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In electrical discharge machining (EDM), it is a much more effective method to improve working characteristics by changing the input process of pulse energy. However, it has not been investigated enough whether pulse form is the most adequate or not. In this study, the effect of superimposed pulse current waveform and its parameter on surface integrity was investigated. The surface topography, roughness, microstructure, white layer thickness, and residual stress were analyzed and discussed. Moreover, the material removal rate was also tested and compared. The results show that with the backward movement of the superimposed pulse current, the material removal rate and surface roughness decrease, while the white layer thickness, residual stress, and surface defects increase. The current waveform has little influence on microstructure. Under the same pulse discharge energy and pulse-on time, the samples processed by superimposed pulse current waveform instead of rectangular current waveform can obtain a thinner white layer, lower residual stress, fewer surface defects, and high surface roughness. With the increase of superimposed pulse-on time and current, the surface integrity becomes worse due to the increase of pulse energy. This paper provides a guide to the development and selection of EDM discharge current waveforms in EDM. [ABSTRACT FROM AUTHOR]

The exploration of Electrical Discharge Machining (EDM) with coated electrodes represents a relatively novel research avenue, thereby yielding limited published research outcomes. The choice of coating material plays a pivotal role in the EDM machining process, and alterations in coating materials can directly influence the adjustment of technological parameters in EDM. Consequently, research dedicated to optimizing these technological parameters for EDM employing coated electrodes is of paramount importance, and it promises to advance the practical implementation of this cutting-edge technique. In this study, we systematically investigate the technological parameters for EDM employing a copper-coated aluminum electrode in the context of Ti-6Al-4V machining. Our research outcomes are framed within a multi-objective optimization paradigm, with a focus on Material Removal Rate (MRR) and Surface Roughness (SR) as vital quality indicators. To address the intricate multi-objective optimization challenge, we have harnessed the combined power of the Taguchi methodology and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The amalgamation of these techniques enables us to navigate the complexities of EDM parameter optimization effectively. Our findings reveal that the most favorable process parameters entail a configuration of U=40V, I=40 A, Ton=1000μs, resulting in an MRR of 0.028mg/min and an SR of 7.56μm. These optimized parameters exemplify a substantial enhancement in machining efficiency and surface quality when utilizing coated electrodes. Moreover, our study scrutinizes the quality of the machined surface under optimal conditions with coated electrodes. We employ the TOPSIS method as a proficient solution for this endeavor, offering a straightforward approach to this intricate calculation process. [ABSTRACT FROM AUTHOR]

Micro electrical discharge drilling (ED-drilling) is a machining method used to make micro holes in hard-to-cut materials. The RC-discharge generator is often used because it creates a short and strong discharge spark. However, this method has issues such as current oscillation between tool electrode and workpiece, causing polarity changes that increase tool wear, and a low material removal rate due to long spark delay time. Furthermore, micro ED-drilling results in a large taper angle due to second discharge sparks created by debris in the narrow gap. To address these issues, the effect of adding graphite powder to the working fluid was studied. The graphite powder in kerosene created a bridge effect that reduced tool wear and taper angle, while improving MRR and surface roughness. The electrical conditions were not changed, and the machining process was improved by only altering the working fluid without modifying the existing system. [ABSTRACT FROM AUTHOR]

This research paper explores the impact of electrical discharge machining process parameters, including current, pulse‐on time (Ton), and pulse‐off time (Toff), on the material removal rate (MRR) and surface roughness (SR) during the fabrication of aluminum silicon dioxide (Al7075–SiO2) composites. The Al7075–SiO2 composites were produced through stir casting, incorporating 10% by weight of SiO2 reinforcements with an average particle size of 54 µm. To systematically investigate the process parameters' effects, Taguchi's L9 orthogonal array was implemented in the design of experiments. Subsequently, the experimental data underwent analysis of variance (ANOVA) for thorough analysis. The response table for MRR and SR demonstrated that the current significantly influenced both responses (MRR and SR). The ANOVA results provided valuable insights into the percentage contribution of each parameter to the responses. Through the analysis, the optimal control variable settings for achieving the highest MRR were identified as a current of 3 A, a pulse‐on time of 1500 µs, and a pulse‐off time of 1 µs. Conversely, to attain the lowest SR, the ideal control variable settings were determined to be a current of 1 A, a pulse‐on time of 500 µs, and a pulse‐off time of 1 µs. Results also suggest that the error was within admissible range of 5% and the percentage contribution of the current (70.19%) had the largest effect on MRR. [ABSTRACT FROM AUTHOR]

Electrical discharge machining is a versatile machining technology that uses precisely directed sparks within the range of the dielectric fluid and between the electrodes to make electrically conductive products. The influence of different processing parameters on diverse metal matrix composites, including new reinforcing elements (silicon carbides, aluminium oxides and nitrides), and the modifications that occur as a consequence of each of these components are discussed in this article. As a result, new reinforcing materials and ways for optimising performance have emerged. The goal of this study is to provide analysts with research data that will allow them to effectively use EDM principles and, more particularly, to investigate process characteristics in order to enhance the process of advanced PMEDM operation. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is widely applied for machining difficult-to-cut materials in mold and die industries. However, the major limitations associated with the EDM are low productivity and poor surface integrity of the machined surfaces. In recent years, several developments have been applied to overcome such limitations of EDM. Electrical discharge grinding (EDG) is a hybrid machining process that simultaneously involves the spark erosion action of EDM and the mechanical abrasion action of the grinding wheel for the material removal purpose. The rotating motion of the grinding wheel also contributes to the easy removal of debris particles, thereby improving the material removal. It is evident from the literature that the rotating motion of the grinding wheel enhances the flushing mechanism resulting in better performance of the process. This paper aims to present a comprehensive review of the research carried out in EDG, highlighting the result of the experimental, modeling, and optimization techniques applied in this area. Initially, the background of EDM and the need for hybrid EDM processes have been presented. Then, a few hybrid EDM processes have been discussed, addressing their advantages and limitations. Further, the concept of EDG and electrical discharge diamond grinding (EDDG) has been discussed, along with the classification of the EDDG process. Finally, this paper explores the current research status and future research perspective in the area of EDG and EDDG processes. [ABSTRACT FROM AUTHOR]

Modern industry is focused on looking for new and effective technologies to manufacture complex shapes from alloys based on nickel and chromium. One of the materials widely used in the chemical and aerospace industry is Hastelloy C-22. This material is difficult to machine by conventional methods, and in many cases, unconventional methods are used to manufacture it, such as electrical discharge machining (EDM). In the EDM process, the material is removed by electrical discharges between a workpiece and a tool electrode. The physical and mechanical properties of the tool electrodes have a direct impact on the process efficiency, machining accuracy, and surface roughness. Currently, there has been a significant increase in the use of graphite as a material for tool electrodes due to the low purchase cost of the raw material, good machinability, and high sublimation temperature. In this work, an experimental investigation of the influence of the grain size of the graphite tool electrode on material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra) of Hastelloy C-22 was carried out. Two POCO graphite tool electrodes with a grain size of 1 µm (AF-5) and 10 µm (S-180) were used. Based on the experimental studies, empirical models describing the influence of machining parameters on technological indicators and the condition of the surface texture were determined. The research indicates that graphite with a larger grain provides higher process efficiency with high relative wear of the tool electrode. The lowest surface roughness was obtained for graphite with a smaller grain size (AF-5). The analysis of the machining parameters proves that the discharge current and pulse duration are the main factors determining the MRR and Ra values for both AF-5 and S-180 graphite. The time interval is the dominant parameter with regard to the relative wear of the graphite electrode. [ABSTRACT FROM AUTHOR]

Recent developments in material science have concentrated not only on the improvement in mechanical properties, but also on the machinability that was difficult for system profiles. The present research explains the machinability assessment of the part of the sintered powder metallurgy using an electric discharge machining. The ferrous clay matrix preparations are constructed from iron–carbon–copper material and bentonite clay. The selected input parameters for the measurement of machinability are wt. % of clay, current (A), pulse on time (µs) and voltage (V), whereas the electrode wear rate, material removal rate and surface roughness (Ra) are considered as performance features. Results show that the performance parameters have been optimized at three different parametric conditions. Further, to obtain single optimum condition the hybrid GRA-TOPSOS methodology has been implemented for maximum MRR with minimum EWR and low surface roughness. The single optimum condition has been found at 5% clay, current 7 A, voltage 49 V and pulse on time 400 µs. The study of micro-structure and chemical composition of machined surfaces has been carried out using scanning electron microscopy with X-ray diffraction and energy-dispersive spectrometry analysis, respectively. The SEM exposes the less recast layer and micro-cracks during electrical discharge machining of ferrous clay composite. [ABSTRACT FROM AUTHOR]

The most important cost element of electric discharge machining (EDM) is the production of tool electrode (shortly electrode). In the EDM process, copper and its alloys are often used as electrode materials. The machining with EDM without increasing the costs can be achieved by selecting the proper electrode with low production and material costs as well as high workpiece material removal rate (MRR), low electrode wear rate (EWR), and relative wear (RW = MRR/EWR). In this study, the EDM performance outputs, namely, MRR and RW were experimentally investigated for electrolytic copper, CuCr1Zr (with and without aging treatment) and CuCo2Be alloy electrode materials for varying machining parameters. The performance outputs were affected by the electrode material and the applied aging treatment. The aged CuCr1Zr alloy electrodes had higher electrical conductivity and better machining performance than the as-received alloy. The CuCo2Be alloy electrodes exhibited moderate to high MRR; however, their RW was the highest. Although the electrolytic copper has moderate MRR performance compared to the investigated alloys, its low cost increased its performance index, making it a more suitable electrode material for EDM applications. [ABSTRACT FROM AUTHOR]

In this research work the thermal modeling of a nonconductive Silicon carbide Ceramic matrix composite (CMC) machined by Die Sinking Electric Discharge Machining (EDM) has been done. Though SiC is a non-conductive material but the presence of CNT makes it a conductive material which can be machined with EDM. The modeling procedure carried out by considering some realistic approach like Gaussian heat Flux, Specific Discharge Energy, Variable Latent heat etc. For this analysis a 2D continuum has been designed as work domain. By simulating the work domain model by a Finite Element Analysis (FEA) Software (COMSOL), material removal rate (MRR) has been estimated with variable thermal properties. Parametric analysis of effect of Variable Specific heat on MRR by considering different current, Voltage and Pulse-On time has been performed. The effect of different input parameters (peak current and Pulse-on time) on Crater geometry has been done. A new concept of Specific discharge energy has been introduced during modelling to make it a more realistic model which can also be used as electrode support for electrochemical energy devices as Polymer Electrolyte Membrane Fuel Cells on Li-ion battery. Desirability analysis has been done to get an optimize set of input parameters for I= 3A, V=30V, Ton= 75 μs for machining ceramic matrix composite by EDM. The optimized MRR at this setting is 7.25 mm3/min whereas PFE is 87%. The experimental analysis has been also performed to strengthen the thermal and mathematical modelling. [ABSTRACT FROM AUTHOR]

The paper details a comprehensive experimental investigation on the influence of operating parameters and cut direction (parallel and perpendicular to fibre orientation) when wire electrical discharge machining (WEDM) unidirectional CFRP composites using zinc-coated brass wire (0.25-mm diameter). A Taguchi L18 fractional factorial orthogonal array considering four variable parameters including open voltage, ignition current and pulse-on time as well as pulse-off time was carried out for each cut direction. Results showed that a ~ 16% increase in maximum material removal rate was achieved when machining parallel to fibre direction (2.41 mm3/min) compared to cutting perpendicular to the fibres (~ 2.08 mm3/min), which was attributed to the higher electrical conductivity of the workpiece along the fibre length leading to greater discharge energies. This however resulted in relatively larger average kerf widths and poorer workpiece surface roughness (Sa) caused by the Joule heating effect. Workpieces machined parallel to fibre direction were generally free of any major edge defects, in contrast to severe delamination observed on both the top and bottom surfaces of specimens cut perpendicular to fibre orientation. High-magnification scanning electron microscopy of the machined surfaces revealed the presence of adhered resin material, fibre cracking, cavities/gaps in the matrix phase and interlayer cracks on most of the samples analysed, with damage severity dependent on the operating parameters and cut direction. [ABSTRACT FROM AUTHOR]

In this study, the effects of low-frequency vibrations on machining SKD61 steel workpiece in electrical discharge machining (EDM) with titanium powder-mixed dielectric fluid were investigated. The results showed that the vibrations incorporated into the workpiece in powder-mixed EDM (PMEDM) led to significant improvement in machining efficiency. The material removal rate had the maximum increase of 141.7% with 70.2% of lower electrode wear rate and 69.9% of lower surface roughness. Hence, it is proved that the effectiveness of vibration in PMEDM can be improved. [ABSTRACT FROM AUTHOR]

The modern industry which widely utilized sinking electrical discharge machining (EDM) with kerosene has many problems including low processing efficiency, unsafety, unfriendly environmental impact, and poor machined surface accompanying with recast layer. In this paper, a new water-in-oil (W/O) nanoemulsion dielectric is proposed to overcome these shortcomings of conventional sinking EDM. The machining performance and mechanism of sinking EDM using W/O nanoemulsion are investigated in both rough and finishing machining by comparing with kerosene. The main characteristic parameters for evaluating machining performance, including material removal rate (MRR) and relative electrode wear rate (REWR) in rough machining, and machined surface quality in finishing machining are studied. Compared with kerosene, using W/O nanoemulsion as a dielectric in sinking EDM, a nearly 34 times higher MRR and a relatively lower REWR are obtained in rough machining, and a better machined surface with no recast layer is attained in finishing machining. [ABSTRACT FROM AUTHOR]

Beryllium Copper (Be-Cu) alloy are advanced engineering alloy bearing high strength, high wear resistance, Corrosion resistance and nonmagnetic nature. These properties of Beryllium copper make it impossible to machining through Conventional machining process. Electrical Discharge machining (EDM) is a revolution to machine any type of harder material (Electrically conductive) without any physical pressure. EDM is best suitable to machine Be- Cu alloy for small holes and intricate shape used in heat exchanger. To know the best suitable input parameters for improving the machining efficiency of EDM numerical analysis is always required. In this study a mathematical modeling of Be-Cu alloy machined by EDM has been performed by finite element modeling (FEM) method. A 3D axi-symmetric computational domain has been considered for the analyses confined by proper boundary condition. The numerical simulation has been performed for single discharge machining. The model has been validated with the experimental results. Simultaneously the Material Removal Rate (MRR) has been calculated with varying Discharge Current (I) (8, 10, 12 A), Fractions of heat (Fc) (18 %, 20 %, 22 %) and Pulse On time (Ton) (100,150, 200 μS). The lowest error of 4.55 % (in MRR) between numerical model and experimental results has been determined at 10A current. [ABSTRACT FROM AUTHOR]

This research paper deals with the study of the thermal modeling of Al-A359 reinforced with 10 % SiC Composites (Particulate metal matrix Composite) machined by Electrical Discharge machining (EDM). The composite has been fabricated by Powder metallurgy (P/M) route. Due to high hardness of the Graphite reinforced particle it has been always difficult to machine these composites by the conventional machining route. In this investigation EDM procedure has been introduced to machining the PMMC. The numerical model has been developed by designing a 3D axi-symmetric work domain with the help of Finite analysis software. The effect of variable thermal properties on the modeling of PMMC is also introduced in this study. The effect of three different types of heat source (Disk heat, Point heat & Gaussian heat source) on the Al-A359 Composite machining has been analyzed. From the analysis it can be concluded that the Gaussian heat source model with varying Specific heat (Model-III) has been validated with the experimental result with least error of 11 %. The highest Material removal rate of 25.12 (*10-3 mm³/min). At 10 A current, 100V voltage and 100µS Pulse-On time has been estimated. [ABSTRACT FROM AUTHOR]

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

In this paper, an inexpensive auxiliary tool vibration device is described that improves the efficiency of deep groove electrical discharge machining (EDM). Titanium alloy samples (Ti-6Al-4V) were machined using two different methods: unassisted normal EDM and vibration-assisted EDM, using copper, copper-tungsten, and graphite tool electrode materials. The vibration-assisted EDM machining was done at 40, 90, and 140 Hz, and the material removal rate, tool electrode wear rate, and surface roughness of the specimens were compared. Experimental results revealed that the material removal rate with vibration-assisted EDM was better than that obtained using unassisted EDM with copper and copper-tungsten electrodes. In this study, the vibration frequency was found to have an optimum value of 90 Hz with respect to surface roughness. It was found that the machining time for a groove 10 mm deep with vibration-assisted EDM was reduced by 200% compared to unassisted EDM. This new vibration device can help in the development of a more efficient deep groove EDM. [ABSTRACT FROM AUTHOR]

Electrical discharge machining is a non-conventional machining method that is used for machining of hard-to-machine materials, components in which length to diameter ratio is very high or products with a very complicated shape. The process is commonly used in automobile, biomedical, chemical, aerospace, tool and die industries etc. It is very essential to select optimum values of input process parameters to maximize the machining performance. In this paper an attempt has been made to carry out multiobjective optimization of the surface roughness (SR) and material removal rate (MRR) for the EDM process of EN 19 on a CNC EDM machine using copper electrode through evolutionary optimization techniques like teaching Learning Based Optimization (TLBO) technique and biogeography-based optimization (BBO) technique. The input parameter considered for the optimization are Current (A), Voltage (V), Pulse off time (µs), and Pulse on time (µs). TLBO and BBO technique wereused to obtain maximum MRR and minimize the SR. It was found that SR and MRR increased linearly when discharge current was in mid-range however non-linear increment of MRR and SR was found when the current was too small or too large. Scanning Electron Microscope (SEM) images also indicated a decreased SR. In addition, obtained optimized values were validated for testing the significance of the TLBO and BBO technique and a very small error value of MRR and SR was found. BBO outperformed TLBO in every aspect like less percentage error and better-optimized values, however, TLBO took less computation time than the BBO. [ABSTRACT FROM AUTHOR]

With the development of micro electro mechanical system (MEMS), the application of micro components is becoming increasingly wide. Micro electrical discharge machining (micro EDM) is one of the most effective manufacturing processes for micro components. During past few decades, some innovative methods for improving micro EDM performance have been proposed. Using special-shaped electrode is just one of them. Although micro EDM with helical electrode has been proposed and the availability has been proved for several years, relatively little is known about the precise effect of helical electrode rotation on micro EDM performance. In this study, micro through-holes were machined on Ti6Al4V sample with a cylindrical electrode and helical electrode. The helical electrode achieves better machining performance overall compared to the cylindrical electrode due to its favorable debris removal ability. The higher the rotational speed of helical electrode, the higher the material removal rate (MRR). When using the cylindrical electrode, the MRR first increases and then decreases after reaching a peak at 3000 rpm. Higher MRR is obtainable with the helical electrode with reverse rotation; with forward rotation, it yields higher machining precision (lower overcut and taper rate). [ABSTRACT FROM AUTHOR]

In order to solve the problem that the material removal rate, the surface roughness and the electrode loss cannot be simultaneously taken into account in electrical discharge machining, the influences of peak current, pulse width and pulse interval on the material removal rate, surface roughness and electrode loss in the electrical discharge machining of P-type monocrystalline silicon are analyzed through central composite design experiments. The response surface method is used to establish a second- order relational model of material removal rate, surface roughness and electrode loss. The results of variance analysis indicate that the proposed model has good fitting degree and adaptability. A process parameter optimization model is established by analyzing the constraints of the actual processing conditions on the process parameters to improve the material removal rate in the electrical discharge machining of monocrystalline silicon, and reduce both the surface roughness and the electrode loss, and the NSGA- II - based algorithm is designed to solve the optimization problems. The average relative errors of validation results of material removal rate, surface roughness and electrode loss under the condition of the optimal solution are 4. 9% , 5. 2% and 5.1% , respectively, compared with the theoretical optimal values. The verification tests show that the proposed algorithm can achieve the process parameters optimization of sili­con materials in the electrical discharge machining. [ABSTRACT FROM AUTHOR]

In powder-mixed electrical discharge machining (PMEDM), a suspension of powder particles is added to the dielectric to achieve a high surface quality and to improve the material removal rate (MRR). However, for biomedical applications, the machined surface must be nontoxic and also contain bioactive species; these constraints limit the choice of powder material. This study focuses on machining orthopedic-implant materials based on titanium and titanium–tantalum alloys using bioactive hydroxyapatite (HA)-powder suspension as the dielectric. The influence of the powder particles and the work-piece composition on the machining performance was investigated. Employing a suspension dielectric with 5 g/L HA caused a smoother surface (Ra 2.1 μm) with a thinner recast layer (∼9 μm) as compared to using water to machine titanium which has surface roughness of Ra 2.4 μm with a recast layer close to 10 μm. In addition, the MRR of titanium machined in the HA-powder-suspension dielectric (6.4 × 10 −4 g min −1 ) was greatly lower than that in water (28.6 × 10 −4 g min −1 ). However, increasing the HA concentration led to a gradual increase in the MRR, electrode wear rate (EWR), surface roughness, and recast-layer thickness. The MRR, EWR, and the surface roughness of titanium and titanium–tantalum alloys under PMEDM exhibited an inverse relation with respect to the melting temperature and thermal conductivity of the alloy. Furthermore, calcium and phosphorus were incorporated into the recast layer, and their amounts decreased when the discharge current was increased. [ABSTRACT FROM AUTHOR]

Limited efforts have been made to transform electrical discharge machining to a green and sustainable machining process. Current electric discharge machining (EDM) processes use hydrocarbon or synthetic-based dielectric fluids. These fluids emit harmful vapors when they break down, raising concerns for machine operators and for the environment. Biodiesel (BD) has similar properties as conventional dielectric and it can be used in place of conventional dielectric fluids. This research aims to study the effects of biodiesel dielectric in EDM process, especially in micromachining. Experiments are carried out in both low and high energy settings, on bulk metallic glass (BMG) and titanium alloy (Ti-6Al-4 V) using 200-μm-diameter electrodes. Canola BD and sunflower BD are compared against conventional dielectric in terms of material removal rate and tool wear ratio. The experimental evidence showed that both canola and sunflower BD are able to outperform conventional dielectric, and thus suggesting that BD has the potential to replace conventional dielectric as to provide a more sustainable machining process in the future. [ABSTRACT FROM AUTHOR]

Porous metals and alloys are ideal lightweight and damping materials which have garnered significant research attention owing to their superior mechanical and metallurgical characteristics. Micro electrical discharge machining (micro EDM) is an alternative method for machining porous metals. In this study, experiments on porous stainless steel (PSS) were conducted to determine the micro EDM performance of austenitic stainless steel (AISI 304) and PSS samples with various porosities and pore sizes. The results were analyzed based on the thermal conduction theory of porous materials. PSS achieved better machining performance overall compared to AISI 304 due to its porosity; further, porosity and pore size were shown to have a significant influence on the machining characteristics of PSS. The larger the porosity and pore size, the higher the material removal rate (MRR) and the lower the relative tool wear ratio (RTWR). Thermal conductivity decreases due to the existence of pores, causing less heat to be lost by heat conduction and more energy to be consumed in order to remove the material. High capacitance in the experimental circuit proved suitable for machining PSS, while high open circuit voltage appeared to be more suitable for machining AISI 304. [ABSTRACT FROM AUTHOR]

It is submitted that new approach is tried to find out what would be the outcome if Aluminum 2618 reinforced by AlN (Aluminum Nitride), Si 3 N 4 (Silicon Nitride) & ZrB 2 (Zirconium Boride) particles were fabricated in Wt % (x = 0,2,4,6,8) by stir casting method. If the wt% is increased, the mechanical properties of the composite will proportionally increase. There will be no other promising technique than Electrical Discharge Machining (EDM) for machining metal matrix composites when they were conducted on the Aluminum 2618 composite work piece using a copper electrode in an EDM machining. It becomes very vital in the field machines and mechanism to find out Current(I), Pulse on time(T ON ), Pulse off time (T OFF ) on Metal Removal Rate (MRR),Tool Wear Rate(TWR) on the machining of hybrid Al2618 metal matrix composites. Taghuchi's design of experiment was used to analyse the machining characteristics of hybrid composites. To effect the parameters like current (I), Pulse on time(T ON ), Pulse off time (T OFF ) has been chosen as the input parameters of this work. Machining results go to show that Al2618 composites have improved mechanical properties and as a result of Material Removal Rate (MRR) and Tool Wear Rate (TWR) are reduced. Hence ANOVA (Analysis of Variance) and signal to Noise ratio are used to determine the influence of input parameters on the Material Removal Rate and Tool Wear Rate (TWR). [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is an advanced technology used to manufacture difficult-to-cut conductive materials. However, the surface layer properties after EDM require additional finishing operations in many cases. Therefore, new methods implemented in EDM are being developed to improve surface characteristics and the material removal rate. This paper presents new research about improving the surface integrity of 55NiCrMoV7 tool steel by using reduced graphene oxide (RGO) flakes in the dielectric. The main goal of the research was to investigate the influence of RGO flakes in the dielectric on electrical discharge propagation and heat dissipation in the gap. The investigation of the influence of discharge current I and pulse time ton during EDM with RGO flakes in the dielectric was carried out using response surface methodology. Furthermore, the surface texture properties and metallographic structure after EDM with RGO in the dielectric and conventional EDM were investigated and described. The obtained results indicate that using RGO flakes in the dielectric leads to a decreased surface roughness and recast layer thickness with an increased material removal rate (MRR). The presence of RGO flakes in the dielectric reduced the breakdown voltage and allowed several discharges to occur during one pulse. The dispersion of the discharge caused a decrease in the energy delivered to the workpiece. In terms of the finishing EDM parameters, there was a 460% reduction in roughness Ra with a uniform distribution of the recast layer on the surface, and a slight increase in MRR (12%) was obtained. [ABSTRACT FROM AUTHOR]