. Therefore, this theoretical model can be effectively applied to predict the axial cutting forces during RUFM of C/SiC. The surface roughness of the workpiece materials was investigated after machining. The relationships of axial cutting force and surface roughness with cutting parameters, including spindle speed, feed rate, and cutting depth, were also investigated. In order to identify the influence of cutting parameters on the RUFM process, correlation analysis was applied. In addition, response surface methodology was employed to optimize the cutting parameters.

Micro ultrasonic machining (micro-USM) is an unconventional micromachining technology that has capability to fabricate high aspect ratio micro-holes, intricate shapes and features on various hard and brittle materials. The material removal in USM is based on brittle fracture of work materials. The mechanical properties and fracture behaviour are different for varied hard and brittle materials, which would make a big difference in the processing capability of micro-USM. To study the processing capability of USM and exploit its potential, the material removal of work materials, wear of abrasive particles and wear of machining tools in USM of three typical hard and brittle materials including float glass, alumina, and silicon carbide were investigated in this work. Both smoothed particle hydrodynamics (SPH) simulations and verification experiments were conducted. The material removal rate is found to decrease in the order of glass, alumina, and silicon carbide, which can be well explained by the simulation results that cracking of glass is faster and larger compared to the other materials. Correspondingly, the tool wear rate also dropped significantly thanks to the faster material removal, and a formation of concavity on the tool tip center due to intensive wear was prevented. The SPH model is proved useful for studying USM of different hard and brittle materials, and capable of predicting the machining performance.

Due to excessive hardness and high strength properties, ceramic materials have been found to be quite difficult to machine using the conventional metal removal processes. Nowadays, various non-traditional machining (NTM) processes have been successfully deployed to generate different complex shape geometries on engineering ceramics with the achievement of the desired dimensional accuracy and surface integrity. To achieve the best machining performance of those NTM processes, it has been recommended to operate them at the optimal combinations of their different input parameters. In this paper, lexicographic method is applied as a multi-objective optimization tool to derive the optimal parametric settings of three NTM processes, i.e. electrical discharge machining, Nd:YAG laser machining and ultrasonic machining which have found wide ranging applications in machining of engineering ceramics. The response values obtained at the derived optimal settings are observed to be better than those measured by the past researchers.

Delamination, an inter-ply debonding failure phenomenon, is considered as the most undesirable and challenging failure mode in hole making of carbon fiber-reinforced plastic (CFRP) composite laminates. The existence of delamination, even small ones, noticeably damages the strength and stability of the assembled products. It is reported that delamination is responsible for up to 60% of composite components’ rejection during assembling. In order to reduce delamination, rotary ultrasonic machining (RUM) has been studied and utilized in hole making of CFRP composites. Existing investigations on delamination of CFRP composites in RUM hole making are experimental studies, in which several methods (such as adjusting input variables and the use of supportive plate) to reduce delamination are reported. To understand delamination generation mechanisms and predict delamination initiation, theoretical investigations are needed. Cutting force models in RUM of CFRP composites have been developed, and it is well accepted that delamination is correlated to thrust force. However, there are no reported investigations to predict delamination initiation and study the impact of thrust force on the delamination of CFRP composites in the RUM hole-making process. Finite element analysis (FEA) could be an effective way to study the delamination in the RUM process. In this paper, FEA was conducted to predict delamination initiation and establish the relationship between the thrust force and delamination thickness in RUM, for the first time. In addition, experiments were conducted to validate the FEA model. The proposed model was proved to be effective in predicting delamination initiation, and the trends of the FEA results agreed well with those of the experimental results.

Subsurface damage (SSD) generated in rotary ultrasonic machining (RUM) process significantly deteriorates the technological and structural performance of the optical components. However, the invisibility of subsurface cracks underneath the machined surface makes it difficult to accurately and online evaluate the SSD depth. In the present research, incorporated with the probability statistics of the abrasive heights and the indentation fracture mechanics of the brittle material, a theoretical prediction model was established by investigating the inherent correlation between the measured cutting force of the diamond tool and the maximum depth of the subsurface cracks. Utilizing this predictive method, the SSD depth could be rapidly and precisely calculated through the mechanical properties of the material, the cutting force of the diamond tool, and the geometrical characteristics of the abrasives. To validate the feasibility of prediction technique, the experimental measurements of the maximum SSD depths were compared with the predicted results, revealing the acceptable consistency in their values.

Ceramic matrix composites of type C/SiC have great potential in space applications because of their superior properties such as low density, high wear resistance, and high-temperature resistance. However, due to their heterogeneous, anisotropic, and unstable thermal properties, the machining is still challenging to achieve desired efficiency and quality. For advanced materials, rotary ultrasonic machining (RUM) is considered as a highly efficient technology. Predicting mechanical load in RUM can help to optimize input variables and reduce processing defects in composites. In this research, a mathematical axial drilling load (force and torque) model has been developed based on the indentation fracture theory of material removal mechanism considering penetration trajectory and energy conservation theorem for rotary ultrasonic drilling (RUD) of C/SiC. Experiments were conducted on C/SiC composites to validate the model, and experimental results agreed well with model predictions with less than 14% (force) and 10% (torque) error. Therefore, this theoretical model can be effectively applied to predict axial drilling load during RUD of C/SiC. The relationships of axial drilling force and torque with machining process parameters, including spindle speed, feed rate, and ultrasonic power, were investigated. A specific range of experiments was carried out to demonstrate the benefit of ultrasonic vibration in RUD over conventional drilling (CD) on mechanical load for a designed drilling tool. It was noticed that RUD outperformed CD with a maximum of 38.11% and 34.30% in axial drilling force and torque reduction, respectively. The influence of drilling tool flute length on drilling performance was also elucidated based on a set of experiments using several designed drilling tools.

Compared with conventional surface grinding (CSG) process, surface machining of carbon fiber-reinforced plastic (CFRP) composites using rotary ultrasonic machining (RUM) with vertical ultrasonic vibration generates smaller cutting forces because of improved machining performance and more damages to the machined CFRP surface due to the intermittent knocking induced by vertical ultrasonic vibration. It is reported that surface quality can be improved when the ultrasonic vibration is parallel to the feeding direction. In addition, elliptical ultrasonic vibration can be formed by the combination of horizontal and vertical ultrasonic vibrations. However, the effects of elliptical ultrasonic vibration in RUM surface machining of CFRPs are still unknown. This paper will study the influences of elliptical ultrasonic vibration on the machining performance and machined surface quality in RUM surface machining of CFRPs. The comparisons of output variables (including cutting forces, surface roughness, and machined surface topography) between RUM surface machining with elliptical ultrasonic vibration and the CSG process as well as RUM surface machining with vertical ultrasonic vibration will be conducted under different levels of input variables (including depth of cut, feedrate, and tool rotation speed). The abrasive-grain trajectory and the tool-workpiece contacting modes in these three machining processes are analyzed. It is found that RUM surface machining with elliptical ultrasonic vibration produced smallest feeding-direction cutting force, smallest vertical-direction cutting force, best morphology of machined surface, and smallest surface roughness among these three kinds of machining processes.

Longitudinal-torsional (L-T) vibration in rotary ultrasonic machining (RUM) can further reduce the cutting force and improve the machining efficiency compared with the single longitudinal vibration in RUM. In this study, an ultrasonic step horn with spiral slots using the principle of mode conversion was designed to realize L-T vibration. The torsional amplitude to longitudinal amplitude (AT/AL) ratio is proposed to quantify the efficiency of mode conversion. Moreover, a simulation method was used to carry out the frequency coupling design of the ultrasonic horn with spiral slots. The influence of the step position and slot position with a spiral angle of 52° on the resonant frequency and amplitude of the ultrasonic horn were analyzed, respectively. Based on the simulation results, ultrasonic horns with different AT/AL were designed and fabricated. Finally, the results obtained through experiments with milling glass plane revealed that the cutting force was reduced by 48–73%, while the surface quality improved compared with single longitudinal vibration when the torsional vibration is coupled with the longitudinal vibration in RUM. The reasonable AT/AL ratio could effectively reduce the cutting force when the synthetic amplitude was the same. This indicates that the L-T vibration changes the trajectories of the diamond abrasives, which improves the machining performance.

A giant magnetostrictive rotary ultrasonic machine tool (GMRUMT) with a large and stable amplitude output was developed. The purpose of this study was to comprehensively evaluate the performance and technological characteristics of the GMRUMT by conducting large amplitude experiments of rotary ultrasonic machining. Combined with the transducers’ characteristic curves of vibration amplitude versus frequency, the GMRUMT has the advantages of greater amplitude, higher power, and better stability compared with the conventional piezoelectric actuated rotary ultrasonic machine tool. The vibration stability of the GMRUMT during the machining process was evaluated by carrying out the rotary ultrasonic face milling of quartz glass and the measurement of the actual ultrasonic amplitude. The processing performance of the GMRUMT was evaluated by obtaining the cutting force, the critical feed rate, and the edge-chipping size at the exit hole via rotary ultrasonic drilling experiments. The tool life was evaluated by observing the abrasive wear of the tool. Finally, the GMRUMT was studied in a stable amplitude output condition via tuning to verify the machining advantages of the GMRUMT.

In production-based trades, Al/SiC composite is vastly required owing to its outstanding possessions. Though, the problems in its machining confine the application and attractiveness of this material. Present study focused on different experimental conditions (spindle speed, rate of feed, and ultrasonic power) on responses of interest like surface roughness (SR), material removal rate (MRR), and chipping thickness in rotary ultrasonic machining of Al/SiC composite. Microstructure scrutiny of the processed samples has been employed to illustrate the chipping size and thickness over the end-edge through SEM process. The experimental results showed that rate of feed was the most significant variable for MRR and SR.

To alleviate the alarming surface integrity defect (chipping) and tool wear issues, new machining technique has been introduced. First time, an attempt has been made by hybrid the ‘Rotary ultrasonic machining’ and ‘Chemical etching process’ that pioneer as ‘Chemical assisted Rotary ultrasonic machining’. In this work, authors have investigated a novel study to explore the float glass’s drilled hole surface integrity and tool wear. The mechanism behind the hole surface integrity and tool wear is also discussed. The results pointed that the Chemical assisted Rotary ultrasonic machining (CRUM) gives slightest chipping size (0.32 mm) using abrasive coated hollow tool of 6 mm diameter over the 5% HF acid dipped float glass specimen. However, coz of highly chemical reacting behaviour of HF acid with the tool material, it is deteriorated. Thus more research needed to be carried for the tool selection. Finally, authors recommended that the Chemical assisted Rotary ultrasonic machining is having a vibrant future.

This paper presents a new design of an ultrasonic vibrator that transforms longitudinal vibration into torsional vibrations for both manufacturing and medical applications. Conventional design methods of the ultrasonic vibrators are difficult to achieve complex hybrid vibration due to the limit of traditional straight shape and the tedious machining processes in fabrication. To overcome the disadvantages, this paper presents a new design of a hybrid longitudinal-torsional (L&T) ultrasonic vibrator. The hybrid L&T vibrator was designed using the acoustic waveguide principle and successfully transform the longitudinal vibration into a harmonic torsional vibration on the sample plane. An analytical finite element modeling was conducted for optimizing the hybrid L&T design parameters. Due to the complex design geometry, the new L&T design is difficult to be manufactured by conventional machining processes. Selective laser melting additive manufacture (SLM-AM) was used to fabricate the new hybrid L&T vibrator design. The designed hybrid longitudinal-torsional (L&T) vibrator was driven by axially polarized piezo-ceramic stacks for ultrasonic vibration applications. The experiments validate that the developed L&T vibrator is able to deliver high-energy efficiency vibration in both the longitudinal and the torsional directions. The presented new design of L&T ultrasonic vibrators can be used for applications of ultrasonic machining, surgical bone drilling, high efficient ultrasonic motors, or vibrational needle insertions or surgical tools for medical treatments.

In recent years, the budding researchers have an unquenchable desire to highlight the demand and properties of metal matrix by doing commendable researches. The demands of multipurpose metal matrixes are rapidly increasing due to its excellent properties. The phase structure plays an important role in metal matrix. The material properties and characterization is improving based on the phase structure of the material. The present work describes two phases namely soft and hard phase in brass metal matrix which has been fabricated through stir casting process. The material characterization and properties have been studied. The morphology of the material structure has been analyzed through Scanning Electron Microscope (SEM) and material composition has been proved by Energy Dispersive Analysis of X-rays (EDAX). The duplex phase in this metal matrix provides better material properties like strength, hardness, tensile strength and impact strength. Due to dual phase, it is difficult to machine by conventional machining process. Hence, ultrasonic machining process is used for machining this metal matrix. During machining, the various input parameters such as power rating, slurry concentration and grit size have been considered. The material removal rate (MRR) and surface roughness (SR) have been considered as output parameters. The wear properties have been also evaluated by tribometer. The most influential parameter for ultrasonic machining process and wear test has been confirmed through analysis of variance (ANOVA).

The possibility for using of surface plastic deformation when applying ultrasonic vibrations to the instrument to form microgeometric state of the parts surface made of copper M1 and aluminum alloy D16 are studied. Two ultrasonic machining schemes are compared: when the direction of vibration is normal to the surface of the part and tangent to this surface. It is shown that the use of tangent scheme changes the interaction nature of the tool with the surface of the part and the trajectory of the tool motion. It is established that the angle β between the direction of the rotation speed vector of the part and the vibration speed vector of the tool significantly affects on the microgeometry being formed. Therefore, angle β together with the main motion speed, feed, static load, frequency and amplitude of the tool’s vibrations, is technological parameter that extend the capabilities of tangential scheme in surface roughness forming. It is revealed that processing according to this scheme allows escaping the intensive flow of material in the deformation zone and the formation of waves on the surface of the part.

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 ...

Hybrid composites stacks are multi-material laminates which find extensive applications in industries such as aerospace, automobile, and electronics and so on. Most hybrid composites consist of multiple layers of fiber composites and metal sheets stacked together. These composite stacks have excellent physical and mechanical properties including high strength, high hardness, high stiffness, excellent fatigue resistance and low thermal expansion. Micromachining of these materials require particular attention as conventional methods such as micro-drilling is extremely challenging considering the non-homogeneous structure and anisotropic nature of the material layers. Micro Ultrasonic Machining (μUSM) is a manufacturing process capable of machining such difficult-to-machine materials with ultraprecision. Experimental study showed that μUSM process could successfully machine hybrid composite stacks at micron scale with a relatively good surface finish. This research uses finite element simulation technique to investigate the material removal during the μUSM process for micromachining hybrid composite stacks. The effects of critical process parameters including the amplitude of vibration, feed rate and tool material on the cavity depth, cutting force and equivalent stress distribution are studied. The outcome of this research can be utilized to further our understanding of performing precision machining of hybrid composite stacks for use in several critical engineering applications.

Conventionally, converging-diverging ducts are used to restrict the flow rate of gases. This process makes it possible to create a flow rate which is independent of the conditions prevailing downstream of the point of pressure drop and can be directly calculated by applying the standard formulae of compressible flows. Ultrasonic machining consists of making a tool vibrate at a very small distance from the work piece. The combination is placed in a coupling fluid containing abrasive grains. The tools are generally located at the extremity of a rod having an exponential profile which serves as an amplifier of displacement. This type of machining can produce various special shapes with a very good precision and the machined surfaces are remarkably smooth. Some manufacturers of dish-washers are thinking of incorporating these techniques in their product in order to reduce contamination by detergents as well as to reduce consumption of water and energy.

This paper aims at selecting the optimal parameters for micro-hole drilling of graphene oxide/Pineapple leaf filler reinforced epoxy hybrid composite using ultrasonic machining (USM). The selection of optimal parameters has been done using evaluation based on distance from average solution (EDAS) method. The subsequent process parameters are kept constant: boron carbide abrasive, amplitude of vibration (3–5 µm) and frequency (20 kHz) and the other parameters abrasive grit size, abrasive flow rate, power rating and slurry concentration are considered for evaluation. The corresponding response parameters viz material removal rate (MRR), tool wear rate (TWR) and overcut (OC) are measured for every experimental runs. Two different levels of abrasive grit size and four different levels of flow rate, power rating and slurry concentration are selected for detailed experimentation. CRITIC method has been applied for identifying the most influencing process parameter and accordingly weights have been assigned to the other process parameters. By implementing the EDAS method, the highest rank of the parametric combinations of process parameters are found out which tends to maximize MRR and minimize TWR and OC. Among all the parameters abrasive grit size is found to be the most significant parameter influencing the response parameters.

The existing contactless energy transfer of rotary ultrasonic machining equipment involves a small transmission distance (0.1-1 mm). In this research, magnetically coupled resonant wireless power transfer was used in rotary ultrasonic machining process. A series of theoretical models were established to explore the transmission characteristics of the system, and experiments were carried out to verify transmission characteristics.

Micro-ultrasonic machining (MUSM) is an effective way of processing microstructures made from hard and brittle materials, although controlling the fluctuation of the machining force during processing is difficult. To control the quality of micro-holes fabricated in hard and brittle materials, MUSM with force control (MUSMFC) is used to study the edge chipping rate (ECR) and material removal rate (MRR) during micro-hole fabrication. The process is controlled using a force sensor and a processing control strategy. Various experiments are designed to assess the processing efficacy. Comparative experiments indicate that the ECR with MUSMFC is superior to that with traditional MUSM. Single-factor experiments show that the ultrasonic power and the fluctuation of the machining force exert a significant influence on the ECR. The influence of the spindle speed on the ECR is small. Orthogonal experiments show that the fluctuations of the machining force and ultrasonic power have large impacts on the MRR. The spindle speed has a significant impact on the MRR as well, whereas the mass fraction has little effect. The best combination of ECR and MRR is obtained using a spindle speed of 500 rpm, a machining-force fluctuation of 0.1 N, an ultrasonic power of 50 W, and a mass fraction of 10%.

The load effect is a key factor influencing the amplitude stability of an ultrasonic machining system during processing. To explore the influence of the load, a giant magnetostrictive rotary ultrasonic machining system was designed and fabricated by utilizing giant magnetostrictive materials. Based on the single-degree-of-freedom vibration characteristics of the ultrasonic oscillator, an output amplitude model that considers the load effect was proposed for the system. In order to validate the model, a rotary ultrasonic drilling experiment of quartz glass was performed. A critical cutting ability parameter on the basis of cutting depth for a single abrasive grain was put forward to differentiate between acceptable and unacceptable ultrasonic performance. The actual ultrasonic amplitude in the machining process obtained from the model was explored. The experimental results indicate that the load has a significant effect on the resonant frequency, resulting in a decrease in the actual ultrasonic amplitude. Moreover, the amplitude characteristics can be considerably improved by tuning. The process parameters of the giant magnetostrictive rotary ultrasonic machining system can be optimized by using the proposed model. The results of this study provide reference data for research and development of rotary ultrasonic machining equipment.

In conventional machining, the process of shaping of products from such new materials as alloys with special properties, composite materials and ceramic materials is rather challenged because of low ductility, intense hardness, diversity of physical and mechanical properties of definite components, etc.

Rotary ultrasonic machining has been successfully explored in surface machining of carbon fiber reinforced plastic (CFRP) composites. It has been proven to be an effective and efficient CFRP machining method. Both theoretical and experimental investigations have been conducted with the assumption that the CFRP is removed by brittle fracture removal mode. However, in brittle material machining, ductile flow phenomenon still exists. Ductile scratching marks are also observed on the machined CFRP surfaces. It is still unknown that what actual material removal modes are under different machining variables. To investigate the material removal mechanisms in rotary ultrasonic surface machining (RUSM) of CFRP, single abrasive scratching tests were conducted. The scratching induced characteristics and scratching forces were analyzed. Both the ductile removal mode and the brittle fracture removal mode were observed and identified in both carbon fiber layers and epoxy resin layers on the machined marks by using scanning electron microscopy (SEM) imaging. With the increase of scratching depth, the material removal mode of CFRP was changed from the ductile removal mode to the brittle fracture mode. From the analysis of kinematic trajectory of diamond grain, the scratching cutting forces were decreased in the tests with the assistance of ultrasonic vibration under the same machining variables. The generation mechanisms of the delamination were analyzed and discussed.

Rotary ultrasonic machining (RUM) is effective and efficient in cutting carbon fiber–reinforced plastic (CFRP) composites. With ultrasonic vibration assistance, both machining efficiency and machining effectiveness can be improved. Ultrasonic vibration has two major variables (including ultrasonic amplitude and ultrasonic frequency), which play important roles in RUM processes. Other intermediate variables, such as ultrasonic power and indentation depth, are directly related to these two variables. Effects of ultrasonic vibration amplitude have been extensively investigated in RUM hole making and surface machining processes. However, the effects of ultrasonic frequency in RUM have not been reported. The effects of ultrasonic frequency under different combinations of tool rotation speed, feed rate, and depth of cut on output variables, including cutting forces, surface roughness, and machined surface characteristics, are investigated, for the first time, in this study. The critical frequency is analyzed for the RUM process. Three different levels of ultrasonic frequencies are generated and applied to the RUM process. The kinematic motions of abrasive grains in RUM with different frequencies are analyzed and discussed. The results show that RUM with higher frequency of ultrasonic vibration is a more effective machining process, leading to cutting force reduction and the machined surface quality improvement.

Rotary ultrasonic machining (RUM) shows capabilities in several manufacturing applications specifically for fabrication of high-quality features on ceramic materials. However, surface fracturing and edge chipping are the persistent issues during the RUM of ceramic materials. This research reports an experimental investigation to analyze the machinability of the biolox forte ceramic by milling microchannels using RUM. Machinability is studied by analyzing the performance measures such as the surface roughness, surface morphology, edge chipping and tool wear. The effects of the five major RUM input parameters including spindle speed, feed rate, depth of cut, vibration amplitude, and vibration frequency are taken into consideration on the machinability of the biolox forte material. An attempt has been made to characterize the material removal behaviour within the microchannels. The results reveal more brittle fracturing and deep pits on the channel bed as compared to the channel sidewall due to the difference in the cutting action of the RUM tool. Furthermore, it is observed that the channel sidewalls always show a coarse machined region near the top edge and a relatively smooth machined region up to the channel bed. The energy dispersive spectroscopy (EDS) analysis reveals that no change in the composition of the biolox forte occurs and no traces of tool material are observed in the microchannels. The scanning electron microscopy (SEM) analysis of the tool shows that the plastics deformation, attritious wear, and the tool edge rounding and chipping are the primary tool wear mechanisms. By selecting the appropriate RUM parameters, microchannels with good surface finish (Ra =0.21 μm), smoothed morphology and minimal edge chipping (16.3 μm) can be milled on the biolox forte material.