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Numerical control electrical discharge machining (NC EDM) is one of the most widely used machining technologies for manufacturing a closed blisk flow path, particularly for three-dimensional (3D) curved and twisted flow channels. In this process, tool electrode design and machining trajectory planning are the key factors affecting machining accessibility and efficiency. Herein, to reduce the difficulty in designing the electrode and its motion path in the closed curved and twisted channels, a heuristic search hybrid optimisation strategy based on channel grids is adopted to realise the initial electrode trajectory design search and optimised size reduction. By transferring the trajectory optimisation constraints from the complex free-form surface to numbered grids, the search is found to be more orderly and accurate. The two trajectory indicators, namely argument angle and minimum distance, are analysed separately for the optimised results of the adaptive learning particle swarm optimisation algorithm, demonstrating that they can meet the actual processing requirements. Experimental results of NC EDM indicate that the motion path generated by this design method can meet the machining requirements of 3D curved and twisted flow channels.

Electrical discharge machining (EDM) is a versatile unconventional machining process allowing high precision manufacturing. Due to the thermal main active principle, the process-induced heat affected rim zone always needs to be particularly considered regarding its characteristics as the resulting surface integrity has to fulfill the needed functional properties for advanced applications. Today, no deterministic model is available especially for the residual stress prediction. As consequence, current process design is based on experience and heuristic optimization. The paper therefore mechanistically links the material modification and the process-induced load. Inversion of the according process signature component finally allows model-based process design.

A detailed experimental research study on wire lag phenomena, gap force, and wire lag compensation has been carried out on M2 tool steel material to overcome the error in dimensional accuracy for circular or curved profile job cutting in the wire electrical discharge machining. The design of experimental planning was made based on Taguchi methodology to determine the effect of the WEDM input control parameters on the wire lag related to different machining criteria, as well as the material removal rate, surface finish characteristic in terms of Ra values, spark gap, and specific energy consumption in this research work. The frequency, pulse on time, peak current, wire feed, workpiece height and wire tension, cutting diameter, and the span in between wire guide and job surface are considered as input control parameters for the present study. Parametric analysis shows that wire lag increases with workpiece height and wire lag compensation value increase rapidly with the decrease of job diameter. Parametric analysis is also carried out for MRR, surface roughness, spark gap, and specific energy consumption for optimum output. A further key finding is identified that the energy utilization efficiently increases with larger height job cutting in the WEDM process.

Precision machining characteristics with high-dimensional accuracy make the material more adaptable towards the applications. The present study employs the powder mixed wire electrical discharge machining process to machine Ti6Al4V alloy material. In spite of limited drawbacks and enhanced output in the powder mixed wire electrical discharge machining process, the present problem has been formulated for improving the machining efficiency of Ti6Al4V. The impact of suspended powder characteristics on responses, that is, material removal rate and surface roughness, is examined throughout the process. The current investigation also focuses on the interaction effect of machining constraints along with Al2O3 abrasive mixed dielectric to achieve economical machining output for the Ti6Al4V material. An effort has been presented to obtain optimal solutions using the different methodologies, namely response surface methodology, grey relation analysis, and particle swarm optimization. The study reveals that discharge energy is deeply influenced by the peak current and pulse off time followed by powder concentration in the powder mixed wire electrical discharge machining process. The maximum material removal rate of 6.628 mm3/min and average surface finish of 1.386 μm are the outcome of the present study for a set of optimal machining settings, that is, pulse off time ( Toff) of 7.247 μs, pulse on time ( Ton) of 30 μs, peak current ( Ip) of 2 A, and powder concentration of 4 g/L. Finally, the proposed model has been verified that the hybrid particle swarm optimization technique has the highest adequate capability to achieve maximum output. Thus, the approach offered an enhancement on performance measures of Ti6Al4V alloy in the powder mixed wire electrical discharge machining process.

Nowadays, special attention is paid to the application of nanoparticles to improve the performance of Electrical Discharge Machining (EDM). In this paper, modeling and optimizing the process parameters of Nanopowder Mixed Electrical Discharge Machining (NPMEDM) is studied. In this study, the effect of aluminum oxide (Al2O3) and silicon oxide (SiO2) nanoparticles on the deionized water dielectric is investigated simultaneously in the process of electrical discharge machining of Ti-6Al-4V alloy. After analyzing the parameters, the discharge current, concentration, pulse on time, and relative composition are considered as input factors. Response Surface Methodology (RSM) using Design-Expert software is employed for the design of the experiments, analysis of the results, and optimization of the parameters. The results show that the best surface morphology is obtained by machining with the addition of nanoparticles in the relative composition of 50%. In this percentage of the composition, the surface of the workpiece has the least value of crack and recast layer. In addition, the maximum value of the material removal rate (MRR) and minimum value of tool wear rate (TWR) can be achieved in the discharge current of 12 A, pulse on-time of 100 μs, and relative composition of 75% Al2O3 – 25% SiO2.

One of the important non-traditional machining processes is Wire Electrical Discharge Machining, used for machining difficult to machine materials like composites and inter-metallic materials. WEDM involves complex physical and chemical process including heating and cooling. Accompanying the development of mechanical industry, the demand for alloy materials having high hardness, toughness and impact resistance are increasing. The WEDM satisfy the present demands of the manufacturing industries such as better finish, low tolerance, higher production rate, miniaturization etc. The consistent quality of parts being machined in WEDM is difficult because the process parameters cannot be controlled effectively. The problem of arriving at the optimum levels of the operating parameters has attracted the attention of the researcher and practicing engineers for a very long time. The objective of the present study was to experimentally investigate the effects of various Wire Electrical Discharge Machining variables on Surface Roughness and Material Removal Rate of AISI 1045 using ANOVA method. Taguchi’s L18 Orthogonal Array was used to conduct experiments, which correspond to randomly chosen different combination of process parameters: wire type, pulse on time, pulse off time, peak current, servo voltage, wire feed rate, flushing pressure each to be varied in three different levels. The surface roughness and material removal rate were selected as output responses for the present investigation. The effect of all the input parameters on the output responses have been analyzed using analysis of variance (ANOVA). The effect of variation in input parameters has been studied on the output responses. Plots of S/N ratio have been used to determine the best relationship between the responses and the input parameters. In other words, the optimum set of input parameters for minimum surface roughness and maximum material removal rate were determined. It has been found that wire type, pulse on time are most significant factors for surface roughness and wire type, pulse on time, pulse off time, wire feed rate are most significant factors for material removal rate. Keywords: Input Parameters, Wire Electric Discharge Machining, ANOVA, Taguchi

Efficient and cost effective utilization of WEDM process is a challenge for leading edge era of manufacturing because of the complex and non-linear behavior of the process. The current study focuses on an experimental inquiry carried out for WEDM of Nitronic-30 to obtain optimum process parameters for improved surface roughness (SR) and material removal rate (MRR), Nitronic-30 is austenitic stainless steel offers high strength with good corrosion resistant property which high potential in applications such as automotive parts, aqueous applications, solid handling equipment. Therefore, multi-response optimization of Nitronic-30 on WEDM is very essential. Experiments were carried out with Taguchi's DoE and a L9 orthogonal series, with machining parameters like pulse on time (Ton), pulse off time (Toff), and peak current (IP). Minitab-17 software was used to evaluate response variables such as material removal rate and surface roughness. Analysis of variance (ANOVA) and SN Ratio plot of GRG indicates that peak current is the most important parameter. Grey Relational Analysis (GRA) provides optimal process parameters like pulse on time 124 machine units, pulse off time 40 machine units and peak current 230A for optimal response variables as 4.019 µm SR and 8.683 mm3/min MRR.

The coated electrodes with high heat resistant alloy materials can considerably improve the efficiency of electrical discharge machining (EDM) process. In the present study, the influence of Aluminum Chromium Nickel Coated aluminium electrode was investigated on the quality criteria using EDM while machining Titanium alloy (Ti - 6Al-4V). The peak current, gap voltage and pulse-on time were used as input parameters to analyze the material removal rate, tool wear rate and surface roughness under the L16 based Taguchi method and ANOVA method. It was observed that Aluminum Chromium Nickel (AlCrNi) coated electrode could produce higher material removal rate (MRR), lower of tool wear rate (TWR) and surface roughness (Ra) than uncoated electrode. Compared with EDM with uncoated electrodes, the quality indicators in EDM with coated electrode are better, namely 8% higher MRR, the lower TWR and Ra are 8% and 24%, respectively. The better surface finish was also observed with the coated electrode due to its thermal conductivity.

The present study is designed to study processes occurring during the electrical discharge machining (EDM) of tool steels, the influence of orbiting electrode motion on its accuracy, as well as to justify the application of individual orbiting trajectories and implement these data into production. To that end, a trajectory program was written in machine codes for a Mitsubishi EA-28 die-sinking electrical discharge machine using the CIMCO EDIT software package. Also, a prototype punch and ejector of the blanking die were produced and measured. The standard modes of Mitsubishi EA-28 were used to carry out machining in Blasospark GT 250 dielectric fluid to a roughness of Ra 0.6 in 9 passes. The experiments revealed the influence of electrode geometry on the machining of sharp corners, i.e., the formation of unwanted radii on the workpiece. However, this phenomenon is not observed when the corners are drilled with small diameter holes (0.4–0.6 mm). Depending on the machining process along the inner or outer trajectory, inverse electrode motion is also observed. The production part (punch of the blanking die) was machined using a new orbit adjusted to the geometry of the product. The part was found to be consistent with the requirements and the engineering drawing, thus allowing the assembled die to enter the main production. The results of the performed tests, as well as the study of domestic and foreign experience, were used to develop recommendations on the use of individual orbits in the EDM of tool steels, hard alloys, and other hard-to-machine conductive materials. The method of orbiting motion along a particular trajectory was implemented at Cheboksary Electrical Apparatus Plant (Cheboksary).

This paper studies the application of a path analysis approach to model a wire electrical discharge machining (WEDM) process for investigating the relationships between its different process parame...

In electrical discharge machining, the formation of the modified surface layer depends on the physicochemical properties of the anode and cathode and the machining conditions. Experiments show that the mass transfer and coating thickness decrease with increase in thermal conductivity and decrease in melting point of the anode and cathode. The mass transfer and state of the modified surface are also impaired by increase in energy of the generator pulses and increase in roughness of the machined surface. These data are fundamental in selecting electrode materials and creating metal coatings with specified functional properties.

It is well known that electrical discharge machining can be used in the processing of nonconductive materials. In order to improve the efficiency of machining modern engineering materials, existing electrical discharge machines are constantly being researched and improved or developed. The current machining of non-conductive materials is limited due to the relatively low material removal rate and high surface roughness. A possible technological improvement of electrical discharge machining can be achieved by innovations of existing processes. In this paper, a new approach for machining zirconium oxide is presented. It combines electrical discharge machining with assisting electrode and powder-mixed dielectric. The assisting electrode is used to enable electrical discharge machining of nonconductive material, while the powder-mixed dielectric is used to increase the material removal rate, reduce surface roughness, and decrease relative tool wear. The response surface method was used to generate classical mathematical models, analyzing the output performances of surface roughness, material removal rate and relative tool wear. Verification of the obtained models was performed based on a set of new experimental data. By combining these latest techniques, positive effects on machining performances are obtained. It was found that the surface roughness was reduced by 18%, the metal removal rate was increased by about 12% and the relative tool wear was reduced by up to 6% compared to electrical discharge machining with supported electrode without powder.

Titanium alloys, in particularly Ti-6Al-4V alloy is used enormously in many high-tech sectors specially in aerospace industries due to its superior properties. Machining process (for example wire electrical discharge machining) to reshape this alloy affects the integrity of the newly generated surfaces. This experimental study has identified three affected layers using scanning electron microscopy on the cross section of the machined titanium (Ti-6Al-4V) alloy surface generated from wire electrical discharge machining (WEDM). This study also explained the formation mechanism of those three layers as no detail investigation is available in this area so far. It was found that the top flaky layers are formed due to the highest cooling rate at the outermost surface, which is induced due to the low thermal conductivity of the titanium alloy as well as the quenching effect because of the existence of dielectric. The recast layer is formed at a cooling rate lower than that at the outer surface, where the melted material is resolidified very quickly without having any grain boundaries. The heat-affected zone appears at a slightly different color, which does not melt but experience heat treatment during the machining process.

The unconventional technology of wire electrical discharge machining is a key engineering technology, designed primarily for machining of conventionally difficult machine materials. One of them is nickel alloys, which are majorly used in the aerospace and energy industries. The subject of research in this study was specifically the B1914 nickel-based superalloy, which was subjected to many analyses leading to an overall optimization of its machining using wire electrical discharge machining. In order to determine the effect of machine parameters setup (pulse off time, gap voltage, discharge current, pulse on time and wire feed) on cutting speed, topography, morphology, surface and subsurface layer quality, an extensive Box–Behnken design experiment consisting of 46 rounds was carried out. The analyses of the condition of the surface and subsurface layers were performed, including their chemical composition and changes caused by wire electrical discharge machining. It was found out that the factors like pulse off time, discharge current and pulse on time have the greatest effect on the cutting speed, although from the point of view of surface topography the parameter pulse off time is not significant. The remaining two parameters cause the cutting speed to act against the surface topography i.e. with the increasing cutting speed, the surface topography gets worse and vice versa.

Various novel 3D micro machining technologies were researched and developed for silicon micro mechanical system fabrication. Micro EDM is one of them. The material removal mechanism is thermal sparking erosion and is completely independent with regards to the crystalline orientation of silicon, therefore there is no orientation constraint in processing the complex 3D geometry of silicon wafers. As thermal sparking implied, the process features local area high temperature melting and evaporating, and this characteristic has an adverse side-effect on the sparked surface integrity. One important concern is the generation of micro cracks, which would provide an adverse effect on the fatigue life of the micro feature element made of silicon. For this consideration, in this paper, with the experiment and SEM picture analysis approach, the author explored the micro crack generation characteristics on mono crystalline silicon wafers under micro EDM with available sparking energies and on the different crystal orientation surface machining. The generation of micro cracking is not only related with the sparking energy but also related with the crystalline orientation. The {100} orientation is the strongest surface to resist crack generation. For a strong-doped P type silicon wafer, there exists a maximum crack energy threshold. If single sparking energy is over this threshold, micro cracks unavoidably would be generated on any orientation surface. Two types of chemical etching post processes that can remove cracks on sparked surfaces are also tested and discussed.

Electrical discharge machining (EDM) is very essential unconventional electro-thermal machining process to machine the contour profile of hard materials in modern production industries. The liquid dielectric fluid has been replaced by the gas and minimum quantity of liquid mixed with gas (gas-mist) to encourage the green machining processes. The various gases and gas-mist have been used as the working fluid in dry and near-dry EDM respectively. The research-contextual, various dielectric fluids, sustainable and innovative developments, process parameters, machining characteristics, and optimization techniques applied in various dry and near-dry EDM have been illustrated through an extensive literature survey. Future research opportunities in both dry and near-dry EDM have been summarized to promote eco-friendly EDM research activities.

In this study, wire electrical discharge machining of aluminium matrix composites has been experimentally investigated. A metal matrix composite Al/Al2O3/22 p has been machined at various combinati...

At present, the production of micro parts and components with characteristic sizes ranging from micron to millimeter mainly relies on micro machining technology, but the dimensional size of micro tools (including micro cutting tools, micro grinding tools, and microelectrodes) involved in micro machining is ultra small and made of super hard material like cemented carbide and polycrystalline diamond, which makes the preparation of ultra small micro tools have become the main bottleneck restricting the development of micro machining technology. The non-contact nature of electrical discharge machining (EDM) process makes it more competent in fabricating micro tools with relatively high efficiency and low cost; especially the wire electrical discharge grinding (WEDG) invented in 1985 provides a new approach and direction to fabricate micro tools; following this trend, numerous new design requirements and theoretical concepts of EDM-based processes utilized in fabricating micro tools have been proposed and studied successively, but, very few studies have been proceed from an integrated perspective. To address the gap, this study provides a comprehensive and well-arranged literature survey of the advancements made in the fabrication of micro tools using various EDM-based methods to date along with an insightful discussion on the science and application of EDM process. The critical factors influencing process performance, different numerical models, limitations, as well as possible future research direction and development in the field of micro tools fabricated by various EDM-based methods are identified and reviewed. This article is expected to help the researchers in identifying the existing gaps and contributing towards making EDM-based processes more competent in catering the trend of parameterized and non-standardized fabrication of ultra small micro tools.

Surface machined by high-speed wire electrical discharge machining (HS-WEDM) at super-high thickness (more than 1000 mm) cutting suffers from uneven surface, a major problem that has been investigated in this paper. According to the analysis, as wire frame span increases, the rigidity of the wire electrode decreases, and under the action of discharge explosive force, wire electrode vibration intensifies. As a result, the machining stability inevitably decreases. However, the core problem is whether there is enough working fluid in the slit to dampen and absorb the vibration of the wire electrode so as to ensure the positional stability of the wire electrode. To verify the above point of view: first, the wire guide and gravity take-up with bidirectional tension in the wire feeding system were installed to improve the positional accuracy of the wire electrode; second, to improve the flow of the working fluid into the slit, the slit width was increased by improving the working fluid and a medium carrier with a higher melting point and vaporization point can reduce the vaporization of the working fluid in the slit as much as possible. The experiment showed that the outlet flow of the improved working fluid is 56.72% higher than that of the original working fluid when cutting a 750 mm thick workpiece, which increases the damping and vibration absorption effect of the working fluid on the wire electrode in the long and narrow gap. After the above measures were implemented, super-high thickness cutting can be carried out continuously and steadily, the surface evenness was significantly improved, and the workpiece with a thickness of 2000 mm was cut successfully.

The blades in the high-pressure turbine section of engines of modern aerospace and defense industries need to be drilled for pressurization. The milling and drilling of nickel-base material Inconel-718 are likely to create tool wear and tear, so the drilling process of milling is extensively replaced by deep hole electrical discharge machining (EDM). However, EDM creates reaming or overcut phenomenon, so to reduce this, parameter optimization is important. This study used response surface methodology to establish the influencing factors of machining parameters in hole enlargement and machining speed. The experimental results show that the main influencing factor in the nickel-based alloy deep hole EDM is the discharge voltage; the second factor is the discharge current. The hole enlargement of the processed hole without optimization is 60 ~100 μm. The DOE is used for the measurement of hole enlargement and machining speed to design important parameters and to predict experiment data analysis. The half-normal probability graph, Pareto chart, and analysis of variance (ANOVA) are used to learn about the significant factors of parameters and the influence of interaction. The outlet value of optimized parameters was observed to be relatively uniform, and the hole morphology is relatively free of residue stacking. Finally, the inlet and outlet results improved by 17.9% compared with the original parameters. The optimization parameter value predicted by the fitted model was 0.0392 mm, and the optimized upper and lower holes validation experiment machining error was 0.0380 mm, and the values are quite close, proving that this prediction model is accurate. The model prediction of this DOE can enhance the applied technology of deep hole EDM for nickel-based alloy.

The present study establishes the optimum process condition for additive mixed electrical discharge machining of Al7075–5%B4Cp metal matrix composite by performing experimental investigation. The suspension of chromium particles in a dielectric fluid is used as an additive. The input process parameters selected for experimentation are specifically pulse on-time, gap voltage, pulse off-time and peak current, for analysing their influence on wear of the tool along with surface roughness of the composite. Comparative study of the machined surface is done by analysing microstructures, cracks and recast layers formed at different settings of input parameters using a scanning electron microscope. Rise in amount of current and pulse on-time led to increased height of the recast layer generated on the surface of the machined workpiece. Furthermore, a confirmatory experiment was performed at the optimal setting. The result revealed an error of 5.5% and 7.5% between experimental and predicted value of tool wear rate and surface roughness.

A review of the available literature on powder mixed electrical discharge machining (PMEDM) indicates that most of the research has been done for “die sinking machining mode” whereas the “wire cut machining mode” has not received due attention despite being an important process variant. This work employs silicon carbide (SiC) powder mixed dielectric fluid for machining of AISI D2 in “wire cut” mode with re-circulating molybdenum wire (an economic and chemically stable proposition as a tool). The effect of five process parameters (powder concentration, peak current, pulse on time, nozzle flushing pressure and stand-off distance) has been evaluated on surface roughness, kerf width, material removal rate, and wire wear ratio using Taguchi’s approach followed by analysis of variance (ANOVA) for determining statistically significant factors at 95% confidence level. It is found that for surface roughness, higher current and low to moderate concentration levels (2 to 4g/l) deteriorate surface quality; higher values of pressure and stand-off distance are also seen to adversely affect it. For material removal rate, pulse on time as well as its interactions with powder concentration and current, are statistically significant. A higher pulse on with smaller and moderate powder concentrations (2g/l and 4g/l) reduces MRR. For the wire wear ratio, the current is the sole significant factor (PCR of ~65%). SEM analysis of the machined workpiece for the maximum MRR condition quantifies the recast layer as ~19microns. An indirect comparison with the reported values for non-powdered EDM process indicates that for the similar wire (molybdenum), the use of SiC powder maintains the surface roughness and kerf values, for a much harder D2 material used in this work.

Adding Al and Al2O3 powder creates electrical discharge machining (EDM) in a significant machining gap with stable condition. Practically, it is almost impossible to distribute powder particles evenly into the plasma channel. This study investigates the intermolecular process while the plasma channel’s pressure and temperature are changed. In our research, surfactant Tween 80® and its effects on intermolecular forces (IMF) through the plasma channel were investigated to evaluate surface quality. In the first phase of our research, output parameters ran at three experimental blocks (without surfactant, with 21.81 g/l of surfactant, and 43.3512 g/l of surfactant) in 17 runs while adding Al and Al2O3 powders with the design of experience (DOE) method by Design Expert software. Decomposition phenomena (DP), adhesion phenomena (AP), and nonuniform distribution (NUD) of Al and Al2O3 powders demonstrated how new molecules (aluminum trihydride, aluminic acid, methyl(methylene)aluminum, hydroxy(methyl)aluminum hydride, hydroxy(methylene)aluminum, and methyl(oxo)aluminum) were created on the surface element composition. In our experiment, powders’ even distribution when we decomposed Al and Al2O3 created a more stable plasma channel. Consequently, it led to a more balanced heat transfer on the electrodes’ surface. We used scanning of surface quality by field emission-scanning electron microscopy (FE-SEM), electron dispersive spectrum (EDS), and mapping and have shown how to improve the surface defects (hole, crack, and globule). In the second phase of our research, we investigated the intermolecular forces (IMF) on Al–O bond and Al–Al bond. The percentage of elements obtained by mapping analysis of cross-section illustrated that oxygen and aluminum had increased notably when we used Al powder. Considering physical, chemical, metallurgical, and machining time management (MTM) of PM-EDM, we demonstrated that the fine finishing surface improved by 217.7% at Ip = 15 A and Ton = 50 μs and Cp = 5 g/l when the surfactant was added. We compared the best-optimized points in the final phase of our work and measured the recast layer thickness (RLT) after adding Al and Al2O3. As a result, the RTL was removed entirely when Al was added to the dielectric. We have shown that MRR (g/h) and TWR (g/h) were decreased by 5.23 and 113.36%, and SR (Ra) and machining time were increased by 21.75 and 50.84%, respectively. We note that high strength-to-weight ratio and corrosion resistance are essential for many industries, particularly aerospace and biomedical industries. We believe that these industries can potentially benefit from our study.

Electrical discharge machining (EDM) is a thermophysical-based material removal process that has excellent ability for noncontact machining of brittle and hard materials with accurate 3-D complex shapes. Improvements in machining characteristics, including the material removal rate (MRR), surface integrity, electrode wear rate (EWR), energy consumption, and negative environmental impact, are significant for further developing the performance of the EDM process. Recently, magnetic field assisted method has shown great potential and superiority for enhancing the machining process and its performance due to the ease of contactless forces. In this paper, a review was conducted on the magnetic field-assisted electrical discharge machining process. This review first presented the principles and modeling of magnetic field-assisted electrical discharge machining (MF-EDM) and then analyzed the effect of magnetic fields on machining performance including the discharge status, MRR, EWR, and surface integrity. Parametric optimization and machining characteristics of typical difficult-to-cut materials in the MF-EDM process were further investigated. Finally, future research directions and trends were suggested for exploring new applications of magnetic field assisted technology in the electromachining process.

The paper investigates the influence of boron carbide powder (B4C) mixed in dielectric fluid on EDM of Inconel X-750 alloy. The process parameters selected as discharge current (Ip), pulse on time(Ton), pulse off time(Toff), boron carbide(B4C) powder concentration to examine their performance responses on Material Removal Rate (MRR), Surface Roughness(Ra) and Recast Layer Thickness (RLT).In this study, o examine the process parameters which influence the EDM process during machining of Inconel X-750 alloy using combined techniques of Taguchi and similarity to ideal solutions (TOPSIS).Analysis of variance (ANOVA) was conducted on multi-optimization technique of Taguchi-TOPSIS. ANOVA results identified the best process parameters and their percentages. It developed the mathematical equation on Taguchi-TOPSIS performance characteristics results. The multi optimization results indicated that Ip and Toff are more significant parameters; V, and Ton parameters are less significant. Finally, surface structures were studied at optimized EDM conditions by using scanning electron microscope (SEM).

The present paper concerns with studying the high complexity nature of the EDM multiple discharge analysis transformed into a feasible solvable mathematical model for the die steel workpiece type AISI D2, the copper and graphite materials electrodes, and the kerosene dielectric by setting the Transient Thermal and the Multiphysics analyses domain loads models using the ANSYS 15.0 finite element analysis. Two load steps modeled the entering setting time analysis, six sub-periods setting time cycle, four heating, and two cooling periods, six transient temperature values, and four transient thermal convection models. The radius spark (discharge channel), the total number of discharges sparks, the total heat power generation, the absorbed heat flux fractions by the electrodes, the workpieces and kerosene fluid dielectric, the heat-affected zones (HAZ), the hard white recast layer thickness (WLT) and properties, the workpiece fatigue safety factor and life after EDM machining were determined and simulated. The thermal model errors compared with theoretical calculations and a modeled predicted equation were also deduced and verified. The experimental results evinced that the maximum total heat flux generated using the graphite material electrodes is (2.619E+009 W/m2) which is higher than when using copper material electrodes by (82.4%), while the minimum value of the white layer thickness (WLT) after EDM machining using graphite tool electrodes is (8.34 μm), which it gives an improvement comparing with using of copper tool electrodes by (40.0%). The macrographic and microstructure evaluation manifest that the discharge spark craters sizes when using graphite tool electrodes reached their sizes. The maximum fatigue stresses and fatigue safety factor when using copper tool electrodes are (240 MPa) and (0.89) which is higher by a value of (3.35%) and (3.45%) comparing with the using of graphite electrodes, respectively.

To meet the increasing demand for wire electrical discharge machining (WEDM) under extreme conditions such as ultra-high thickness cutting, micro-wire cutting, micro-energy finishing, and ceramic composites machining, a concept of multichannel discharge WEDM under semiconductor characteristics was proposed. The essence of this conception is that under these extreme machining conditions, the electrode wire or workpiece — or even both of the two electrodes — cannot be treated as electrically conductive materials of the conventional WEDM due to their high electrical resistance. However, they can exhibit electrical discharge behavior like semiconductors, which is defined as semiconductor characteristics. The conventional WEDM theory and related technologies cannot be applied to extreme WEDM because conventional WEDM only has one discharge channel per pulse, whereas multiple discharge channels can be generated by each pulse in extreme WEDM. Therefore, a suitable theory needs to be developed for extreme WEDM under semiconductor characteristics. Based on the multichannel discharge behavior of semiconductors, experiments were conducted on high-efficiency machining with multichannel discharge by stacking several workpieces as an assembly with semiconductor characteristics. It was proved that the multichannel discharge WEDM is capable of achieving high machining efficiency, as well as enhanced surface quality and lower wear of electrode wire. The proposed multichannel discharge WEDM sets up the foundation for the establishment of the theoretical system of EDM under semiconductor characteristics.

This study focused on the mathematical modeling and multi optimization of Electrical discharge machining (EDM) of non-conductive SiC ceramic. As SiC is a bad conductor of electricity so addition of 6vol % Multi wall Carbon Nano tube (MWCNT) makes it a conductor of electricity which can be machined by EDM. The addition of MWCNT as reinforced material further enhances the machining characteristic of SiC ceramic composite. This SiC-CNT ceramic composite has an excellent uses on sensor, bio-sensor, heat exchanger and automobile industries, etc. For this, a three-dimensional axi-symmetric computational domain has been established with the help of COMSOL multiphysics software. In this study, a varying fraction of heat (Fc) factor has been introduced for predicting the material removal phenomena. From the experimentation, it has been cleared that in between 7 to 8% Fc the thermal model gives nearly accurate result. The effect of process parameters viz. current (I), voltage (V), Pulse-On time(Ton) and Duty Cycle (Dc) on the performance measures viz. material removal rate (MRR), Plasma Flushing Efficiency (PFE), Recast layer (Rlt) and Surface Roughness (SR) has been analyzed to enhance the productivity by EDM. For the highest MRR 9.7 mm3/min but the corresponding Surface roughness achieved 6.5 µm. Regression equation has been developed for predicting the effect of input parameters on the output parameters. Finally, by Desirability analysis the optimize set of input parameters i.e., I = 3A, V = 30 V, Ton = 75 µs and Dc = 5% has been achieved for machining ceramic matrix composite by EDM. This setting gives MRR as 7.19 mm3/min whereas PFE as 84%.

Electrical Discharge Machining is one of the non-conventional machining processes used for electrically conductive material. It is widely used for manufacturing complicated parts which are tough to be produced by conventional manufacturing processes. It is based on thermoelectric energy between workpiece and electrode. Metal is removed by melting and vaporizing because of spark occurs in the gap between electrode and workpiece. Workpiece and electrode must have electrically conductive to generate a spark. The performance of the EDM process is largely depends on the electrode. Electrode is considered as tool in EDM process. Selection of the electrode material plays vital role in the EDM process. Different electrode materials have different properties. Hence, the performance of the EDM process changes with different materials. Researchers have used different materials as electrode to investigate the effects of materials and to improve the performance of EDM process. This paper reviews the research work carried out in the field of materials and manufacturing methods for electrodes in EDM process. Keywords: [EDM, Electrodes, Materials, Manufacturing Process].

This paper presents the experimental investigation on cutting of thin carbon fiber-reinforced polymer (CFRP) composite plate by wire electrical-discharge machining (WEDM) with the aid of sandwich assisting-electrodes. The difficulties such as incomplete cut and deviation in machining path during WEDM of CFRP were avoided by using metal plates (H13 steel) as assisting-electrodes. The spark initiation during WEDM of CFRP is difficult without exposing the carbon fiber as fibers are embedded into nonconductive polymer in CFRP. Thus, in this work, assisting-electrode was used to initiate the sparking without changing the surface integrity of the CFRP. The one-factor-at-a-time analysis was applied to study the effect of input parameters namely input current (2, 4, 6, 8, 10, and 12 A), pulse on time (10, 20, 30, 40, 50, and 60 µs), pulse off time (10, 20, 30, 40, 50, and 60 µs), and voltage (70 and 90 V) on the cutting time and the machined surface morphology. A decreasing trend was observed for cutting time with an increase in the current. Whereas, the cutting time was increased with an increase in the pulse off time. It was also observed that the cutting time initially increased with the pulse on time (10 to 30 µs) and then started decreasing with a further increase in the pulse on time (40 to 60 µs). The cutting time was significantly reduced at a higher level of voltage (90 V) when compared one-on-one with lower voltage level (70 V). In this study, microscopic analysis of the surface morphology was also extensively investigated which was not investigated earlier. The investigation showed damages such as breakage of carbon fibers, fiber-matrix debonding, and matrix cracking during WEDM of CFRP using sandwich assisting-electrode.

A hybrid manufacturing method consisting of micro-electrical discharge machining and focused ion beam milling to fabricate single-crystal Cu micropillars with a diameter of several tens of microns or more was proposed. The method first utilized micro-electrical discharge machining, which adopted a micro-tool made of WC-Co material, to fabricate the coarse micropillars, one by one. It took approximately 70 s to fabricate each coarse micropillar. Seventy-six coarse micropillars were fabricated in the process of exploring optimum input parameters of supply voltage and capacitance value. Energy dispersive spectroscopy and electron backscatter diffraction analyses revealed that pristine Cu material could be obtained by removing only 1.2 μm of surface layer. The micropillar was finished using a focused ion beam to form a 15 μm diameter smooth micropillar with an aspect ratio of 3. The desired micropillar was produced by removing a surface layer of 6 μm or more from the side surface to avoid the micro-electrical discharge machining effect. It took approximately 2.5 h to complete the fabrication of a micropillar by stepwise annular milling. In the case of the hybrid method, it was possible to fabricate a high-quality micropillar 17 times faster than the focused ion beam only method.

EDM machines are expected to become more advanced in the future and enhance the productivity and efficiency of the system. Literatures are evident that research interest in electrical discharge machining process has significantly increased in past decade. EDM process involves the erosion of workpiece through spark which includes melting and vaporization, material transformation from tool, repeatedly solidifications and thermal decomposition of dielectric fluid. This paper aims to provide a brief review of surface modification during electrical discharge machining process.

Advanced methods of material removal have been developed for accomplishing the complications in traditional methods of machining and appealed to be a suitable alternatives for conventional machining processes. Wire Electrical Discharge Machining (WEDM) is the variant of Electrical Discharge Machining concept and one among the available method of advanced machining which has especially employed for machining of complicated shapes in harder materials. Apart from these machining methods adopted, the predictive models or intelligent decision making tools which will be helpful to the manufactures for attaining benefits in various applications. Aluminium is one of cheapest and most commonly employed engineering materials that are used for numerous applications. For enhancing the properties of aforementioned material, it is accomplished with the addition of reinforcement element. This present study is discussing about the investigation and development of hybrid ANFIS model for WEDM process. The experiments are planned and analyzed by Taguchi’s approach. Grey Relational Analysis (GRA) is employed for attaining Grey Relational Grade (GRG) by estimating the Grey Relational Coefficient (GRC) values. An ANFIS predictive model has been proposed to predict the GRG values. The model has been developed with the combination of Grey system theory. The performance of developed model has been analyzed with the predicted values.

Inconel 625 is one among the hard to machine material and extensively used in high temperature applications. It has better strength and lower thermal coefficient that leads to poor machining by traditional methods of machining. To overcome such kind of disadvantages, unconventional method of machining processes have been developed and proposed to be a suitable substitute method for conventional methods of machining. Wire Electrical Discharge Machining (WEDM) is one of the variant developed from the perception of Electrical Discharge Machining process that is predominantly employed for machining of difficult to machine alloys and also for making complex shaped components. In this analysis, a study has been done on WEDM of nickel based superalloy and primarily focusing on optimizing the process parameters for machining of Inconel 625 by using Taguchi’s analysis. The experimental runs are planned by Taguchi’s DoE approach. The experiments have been performed by considering the process parameters such as pulse on time, pulse off time and peak current at three various levels. Material removal rate and overcut are the desired performance measures considered in this analysis. Contour plot analysis has been done for disclosing the combine effect of process variables on desired performance measures. Analysis of Variance (ANOVA) has been used to determine the importance of independent variables on the desired dependent variables. From this experimental analysis the influence of individual process parameters on the response parameters have been studied.

The integration of low frequency vibration with the workpiece can enhance the machining efficiency in die sinking electrical discharge machining. Since the adaptation of vibration increases the complexity in such process, the optimization of the process parameters is very important. In the present work, a research attempt has been made on Taguchi based single- objective optimization of vibration assisted die- sinking electrical discharge machining process while machining SKD61 die steel. The process parameters such as pulse current (I), pulse on- time (TON), pulse off- time (TOF), frequency of vibration (F) have been selected as input factors for investigation. Material removal rate has been chosen as quality indicator. From the experimental investigation, it has been found that material removal rate has been significantly improved by integrating vibration into the workpiece. The optimal combination of process parameters has been found with the accuracy of 6.90%.

Wire Electrical Discharge Machining (WEDM) is a contemporary approach of material removal which is conceived from the concept of Electrical Discharge Machining (EDM), predominantly employed for machining of hard to machine materials and also especially used for making difficult shapes on any electrically conductive work material. AA 2024 is an aluminium alloy, generally used as important material for various engineering applications such as aircraft structural applications. The outstanding properties of AA 2024 alloys makes this material to be best suitable for various engineering applications. The parts employed for aerospace applications needs very much nearer tolerances and more accurate shape and size. In this present study an experimental investigation has been done on WEDM of Al-MMC (Aluminium 2024 alloy + Al2O3). Pulse on time ‘Pon’ (µs), Pulse off time ‘Poff’ (µs), and peak current (A) are considered as input process parameters in this present analysis. Material Removal Rate (MRR) and Surface Roughness (SR) are considered as preferred performance measure that are need to be improved. Taguchi’s approach has been adopted for designing and analyzing the experiments. An L27 Orthogonal Array (OA) was employed for conducting the experimental runs. The influence of process parameters on desired outputs such as MRR and SR were examined by Taguchi’s analysis. Multiple regression analysis has been developed for correlating the relationship amongst the selected input process variable and preferred outputs.

Wire Electrical Discharge Machining (WEDM) is one of advanced method of machining conceived from the concept of Electrical Discharge Machining. Unconventional method of material removal processes have been developed to overcome the difficulties in making of complex shapes in any electrically conductive work material by conventional machining methods. Stellite is a difficult to machine superalloy and extensively used in wear environments where its low friction coefficient minimizes the risk of seizing and galling. It possess good strength and lower thermal diffusion results in decreased tool life and poor machinability by conventional methods of machining. The present work details the multi objective optimization of WEDM process parameters by Taguchi-Grey approach. The experimental runs are planned by Taguchi’s design approach and Taguchi’s approach single objective optimization technique was employed for attaining the best possible process parameters combination for obtaining better machining performance. The experiments have been performed by considering the process parameters such as pulse on time, pulse off time and wire tension at three various levels. The ascendency of process variables are determined by ANOVA analysis. Taguchi - Grey methodology has been adopted for the WEDM process and optimum process parameters are determined for attaining improved multi performance characteristics.

Inconel 718 one of the Superalloy which is a high performance material that possess special features such as better mechanical properties, creep strength, oxidation and corrosion resistance and thermal resistance and considered as a difficult to machine material because of its poor machinability by traditional machining methods due to its low thermal diffusivity and high strength. To overcome such kind of shortcomings, nontraditional approach of material removal processes have been developed and expected to be a suitable substitute method for traditional methods of machining. Wire Electrical Discharge Machining (WEDM) is one of the variant developed from the perception of Electrical Discharge Machining (EDM) process that is predominantly employed for machining of hard materials and also for making complex shaped components. In this present work, the machinability study on WEDM of Inconel 718 has been discussed with special attention on parametric optimization by Taguchi’s single response approach. The experimental runs are planned by Taguchi’s DoE approach. The experiments have been performed by considering the process variables such as pulse on time, pulse off time and peak current at three various levels. The ascendency of process variables are determined by ANOVA analysis. Taguchi - Grey methodology has been adopted for the WEDM process and combination of process variables are determined for accomplishing improved multi performance characteristics.

In this paper, the outcomes of an investigation conducted on the sustainable manufacturing of asymmetric rotary miniature-sized ratchet wheels of stainless steel (SS) 304 by a vertically traveling wire electrical discharge machining (WEDM) process are reported. The consumptions of energy and wire material are the process sustainability indicators considered in this work. Box-Behnken-based seventeen experiments were conducted by varying spark-on-time ‘Ton’, spark-off-time ‘Toff’, and wire rigidity ‘WT’. Desirability function analysis (DFA) based on multi-response optimization was performed to obtain an optimum setting of WEDM parameters to manufacture miniature-sized ratchet wheels with minimum energy and wire consumption. Sustainable manufacturing of ratchet wheels is performed at the optimum parameter combination of Ton-1.5 µs; Toff-40.5 µs; WT-1260 g, for the least values of energy consumption of 0.64 kWh and wire consumption of 20.11 g with no wire breakage and a significant reduction in total idle time. This ratchet wheel, manufactured at optimum parameters of WEDM, was also found to have a good finish (average surface roughness ‘Ra’-1.08 µm and maximum surface roughness ‘Rt’-6.81 µm) and defect-free tooth flank surfaces. Overall, it is concluded that WEDM has the potential to achieve sustainability in the manufacturing of miniature-sized ratchet wheels and other gears. The outcomes of this work will extensively facilitate engineers and researchers in selecting a suitable range of machining parameters for sustainable manufacturing of miniature-sized wheels and gears.

Advanced modeling and optimization techniques are imperative today to deal with complex machining processes like electric discharge machining (EDM). In the present research, Titanium alloy has been machined by considering different electrical input parameters to evaluate one of the important surface integrity (SI) parameter that is surface roughness Ra. Firstly, the response surface methodology (RSM) has been adopted for experimental design and for generating training data set. The artificial neural network (ANN) model has been developed and optimized for Ra with the same training data set. Finally, an adaptive neuro-fuzzy inference system (ANFIS) model has been developed for Ra. Optimization of the developed ANFIS model has been done by applying the latest optimization techniques Rao algorithm and the Jaya algorithm. Different statistical parameters such as the mean square error (MSE), the mean absolute error (MAE), the root mean square error (RMSE), the mean bias error (MBE) and the mean absolute percentage error (MAPE) elucidate that the ANFIS model is better than the ANN model. Both the optimization algorithms results in considerable improvement in the SI of the machined surface. Comparing the Rao algorithm and Jaya algorithm for optimization, it has been found that the Rao algorithm performs better than the Jaya algorithm.

The scientific paper presents an extensive research on modeling and optimizing the technological parameters of the process for processing by processing electric discharges with massive electrode with and without magnetic activation. Scientific research is based on real data collected from the process of electrical discharges performed on various samples extracted from areas of welded joints of metal components made of high alloy steel. The processing of experimental data was performed both classically and actively, especially the method of the central factorial experiment composed of orthogonal and rotary. The process parameters that were initially modeled and subsequently optimized were based on a series of independent variables characteristic of dimensional processing by copying the shape of the electrical discharge processing. Subsequent research conclusions and directions, as well as original contributions, are an experimentally validated point of view and worthy of consideration. All these fundamental ideas highlighted above find their explanations and the corresponding explicit treatment in the content of this scientific paper that addresses both managers at all levels and researchers.

Emerging trends toward miniaturization and growing demands have led to fabricate the nanofeatures size product for electronics, robotics, aeronautics, biomedical, automobile, and Bio-MEMS sectors. ...

Mathematical models are obtained for the temperature fields at the surface of a coated polymer tool electrode and a workpiece electrode in electrical discharge machining (EDM). In electrical discharge machining with a coated polymer tool electrode, the temperature distribution at the surface of the tool is nonuniform. That may disrupt the applied coating. Models of the temperature distribution within the workpiece at the instant of a single pulse are derived. Structural changes at the machined surface of the workpiece may be predicted.

Electrolytic plasma polishing may be used to improve the surface quality of ЭП517ш steel after wire-cut electrical discharge machining (EDM). With increase in polishing time from 0 to 900 s, the surface roughness Ra declines by almost 70%. Surface destruction of the sample under the action of microplasma discharges is most intense on sections with 20°–30° tooth sharpening. In using wire-cut electrical discharge machining with subsequent electrolytic plasma polishing, the destruction of thin sections of the machined workpiece under the action of microplasma discharges must be taken into account, with correction of the workpiece size in wire-cut electrical discharge machining.

In the present work, wire electrical discharge machining (WEDM) has been investigated for surface characteristics and corrosion behavior of Mg-4Zn alloy. Using Taguchi’s design of experiment technique, the influence of WEDM parameters, namely spark-on time, spark-off time, and servo voltage, has been studied on surface roughness (SR) and corrosion rate (CR). SEM observations showed that WEDM processing has a significant influence on the surface modification of Mg-4Zn alloy. Increasing discharge energy in the WEDM process has resulted in large surface craters, a higher density of micro-cracks, and micropores resulting in higher SR and accelerated CR in Mg-4Zn alloy. Corresponding to minimum SR and CR, the optimal set of WEDM parameters has been selected to prepare the WEDMed Mg-4Zn samples that were further analyzed for electrochemical polarization, apatite formation, and weight loss in simulated body fluid (SBF) and were additionally compared to polished samples of Mg-4Zn over a period of 21 days. Electrochemical polarization tests demonstrate that the CR increases rapidly upon the exposure time of 7 days; beyond that, the CR decreases with further exposure time up to 21 days. Initially, up to 24 hours, WEDMed samples showed better electrochemical corrosion resistance, whereas, later on, polished samples demonstrated an increased corrosion resistance for up to 21 days. Higher mineralization (or apatite formation) has been observed on WEDMed samples, which directly affects the amount of Mg ions released into the SBF solution; thus, weight loss was higher in the WEDMed sample than the polished sample. The weight loss for polished and WEDMed Mg-alloy samples after 21 days of immersion test was 9.3% and 13.5%, respectively. SEM analysis revealed the distinct corrosion morphology among the corroded surface of polished and WEDMed samples.

Micro-electrical discharge machining (μEDM) is an unconventional machining method that is suitable for machining of conductive materials including highly doped silicon (Si) wafers. This paper reports a novel method of heat-assisted μEDM machining of Si wafers by varying the temperature to increase the electrical conductivity of Si. In order to achieve this condition, a ceramic heater is used to heat the Si wafers within the temperature range of 30–250 °C. In this study, the machining performances in terms of the material removal rate, tool wear rate, surface quality, and materials characterization have been investigated accordingly. The machining performance of p-type (1–10 Ω cm) Si wafers was investigated to machine a cavity based on different temperatures with a constant discharge energy of 50 μJ and a feed rate of 50 μm/min. The results indicated that increasing the machining temperature allowed achieving a higher material removal rate, lower tool wear rate, and lower surface roughness. The highest material removal rate of 1.43 × 10−5 mm3/s and a surface roughness of 1.487 μm were achieved at 250 °C. In addition, the material removal rate increased by a factor of ~16 times compared to the results obtained at the lowest temperature, 30 °C, and the Raman spectroscopy analysis revealed that no significant changes occurred in the Si structure before and after machining.