Narrow Results

The virgin copper electrode has limited application due to its wear and mechanical properties using Electrical Discharge Machined (EDMed) on Inconel 718 superalloys. In order to enhance the performance of copper electrodes, in this work, Ion Nitriding (IN), Surface Hardening by Laser (LSH) and Hybrid Process ($\mathrm{\text{IN}}+\mathrm{\text{LSH}}$) are performed on copper electrodes to reduce the electrode wear in frontal and lateral. The electrode wear in the frontal and lateral of virgin copper electrode is processed and studied using EDM with varying pulse durations, current and Silicon Carbide (SiC) mixed EDM oil. The surface hardness in virgin and processed electrodes is also investigated. Overall analysis found that the hybrid technique produced a 59% higher hardness than that of virgin copper. The hardness in the EDMed surface was higher than that of the processed copper surface. A 1000$\mu$s pulse duration, 2 A current and 15 g/l SiC powder mixing EDM oil produced a low frontal wear in both virgin and processed copper electrodes. The electrode wear was reduced by 30% for frontal and 76% for lateral using a hybrid method.

This investigation explores the application of electrical discharge machining (EDM) to ceramic composites constructed from Si₃N₄–TiN (Syalon 501) by testing both square and cylindrical electrodes. Various experimental methods have been employed, including design-of-experiments (DoE), Grey relational analysis (GRA), analysis of variance (ANOVA), confirmation testing, and scanning electron microscopy (SEM), in an effort to optimize machining settings and comprehend their effect on performance. While ANOVA revealed crucial parameter levels influencing overall machining conditions as measured by the grey relational grade (GRG), the sophisticated method of GRA considerably improved the machining characteristics. Significant improvements in the EDM process were shown experimentally, resulting in outstanding results for material removal rate (MRR), surface roughness (SR), and electrode wear rate (EWR). In particular, numerous benefits of the square electrode layout over the more common cylindrical arrangement stood out. All of the aforementioned resulted in an impressively high MRR (measured at 0.0281gm/min), a low EWR (at 0.0020gm/min), and a significant improvement in SR (at 0.3150$\mu$m). The GRG value was 0.0163 for the square electrode design, which was excellent, and 0.0025 for the cylindrical electrode, which was significantly better. The optimized parameters were successfully used, especially with the square electrode arrangement, leading to significant improvements in MRR and decreases in EWR. On the other hand, surface quality was negatively affected by larger parameter values, which increased the development of microfractures, particularly when using the square electrode design. In any case, our study provides strong proof that adjusted settings can greatly improve EDM performance, allowing for accurate machining of Si₃N₄–TiN composites with increased MRR, great surface texture, and reduced electrode wear. In conclusion, our study provides useful information to improve EDM procedures for Si₃N₄–TiN ceramic composites, as well as practical insights into increasing the efficiency and quality of EDM operations in a variety of industrial sectors.

In this research, stir casting was used to create the aluminium alloy (AA7075) composite filled with 10wt.% zirconia (ZrO₂) particles as reinforcement. Die sinking electric discharge machining (EDM) was used to examine the machining characteristics of the proposed composite. The machining experiments were executed in accordance with the $L_9$ orthogonal layout. Here, the material removal rate (MRR) and surface roughness (SR) were taken into account as the output responses, and the discharge current ($I_p$), pulse on-time ($T_{\mathrm{\text{on}}}$), and pulse off-time ($T_{\mathrm{\text{off}}}$) were taken as the machining parameters. To determine the optimal parameter conditions for the output responses, the technique for order preference by similarity to ideal solution (TOPSIS) approach was applied. According to the experimental findings, the optimum settings of the parameters are determined at 15amps of ‘$I_p$’, 750$\mu$s of ‘$T_{\mathrm{\text{on}}}$’ and 50$\mu$s of ‘$T_{\mathrm{\text{off}}}$’. ANOVA results stated that ‘$T_{\mathrm{\text{on}}}$’ has the most notable factor with a contribution of 90.85%. The interaction effect of parameters on the responses was shown by the contour plots. The confirmatory experiment was finally conducted at the optimum machining parameter settings, and it was found that the error only occurred in 8.4%.

Electrical discharge machining (EDM) was performed on a copper electrode and the implications of changing factors such as current, pulse on time, pulse-off time, spark gap voltage and speed have been investigated in this research. The process used an intermetallic MoSi₂–SiC ceramic composite. Multiple performance characteristics, including material removal rate, electrode degradation rate and surface roughness, run out, radial overcut, circularity, cylindricity and perpendicularity were considered when optimizing these parameters using the Taguchi-based ${\text{L}}_{25}$Orthogonal Array with Design of Experiments (DoE). For this purpose, techniques such as analysis of variance (ANOVA), Response Surface Methodologies (RSM) and graphical analysis were utilized. The outcomes revealed that geometric tolerances were decreased as a consequence of significant improvements in the rates of material removal, tool degradation, form tolerance, and orientation tolerance. The optimal machining settings for producing high-quality holes and electrodes in the conductive MoSi₂–SiC composite were determined by scanning electron microscopy (SEM) testing the anomalies of the machined composite for various holes of trials. The experimental results suggest that the precision, presence of microvoids and surface roughness of the copper electrode can be enhanced through selecting an appropriate optimal combination.

Wire Electrical Discharge Machining (WEDM) to achieve high-quality finishes by minimizing the experimental errors in the application of Metal Matrix Composites, which are often necessary with various manufacturing industries. The Al 6061 composites have been made by the fabrication the alloy through stir casting process. In this work, metallurgical and the effect of machining characteristics of Al alloy, Al 6061, through reinforcing with B₄C and Fe₂O₃ investigated. This work an effort has been made on applying Taguchi and ANOVA methods in order to optimize the outcomes L${}_{16}$ orthogonal array was utilized in this investigation. The third dimension perspective to this composite has been acquired for the input settings, comprising higher composites (wt.%) and current, lower pulse on time ($T_{\text{on}}$) and pulse off time ($T_{\text{off}}$), and the output variables, which include material removal rate (MRR), electrode wear rate (EWR), and depth, with the aid of the Signal to Noise (S/N) and the small is preferable. The analysis of these trial results via S/N ratios makes it clear that the minimized pulse on and off and more current found in machining, and lower pulse on and off, optimal results parameters were also reached.

This paper presents an innovative technique for fabricating complex-shaped powder metallurgical (PM) tool electrodes using electrical discharge machining (EDM). This approach enhances design flexibility in tool fabrication, enabling selective surface treatments and pattern generation. The tool made of 75% tungsten (W) and 25% copper (Cu), is compacted and pasted to a copper shank by conductive materials. The tool design is initially generated using AutoCAD software and processed on the wire-cut EDM machine. The final tool is then produced through die-sinking EDM operations in reverse polarity. Key input parameters include compact load (CL), peak current ($I_p$) and pulse on-time ($T_{\text{o}\text{n}}$), while the output responses are tool wear rate (TWR), unwanted material transfer rate (MTR${}_{\text{U}}$) and edge deviation (ED). The study reports several significant numerical findings related to the fabrication of complex-shaped PM tool electrodes using the EDM process. These parameters lead to notable performance outcomes, with a minimum TWR of 10.14 mg/min, MTR${}_{\text{U}}$ of 1.56 mg/min and ED of 18.71 $\mu$m, showcasing the effectiveness of the process in achieving the desired tool characteristics. The process offers an efficient solution for producing complex geometries suitable for different applications.

This study deals about the influence of vibrations incorporated into a workpiece during powder-mixed electrical discharge machining (PMEDM) on quality measures such as material removal rate (MRR), surface roughness $(R_a)$ and microhardness. It has been found that the low-frequency vibration incorporated into the workpiece positively affects the processing efficiency of electrical discharge machining (EDM) and PMEDM. However, the effect of low-frequency vibration in PMEDM has been better than EDM. The higher vibration frequency significantly improves the MRR and $R_a$ in PMEDM. The MRR has been improved by 95.89% and with lower $R_a$ of 63.2% in PMEDM. The hardness of the machined surface after PMEDM using titanium powder mixed in dielectric liquid was increased approximately two times as compared with conventional EDM.

Electrical discharge machining (EDM) process is widely used to process hard materials in the industry. The process of electrical discharge is changed and called PMEDM when alloy powder is added in the oil dielectric. In this study, the effect of tungsten carbide alloy powder added in the dielectric on the microhardness of surface (HV) status of the workpiece SKD61 after machining is investigated. Studies show that the microhardness of surface obtained by PMEDM is generally better than that by normal EDM. The experiment shows that at the selected process window, adding the powder has resulted in an improvement of the microhardness up to 129.17%.

Electrical discharge machining (EDM) is one of the importantly non-traditional processing technologies employed for ceramics’ surface processing. Modeling and optimization of the EDM process are essentially applied to find and obtain the optimal values of the responses for materials having smaller surface roughness, higher removing rate of materials, lower electrode wear rate. In this study, the Grey-Taguchi system with AHP weighting was applied in order to optimize the multi-responses of the EDM processing for ceramics. When the EDM processing was used in the ZrO₂ ceramics for adhesive metal foils, the multi-response gray relational grade for the optimal level of machining parameter was 0.2685, which was higher than those using the initial experimental conditions. This study has proven that using the Grey-Taguchi system method with AHP weighting to find a model with a highly efficient standard for optimizing differently advanced machining processes is profitable.

We review the current status of the study of parity and time invariance violation in atoms, nuclei and molecules. We focus on parity nonconservation (PNC) in cesium (CS) and three of the most promising areas of research: (i) PNC in a chain of isotopes, (ii) search for nuclear anapole moments, and (iii) search for permanent electric dipole moments (EDMs) of atoms and molecules, which in turn are caused by either an electron EDM or nuclear T, P-odd moments such as a nuclear EDM or nuclear Schiff moment.

Nowadays, composites are used in different parts of industries and it is one of the most important subjects. The most widely used reinforcements in metal matrix composites are Al₂O₃ and SiC fibers and particles which may be used in cutting-edge functional and structural applications of aerospace, defense, and automobile industries. Depending on the type of powder used, composite materials are difficult to machine by conventional cutting tools and methods. The most appropriate way for machining of these composites is electro discharge. For the reason of improving the surface quality, tool wear rate and material removal rate and reducing the cracks on the surface, Al₂O₃ powder was used. In this study, the effect of input parameters of EDM such as voltage, pulse current, pulse on-time and pulse off-time on output parameters like material removal rate, tool wear rate and surface roughness in both conditions of the rotary tool with powder mixed dielectric EDM and the stationary tool excluding powder mixed dielectric were investigated. The critical parameters were identified by variance analysis, while the optimum machining parameter settings were achieved via Taguchi method. Results show that using of powder mixed dielectric and rotary tool reduce the tool wear rate, surface roughness and the cracks on the surface significantly. It is found also that using of powder mixed dielectric and rotary tool improve the material removal rate due to improved flushing action and sparking efficiency. The analysis of variance showed that the pulse current and pulse on-time affected highly the MRR, TWR, surface roughness and surface cracks.

Electrical discharge machining (EDM) is an unconventional machining process used for machining of hard-to-cut materials. Both EDM and micro-EDM processes are extensively used for producing dies and molds, complex cavities, and 3D structures. In recent years, researchers have intensively focused on improving the performance of both micro-EDM and EDM processes. This paper reviews the research work carried out by the researchers on vibration-assisted EDM, micro-EDM, and wire EDM. The consolidated review of this research work enables better understanding of the vibration-assisted EDM process. This study also discusses the influence of vibration parameters such as vibration frequency and amplitude on the material removal rate (MRR), electrode wear rate (EWR), and surface roughness (SR). The important issues and research gaps in the respective area of research are also presented in this paper.

This study deals with the investigation on the effect of Electrical Discharge Machining (EDM) parameters during machining of hybrid composite (Al 7075/TiC/B₄C). The optimum process parameters of die sinking EDM like pulse current, pulse duration and gap voltage on metal removal rate, tool wear rate and surface finish were investigated. Full factorial experimental design was selected for experiments. Analysis of variance was employed to study the influence of process parameters and their interactions on response variables. Among the process parameters considered, it was observed that the pulse current was found to be more influential in affecting MRR, TWR and SR. The other parameters have little effect on the response variable. Multi-objective optimization study was also performed using genetic algorithm to find the optimum parameter setting for controversial objective function combination such as high MRR and low SR and High MRR and low TWR. Scanning electron microscope study was performed to study the surface characteristics.

Magnesium is reinforced with three different weight percentages (5%, 10% and 15%) of SiC particles (200 mesh size) by stir casting technique to fabricate Mg/SiC_p composites. The Scanning Electron Microscope (SEM) images, micro and macro hardness of three different composites are investigated. The comparison of micro and macro hardness clearly shows that increase in the weight percentage of SiC contributed to increase in hardness. However, uniform dispersion of SiC can be achieved while adding 5% SiC in the composite. Then, the Box Behnken experimental design in response surface methodology is employed for machining 3mm diameter hole in the Mg/SiC_p samples using EDM. The second-order model for Material Removal Rate (MRR) and Tool Wear Rate (TWR) are developed with the influencing parameters of weight percentage of SiC, current, pulse on time and pulse off time. The parameter optimization yields maximum MRR and minimum TWR.

Cenosphere fly ash particles are incorporated into AA6061 alloys with different concentrations ranging from 0wt.% to 10wt.% using a modified semi-solid metal processing technique. X-ray diffraction patterns were recorded to analyze the morphology of the aluminum-based metal matrix composites (AMCs). The major diffraction peaks of Al, SiO₂, Al₂O₃ and Fe₂O₃ are distinctly identified which revealed the presence of cenosphere particles and their integrity within the matrix is preserved. The high-resolution optical micrograph identifies the homogeneous distribution and uniform dispersion of the particles. Machinability of the prepared AMCs was investigated by electro discharge machining (EDM) using response surface methodology (RSM). Face-centered CCD of RSM was considered to design the number of experimental runs required. ANOVA was used to explore the influence of selected process parameters and their interactions on the performance characteristics of the systems by developing a second-order quadratic mathematical model for all the responses. Pulse on-time and pulse current were observed to be the most influencing independent variables of EDM system that affect the selected performance measures during spark erosion process. Finally, desirability function approach was employed to optimize the parameters. The optimal processing condition was identified as follows: pulse current: 6 A, pulse on-time: 1010$\mu$s, percentage of reinforcement: 2% and flushing pressure: 0.2 MPa. Very small percentages of deviation have been observed while comparing with the experimental results obtained for MRR (8.6%), TWR (10.3%) and SR (2.18%).

This study employs Taguchi orthogonal design (L₉) to optimize the machining parameters of electro-discharge machining (EDM). The aluminum matrix composite (AMC) with 16wt.% titanium carbide (TiC) and 4wt.% graphite (Gr) specimen was prepared by stir casting process. This study involves three control parameters with three levels, namely pulse current, voltage and fluid pressure to predict the process response, such as material removal rate (MRR) and surface roughness (SR) of the worn surface. Maximum MRR of 0.1661g/min was attained for 10A, 500V and 15kgf/cm² fluid pressure with corresponding roughness of 11.43$\mu$m and the minimum value of 7.51$\mu$m was observed for 10A, 100V and fluid pressure of 5kgf/cm². A regression model was developed and the effect of control parameters on process responses were determined by analysis of variance (ANOVA). According to ANOVA outcome, the machining parameters which control the process response MRR were determined as voltage (47.94%), pulse current (33.19%) and fluid pressure (17.58%). Similarly, the SR was affected by machining parameters voltage (55.17%), pulse current (22.41%) and flushing pressure (21.47%). The optimum machining parameters were predicted and confirmed by conducting experiments with reasonable error of 2.49% and 2.02% for MRR and SR, respectively. Surface characteristics of the machined AMC was analyzed by scanning electron microscope (SEM) to observe the defects like craters, voids, glued debris and recast layers.

In this paper, the copper (Cu)-based multi-wall carbon nanotube (MWCNT) composite tools were fabricated using electro-co-deposition method. The composite tools were prepared from different MWCNT concentrated (0.5, 0.75 and 1g/L) electrolytic solution and these tools were utilized in electro discharge machining (EDM). The experiments were performed with varying discharge currents. The results indicated that the incorporation of MWCNTs into the copper matrix greatly influenced the machining performances. A lower rate of tool wear and higher material removal rate (MRR) were observed for the copper-based MWCNT composite tools at different discharge currents. The highest tool wear rate (TWR) was reduced by 45.68% and the MRR was improved by 63% for the Cu-MWCNT (0.5g/L) composite tool compared to copper coated tool. At higher discharge current, smoother machined surfaces were generated using copper-based MWCNT composite tools compared to the copper tools. The SEM image exhibits that the micro-crack-free machined surfaces were produced by using copper-based MWCNT composite tools. The migration of tool material to the machined surface was also reduced for copper-based MWCNT composite tools.

Nowadays, there has been continuous development of metallic biomaterials to meet special needs in the manufacturing of biomedical implants, units and systems so as to function well in the required environment. Developed biomaterials which possess exceptional properties in terms of biocompatibility and biomechanical compatibility require precision processing and machining to obtain the desired dimensional tolerances. Electrical discharge machining (EDM) is the noncontact or nontraditional process of machining that suits the precision machining of biomaterials. In this work, an effort was made to optimize the EDM parameters during machining of titanium-based biomaterials Ti-6AL-4V, so that the multi-objective responses could be obtained. The response surface method was used in designing the experiment, while the grey relational method was used to analyze the effect of multiple objectives into a single unit. The electrical parameters that were considered in this study include peak current, gap voltage, pulse turn-on and duty cycle. These parameters were set within the acceptable limits of the equipment. Three responses were studied, which are tool wear rates (TWRs), material removal rate (MRR) and surface roughness (SR). Using the signal-to-noise ratio and ANOVA optimum tool/electrode wear rate (TWR) is obtained at $5\times 10^{-5}$ g/min with process parameters $\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=30$ V, $\mathrm{\text{Ton}}=200$  $\mu$s, $D=65$%. Optimum values of material removal rate (MRR) are obtained as 0.01035g/min with process parameters $\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=60$ V, $\mathrm{\text{Ton}}=140$  $\mu$s, $D=50$%. Optimum SR is observed as 2.258 $\mu$m with EDM process parameters $\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=90$ V, $\mathrm{\text{Ton}}=200$  $\mu$s, $D=65$%. Surface characteristics are verified with SEM micrographs. Whereas, grey relation analysis predicted the multi-objective optimum response characteristics. Based on the grey relation grade, experiment number 7 ($\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=90$ V, $\mathrm{\text{Ton}}=200$  $\mu$s, $D=65$%) secured the first rank among the experiments/trails.

Shape memory alloys (SMAs) are an excellent material for producing components for a wide range of industrial applications, such as orthopedic implacers, micro-equipment, actuators, fittings, and screening components, as well as military equipment, aerospace components, bio-medical equipment, and fabrication requirements. Despite its remarkable qualities, the production of SMAs is a problem for investigators all over the globe. The purpose of this research is to evaluate the effects of altering the $T_{\mathrm{\text{on}}}$, $T_{\mathrm{\text{off}}}$, $I_{\mathrm{\text{p}}}$, and GV while processing copper-based SMA in an electrical discharge machining process on the material removal rate (MRR) and surface roughness (SR). The major runs were designed using a central composite design. SEM was also utilized to examine the micro-structure of EDM-processed electrode tools and work samples. SEM scans indicated the presence of debris, micro-cracks, craters, and a newly formed recast layer on the electrode tool and workpiece surface. High $I_{\mathrm{\text{p}}}$ and prolonged $T_{\mathrm{\text{on}}}$ provide huge spark energy simply at the work sample-tool contact, resulting in debris production. The experimental results reveal that the least and highest MRR values are 10.333 and 185.067mm³/min, respectively, while the minimum and maximum SR values are 3.07 and 7.15$\mu$m. The desirability technique, teacher learning based optimization (TLBO), and the Jaya algorithm were also utilized to optimize the studied solutions (i.e. MRR and SR) on a single and multi-objective basis. The best MRR and SR were determined using the desirability approach, the Jaya Algorithm, and the TLBO to be 152.788mm³/min and 4.764$\mu$m; 240.0256mm³/min and 1.637$\mu$m; and 240.0257mm³/min and 1.6367$\mu$m.

Pure copper, copper-based alloys, brass, graphite and steel are the most common tool materials for the electrical discharge machining (EDM) process. The electrode material, which exhibits good conductivity to heat and electricity and possesses better mechanical and thermal properties, is preferred for EDM applications. The major problem with conventional electrodes like copper and graphite is their low wear resistance capacity. This study is on the fabrication of Cu–SiC composites as an electrode of EDM with improved wear characteristics for machining of hardened D2 steel which is widely used in die formation. Powder metallurgy route was used to fabricate the samples which was further followed by three-step sintering process. Copper metal was used as a matrix element which was reinforced with SiC in volume fractions of 10%, 15% and 20%. Based on the desirable properties for the EDM tool, the best composition of Cu–SiC composite tool tip was suggested and was further used for machining of D2 steel. The performance of newly developed Cu–SiC composite electrode in terms of surface roughness (SR), material removal rate (MRR) and tool wear rate (TWR) was explored, and it was compared with the pure copper electrode. Pulse on-time, pulse off-time and the input current were selected as the input process parameters. Result reveals that the TWR and SR were decreased by 12–18% and 10–12%, whereas the MRR was increased by 9–28% for Cu–SiC composite tool as compared to the pure Cu electrode. Adequacy of the results was checked by statistical analysis. The surface texture of tool and machined surface was analyzed using scanning electron microscopy (SEM). SEM micrograph revealed that surface cracks on composite tool tip were lesser than pure Cu tool tip, whereas the work surface was rough while machining with the copper tool surface. Therefore, the result indicates that the newly developed Cu–SiC composite tool can be used for machining of hard materials with EDM.