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Micro-EDM technology is widely used in the field of micro-fabrication due to its low cost, non-contact, and other processing characteristics. The EDM method involves molding parts by implementing the principle of melting metal at a high temperature, which results in a thin recast layer on the surface of the workpiece. The recast layer can criticall...
Citations
... The dominating mechanism changed with the gap distance and drilling depth, and the recast layer was effectively removed during ECM processing. Chu et al. [16] used micro-EDM-ECM -integrated processing technology based on different structures corresponding to different machining strategies to improve the surface quality of microgroove structures. ...
In this study, the persistent challenges of high surface roughness and large thickness of the re-solidified layer (RSL) and the heat-affected zones (HAZ) in short electric arc machining (SEAM) are confronted by a hybrid simultaneous SEAM and ECM (SEACM) technique. The SEACM is investigated in low conductivity NaCl electrolytes as the working medium with an additionally applied air pressure, which can meet the requirements of both SEAM and ECM. Firstly, the effect of feed rate and electrolyte conductivities on material removal rate (MRR), roughness, line profiles, and surface morphologies were studied. Later, the current-voltage waveforms, topographies, PSD curves, and dimensional accuracy at different feed rates and electrolyte conductivities were analyzed. The SEACM significantly reduced the roughness and the thickness of RSL and HAZ at an appropriately optimized electrolyte conductivity and feed rate. The developed technique provides the basis for transferring from rough machining to finishing in SEAM.
... These carbide and oxide layers on the machined surface increase the wear and corrosion resistance of the material. Furthermore, for selective removal of the severe accumulation of solidified molten material, techniques such as electrolytic polishing 28 and selective chemical etching 29 can be performed to enhance the surface quality as per the desired application. ...
In the current scenario, micro-manufacturing through the electro-discharge machining (EDM) process is a prominent technique for achieving desired complex micro/nano-features of any product. The precision and accuracy of producing features are the prerequisites of micro-machining. The current work aims to check the feasibility of the novel Maglev EDM for fabricating micro-holes on a thin nickel sheet (thickness = 500 µm). The study presents the viability of the newly developed system by comparing it with the conventional EDM process. A pure direct current power supply is assembled with a magnetic levitation-based gap monitoring mechanism to overcome the setbacks of conventional EDM. The novel setup utilizes the combined effect of the permanent electromagnet to diminish arcing and short-circuiting. The control parameters for the operation were 12 V open-circuit voltage and 2 A peak current while maintaining a duty factor of 95.564 percent. The measured discharge voltage and discharge current were 6.64 V and 900 mA, respectively. Tungsten rod (ø 650 µm) and deionized water were used as a tool and a dielectric medium, respectively, for the experiment. Further, the machined micro-hole and micro-tool analysis have been carried out using high-resolution microscopy, scanning electron microscopy and energy dispersive spectroscopy reports. The newly developed Maglev EDM's feasibility to produce micro-holes on conductive materials has been confirmed in the present work with an average material removal rate of 40 µg/min.
... The surface quality is finer, but there are still some problems, such as low processing efficiency and very poor debris removal conditions. The third is to employ a hybrid machining method or carry out post-processing of the machined surface with the help of other machining technologies [16][17][18]. The surface quality can be improved, but the processing complexity is increased and the comprehensive processing efficiency is low. ...
To further explore the machining characteristics of very high-frequency micro-electrical discharge machining (VHF micro-EDM), the range of radio frequency (RF) power amplifier was expanded to 110 MHz, and the power of the RF power amplifier was also greatly increased up to 91 W. The principle of the VHF pulse generator was discussed in detail, and an electro-thermal model suitable for VHF micro-EDM was established to determine the diameter of the plasma channel and the energy distribution ratio. Experimental studies for VHF micro-EDM were also carried out, and the effects of power and frequency on machining characteristics were then analyzed and discussed. The results show that at the same frequency, the higher the power is, the higher the material removal rate (MRR) and the larger the number of discharge craters. At the same power, both the MRR and the size of discharge craters first increase and then decrease with increasing frequency and peak at 65 MHz. For a copper workpiece, when the frequency is 110 MHz and the total power of the power amplifier is 8.0 W, 5.6% of the energy is used for the material removal of the workpiece and the finest processing surface is obtained with the surface roughness Ra = 12 nm. The average diameter of the discharge craters is as small as 0.268 μm, and the diameter of the plasma channel is only 0.350 μm. In addition, the effects of different workpiece materials and dielectric fluids are also analyzed in this paper.
... Electrical discharge machining (EDM) is a commonly technology for processing titanium alloy [1,2], which completes material removal through the electric spark discharge. In the process of EDM, the recast layers are easily generated on the workpiece surface [3][4][5]. In the process of the interaction between the electric spark discharge and the workpiece, the partially molten workpiece was not expelled in time [6]. ...
Titanium alloy has been widely applied in industrial fields because of its excellent material properties. Electrical discharge machining (EDM) is commonly technology for processing titanium alloy. When titanium alloy was processed by EDM, a recast layer was inevitably be produced on its surface, which can adversely affect the surface quality and working life. Focus on the above problem, this paper proposed to add B4C powders into the spark oil and cooperate with the tool electrode sloshing for powder mixed electrical discharge machining (PMEDM) of titanium alloy, which can reduce the thickness of the recast layer and thereby improve the quality of the machined surface. Firstly, B4C powders were mixed in the spark oil and the PMEDM of the titanium alloy was carried out. In this step, the thickness of recast layer was preliminarily reduced and the quality of machined surface was improved. Secondly, when the PMEDM of the titanium alloy was nearly completed, the tool electrode sloshed along the machine tool spindle within the EDM gap. Combining PMEDM with the tool electrode sloshing, the recast layer on the machined surface was further eliminated and the quality of machined surface was further improved. By adding 3000 mesh B4C powders into the spark oil, the paper carried out the PMEDM of titanium alloy combining with the tool electrode sloshing. Under the action of appropriate process parameters, the micro-groove structure with surface roughness Ra of 0.205 μm was obtained in the titanium alloy and the recast layer on the machined surface was almost invisible.
... The surface quality is finer, but there are still some problems, such as low processing efficiency and terrible debris removal conditions. The third is to employ a hybrid machining method or carry out post-processing of the machined surface with the help of other machining technologies [16][17][18]. The surface quality can be improved, but the processing complexity is increased and the comprehensive processing efficiency is low. ...
To further explore the machining characteristics of very high-frequency micro-electrical discharge machining (VHF micro-EDM), the range of radio-frequency (RF) power amplifier was expanded to 110 MHz, and the power of the RF power amplifier was also greatly increased up to 91 W. The principle of the VHF pulse generator was discussed in detail, and an electro-thermal model suitable for VHF micro-EDM was established to determine the diameter of the plasma channel and the energy distribution ratio. Experimental studies for VHF micro-EDM were also carried out, and the effects of power and frequency on machining characteristics were then analysed and discussed. The results show that at the same frequency, the higher the power is, the higher the material removal rate (MRR) and the larger the number of discharge craters. At the same power, the MRR and the size of discharge craters both first increase and then decrease with increasing frequency and reach the maximum value at 65 MHz. For the copper workpiece, when the frequency is 110 MHz and the total power of the power amplifier is 8.0 W, 5.6% of the energy is used for the material removal of the workpiece, and the finest processing surface is obtained with the surface roughness Ra=12 nm. The average diameter of the discharge craters is as small as 0.268 μm, and the diameter of the plasma channel is only 0.350 μm. In addition, the effects of different workpiece materials and dielectric fluids are also analysed in this paper.
Fabrication of surface features like effusion holes on ultra-high temperature (UHT) alloys with micro electro-discharge machining ([Formula: see text]-EDM) is a very convolute strategy. Due to the exceptional mechanical properties and resistance to ease brittle transformation at elevated temperatures, UHT alloys are being widely used in hot sections of aero engines. This research tailored the existing capabilities of [Formula: see text]-EDM setup by employing a copper-tungsten (Cu-W) hybrid tool electrode which has been rarely reported. This research addresses investigations, predictive modeling, and optimization during [Formula: see text]-EDM of UHT alloy, namely Inconel 718. For experimentation, the factors like inter-electrodes gap (IEG), current ([Formula: see text]), and pulse on/off time ([Formula: see text], [Formula: see text]) were considered as input variables to analyze the responses like overcut (OC), tool wear rate (TWR), material removal rate (MRR), and diametric alterations in between the top and bottom shape of holes’ feature (DE). The multi-objective desirability-based artificial bee colony optimization (MOABC) projected optimal parametric settings of 5.276 A, 16.389 [Formula: see text]s, 1.77 [Formula: see text]s, and 50 [Formula: see text]m for [Formula: see text], [Formula: see text], [Formula: see text], and IEG, respectively. These settings provide MRR, TWR, OC, and DE solutions of 0.001479, − 0.00038, 0.030239, and 0.047048 mm, respectively. Further, the confirmation test has been performed to validate the optimal solution. The results supported the ideal settings with error values of 0.03177, 1.31578, 0.05863, and 0.04704 for MRR, TWR, OC, and DE, respectively. Distinctive diagnostic tests assessed by several statistical parameters ([Formula: see text], [Formula: see text], [Formula: see text], AD-P values) confirmed that the accuracy of developed models for prediction of various performance characteristics has high degree of resemblance with experimental results and the adequacy as well as accuracy of models is also demonstrated. Moreover, the surface morphology has also been scrutinized by microscopical observation to perceive the consequences of the electro-discharge phenomenon on both electrodes. Overall, the research comprises experimentation, surface integrity study, and parametric optimization followed by a confirmation test to perform the betterment of the current [Formula: see text]-EDM approach.
Electro discharge machining (EDM) is a cycle for molding tough materials and framing profound contour formed openings by warm disintegration in all sort of electrically conductive materials. The goal of the venture to be concentrating because of working parameters of EDM for machining of silicon nitride-titanium nitride in the machining qualities with copper electrode, for example input Spark on time (Son), current (Ip), Spark off time (Soff), spark gap and dielectric pressure on the metal removal rate (MRR) and Electrode Wear Rate (EWR) were analyzed. Subsequently, using Taguchi analysis of various plots like Mean effect plots, Interaction plots, and contour plots, performance characteristics are looked at in relation to multiple process factors. Fuzzy logic and Regression analysis is utilized to combine various reactions into a solitary trademark record known as the Multi Response Performance Index (MRPI).The trial and anticipated qualities were in a decent programming instrument for discovering the MRPI esteem. For numerous performance aspects, such as material removal rate, electrode wear rate and so on, the optimal process parameter combination was established using fuzzy logic analysis. The key process factors, which included spark off time and current, were found using an ANOVA based on a fuzzy algorithm. Topography on machined surface and cross-sectional view of conductive Si3N4-TiN composite and surface characteristics of machined electrode is examined by SEM analysis and identified the best hole surface and worst hole surface. Sensitivity analysis is being utilized to determine how much the input values, such as Ip, Son and Soff, will need to alter in order to get the desired, optimal result. In the complexity analysis, each constraint of the machine, composite and process is addressed. Future researches might look into various electrodes to assess geometrical tolerances including angularity, parallelism, total run out, flatness, straightness, concentricity, and line profile employing other optimization methodologies to achieve the best outcome. The findings of the confirmatory experiment have been established, indicating that it may be feasible to successfully strengthen the spark eroding technique.
In order to improve the machining efficiency and the surface quality of EDM/ECM, adding a small amount of sodium nitrate into deionized water as the working medium, a novel simultaneous machining approach of EDM and ECM (SEDCM) was developed. In this work, a comparative study was conducted on the SEDCM performance of TC4 alloy using different electrode materials viz. brass, copper and copper-tungsten alloy. In addition, the effects of process parameters, such as peak current, pulse on time and gap voltage on material removal rate (MRR), tool wear rate (TWR), surface roughness (Ra), and surface micromorphology were investigated. The results show that brass electrode provides the smallest MRR, the highest TWR and the worst surface quality. The copper electrode has the smallest average diameter of a single discharge craters and the best surface finish. The MRR and TWR of copper-tungsten electrode are similar to those of copper electrode. As peak current increases, TWR increases and Ra deteriorates for all the electrodes, as well MRR increases and then decreases for copper and copper-tungsten electrodes. Increase in pulse on time and gap voltage, MRR and TWR increases and then decreases gradually. At higher pulse on time and gap voltage, Ra becomes greater for three type electrodes.
