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Electrical discharge machining (EDM) is a highly precise technology that not only facilitates the machining of components into desired shapes but also enables the alteration of the physical and chemical properties of workpieces. The complexity of the process is due to a number of regulating factors such as the material of the workpiece and tools, dielectric medium, and other process parameters. Based on the material type, electrode shape, and process configuration, various shapes and degrees of accuracy can be generated. The study of erosion is based on research into processing techniques, which are the primary tools for using EDM. Empirical knowledge with subsequent optimization of technological parameters is one of the ways to obtain the required surface quality of the workpiece with defect minimization, as well as mathematical and numerical modeling of the EDM process. This article critically examines all key aspects of EDM, reflecting both the early foundations of electrical erosion and the current state of the industry, noting the current trends towards the transition of EDM to the 5.0 industry zone in terms of safety and minimizing the impact of the process on the environment. [ABSTRACT FROM AUTHOR]

This paper presents an analysis and theoretical model for assessing the quality and accuracy of wire-cut electro-discharge machining (WEDM) of products made from novel heat-resistant nickel alloys such as CrNi56KVMTYB. It is observed that WEDM processing of Ni alloy led to high surface roughness for the thick specimens, and electrical parameters such as pulse duration for the selected range depict an insignificant role in the value of surface roughness. On the other hand, the cut width of the machined surface decreases as the pulse duration increases, while the cut width is elevated for thick workpieces. Secondary discharges developed in WEDM have negative effects that cause sludge adhering and deterioration in the quality and productivity of processing. The regression model is developed to predict the surface roughness and cut width of machined surfaces, which holds significant importance in modern engineering. The workpiece is examined for surface integrity and material deposition. It is observed that an increase in the height of the specimen leads to the occurrence of secondary discharges, which in turn results in the formation of cracks on the surfaces of high-temperature nickel alloys. These cracks have a detrimental effect on the performance of critical products made from next-generation heat-resistant nickel alloys. [ABSTRACT FROM AUTHOR]

This study investigates the effect of electrolytic plasma processing on the degree of defective layer removal from a damaged layer obtained after manufacturing operations. Electrical discharge machining (EDM) is widely accepted in modern industries for product development. However, these products may have undesirable surface defects that may require secondary operations. This work aims to study the die-sinking EDM of steel components followed by the application of plasma electrolytic polishing (PeP) to enhance the surface properties. The results showed that the decrease in the roughness of the EDMed part after PeP was 80.97%. The combined process of EDM and subsequent PeP makes it possible to obtain the desired surface finish and mechanical properties. In the case of finishing EDM processing and turning, followed by PeP processing, the fatigue life is enhanced without failure up to 109 cycles. However, the application of this combined method (EDM + PeP) requires further research to ensure consistent removal of the unwanted defective layer. [ABSTRACT FROM AUTHOR]

Plantar foot pain is one of the most common musculoskeletal conditions affecting the foot. It is regularly experienced by the population with occupations that require prolonged standing hours, especially in nurses. The etiology of plantar foot pain remains unclear, but it is likely to be multi-factorial, with many associated risk factors including increased hours of standing. Orthoses and insoles are often recommended to plantar foot pain patients, however with minimal scientific advancements and limited customizations. In this study, a novel 3D-printed multi-material customized foot orthosis was developed, and its effectiveness on plantar foot pain reduction and functional ability improvement was studied in the nursing population. A total of thirty-six subjects were recruited and were randomized into two groups. The experimental group received the novel 3D-printed multi-material customized foot orthosis, whereas the control group received the standard-of-care (or traditional) intervention. Pre-test and the post-test scores of pains, functional ability and plantar pressure were observed using SPSS software. Improvements were observed in both of the groups; however, better improvements were seen in the experimental group. Overall, the novel 3D printing-based customized foot orthosis showed significant efficacy in reducing plantar foot pain and pressure, and also in increasing functional ability in the nursing population as compared to the traditional method. [ABSTRACT FROM AUTHOR]

Foot-related problems are prevalent across the globe, and this issue is aggravated by the presence of diabetes mellitus. Diabetic-foot-related issues include extreme foot pain, plantar corns, and diabetic foot ulcers. To assess these conditions, accurate characterization of plantar pressure is required. In this work, an in-shoe, low-cost, and multi-material pressure measuring insole, based on a piezoresistive material, was developed. The device has a high number of sensors, and was tested on 25 healthy volunteers and 25 patients with different degrees of diabetes. The working range of the device was observed to be 5 kPa to 900 kPa, with an average hysteresis error of 3.25%. Plantar pressure was found to increase from healthy to diabetic volunteers, in terms of both standing and walking. In the case of the diabetic group, the-high pressure contact area was found to strongly and positively correlate (R² = 0.78) with the peak plantar pressure. During the heel strike phase, the diabetic volunteers showed high plantar pressure on the medial heel region. In regard to the toe-off phase, the central forefoot was found to be a prevalent site for high plantar pressure across the diabetic volunteers. The developed device is expected not only to assist in the prediction of diabetic ulceration or re-ulceration, but also to provide strategies and suggestions for foot pressure alleviation and pain mitigation. [ABSTRACT FROM AUTHOR]

Slippery flooring often leads to unintentional slips and falls, which results in traumatic injuries. To reduce slipping risks, adequate traction at the shoe and flooring contact is essential. In addition, viscous slippery contaminants like water or oil reduce a floor's traction performance and increase slipping hazards. In this work, the effect of commonly available protective floor coatings on the traction performance of safety-labelled shoes was extensively studied. The study included three floor coatings, namely acid-based etchant coating, epoxy floor paint, and polyurethane, which were tested across five safety shoes. The coated floorings were tested using a robotic slip-testing device in dry and in the presence of water and machine oil—as separate contaminants. The application of floor coatings produced varying surface roughness for the flooring. Significant traction was generated by the etchant coating for the dry flooring, epoxy coating for the wet flooring, and polyurethane coating for all flooring conditions. A comparison of uncoated and coated floorings showed a high effectiveness of generating traction with epoxy coating on wet flooring and polyurethane coating on both wet and oily conditions. The study results are novel and are anticipated to provide valuable guidelines for the selection of slip-resistant coatings for different slippery floorings, and to reduce risks related to slips and falls. [ABSTRACT FROM AUTHOR]

The current study develops a numerical model to investigate the nanoindentation behavior of heat-affected zones (HAZ) on glass material produced via the electrochemical spark machining (ECSM) method. Initially, microchannels were created using the ECSM method on soda–lime glass. Following that, a nanoindentation test was conducted to quantify the Young's modulus and hardness of the glass sample. After that, a numerical model based on finite elements was created to characterize the changes in mechanical characteristics of HAZ. According to the findings, increasing the electrolyte concentration from 10 to 30% increases the intensity of electrochemical discharges, and thereby decreases the hardness of the work material by 16.29 to 30.58% compared to unmachined glass. The results obtained from the simulation are in close agreement with the experimental values. The maximum error obtained between simulation and experimental results is only 4.18%. [ABSTRACT FROM AUTHOR]

In the present work, the effect of tool surface roughness on energy channelization behavior was analyzed during the fabrication of micro holes by an electrochemical spark machining (ECSM) process. In this study, rough tools were fabricated by a rotary mode multi tip electric discharge machining (RM-MT-EDM) process. The electrical characterization was also carried out to investigate the electric field intensity over the surface of tool electrode, and it was found that the use of rough tools improves the electric field intensity by 265.54% in comparison to the smooth tool electrodes. The use of rough tools in the ECSM process forms thin and stable gas film over the tool electrode, and as a result the rough tools produced high frequency spark discharges. Energy channelization index and specific energy were considered as response characteristics. The use of rough tools improves energy channelization index by 248.40%, and the specific energy is reduced by 143.263%. The material removal mechanisms for both of the processes (RM-MT-EDM and ECSM process) have also been presented through illustrations. [ABSTRACT FROM AUTHOR]

The present study explores the effectiveness of powder mixed electrical discharge machining (PM-EDM) by utilizing the unique properties of multi-walled carbon nanotubes (MWCNTs) on machining of hard-grade medical alloy (β-type titanium). To investigate the capabilities of the PM-EDM in terms of machinability, biocompatibility, tribological characteristics and surface integrity, the experiments were conducted according to the L18 orthogonal array. The analysis of variance (ANOVA) technique was employed for identifying the significant process parameters affecting metal removal rate (MRR). The ANOVA results revealed that the dielectric medium was the most significant factor that majorly affects the MRR (63.25 mm3/mm) and it was followed by the peak current (Ip), pulse on (pon), pulse off (poff) and electrode material. A 15A peak current at pulse-on/pulse-off time of 100/20 μs by using MWCNTs in the dielectric medium with a tungsten/copper tool electrode is the optimum parametric set. The biocompatibility of machined surfaces was scrutinized by cytotoxicity test which confirmed that the machining with MWCNTs elevated the biological responses of reformed surface and contributed to achieve the cell viability of 94%. The pin-on-disc wear results revealed that MWCNTs machined surface had the least value of wear rate and acted as a low frictional surface. Also, the recast layer produced after MWCNTs machining adhered strongly to the base material and exhibited twofold adhesion strength as compared to the water machined substrate. The formation of oxides and carbides in the presence of MWCNTs entities contributed to the tribological behaviour and biocompatibility of alloy. Thus, the excellent assets of MWCNTs elevate the potential of EDMing by diminishing the bottlenecks like the creation of surface defects in conventional EDM (deionized water medium) at high discharge energies. [ABSTRACT FROM AUTHOR]

Cobalt-chromium alloy (F-90) and duplex stainless steel (DSS-2205) belong to the family of metallic biomaterials, which are frequently used for the manufacture of dental prosthetics, artificial implants including knee and hip joints. This article addresses the investigation highlights of electrical discharge machining (EDM) of Co-Cr alloy and duplex stainless steel using different electrode materials for the evaluation of optimum machining parameters. The samples with superior machining performance and surface integrity were analyzed by electrochemical corrosion testing and found that the EDM treated samples portrayed a notable improvement in the corrosion resistance compared to bare metal. Our results demonstrated that both the substrates i.e. Co-Cr alloy and DSS-2205 were dominantly affected by the intensity of the applied current, and participated in the material removal rate with a contribution of 93.81% (23.37 mm3/min., Co-Cr alloy) and 87.32% (39.76 mm3/min., DSS-2205) respectively. However, the surface roughness of the machined Co-Cr alloy (1.080 µm) was majorly influenced by the current (contribution: 67.24%) and electrode (contribution: 28.27%). Whereas, pulse-on (contribution: 58.37%) and electrode (contribution: 30.52%) were significant for the surface roughness (1.150 µm) of the machined DSS-2205. Moreover, the machined surface also demonstrates the porosity (∼3 to ∼5 µm) and formation of intermetallic oxides, carbon phases on the samples machined at a higher value of current i.e. 16 Ampere. Field emission scanning electron microscopy and X-ray diffractometer were used to scrutinize the surface topography and compositional analysis of the machined substrates. The alternation of the substrate surface observed helpful in enhancing the corrosion resistance of Co-Cr alloy and duplex stainless steel by 80.88% (corrosion rate: 0.00029 mm/year) and 96% (corrosion rate: 0.00763 mm/year), comparative to their respective untreated samples. [ABSTRACT FROM AUTHOR]

Purpose: The quality of lost foam casted engineering components is directly influenced by the characteristics of the respective ceramic shell mold (CSM) and hence casting pattern. In this present work, rapid prototyping (RP) was used to fabricate the lattice structured patterns (LSPs) to reduce the defects and cracks in CSM during the heating stage. Design/methodology/approach: The quality of the LSPs was accessed by measuring the dimensional accuracy. Further, the thermal stress in the CSM during the heating of porosity varied LSPs was analyzed using ANSYS software package 16.0. The Ni-alloy casting was fabricated by using the designed LSP and compared with its respective CAD model to access its quality. Findings: The obtained results revealed that the Wigner–Seitz LSPs retained high accuracy and minimized the stress for defect-free CSM. Also, the thermal stress generated in the CSM depends upon the porosity coefficient of the LSP. Hence the interplay with porosity coefficient of LSPs leads to the formation of defect free CSM and hence high quality casting. Originality/value: RP was used to develop LSPs and investigated the dependency of unit cell parameters on the accuracy of the final casting. [ABSTRACT FROM AUTHOR]

The study presents the surface modification of β-titanium alloy by the electrical discharge chemical treatment (EDCT) to achieve a corrosion-resistant surface. This technique incorporated multi-walled carbon nanotubes (MWCNTs) in the dielectric medium to alter the surface properties of the substrate. Herein, the MWCNTs act as potential candidates due to its chemical inertness and physical as well as electrical properties for achieving desired surface properties. For the sake of comparison, the μ-hydroxyapatite (μHAp) powder was also utilized in the dielectric medium. Surface morphology, topography, and elemental composition of the treated surfaces were investigated by FE-SEM, EDS, and XRD techniques, respectively. The electrochemical potentiodynamic test was carried out to investigate the corrosion resistance of untreated and treated surfaces. The treated surfaces were also evaluated in terms of change in surface morphology, wettability, and surface free energy. The outcome revealed that the alloy treated with MWCNTs favors the synthesis of the chemically stable corrosion-resistant surface. The existence of TiO2, ZrO2, Nb2O5, TaO, ZrO2, TiC2, and NbC phases detected from XRD examination affirmed that the corrosion resistance of the substrate is significantly affected by multi-walled carbon nanotube deposition. The MWCNT-treated surface presented the improved wettability and surface free energy which are twofold higher than the untreated surface. [ABSTRACT FROM AUTHOR]

Nano-hydroxyapatite powder was used in electric discharge machining to modify the surface of Ti-6Al-4V medical alloy. Herein, electric discharge machining was performed, with and without powder-mixed flushing for evaluation of the material erosion rate and surface roughness. In addition to dielectric type, several process parameters including current, pulse-on duration, pulse-off duration, and electrode hole diameter were considered. The experiments were planned by Taguchi design technique and conducted to analyze the material erosion rate and surface roughness. After machining, scanning electron microscope, energy-dispersive X-ray spectrometry, and X-ray diffraction techniques were used to evaluate the surfaces of the samples. Furthermore, wear and corrosion tests were also carried out on the Ti alloy with modified surfaces. The influential factors were identified based on analysis of variance results. Current and dielectric type were the significant factors, both for the material erosion rate and surface roughness. The scanning electron microscope images of Ti-6Al-4V samples highlighted that the process parameters exhibited a vital influence on the topology and microstructure of machined surface. Furthermore, energy-dispersive X-ray spectrometry and X-ray diffraction analyses confirmed the presence of hydroxyapatite on Ti alloy surface after machining. Moreover, the results of wear and corrosion tests revealed lower wear and corrosion rates of the surface-treated workpiece with nano-hydroxyapatite. [ABSTRACT FROM AUTHOR]

In this report, a study of the wear mechanisms involved in the spinning ring and the traveler of textile industry are presented. These components, after surface processing with various coatings techniques, were analyzed on the test rig so as to analyze the wear mechanism. The objective was accomplished by comparing various plasma sprayed coatings on E52100 steel pins using a pin-on-disc machine. The surface morphology as well as mechanical properties of the deposited coatings, namely WC-Co- Cr, Al2O3+TiO2 (Alumina-Titania) and Cr3C2NiCr, as well as uncoated E52100, were comparatively studied. This study elucidates towards improving the working life of the ring in a textile mill in the spinning operation. An x-ray diffractometer (XRD) and scanning electron microscope (SEM) were employed to characterize the unworn and worn surfaces of the specimens. The study revealed that the wear rate of plasma sprayed thermal coatings enhanced with augmenting load. The plasma sprayed WC-Co-Cr, Cr3C2NiCr, Al2O3+13TiO2 coatings developed on workpiece pins exhibited a notable decrease in volume loss of the material as compared to uncoated E52100 substrate. WCCo- Cr coating turned out to be the best performer in terms of the lowest cumulative volume loss among all the variants of coatings. [ABSTRACT FROM AUTHOR]

The development of biomaterials for implants nowadays requires materials with superior mechanical and physical properties for enhanced osseointegration and sustained longevity. This research work was conducted to investigate the influence of nano hydroxyapatite (HAp) powder mixed electrical discharge machining (PMEDM) on surface morphology and microhardness of modified 316L stainless steel surface. The chosen process parameters were discharge current, pulse on/off duration and gap voltage in order to analyze the selected output responses. HAp concentration (15 g/l) along with reverse polarity was kept constant for current experimentation. The experimental results testified that surface morphology of PMEDM surface was significantly improved along with augmentation of 79% in microhardness (HV) of HAp modified surface of medical grade stainless steel. Furthermore, XRD and SEM characterization confirmed the deposition of calcium, phosphorous and inter-metallic compounds on HA-PMEDMed surface. The surface thus produced is expected to facilitate better bone-implant adhesion and bioactivity. [ABSTRACT FROM AUTHOR]

Purpose: With technology advances, metallic implants claim to improve the quality and durability of human life. In the recent decade, Ti-6Al-4V biomaterial has been additively manufactured via selective laser melting (SLM) for orthopedic applications. This paper aims to provide state-of-the-art on mechanobiology of these fabricated components. Design/methodology/approach: A literature review has been done to explore the potential of SLM fabricated Ti-6Al-4V porous lattice structures (LS) as bone substitutes. The emphasize was on the effect of process parameters and porosity on mechanical and biological properties. The papers published since 2007 were considered here. The keywords used to search were porous Ti-6Al-4V, additive manufacturing, metal three-dimensional printing, osseointegration, porous LS, SLM, in vitro and in vivo. Findings: The properties of SLM porous biomaterials were compared with different human bones, and bulk SLM fabricated Ti-6Al-4V structures. The comparison was also made between LS with different unit cells to find out whether there is any particular design that can mimic the human bone functionality and enhance osseointegration. Originality/value: The implant porosity plays a crucial role in mechanical and biological characteristics that relies on the optimum controlled process variables and design attributes. It was also indicated that although the mechanical strength (compressive and fatigue) of porous LS is not mostly close to natural cortical bone, elastic modulus can be adjusted to match that of cortical or cancellous bone. Porous Ti-6Al-4V provide favorable bone formation. However, the effect of design variables on biological behavior cannot be fully conclusive as few studies have been dedicated to this. [ABSTRACT FROM AUTHOR]

The present study deals with the optimization of parameters to check the effectiveness of thermoelectric machining of aluminum based SiC reinforced composites. Here, hybrid ED machining of Al-SiC metal matrix composites (MMCs) is investigated in magnetic field incorporated conventional Electrical Discharge Machining (EDM). The input processing parameters, such as pulse-on/off duration, current were assessed to analyze their outcome on the response parameters in terms of material erosion rate (MER), microhardness (MH), surface roughness (SR) and recast layer formation. The experimental results witnessed decrease in microhardness values and reduced thickness of recast layer, accompanied by a significant effect on MER and surface finish while machining in the magnetic field coupled higher spark energy. The experimental results conferred the process stability and an excellent correspondence with experimental verifications. [ABSTRACT FROM AUTHOR]

The present study investigates optimal parameters for machining of Ti-6Al- 4V using EDM with graphite electrode. Herein, another technique of modifying surface properties and enhancing machining rate using electrical discharge machining (EDM) was developed. In the present study, design of experiment (D.O.E) was developed using the Taguchi's orthogonal array to examine the effect of the input machining factors on the machining characteristics, and to forecast the optimized EDM parameters in terms of peak current, pulse-on time, pulse-off time and applied gap voltage. Each experiment was performed to obtain a hole of 1mm depth on the workpiece. From the results, it is found that the discharge current has significant influence on material removal rate (MRR) and surface roughness (SR) followed by other selected parameters, i.e. pulse-on time, pulse-off time. The MRR augmented steeply with the current and was recorded as maximum at 4 Amps. In-vitro bioactivity test was conducted in the simulated body fluid to examine bioactivity confirming a significant apatite growth on the surface treated with ED sparks. The surface and chemical alteration were analyzed by using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) along with the identification of the substantially enhanced morphology for clinical success. [ABSTRACT FROM AUTHOR]

The current research study for hybrid machining of Al-based metal matrix composites (MMCs) employs magnetic field coupled traditional electrical discharge machining (EDM) to address the manufacturing demands in aeronautics, automobile, medical equipment, etc. The input processing parameters, for instance, magnetic field intensity, pulse-on/off duration, peak current, variant of electrodes as well as workpiece were evaluated to determine their after-effects on the responses in terms of microhardness (MH) and recast layer formation while machining of Al-SiC composites. The experimental results show 22% decrease in the surface microhardness values and thinner recast layer formation at magnetic field coupled higher spark energy. The results demonstrate the process stability and exhibit a good accord with experimental verification. [ABSTRACT FROM AUTHOR]

With increasing popularity of Electrical Discharge Machining (EDM) method upon part manufacturing precision with tailorable surface properties; the assessment of EDM process was therefore carried out concerning the surface alteration of medical grade Co-Cr alloy biomaterials. The samples surface were EDMed at different spark energy levels by varying current and On-time to investigate the surface characteristics, and it's biological responses. MTT assay and cytocompatibility test were conducted to examine the in-vitro biocompatibility confirming the higher competent cell viability and proficient RBC lysis for the surface treated with spark energy ranging from 960J-1500J.  Here the experimental results revealed that application of low-current (5 A) and high  On-time (200 µs) favors the synthesis of high-quality biocompatible substrates. Thus, surface modification of Co-Cr implants using EDM can be considered as a promising method for improving surface properties essential for biomedical applications. [ABSTRACT FROM AUTHOR]

The Electrical Discharge Machining (EDM) technique was performed under the magnetic field influence to determine the material removal mechanism as well as surface roughness (SR) of nonmagnetic material. This study presents an exploration of the hybrid EDM technique assisted by magnetic field, with an aim to improve process performance. Herein, magnetic field intensity, peak current, duration of pulse-on/off, tool electrode material, and SiC percentage distribution were opted as the machining parameters. The chosen parameters were analyzed for their effects on the material removal rate (MRR) and SR while machining of SiC-reinforced aluminum-based metal matrix composites. Taguchi methodology was adopted for optimization of process parameters to achieve better MRR and lower SR. The experimental results witnessed improved surface finish and enhanced material removal ability of the process and also inferred that the magnetic field-assisted EDM facilitated the process stability. [ABSTRACT FROM PUBLISHER]

The present study investigates the thermal conductivity of bimodal SiC particulate distribution in aluminum matrix composites fabricated via powder metallurgy route. The effects of the SiCp reinforcement size distribution and processing parameters such as sintering time and temperature on the thermal conductivity have been examined. The Box-Behnken experimental array was employed to identify the effects of selected variables on the thermal conductivity of the composite. A reasonable augmentation in the thermal conductivity was observed with an increase in sintering time and %volume fraction of fine SiC particulates. It has been demonstrated that the matrix doped with fine SiC particulates (37 µm) occupied interstitial positions and formed continuous SiC-matrix network resulting in minimizing the micropores that contributed for good thermal conductivity, that is, 235 W/mK. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were conducted to evaluate the microstructure architecture and interfacial phase formation. [ABSTRACT FROM AUTHOR]

The aim of the study is to predict the optimal machining conditions in electrical discharge machining (EDM) of particulate-reinforced metal matrix composites (30 vol% SiC/A359). Three independent machining variables viz: current, pulse-on time and pulse-off time are investigated to encompass the EDM performance in terms of induced residual stresses on the machined surface, tool wear rate and material removal rate. The L9 orthogonal array is employed as an experimental plan. The responses results are globally optimized using desirability function approach and lexicographic goal programming (LGP) approach to predict the ideal parametric combinations for the machining of selected composite material. It was observed that both the techniques give a nearly identical optimum solution, i.e. the optimal predicted process parameters value deviation varies from 0 to 1.82%. However, LGP technique is the simplest prioritybased approach that can be utilized more efficiently in the complex decision-making conditions. Confirmation test on the predicted optimal results is executed experimentally, and the value of confirmation error is found to be satisfactory. [ABSTRACT FROM AUTHOR]

The present study deals with an investigation of the hybrid electric discharge (ED) machining process executed in a magnetic field for improving process performance. Previous magnetic field-assisted electric discharge machining (MFAEDM) techniques, however, are limited to use with a class of magnetic workpieces. In this particular study, the magnetic field was coupled with the conventionalEDMplasma zone to test the hybrid process on Al-based metal matrix composites (MMCs). The machining parameters, for instance, peak current as well as duration of pulse-on were selected to nail down thereafter effects on the response parameters like the material removal rate (MRR) and the surface integrity. The experimental results show an improvement of 12.9% MRR and reduction in recast layer formation at higher spark energy in the magnetic field environment. As the experimental outcome implied that the MFAEDM imparted appreciable process stability, a highly efficient pertinent process of EDM with high quality of the machined surface could be accomplished to satisfy modern industrial applications. [ABSTRACT FROM AUTHOR]

Intrinsically smart, metal matrix composites (MMCs) are lightweight and high-performance materials having ever expanding industrial applications. The structural and the functional properties of these materials can be altered as per the industrial demands. The process technologies indulged in fabrication and machining of these materials attract the researchers and industrial community. Hybrid electric discharge machining is a promising and the most reliable nonconventional machining process for MMCs. It exhibits higher competence for machining complex shapes with greater accuracy. This paper presents an up-to-date review of progress and benefits of different routes for fabrication and machining of composites. It reports certain practical analysis and research findings including various issues on fabrication and machining of MMCs. It is concluded that polycrystalline tools and diamond-coated tools are best suitable for various conventional machining operations. High speed, small depth of cut and low feed rate are a key to better finish. In addition, hybrid electrical discharge machining has proved to be an active research area in critical as well as nonconventional machining since last few years. This paper incorporates year-wise research work done in fabrication, conventional machining, nonconventional machining, and hybrid machining of MMCs. Conclusions and future scope are addressed in the last section of the paper. [ABSTRACT FROM PUBLISHER]

The most challenging objective in the electronic industries is to develop materials that demonstrate a tunable thermal property with today's microelectronic devices. The development of composite material with balanced thermal properties is highly appreciated and currently competing the traditional monolithic conductive material. However, the tailored thermal properties of the composite are significantly influenced by the composites constituents and their fabrication routes. This article presents a review of thermal properties of particulate as well as fiber-reinforced composite proportional to matrix microstructure, reinforcement architecture. The processing techniques used to fabricate composites have been addressed with an objective to achieve suitable thermal properties. The developments in the analytical and numerical simulation approach to predict the thermal conductivity and CTE of the developed composites have been critically reviewed. Lastly, future work needs attention is summarized. [ABSTRACT FROM AUTHOR]

This article reports the result of an experimental study to analyze the effect of parameters that induce residual stresses during electric discharge machining of two particulate-reinforced metal matrix composites. Several factors were varied to study their impact on the formation of residual stresses, and pulse-off time was identified as the most significant factor. Artificial neural network was implemented to predict the residual stresses. Metal matrix composites with low coefficient of thermal expansion and high reinforced particle exhibit lower residual stresses. Also, better conductive electrode materials used during machining cause lower residual stress. The artificial neural network model accurately predicts the residual stresses and is a reliable tool for predicting residual stresses. The micrographs show that the workpiece with a higher concentration of reinforced particulates results in lesser flow line in the matrix material hence less residual stresses. X-ray spectra also reveal the phase transformation on the machined surface. [ABSTRACT FROM PUBLISHER]

Processability of metal matrix composite depends upon the appropriately chosen elements, their properties, distributions and interface between them. The ductile property of matrix embedded with ceramics reinforced particles serves to reduce the coefficient of thermal expansion and increase strength and modulus. High tool cost in traditional machining process results in limiting the application of these materials in advance technologies; hence, electric discharge machining process is a widely accepted machining option for geometrically complex-shaped components. This article presents the basic selection of elements and fabrication methods of metal matrix composites and further reviews the research work carried in the field of electric discharge machining to explore ways to improve the efficiency of the machining process. Finally, the research works carried out to measure the residual stress are also addressed, followed by concluding remarks and future scopes. [ABSTRACT FROM PUBLISHER]

The present study reports on the method used to obtain the reliable outcomes for different responses in electric discharge machining (EDM) of metal matrix composites (MMCs). The analytic hierarchy process (AHP), a multiple criteria decision-making technique, was used to achieve the target outcomes. The process parameters were varied to evaluate their effect on the material erosion rate (MER), surface roughness (SR), and residual stresses (σ) following Taguchi's experimental design. The process parameters, such as the electrode material (Cu, Gr, Cu-Gr), current, pulse duration, and dielectric medium, were selected for the analysis. The residual stresses induced due to the spark pulse temperature gradient between the electrode were of primary concern during machining. The optimum process parameters that affected the responses were selected using AHP to figure out the most suitable conditions for the machining of MMCs. [ABSTRACT FROM AUTHOR]

Recently, the range of crystal materials used in industrial microelectronics has significantly increased. Lithium niobate single crystals are most often used in integrated optics, due to the high values of optical and electro-optical coefficients. An integral-optical circuit based on a lithium niobate single crystal is a key element in the production of local high-precision fiber-optic gyroscopic devices used in civil and military aviation and marine technologies. In the process of production of an integral-optical circuit, the most labor-intensive operations are mechanical processing, such as lapping and polishing. Technological problems that arise while performing these operations are due to the physical and mechanical properties of the material, as well as target surface finish. This work shows the possibility to achieve the required surface quality of lithium niobate single crystal plates by mechanization of lapping and polishing process in this article. [ABSTRACT FROM AUTHOR]

Porous Lattice Structure (PLS) scaffolds have shown potential applications in the biomedical domain. These implants' structural designs can attain compatibility mechanobiologically, thereby avoiding challenges related to the stress shielding effect. Different unit cell structures have been explored with limited work on the fabrication and characterization of titanium-based PLS with cubic unit cell structures. Hence, in the present paper, Ti6Al4V (Ti64) cubic PLS scaffolds were analysed by finite element (FE) analysis and fabricated using selective laser melting (SLM) technique. PLS of the rectangular shape of width 10 mm and height 15 mm (ISO: 13314) with an average pore size of 600–1000 μm and structure porosity percentage of 40–70 were obtained. It has been found that the maximum ultimate compressive strength was found to be 119 MPa of PLS with a pore size of 600 μm and an overall relative density (RD) of 57%. Additionally, the structure's failure begins from the micro-porosity formed during the fabrication process due to the improper melting along a plane inclined at 45 degree. [ABSTRACT FROM AUTHOR]

This study presents the analysis of wire-cut electro-discharge machining (WIRE-EDM) of polymer composite material (PCM). The conductivity of the workpiece is improved by using 1 mm thick titanium plates (layers) sandwiched on the PCM. Input process parameters selected are variable voltage (50–100 V), pulse duration (5–15 μs), and pause time (10–50 μs), while the cut-width (kerf) is recognized as an output parameter. Experimentation was carried out by following the central composition design (CCD) design matrix. Analysis of variance was applied to investigate the effect of process parameters on the cut-width of the PCM parts and develop the theoretical model. The results demonstrated that voltage and pulse duration significantly affect the cut-width accuracy of PCM. Furthermore, the theoretical model of machining is developed and illustrates the efficacy within the acceptable range. Finally, it is concluded that the model is an excellent way to successfully estimate the correction factors to machine complex-shaped PCM parts. [ABSTRACT FROM AUTHOR]

In the present work, a hybrid magnetic field assisted powder mixed electrical discharge machining had been carried out on the Aluminum-Silicon Carbide (Al-SiC) metal matrix composite. The aim of the study was to obtain higher surface finish, and enhanced material removal rate. The dielectric mediums employed were plain EDM oil, SiCp mixed and graphite powder mixed EDM oil for flushing through the tube electrode. The magnetic field intensity, discharge current, T-on/off duration and type of dielectric were the control variables used for present investigation. From the results, it was observed that the machining variables for instance, discharge current, T-on/off duration and type of dielectric conditions remarkably affected the material removal rate, micro-hardness and surface roughness of the machined composite material. The MRR augmented considerably with an increase in the magnetic field intensity along with peak current. Subsequently, the composite with lesser vol.% of SiC particulates witnessed sharp rise in MRR in maximum magnetic field environment (0.66T). In addition, quality of the machined surface improved significantly in graphite powder mixed dielectric flushing condition with intermediate external magnetic field environment. Besides, an enhancement of micro-hardness was quantified as compared to base material due to the transfer of the material (SiCp) during powder mixed ED machining. [ABSTRACT FROM AUTHOR]

The present article focused on the surface characterization of electric discharge machined duplex stainless steel (DSS-2205) alloy with three variants of electrode material (Graphite, Copper-Tungsten and Tungsten electrodes). Experimentation was executed as per Taguchi L18 orthogonal array to inspect the influence of electric discharge machining (EDM) parameters on the material removal rate and surface roughness. The results revealed that the discharge current (contribution: 45.10%), dielectric medium (contribution: 18.24%) majorly affects the material removal rate, whereas electrode material (contribution: 38.72%), pulse-on-time (contribution: 26.11%) were the significant parameters affecting the surface roughness. The machined surface at high spark energy in EDM oil portrayed porosity, oxides formation, and intermetallic compounds. Moreover, a pin-on-disc wear analysis was executed and the machined surface exhibits 70% superior wear resistance compared to the un-machined sample. The surface thus produced also exhibited improved surface wettability responses. The outcomes depict that EDMed DSS alloy can be considered in the different biomedical and industrial applications. [ABSTRACT FROM AUTHOR]

The present article focuses on the electrical discharge treatment of duplex stainless steel (DSS-2205) to enhance its biological responses and corrosion resistance. Electrical discharge machining (EDM) was executed at different spark energy levels (by varying input factors) and 18 different morphological DSS substrates were prepared according to the L18 experimental array. Further, an electrochemical potentiodynamic test was performed on the unmachined and treated surfaces to investigate the corrosion performance. Moreover, the high corrosion resistance substrates along with untreated specimen were further analyzed for the in-vitro interaction with human red blood cells. The results claimed that the surface treatment by EDM significantly enhances the corrosion resistance (< 90%) as well as the biological responses of DSS alloy. The current of 10A, on-time = 60 µs, off-time = 150 µs, machining with W-Cu electrode in deionized water was witnessed as the best set of parameters in both corrosion and hemocompatibility test. Thus, surface alteration of DSS-2205 by EDM can be believed as a promising technique for improving the corrosion resistance and biological responses that essential for biomedical applications. [ABSTRACT FROM AUTHOR]

This paper presents wear and corrosion resistance analysis of carbon nanotubes coated with Ti-6Al-4V alloy processed by electro-discharge treatment. The reported work is carried out using Taguchi's L18 orthogonal array to design the experimental matrix by varying five input process parameters i.e., dielectric medium (plain dielectric, multi-walled carbon nanotubes (MWCNTs) mixed dielectric), current (1–4 A), pulse-on-time (30–60 µs), pulse-off-time (60–120 µs), and voltage (30–50 V). The output responses are assessed in terms of microhardness and surface roughness of the treated specimen. X-ray diffraction (XRD) spectra of the coated sample reveal the formation of intermetallic compounds, oxides, and carbides, whereas surface morphology is observed using scanning electron microscopy (SEM) analysis. For the purpose of the in-vitro wear behavior of treated samples, the surface with superior microhardness values in plain dielectric and MWCNTs mixed dielectric is compared using a pin-on-disc type wear test. Furthermore, electrochemical corrosion test is also conducted to portray the dominance of treated substrate of Ti-6Al-4V alloy for biomedical applications. It is concluded that the wear-resistant and the corrosion protection efficiency of the MWCNTs treated substrate enhanced to 95%, and 96.63%, respectively. [ABSTRACT FROM AUTHOR]