Electrical Discharge Machining（EDM）

In the present study, the nickel aluminide NiAl-based composite, reinforced with yttrium oxide Y2O3 with addition of titanium, was prepared by sintering at 1350 ° C for one and a half hours under an atmosphere of argon gas. Experimental investigation on electrical discharge machining of NiAl composite is performed with a view to correlate the process parameters with the responses for indicating the effect of the alloying addition on the machining performance of NiAl. Electro-discharge machining was used to study the machinability of the prepared composite. The machinability of NiAl was investigated based on the material removal rate, electrode wear rate, white layer thickness, and the surface roughness of the machined samples. The machining tests were performed under a wide range of machining parameters involving the pulse current (Ip) (8, 12, and 20) Amp. , pulse on time (TON) (45, 60, and 80) µsec, and pulse off time (TOFF) (20, 35, and 50) µsec, keeping the other parameters at fixed values. Electro-discharge machining process has been successfully modeled using response surface methodology (RSM) and central composite design (CCD) within "Minitab 17" and model adequacy checking is also carried out. The second-order response models have been validated. Analysis of variance (ANOVA) at constant significance levels of 0.05 was used to predict the most affecting parameters on the machining outputs. Optimization plots indicated that the maximum material removal rate (9.9312 µm) can obtained at (TON = 80 µs, TOFF = 20 µm, and Ip = 17.8182 Amp.), minimum electrode wear rate (0.2552 µm) can achieved at (TON = 45 µs, TOFF = 50 µm, and Ip = 8 Amp.), minimum surface roughness can gained at (TON = 45 µs, TOFF = 50 µm, and Ip = 8 Amp.), and minimum white layer thickness (4.9335 µm) can gotten using machining conditions of (TON = 45 µs, TOFF = 50 µm, and Ip = 8 Amp.

This paper presents the results of the study of plates with a combined "steel basetitanium, oxide coating" structure, which was obtained by resistive welding and strengthening induction heat treatment. The data of measurements of hardness and preliminary test for wear resistance were given. The possibility of finishing turning on structural chromium steel X40Cr13 was shown.

A comparative analysis of the influence of the method of applying a smearing layer of graphite paste and anatase powder on the morphology and hardness of stainless chromium-nickel steel X12CrNiTi18-10 was carried out. It has been established that for hardening the surface of stainless steel it is advisable to use a smearing consisting of two layers: 1 - graphite paste and 2 - anatase nanoparticles powder. Laser pulsed doping of the surface with the specified coating structure allows forming a hardened modified layer with a thickness of 60 μm on steel, with a hardness value of up to 6 ±0.1 GPa with a total porosity of 44%.

Wire Electrical Discharge Machining (WEDM) is one of the important non-traditional machining processes. The Wire Electrical Discharge Machining plays an important role in manufacturing sectors especially industries like aerospace, automobile and general engineering etc. Intricate profiles used in prosthetics, bio medical applications can also be done in WEDM. INCONEL-825 is a nickel-based high-temperature strength super alloy found applications in aerospace, missile, nuclear power, chemical and petro chemical, heat treatment, marine and space shuttle components. The characteristics such as higher strain hardening tendency, high dynamic shear strength and poor thermal diffusivity are the major causes of difficulty in machining of this alloy. These, in turn produce higher cutting forces, highly strain hardened and toughened chips and cause surface damages extending to subsurface levels. All these effects, in general, hamper the machinability of this alloy.

The present paper deals with studying the effect of electrical discharge machining (EDM) and shot blast peening parameters on work piece fatigue lives using copper and graphite electrodes. Response surface methodology (RSM) and the design of experiment (DOE) were used to plan and design the experimental work matrices for two EDM groups of experiments using kerosene dielectric alone, while the second was treated by the shot blast peening processes after EDM machining. To verify the experimental results, the analysis of variance (ANOVA) was used to predict the EDM models for high carbon high chromium AISI D2 die steel. The work piece fatigue lives in terms of safety factors after EDM models were developed by FEM using ANSYS 15.0 software. The results appeared that the experimental fatigue safety factors (at 10 6 cycles) decreased by (11 %) after EDM using copper electrodes compared with as-received material and this value is higher by (3.35 %) when using graphite electrodes. The fatigue strength at the same number of cycles was (0.88) and (0.84) times the fatigue strength of asreceived material for copper and graphite electrodes respectively. While fatigue strength and safety factors increased after EDM when increasing shot peening time, at the higher shot peening time is by (19.1 %) when using copper electrodes and by (23.26 %) when using graphite electrodes.

Copper and graphite separately are used widely as an EDM electrode and it has its own advantages and disadvantages. In this paper the research and development of copper graphite composites used as electro thermal components are studied. Graphite powder varying from (7-27) % weight proportion is combined with copper powder to form copper graphite composites via powder metallurgy process. At different composition of copper and graphite, electro thermal and mechanical properties are investigated. Study insists that copper graphite composites can be used as electrode in die sinking EDM.

Inconel 625, Introduction: The aviation, naval, and petrochemical industry industries frequently utilize the superalloy Inconel 625 because of its exceptional corrosion resistance and great tensile strength. However, because of its high heat conductivity and tremendous hardness, it is challenging to machine using standard techniques. Conventional machining techniques like Various nano (Wire-Machining) may efficiently drill tiny holes in Inconel 625. In this study, the micro-EDM drilling conventional methods of Inconel 625 were optimized using the WPM (Weighted Multilayer Perceptron Genetic Algorithm) approach. The pulse-on and pulse-off times as well as the peak current and during the simulation, servo voltage was considered as an input parameter optimization procedure. Materials percentage removal (MRR) and increased wear ratio were the output metrics (EWR). A multi-objective machine learning model was used in the optimization process to find the ideal combination of various parameters that would maximize the MRR and decrease the EWR. According to the experimental findings, the WPM approach was successful in optimizing the Inconel 625 micro-EDM drilling process parameters, which increased MRR and decreased EWR. Inconel 625 micro-EDM drilling may be made more effective and high-quality by using the optimized process parameters. Research significance: Due to its extreme hardness and heat conductivity, Inconel 625 is a difficult alloy to manufacture. A hole is made in the material by eroding it with a sequence of electric sparks using the non-traditional machining technique known as Micro-EDM. When drilling tiny holes in Inconel 625 or other difficult-to-machine materials, this method is quite helpful. Several process parameters, including signal time, wave time, peak current, but also servo voltage, have a substantial impact on the success of a micro-EDM drilling procedure. When these variables are combined in an ideal way, drilling efficiency, electrode wear, and surface quality can all be enhanced. In this study, the Inconel 625 micro-EDM drilling process parameters were optimized using the WPM approach. The WPM approach is a multi-objective plan that finds the ideal set of process variables to concurrently increase material removal (MRR) and reduce electrode wear ratio using singular value decomposition and just a genetic algorithm (EWR). Methodology: A well-liked technique for multi-criteria decision analysis (MCDA) and multi-criteria decision making (MCDM) is the weighted product model (WPM).

Inconel 625, Introduction: The aviation, naval, and petrochemical industry industries frequently utilize the superalloy Inconel 625 because of its exceptional corrosion resistance and great tensile strength. However, because of its high heat conductivity and tremendous hardness, it is challenging to machine using standard techniques. Conventional machining techniques like Various nano (Wire- Machining) may efficiently drill tiny holes in Inconel 625.
In this study, the micro-EDM drilling conventional methods of Inconel 625 were optimized using the WPM (Weighted
Multilayer Perceptron Genetic Algorithm) approach. The pulse-on and pulse-off times as well as the peak current and during the simulation, servo voltage was considered as an input parameter optimization procedure. Materials percentage removal (MRR) and increased wear ratio were the output metrics (EWR). A multi-objective machine learning
model was used in the optimization process to find the ideal combination of various parameters that would maximize the MRR and decrease the EWR. According to the experimental findings, the WPM approach was successful in optimizing the Inconel 625 micro-EDM drilling process parameters, which increased MRR and decreased EWR. Inconel
625 micro-EDM drilling may be made more effective and high-quality by using the optimized process parameters. Research significance: Due to its extreme hardness and heat conductivity, Inconel 625 is a difficult alloy to manufacture. A hole is made in the material by eroding it with a sequence of electric sparks using the non-traditional machining technique known as Micro-EDM. When drilling tiny holes in Inconel 625 or other difficult-to-machine materials, this method is quite helpful. Several process parameters, including signal time, wave time, peak current, but also servo
voltage, have a substantial impact on the success of a micro-EDM drilling procedure. When these variables are combined in an ideal way, drilling efficiency, electrode wear, and surface quality can all be enhanced. In this study, the Inconel 625 micro-EDM drilling process parameters were optimized using the WPM approach. The WPM approach is
a multi-objective plan that finds the ideal set of process variables to concurrently increase material removal (MRR) and reduce electrode wear ratio using singular value decomposition and just a genetic algorithm (EWR). Methodology: A well-liked technique for multi-criteria decision analysis (MCDA) and multi-criteria decision making (MCDM) is the
weighted product model (WPM). The weighted sum model is comparable to this (WSM). The primary distinction is that multiplication is used as the primary mathematical operation rather than addition. Alternative: Process parameters levels 1, Process parameters levels 2, Process parameters levels 3. Evaluation preference: Current (A), Pulse on time (μs), Pulse off time (μs), Gap Voltage (V), Capacitance (pF), EDM feedrate (μm/s) Results: From the result it is seen that Pulse off time (μs) is got the first rank whereas is the Capacitance (pF) is having the lowest rank.

In electrical discharge machining (EDM), Copper and Graphite are commonly used as electrode (tool) materials. EDM process is based on thermoelectric energy between an electrode and workpiece. In this paper, the effect of electrode wear rate (EWR) in 202 stainless steel is observed. Copper Electrode is used as tool material and SS-202 is used as workpiece. Copper

The abrasive waterjet machining process was introduced in the 1980s as a new cutting
tool; the process has the ability to cut almost any material. Currently, the AWJ process is used in
many world-class factories, producing parts for use in daily life. A description of this process and its
influencing parameters are first presented in this paper, along with process models for the AWJ tool
itself and also for the jet–material interaction. The AWJ material removal process occurs through the
high-velocity impact of abrasive particles, whose tips micromachine the material at the microscopic
scale, with no thermal or mechanical adverse effects. The macro-characteristics of the cut surface, such
as its taper, trailback, and waviness, are discussed, along with methods of improving the geometrical
accuracy of the cut parts using these attributes. For example, dynamic angular compensation is
used to correct for the taper and undercut in shape cutting. The surface finish is controlled by the
cutting speed, hydraulic, and abrasive parameters using software and process models built into
the controllers of CNC machines. In addition to shape cutting, edge trimming is presented, with
a focus on the carbon fiber composites used in aircraft and automotive structures, where special
AWJ tools and manipulators are used. Examples of the precision cutting of microelectronic and
solar cell parts are discussed to describe the special techniques that are used, such as machine vision
and vacuum-assist, which have been found to be essential to the integrity and accuracy of cut parts.
The use of the AWJ machining process was extended to other applications, such as drilling, boring,
milling, turning, and surface modification, which are presented in this paper as actual industrial
applications. To demonstrate the versatility of the AWJ machining process, the data in this paper
were selected to cover a wide range of materials, such as metal, glass, composites, and ceramics, and
also a wide range of thicknesses, from 1 mm to 600 mm. The trends of Industry 4.0 and 5.0, AI, and
IoT are also presented.

Powder mixed-EDM is a newly emerging proposed manufacturing process which can simultaneously shape and coat the surface of conductive materials. Transformation of machined surface is occurred through melting and chemical reactions of the added powders, tools materials and dielectric fluid due to elevated temperature generation during the operation. Though the biomaterials such as titanium alloy, magnesium, 316 L SS and Co-Cr alloy attribute to higher mechanical strength, corrosion and wear resistance, and enough biocompatibility, these are limited to apply directly because of releasing the toxic elements and having inferior biological responses. Surfaces of bio-implants made from these biomaterials are therefore protected using bioactive and biocompatible coating. Hydroxyapatite is a bioceramic that possesses bone like element composition and excellent biocompatibility. The PM-EDM process with hydroxyapatite can enhance not only adhesion strength and roughness but also biocompatibility of the treated surface. It is proposed in this paper that carbide and oxide coating formation can improve the microhardness, bonding strength and roughness of surface of the substrates. This study comprehensively reports the current status of adhesion and surface coarseness of bio-ceramics based coating through PM-EDM process. A comparative critical analysis of employing bio-ceramic powder using various deposition techniques is presented in this review.

A novel compact high-efficient circularly polarized conical horn antenna is realized with Wire Electrical Discharge Machining (EDM) technique operating at 300 GHz for 6G wireless communications is presented. The proposed antenna structure consists of three main components; a waveguide feed, a circular polarizer disk, and a conical horn. The waveguide feed is a standard WR-03 rectangular waveguide which feeds the whole structure. The circular polarizer disk is comprised of a crossed slot with unequal lengths which are perpendicular to each other. By adjusting the lengths of both slots, two orthogonal modes are excited in the antenna to produce circular polarization. The conical horn is mounted on the circular polarizer disk. The proposed antenna was designed and optimized using CST Microwave Studio and is validated experimentally by an inexpensive direct Wire-cutting EDM technique over the WM-860 frequency band. The fabricated circularly polarized horn antenna achieved a wide impedance bandwidth of 20 % from 270 GHz to 330 GHz with a reflection coefficient ≤ −15 dB. The measured results show that the 3 dB axial ratio of the fabricated antenna prototype has a bandwidth of 7 GHz from 309 GHz to 316 GHz with a minimum axial ratio of 1.15 dB at 312 GHz. The measured normalized radiation patterns show good agreement with simulated results for different frequencies in both the elevation and azimuth planes at broadside direction with good symmetry in both planes. INDEX TERMS Axial ratio (AR), circularly polarized (CP), electrical discharge machining (EDM), horn antenna, sixth-generation (6G), terahertz (THz).

In this study the effect of input parameters of the EDM process (pulse on-time, duty cycle and tool polarity), on the material removal rate (MRR), tool wear ratio (TWR) and maximum surface roughness (Rmax) in the machining AISI H13 tool steel has been studied. This study shows that increasing the duty cycle in the two conditions of tool polarity, material removal rate and the maximum surface roughness are increased and the tool wear ratio is reduced. Also in the positive polarity, by increasing pulse on- time, material removal rate and surface roughness are increased and tool wear ratio declines; but in the negative polarity by increasing pulse on time, material removal rate and surface roughness are first increased and then decreased. Furthermore, based on results obtained in the negative polarity mode, on the low pulse on-time, material removal rate is high, and tool wear ratio is lower than positive polarity.

Electric discharge machining is one of the non-traditional machining methods. In this process, many of the limitations of traditional machining methods have been removed, which is why the use of EDM in the manufacture of industrial parts and molds has greatly increased today. However, electric discharge machining has low efficiency and high energy consumption, and the quality of the machined surface in this method is low. For this reason, researchers have always been trying to find a way to increase the efficiency and quality of the surface. One of the most effective methods is the application of external magnetic field in electric discharge machining. Applying a magnetic field around the machining range in EDM leads to increased machining efficiency, reduced tool corrosion, increased chipping rate, reduced surface roughness and improved surface integrity. Previous research has shown positive results from magnetic field applications, but so far, no mention has been made of how to design a magnetic field application system. Undoubtedly, building an efficient system to apply the magnetic field in EDM is a challenges of using this method. In this article, using previous research, experiences gained and scientific foundations of a method to build this system will be presented.

Efficient three-dimensional (3D) microfabrication techniques of an Si are in high demand for producing micrometer-scale 3D structures. Here, we report a new method for processing Si back surfaces using a 1552.5 nm femtosecond laser. As the Si is optically transparent at this wavelength, we attempted to machine the Si back surfaces via a nonlinear absorption process using the laser. Given that the etch rate of the back surface would be higher, wet etching was performed using an aqueous KOH solution. The 40% KOH solution was maintained in contact with the Si back surface at 25 C while the laser was irradiated from the front surface. The laser beam was focused on the back surface and linearly scanned under different conditions. Focusing the laser approximately 15 μm into the liquid yielded deeper grooves as compared to those when it was focused precisely on the Si back surface. Further, the etch rate was significantly higher compared to that during dry etching. We could achieve the maximum etch depth of approximately 6 μm during the wet etching process, in contrast to 0.3 μm during dry etching. However, the groove depth was not constant along the processing path. The results demonstrate a possibility of a new, efficient, and debris-free microfabrication technique.

The present paper deals with studying the effect of electrical discharge machining (EDM) and shot blast peening parameters on work piece fatigue lives using copper and graphite electrodes. Response surface methodology (RSM) and the design of experiment (DOE) were used to plan and design the experimental work matrices for two EDM groups of experiments using kerosene dielectric alone, while the second was treated by the shot blast peening processes after EDM machining. To verify the experimental results, the analysis of variance (ANOVA) was used to predict the EDM models for high carbon high chromium AISI D2 die steel. The work piece fatigue lives in terms of safety factors after EDM models were developed by FEM using ANSYS 15.0 software. The results appeared that the experimental fatigue safety factors (at 10 6 cycles) decreased by (11 %) after EDM using copper electrodes compared with as-received material and this value is higher by (3.35 %) when using graphite electrodes. The fatigue strength at the same number of cycles was (0.88) and (0.84) times the fatigue strength of asreceived material for copper and graphite electrodes respectively. While fatigue strength and safety factors increased after EDM when increasing shot peening time, at the higher shot peening time is by (19.1 %) when using copper electrodes and by (23.26 %) when using graphite electrodes.

In this paper new concept of manufacturing uses non-conventional energy sources like sound, light, mechanical, chemical, electrical, electrons and ions. With the industrial and technological growth, development of harder and difficult to machine materials, which find wide application in aerospace, nuclear engineering and other industries owing to their high strength to weight ratio, hardness and heat resistance qualities has been witnessed. New developments in the field of material science have led to new engineering metallic materials, composite materials and high tech ceramics having good mechanical properties and thermal characteristics as well as sufficient electrical conductivity so that they can readily be machined by spark erosion. Erosion pulse discharge occurs in a small gap between the work piece and the electrode. This removes the unwanted material from the parent metal through melting and vaporizing in presence of dielectric fluid. In recent years, EDM researchers have e...

EDM can be employed to machine hard materials effectively. The magnetic force was added to the conventional EDM to investigate the effect upon surface characteristics and surface roughness of electrical discharge machined H11 die steel. The machining was accomplished at discharge current of 3, 5 and 7A with constant no-load voltage and pulse duration. The magnetic field (B) was added to the conventional EDM as 250, 450 and 600 gauss and the results were drawn in terms of surface roughness and surface topography. The results indicated that the magnetic force has the remarkable effect on EDM. Surface roughness decreased by 44.8% with the application of magnetic force. The number and size of surface cracks on the machined surface reduced, especially, at lower discharge current. SEM images indicated that the topography of the machined surface was finer with shallow discharge craters and folds in magnetic force assisted EDM.

The material melted and quickly solidified on the surface, forming a Recast layer over the machined surface. The present experimental assessment measures the extent of influence of machine variables towards the deposition of recast material post-machining Die Steel D3. The microstructure of the recast layer is dendritic and columnar due to sudden quenching, causing complex phase transformation. Scanning Electron Microscopy is utilized to assess the range of recast deposition. The range of average recast deposition is between 32.7 to 68.5 µm. The sequential model and lack of fit tests depict that the EDM parameters and recast layer can be modeled using 2FI equations. The analysis apprised that peak current (p-value < 0.0001) has a crucial impact on recast deposition. The duration (p-value = 0.4694) was the minimal affecting factor amid selected variables for white layer thickness, which aligns with the previous literature. The impact of current and duration is almost linear towards recast layer thickness and higher deposits of recast layer (RL) are observed at higher levels of current and duration. Lower RL can only be attained by setting a lower current and on duration. The influence of lower voltage is not much on recast layer thickness at minimum value of peak current. The residual error of 3.13% during model validation illustrates the adequacy of the model.

This study aimed to enhance the cutting process parameters in molybdenum HS-WEDM of thin-walled carbon fiber composite (CFRP) products. Various hole quality characteristics were examined, including out-of roundness, delamination factor, hole dimensional deviation, and cutting speed. The study utilized input parameters, including pulse-on duration, pulse-off duration, input current, and CFRP thickness. Optimization techniques, involving a second-order regression model and a genetic algorithm were used to individually optimize each hole characteristic. The combined compromise solution (COCOSO) method was employed to concurrently adjust the hole quality characteristics into a unified metric called the multiple performance criteria index (MPCI), with weight criteria for each response established using an entropy principle. The MPCI was then optimized using a genetic search algorithm. The findings reveal that the entropy, COCOSO, and genetic algorithm approaches efficiently optimize the HS-WEDM process parameters at various CFRP thicknesses to obtain precise hole quality characteristics. The implementation of these methods is expected to significantly improve hole quality, with enhancements of 29.57 % at 0.5 mm, 1.35 % at 1.0 mm, 9.65 % at 1.5 mm, and 6.05 % at 2.0 mm CFRP thicknesses.

The Electric Discharge machine (EDM) has evolved from a nontraditional machining process and positioned itself in industries as a most indispensable conventional machine. It is multipurpose and excels with ability of precisely producing difficult-to-machine, geometrically complex component of any hardness. Low material removal rate (MRR) restricts its productivity. Abrasive Jet Machine (AJM), another versatile process acquires edge of quick set up and rapid machining of virtually any material. Key advantage is that it do not cause any heat affected zone; is flexible and able to machine hard and brittle materials. The major limiting factor is that the process produces a tapered cut.Hybridization is an approach to tackle more than one process in order to add their advantages and avoid the limitations. This paper proposes an indigenously developed hybrid system to take advantage of the best part of each of the above processes. The appropriate abrasives are routed along with compressed air through the hollow electrode to construct the hybrid process of AJM and EDM i.e. Abrasive Assisted Electric Discharge Machining (AAEDM). An attempt is made to study the benefits of the hybrid process over the standard EDM and results are verified by confirmation experimentation. The main process parameters were varied to explore their effects on material removal rate and surface integrities. The experimental results show that the hybrid process of AAEDM can enhance the machining efficiency and the developed hybrid process can fit the requirements of modern manufacturing challenges.

The paper deals with a rotary head for ultrasonically aided electrical discharge machining (EDM+US) that can be used at finishing and semifinishing modes and EDM with complex kinematics-"milling EDM". The rotary movement of the electrodetool has the advantage that during the discharge duration, the energy is dissipated over the machined surface, and thus it and be levelled, i.e. the roughness is decreased, but the disadvantage of the instability of EDM process that is increased-often short-circuits between the tool and the workpiece. The ultrasonic vibration of the tool has the capacity to increase the stability of the removal process and hence the output EDM technological parameters. The paper presents the construction of the rotary head in two variants. The first one is more compact and more compatible to be used on CNC machining. The second one has an airier construction, which allows a better cooling of the ultrasonic transducer zone, susceptible to be overheated during EDM process KEY WORDS: electrical discharge machining, tool rotation, ultrasonic vibration.

In this paper illustration of the influence of input machining parameters on the material removal rate are determined along with performance measurement analysis. Experimentation was conducted on EN-19 alloy steel with Tungsten Copper as tool electrode. The data collected during experimentation has been used to yield responses in respect of material removal rate (MRR). The objective of this paper is to study the influence of operating input parameters of copper electrode on material removal rate of EN-19 material followed by optimization. The effectiveness of EDM process with tungsten copper electrode is evaluated in terms of the material removal rate. In this work the parameters such peak current, voltage gap, pulse on time, duty cycle and flushing pressure were selected. Analysis is carried using the response surface method and Anova analysis.

In the modern context, ceramic composites are being developed not just for increased strength and hardness but also for the ability to manufacture difficult to machine geometries that can use Electrical Discharge Machining. Sparking parameters such as current (I), pulse on time (T on), pulse off time (T off), and dielectric flushing pressure (P) are improved with multi-response factors such as material removal rate, Electrode Wear Rate, and Geometrical Errors. The results of the confirmation experiments indicate that machining time was decreased from 12.517 to 10.121 min, Material Removal Rate was increased from 0.0183 to 0.0215 g/min, Electrode Wear Rate was reduced from 0.0024 to 0.0002 g/min, circularity was decreased from 0.175 mm to 0.098 mm, cylindricality was decreased from 0.761 to 0.541 mm, and perpendicularity was decreased from 1.071 to 0.085 mm. By optimizing the data to its optimum level, the gray relational grade has been enhanced to 0.16464. Consequently, the experimental findings suggest that gray relational analysis can be effectively employed to optimize the machining settings of Spark Electrical Discharge Machining for various performance aspects.

This study presents a finite element model (FEM) to model temperature distribution for AISI H13 tool steel workpiece in electrical discharge machining (EDM) at different machining parameters (pulse current, pulse on-time, temperature-sensitive material properties, size of heat source, and material flushing efficiency). Scanning electron microscopy (SEM) with energy dispersive x-ray (EDX) and micro-hardness tests were used to validate accuracy of FEM predictions. Increasing pulse on-time leads to a higher depth of heat affected zone and increasing pulse current results in a slight decrease of depth of heat affected zone. There is a good agreement between experimental and numerical results.

Modern converter-supplied ac motors are exposed to bearing currents. Despite extensive research and development, the industry still does not have a final solution with acceptable cost and high efficiency. This article focuses on capacitive bearing currents. After a brief explanation of the phenomenon, an unconventional approach for effective mitigation of the capacitive bearing currents is proposed. The approach suggests using grounded electrodes in the slot openings to reduce the stator-windingto-rotor-core capacitance and thereby the bearing currents. Different electrode diameters are considered and evaluated by a finite element method (FEM) analysis. The results are verified by laboratory tests. The bearing voltage ratios of the original and modified induction motor are compared. Index Terms-Ball bearings, electrical discharge machining bearing currents, electrical machines, finite element analysis (FEA), induction machines, variable speed drives.

EDM is an important and commercial method of machining very tough and brittle electrically conductive materials. It is broadly used in the process of making moulds and dies and sections of complex geometry and complicated shapes. The work piece material selected in this experiment is Inconel 904 taking because it’s widely usage in industrial applications. The input variables are Voltage, current and pulse on time. Taguchi L9 orthogonal array is applied to optimize the processes variable. The effect of the variable parameters mentioned above upon machining characteristics such as Material Removal Rate (MRR) and Surface Roughness (SR) is studied and investigated. The obtained results showed that current was the most significant parameter followed by voltage and pulse on time for the Material removal rate (MRR) and, for Surface roughness (Ra) current was the most significant parameter followed by pulse on time and voltage. The selected electrode material is cupper and duty cycle is 90%...

Improving the quality of surface molds after electrical discharge machining is still being considered by many researchers. Powder-mixed dielectric in electrical discharge machining showed that it is one of the processing methods with high efficiency. This article reports on the results of surface quality of mold steels after powder-mixed electrical discharge machining using titanium powder in fine machining. The process parameters such as electrode material, workpiece material, electrode polarity, pulse on-time, pulse off-time, current, and titanium powder concentration were considered in the research. These materials are most commonly used with die-sinking electrical discharge machining in the manufacture of molds and has been selected as the subject of research: workpiece materials were SKD61, SKT4, and SKD11 mold steels, and electrode materials were copper and graphite. Taguchi’s method is used to design experiments. The influence of the parameters on surface roughness was evalua...

This article has been addressed various sustainability aspects of EDM and introduced transesterified neem as a green dielectric. Here, the machining is performed at 4-16 A of current, 50-250 μs of pulse on time, 10-50 μs of pulse off time, and 20-50 V of gap voltage using both the kerosene and neem as a dielectric medium. The comparative assessment of the obtained responses claims that the neem dielectric exhibits 22% more removal rate and 17% less surface roughness than kerosene. Apart from these, the impact of each dielectric on the texture of processed surfaces has been assessed with the help of the microscopic images captured with a scanning electron microscope (SEM). Finally, the sustainability evaluation is performed to check the feasibility of the neem oil as a reliable dielectric of EDM. It is observed that the neem dielectric is capable of ensuring comparatively fine surface textures due to the repeated overlapping of the radially extended craters and consumes less time to attain the targeted removal depth (RD). Therefore, based on the results, the neem dielectric can be recommended as a potent and reliable alternative of conventional kerosene.

Micro-chip removal and heat dissipation are two important and essential utilities of dielectric medium along with its vital contribution in plasma channel formation, which has a significant influence in metal removal, tool wear, and surface integrity. The vapor bubbles, which are formed after every progressive spark, expand and collapse in the electric field and finally condensed inside the dielectric medium. As the localized heat and excess temperature of the eroded spot increases, the dynamic properties of the bubbles accelerate and develop a lower pressure region, which is responsible for dielectric flushing. In this paper, the integrated approach of vapor bubble dynamics and computational fluid dynamics is used to study the dynamic behavior and heat dissipation of dielectric fluid through the plasma channel. At the very beginning of machining, the excess temperature is comparatively low; so, the detached bubbles are condensed inside the fluid medium and are not able to move above the free surface. However, as the temperature of the machined zone rises, excess temperature also increases and bubbles are able to carry the heat up to the free surface of the dielectric medium and finally condense. This phenomenon is very much analogous to the boiling process. Earlier, many simulation processes are used by researchers to investigate heat flux and heat dissipation rate of the dielectric fluid, but, here, vapor bubble dynamics and periodic heating are introduced to consider heat absorption by vapor bubbles, which gives more accurate heat transfer analysis of electric discharge machining. It is observed that the adopted model has the accuracy level of more than 95% with 4.5-4.6% of average prediction error and 1.5-2% more efficient than the existing models.

Titanium alloys are usually selected for orthopedic implants because they are biomaterials that withstand biological environment with combined dynamical mechanical loads and very aggressive body fluids. However, these alloys are considered difficult to be processed by conventional machining, owing to their mechanical characteristics. Due to the ED-machining thermoelectric material removal nature, which is independent of material mechanical properties, it appears as an alternative to conventional machining processes and a technique suitable to modify surface mechanical properties. This work evaluates the ED-machining surface modification influences on the tribocorrosion properties of Ti6Al4V alloy using two different dielectric fluids, a hydrocarbon and deionized water (DI) mixed with a glycerin solution. The analysis shows that the ED machined with hydrocarbon dielectric produces a modified titanium surface with lower roughness and higher hardness due to the formation of TiC phase. The produced surface improves the tribocorrosion and wear properties of the Ti6Al4V samples. The hydrocarbon-machined samples present also a lower friction coefficient when compared with ED-machined glycerin water solution and control samples (Ti6Al4V).

Investigation of the machining performance of the titanium alloy (Ti-6Al-4V) at low range parameters by
the electrical discharge machining (EDM) using copper and graphite as electrodes with positive polarity.
The objective of this paper is to investigate the peak current (A), servo voltage (V), on time (Ton
), off time
(Toff
) and show the effects on material removal rate (MRR), electrode wear rate (EWR) and surface
roughness (SR).Design of experiments (DOE) method by using Taguchi technique (L18) mixed level
implemented. The validity test of the fit and adequacy of the proposed model has been carried out
through analysis of variance (ANOVA).SR was set the lower the better to attain the optimum
dimensional precision. Experimental results indicate that copper as a tool electrode shows a better
surface roughness than a graphite electrode.

Electrical discharge coating a significant process of depositing alloying materials over the surface for improved wear resistance. In present investigation reinforcement of silica with a varying concentration in working fluid together with carbon over duplex stainless steel and their effects on coating formation, porosity, microstructure, microhardness and wear resistance properties under the elevated temperature of 600°C has been investigated. While the silica percentage increases the surface roughness, deposition of carbon and porosity of the coating are reduced, with varying decarburizing depth, frictional coefficient and modified microstructure having finer in phase transformation beneath the coating. The carbide bands the microstructure of the pyrolysis carbon retains outstanding metallurgical bonding, grain refinement and makes hard metal matrix composite layer towards high temperature wear resistance. The frictional coefficient at higher temperature reduces while the carbon percentage increases the specific wear rate due to oxides that minimize the third body wear.

Electrical discharge coating a significant process of depositing alloying materials over the surface for improved wear resistance. In present investigation reinforcement of silica with a varying concentration in working fluid together with carbon over duplex stainless steel and their effects on coating formation, porosity, microstructure, microhardness and wear resistance properties under the elevated temperature of 600°C has been investigated. While the silica percentage increases the surface roughness, deposition of carbon and porosity of the coating are reduced, with varying decarburizing depth, frictional coefficient and modified microstructure having finer in phase transformation beneath the coating. The carbide bands the microstructure of the pyrolysis carbon retains outstanding metallurgical bonding, grain refinement and makes hard metal matrix composite layer towards high temperature wear resistance. The frictional coefficient at higher temperature reduces while the carbon percentage increases the specific wear rate due to oxides that minimize the third body wear.

Machining of present days superior engineering materials is still a challenging task before industries, as conventional machining processes have proven to be inefficient to process these materials. In order to meet challenges, numerous processes with innovative mechanism of material removal have come into existence. Electrical discharge machining (EDM) is one among many such processes that has got wide attention. However, EDM results in very poor material removal and requires very high specific energy as compared to conventional machining processes. Electrical arc machining (EAM) is a process, which is very similar to EDM but results in very high material removal rate (MRR). In the present research, an innovative process known as vibration-assisted electrical arc machining has been developed. The process has been used to machine aluminium-boron carbide metal matrix composite. Peak current, frequency of vibration and dielectric flushing velocity has been considered as input control factors to evaluate MRR and surface roughness (SR). An artificial intelligence (AI)-based approach has been applied for single objective optimisation for MRR and SR. The AI-based approach results in an improvement of approximately 230 and 50% in MRR and SR, respectively.

Electrical arc machining is the thermal energy-based unconventional machining process, which utilizes energy of arc to melt and vaporize workpiece material. Electrical arc machining has the capability to machine advanced materials such as metal matrix composites, superalloys, and conductive ceramics effectively. The process is considered to be efficient than most of the other unconventional machining processes in terms of the material removal rate. But it has got limitations because it results in a very poor surface finish. Tool wear rate, recast layer formation, surface and subsurface cracks, and geometrical inaccuracy are other limitations up to a certain extent. In this paper, the comprehensive review of research carried out so for in the area of electrical arc machining has been presented. The paper discusses the detailed experimental and theoretical studies done on electrical arc machining to elucidate the effects of various input control factors on different quality characteristics. The paper also contains modeling and optimization studies done so far in electrical arc machining and finally discusses the future research possibilities in the area.

Electrical arc machining is the thermal energy-based unconventional machining process, which utilizes energy of arc to melt and vaporize workpiece material. Electrical arc machining has the capability to machine advanced materials such as metal matrix composites, superalloys, and conductive ceramics effectively. The process is considered to be efficient than most of the other unconventional machining processes in terms of the material removal rate. But it has got limitations because it results in a very poor surface finish. Tool wear rate, recast layer formation, surface and subsurface cracks, and geometrical inaccuracy are other limitations up to a certain extent. In this paper, the comprehensive review of research carried out so for in the area of electrical arc machining has been presented. The paper discusses the detailed experimental and theoretical studies done on electrical arc machining to elucidate the effects of various input control factors on different quality characteri...

Because of its significant advantages of low thermal influence on workpiece and possibility of cutting different type of materials, the abrasive water jet cutting is more and more present in industry. One of the bigger costs during abrasive water jet cutting is the cost of abrasives. Recommended and required abrasive flow rate is mostly determined by type of workpiece material and its thickness and pump pressure. In intent to reduce the abrasive mass consumption in cutting, some experiments were done and the paper presents the results of changing the abrasive flow rate (mass flow) and its influence on surface cut quality in abrasive water jet cutting. Abrasive saving possibility and also the influence of cutting nozzle distance from workpiece surface on surface cut quality in abrasive water jet cutting are discussed in this paper.

ASTM A131 EH36 shipbuilding steel is a high tensile strength steel used in various shipbuilding applications. Specific low volume high mix applications of EH36 components are commonly required for new-builds and repair vessels. Manufacturing technologies suitable for high mix low volume applications, such as 3D printing, can help solve many production related woes. This study reports on the tensile properties of ASTM A131 EH36 shipbuilding steel processed by selective laser melting. Tensile test coupons were fabricated and tested to ASTM standards.

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Titanium and titanium alloys are broadly used in biomedical applications, particularty orthopaedic and dental implants, due to their suitable properties, such as low modulus, high specific strength to weight, high machining, high corrosion resistance, and biocompatibility. Micro-arc oxidation (MAO) is one in every of many surface modification processes that can provide porous, adhesive, and bioactivity for implantation, resulting in better and more improved osseointegration. Furthermore, antimicrobial surface coatings hold a lot of promise for reducing infection-related errors. This study provides a summary of the biological evaluation of bioactive coatings. It primarily focuses on ways for enhancing the biological characteristics of MAO-coated titanium and related alloys. The overview is to discuss the MAO process of the titanium implant to enhance bone/implant interaction.

Surface characteristics and machining performances of micro-pockets manufactured by μEDM as a function of different process conditions are studied in this paper. The micro-pockets were obtained using different combinations of process parameters on different ultra-high temperature ceramics (UHTCs) with the same base matrix (ZrC) and different volume fraction of the second phase (MoSi 2 ). This work presents an analysis of the process performances with different machining approaches, from pre-roughing down to fine-finishing. Microstructure analysis of the as-sintered and machined materials was conducted to identify materials modification due to the electrical discharges. A removing material mechanism during the μEDM process has been hypothesized, correlating the ED-machined surface structure and the main process performances.

Volatile organic compounds (VOC) generated from various sources like car combustion is one of the most surrounding pollutants, which can be transferred from one form to another in the presence of sunlight. In the present work the ability of the reduction of VOC have been conducted on cementitious samples surfaces by using toluene as a pollutant gas and TiO2 as an environmentally friendly photocatalyst . Two coating methods have been used (dip and spray) with two types of aqueous solution, prepared by spreading 3g/L micro and nano TiO2 powder with deionized water. A laboratory test procedure was adopted to assess the performance of the coated specimens. The specimens were subjected to toluene gas and there efficiency in gas removal was monitored with time. Furthermore, contact angle for the coated samples was also examined to investigate the hydrophilicity of the coated substrate. The results showed that TiO2 give high activity and work as a good photocatalyst for mitigation of air p...

This research article delves into the optimization of WEDM operating parameters through the application of Design of Experiments (DOE) principles. As traditional machining techniques give way to non-traditional methods for enhanced surface quality and intricate form geometries, wire EDM stands out as a prominent contender. Focusing on machining brass-based metals, renowned for applications like gears, bearings, and locks, the study aims to find the most effective process parameters. The investigation involves pivotal factors including pulse on/off, servo voltage, and input current, with MRR and surface roughness serving as key performance indicators. Employing the Taguchi L9 orthogonal array, the research dissects the influence of each control component on performance measures via S/N ratio analysis. Notably, the study underscores the malleability of wire EDM settings in enhancing both MRR and surface quality, effectively harnessing the Taguchi approach to attain an optimized parameter set.

This experimental assessment is performed to estimate the impact of EDM parameters on surface quality while machining AISI 4147 with a copper tool. The need of the present-day is to achieve good surface quality. Here, an investigation was performed to depict surface quality characteristics with respect to machine variables. The machined specimens were examined under white light interferometry (WLI) for the crests and troughs developed post-machining. The range of average surface finish was found to be between 5.32 to 7.67 µm. The test of model highlighted that the relation linking the EDM variables and surface roughness could be modelled using quadratic equations. As per the SMSS and lack of fit tests, a quadratic model is suggested for the roughness trend obtained. The analysis apprised that duration (p-value = 0.0006) major influence on the surface quality produced while the depth of machining (p-value = 0.9251). At all levels of on time, the surface roughness initially increases and then tends to decrease on increasing peak current. At all current levels, the surface roughness is almost constant with the machining depth; as suggested by ANOVA, it is the least influencing factor. At all levels of duration, the surface roughness is almost constant with depth of machining, and as suggested by ANOVA, it is the least influential factor. Model surface plots are curved representing the presence of quadratic terms in the model. Model validation for surface finish showed that the residual error was lower than 1.48%, proving the adequacy of the model.

Developing and standardising two-dimensional roughness parameters have received considerable attention for many years, but the recent work to describe roughness on a three-dimensional surface has been on the millimetre scale. The invention of the scanning probe microscope (SPM) makes it possible to obtain good resolution for surface imaging and measuring on scanning areas from 1 00 ~m x 1 00 ~m down to 1 nm x 1 nm. As a member of the SPM family, the Atomic Force Microscope (AFM) allows surface roughness, a key issue for the characterisation of the surface, to be measured in three dimensions on the nanometre scale. This paper presents the results of the investigation of the surface quality of a tool electrode and micro-holes using micro-EDM. The samples, having concave and convex surfaces, were imaged and measured by using high precision AFM. A series of 2-dimensional and 3-dimensional topographic pictures were obtained. A large number of cracks with maximum depth of 1.3 ~m and width 1.5 ~m was imaged and measured. The evidence of small particles with diameters 80-150 nm was revealed on the machined surface. The typical Ra was 180-300 nm for a tool electrode with a higher Ra of 200-400 nm for the micro-holes, over the same scanning area. AFM provided a better understanding of the process capabilities of micro-EDM in terms of surface quality of the machined product compared with other measuring instruments used previously.

The objective of this research work is to perform boring operation in electrical discharge machining process on AISI 304 workpiece material. Boring operation was successfully accomplished using tool actuation on radial path in electrical discharge machining process. The diameter of predrilled hole cavities were enlarged to 10 mm bore diameter. The boring operations were performed with three different diameter of tool electrode i.e. 7, 8 and 9 mm at three different orbital speed of tool electrode i.e. 0.05, 0.09 and 0.13 mm/s. The machining responses were measured in terms of material removal rate (MRR), surface roughness (R a) and radial overcut (O c).