Micro-electro Discharge Machining Research Articles

How the Electrical Conductivity of Water Fluids Affects Micro-EDM in the Short-Pulse Regime.

This work investigates micro-electro discharge machining (EDM) performance involving deionized and tap water. The chosen machining regime was semi-finishing, where open voltage (from 100 to 130 V) and current values (5-10 A) were applied using a 0.5 µs pulse-on time and a frequency of 150 kHz, i.e., a duty cycle of 25%. First, numerical analyses were performed via COMSOL Multiphysics and used to estimate the plasma channel distribution and melted material, varying the current, sparking gap, electrical conductivity, and permittivity of the two fluids. Then, experimentally, the micro-EDM of holes and channels in hardened thin steel plates were replicated three times for each considered fluid. The material removal rate (MRR), tool wear ratio (TWR), radius overcut, and surface roughness were plotted as a function of open voltage and electrical conductivity. The study proves that as voltage and current increase, the MRR and TWR decrease with electrical conductivity. Nonetheless, for higher electrical conductivity (tap water), the process did not proceed for lower open voltages and currents, and the radius overcut was reduced, contrary to what is commonly acknowledged. Finally, the crater morphology and size were evaluated using a confocal microscope and compared to simulated outcomes.

Micro-electro discharge machining characteristics of tungsten-copper for electronic devices

ABSTRACT Micro-machining involves the removal of small amounts of material by action other than that of a sharp-edged tool. The most common technique being electrical discharge machining (EDM). The material removal rate and edge definition of the finished product are based on different process parameters. This study is aimed to characterise micro-EDM process parameters for tungsten–copper and to achieve maximum material removal rate without affecting the edge definition and surface roughness while using smaller electrodes. Eight process parameters were studied for their influence on the material removal rate (MRR), surface roughness (Ra) and tool wear rate (TWR). Taguchi design of experiments was carried for 36 experimental runs. The ANOVA analysis showed that the MRR depends largely on voltage, energy and current, while the TWR depends on the energy and voltage. The surface roughness value (Ra) was influenced more by energy, incremental depth and the pulse width, thus differing from MRR and TWR. The optimum parameter set for higher MRR (10e-3 mm3/min) and lower Ra (0.13 µm) was deduced from regression analysis, and the confirmation tests showed less than 8 % deviation from the predicted values. The SEM studies showed greater depths of craters in the surface machined for higher MRR.

GENERATION OF EFFUSION HOLES ON ULTRA-HIGH TEMPERATURE ALLOY BY MICRO ELECTRO-DISCHARGE MACHINING PROCESS

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]on, [Formula: see text]off) 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]on, [Formula: see text]off, 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]2, 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.

Experimental investigation on machining of multiple micro-square holes

ABSTRACT Miniature components with multiple holes are commonly observed in many precision elements like micro filters, aerostatic bearings, turbine blades, etc. Micro-Electro Discharge Machining (µ-EDM) is a popular micromachining technique, which includes melting and vaporizing electrode materials to produce the required miniaturized features on various components. This paper focused on multiple micro-square holes machining on the copper sheet using the tailor-made copper multi-tool electrode. Three micro-square holes are machined at a time with different machining parameters such as voltage, frequency, current, and varying pitch of the multi-tool electrode. The responses of the machined geometrical features are estimated, including material removal rate (MRR), side gap (SG), taper angle (TA), and tool wear rate (TWR). Experimental runs are designed based on four factors varied in three levels using the box-behnken method. The ideal set of µ-EDM parameters to maximize MRR while simultaneously minimizing TWR, SG, and TA is identified with a Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS). The obtained optimum combination of machining parameters are voltage: 40 V, current: 3 A, frequency: 6 kHz, pitch: 1.4 mm, and the corresponding output responses are MRR: 813.48 µg/min, TWR: 82.03 µg/min, SG: 65.49 µm, and TA: 1.18°. Further, the heat-affected zone (HAZ), microstructure, and microhardness around the machined holes are analyzed, and the obtained results are discussed in the paper.

Comparative Study of Material Removal Rate of Single-Spark And Multi-Spark Micro-EDM of Copper

Micro-electro discharge machining (micro-EDM), a noncontact material removal process, is a well-established technique for making mold cavity on any workpiece materials having a minimal electrical conductivity of 0.1 Scm-1. The spark between tool electrode (-ve) and workpiece electrode (+ve) removes materials mostly from workpiece. Knowing the time and amount of material removed in a single spark, MRR can be estimated. A number of analytical study have been reported for the estimation of MRR based on the ideal situation single-spark erosion. In case of multi-spark micro-EDM, charging and discharging do not always follow the ideal conditions of the circuit and a lot of unwanted pulses such as arching and short circuit are produced which in turn reduce the effective number of pulses per second. Moreover, in RC pulse micro-EDM, the discharges are not uniform and the current and voltage are not constant with time. As a consequence, the performances estimated based on single-spark erosion formula could be misleading in multi-spark cases. This paper presents an analytical estimation of MRR as a function of machining parameters capacitance and voltage for single spark which is then compared with the multi-spark erosion of RC pulse micro-EDM. The single spark erosion rate is estimated using the electro-thermal theories in which charging and discharging duration are derived from the RC pulse time constant and the number of sparks per unit time is counted from the single spark duration. The expression of single spark erosion volume is estimated using heat transfer equations. It is also difficult to conduct single-spark EDM experiment and it has very little practical implications. Experiments are conducted to investigate the multi-spark erosion rate. It is shown that, theoretically, the number of sparks depends on the capacitance and resistance of the circuit. However, in multi-spark erosion, it is found that the number of effective sparks depend not only the capacitance and voltages but also the conditions of micro-EDM such as the workpiece and tool materials, flushing conditions, depth of cut. It is shown that the multi-spark MRR is almost half of the calculated value which is found using the equation of single spark MRR in micro-EDM of copper. Therefore, the single spark erosion formula needs to be adjusted for each of the workpiece to incorporate with the multi-spark erosion in real conditions.

Machining of micro features through µ-ECSM process and evaluation of surface integrity

In the present experiment, micro features were fabricated on titanium alloy by means of the micro-electrochemical spark machining (µ-ECSM) process and the micro-electro discharge machining (µ-EDM) process, using similar electrical parameters. However, in case of the µ-ECSM, the types of electrolyte (KOH, NaOH, KOH+NaOH) and their concentration (0.5 M to 2.5 M) varied from that of the µ-EDM process. In course of the study, different machining output parameters, such as, material removal rate (MRR), recast layer (RCL) thickness, heat affected zone (HAZ) and surface topography, were analysed and compared. The results indicated that the µ-ECSM process produces higher MRR (7.29 times), RCL thickness (0.436 times) and HAZ (0.595 times) as compared to the µ-EDM process. Moreover, the mixed (KOH+NaOH) electrolyte at 0.5 M concentration, 25 V machining voltage, 15% duty factor and 10 kHz of frequency showed better machining performance as compared to the parent electrolyte and produced lower RCL thickness (3.54 µm) and HAZ (26.83 µm), respectively. The surface topography of the work piece, machined by the µ-EDM process, showed rough surface whereas the NaOH electrolyte-based µ-ECSM process produced smoother and clean surface.

Energy storage and photosensitivity of in-situ formed silver-copper (Ag-Cu) heterogeneous nanoparticles generated using multi-tool micro electro discharge machining process

The present work focused on the energy storage and photosensitivity of in-situ formed segregated type silver-copper (Ag-Cu) heterogeneous nanoparticles generated by using the developed Micro-Electro Discharge Machining (Micro-EDM) process. The investigation includes analysis of useful heat gain, temperature gain, and thermal efficiencies by the nanofluids using fabricated mini parabolic solar trough collector. Photosensitivity of nanoparticles are studied by evaluating light absorbance and bandgap energies at different light intensities. Theoretical study includes understanding of the effects of the metallic vapor pressure, dielectric temperature, and the material properties on heterogeneous particle formation mechanisms. The experimentation work comprises of conduction of ten experiments by keeping silver plate (workpiece) at anode terminal and varying copper multi-tool pins from 1, 2, 3…10 at cathode terminal submerged in deionized water with 0.7 mM concentration of CTAB surfactant. Particles generated are found to be well dispersed, heterogeneously arranged structures with average particle size ranging from (4.83 ± 3.35 in 3rd experiment) nm to (15.37 ± 5.46 in 5th experiment) nm. XRD crystallographic studies confirmed the presence of the FCC structure of Ag and BCC structure of Cu2O. The maximum particle synthesis is from the 9th experiment producing 5.4 g/L for 30 min of machining with the spark energy of 2.88 mJ. The highest useful heat gain is obtained by the 3rd experiment due to higher silver content whereas highest overall thermal efficiency of 14.5% and bandgap energy of 2.75 eV is obtained by the 7th experiment nanofluid.

The Development of Design and Manufacture Techniques for Bioresorbable Coronary Artery Stents.

Coronary artery disease (CAD) is the leading killer of humans worldwide. Bioresorbable polymeric stents have attracted a great deal of interest because they can treat CAD without producing long-term complications. Bioresorbable polymeric stents (BMSs) have undergone a sustainable revolution in terms of material processing, mechanical performance, biodegradability and manufacture techniques. Biodegradable polymers and copolymers have been widely studied as potential material candidates for bioresorbable stents. It is a great challenge to find a reasonable balance between the mechanical properties and degradation behavior of bioresorbable polymeric stents. Surface modification and drug-coating methods are generally used to improve biocompatibility and drug loading performance, which are decisive factors for the safety and efficacy of bioresorbable stents. Traditional stent manufacture techniques include etching, micro-electro discharge machining, electroforming, die-casting and laser cutting. The rapid development of 3D printing has brought continuous innovation and the wide application of biodegradable materials, which provides a novel technique for the additive manufacture of bioresorbable stents. This review aims to describe the problems regarding and the achievements of biodegradable stents from their birth to the present and discuss potential difficulties and challenges in the future.

Micro-electro discharge machining (Micro-EDM) models for conductive and nonconductive materials: A review

Models are useful in controlling the process effectively and efficiently in micro electro discharge machining (Micro-EDM). There are two types of models which are empirical models and theoretical models. Most of the models are basically formulated for conductive work materials. However, nowadays there is a trend to cut nonconductive materials using micro-EDM where the models developed for conductive materials are not applicable. There are only few models that are developed to cut nonconductive materials with micro EDM but these models have limitations. In this article, models for cutting conductive materials and nonconductive materials using micro EDM are compared in view of their applications.

An experimental study to investigate the effect of solid, single-channel and multichannel electrodes in micro-electrodischarge drilling process

Micro-electrodischarge machining (micro-EDM) is one of the most sustainable processes used to machine 3D features on metallic surfaces. It is an effective method of machining extremely hard and difficult to cut materials. Material is removed from anode surface, primarily, by heat generated due to controlled sparking. Size and shape of electrodes play significant role in the stability of the micro-EDM process by governing the debris flushing out of inter-electrode gap. The present study addresses the effect of geometries on the performance of the micro-EDM process. Designed experiments have been conducted by using solid, single-channel and multichannel electrodes. Material removal rate (MRR) and tool wear rate (TWR) being the important indicators of micro-EDM process, effect of different process parameters on MRR and TWR have been evaluated for different set of experiments on solid rod, single-channel and multichannel electrodes. From the analysis, a solid electrode has been found to provide a better performance than the other two type of electrodes. Highest MRR and lowest TWR is observed for the solid electrode. A 16.63% of maximum increment was found in MRR with the use of solid electrode.

Experimental investigation on micro-electro discharge machining process using tungsten carbide and titanium nitride-coated micro-tool electrode for machining of Ti-6Al-4V

ABSTRACT Titanium alloy Ti-6Al-4 V is used in numerous applications because of its low weight associated with high strength, excellent resistance to fatigue and creep, good resistivity in corrosive environments, and biocompatibility. The Micro-Electro Discharge Machining (MEDM) is one of the finest non-conventional machining processes used for machining Ti-6Al-4 V. In this research article an attempt has been made to study effect of thin film coating of titanium nitride (TiN) on tungsten carbide (WC) micro-electrode on tool wear rate (TWR), over cut (OC) and depth of machining (Z coordinator) during micro-drilling of Ti-6Al-4 V. A detailed experimental investigation has been carried out with the help of Taguchi’s L9 orthogonal array for understanding the mechanism of the process. The process parameters such as voltage, spindle rotation and capacitance are considered to perceive their effect on TWR, OC and Z coordinator. Uncoated WC and TiN-coated WC micro-tool electrodes has been used during machining Ti-6Al-4 V in order to compare listed responses. The experimental results of TiN-coated micro-electrode showed that TWR decreased by 16.32 %, depth of machining increased by 20.83% and OC reduced by 12% as compared to uncoated WC micro-tool electrode.

Pulse-Type Influence on the Micro-EDM Milling Machinability of Si3N4-TiN Workpieces.

In this paper, the effect of the micro-electro discharge machining (EDM) milling machinability of Si3N4–TiN workpieces was investigated. The material removal rate (MRR) and tool wear rate (TWR) were analyzed in relation to discharge pulse types in order to evaluate how the different pulse shapes impact on such micro-EDM performance indicators. Voltage and current pulse waveforms were acquired during micro-EDM trials, scheduled according to a Design of Experiment (DOE); then, a pulse discrimination algorithm was used to post-process the data off-line and discriminate the pulse types as short, arc, delayed, or normal. The analysis showed that, for the considered process parameter combinations, MRR was sensitive only to normal pulses, while the other pulse types had no remarkable effect on it. On the contrary, TWR was affected by normal pulses, but the occurrence of arcs and delayed pulses induced unexpected improvements in tool wear. Those results suggest that micro-EDM manufacturing of Si3N4–TiN workpiece is relevantly different from the micro-EDM process performed on metal workpieces such as steel. Additionally, the inspection of the Si3N4–TiN micro-EDM surface, performed by SEM and EDS analyses, showed the presence of re-solidified droplets and micro-cracks, which modified the chemical composition and the consequent surface quality of the machined micro-features.

Energy efficient and cost effective method for generation of in-situ silver nanofluids: Formation, morphology and thermal properties

In the present work, silver nanoparticles (AgNPs) are generated using the Micro-Electro Discharge Machining process (micro-EDM). Nanofluids are synthesised in dielectric fluids such as polar fluid like Deionized water (DI), Deionized water with 4 wt% of Poly-Vinyl Alcohol (DI + PVA), and non-polar fluids like Ethylene Glycol (EG) and Kerosene (KR). Low energy consumption, in-situ nanofluid synthesis, cleaner work environment, non-essential chemical post-processing during the synthesis using micro-EDM are the significant reasons creating broad scope for this process exploration. To understand the process, theoretical approach is explored to study the effect of dielectric fluids on particle formation mechanism, critical radius and nucleation rate of nanoparticles. In the experimental approach, silver nanoparticles are generated and characterized for the particle concentration, morphology and size distributions in all four dielectric fluids. High Resolution Scanning Electron Microscopy (HRSEM), Dynamic Light Scattering (DLS), and UV–Visible spectroscopy (UV–Vis) are used for the study. Nanofluid's decomposition temperatures and latent heat of vaporization are investigated using ThermoGravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), respectively. Particles generated in DI + PVA fluid found to be smaller mean size of (30.06 ± 1.12) nm followed KR fluid of (40.32 ± 1.29) nm, EG fluid of (47.85 ± 1.24) nm, and in DI fluid of (149.04 ± 1.93) nm. Also polar liquids yielded wider and non-polar liquids yielded narrower particle distribution. KR nanofluid is thermally stable followed by DI + PVA, DI, and EG nanofluid. With the spark energy of 1.15 mJ, the in-house developed micro-EDM process yielded highest nanoparticles concentration of 2.68 g/L in KR fluid followed by DI + PVA fluid of 2.13 g/L, DI fluid of 2.09 g/L and least by EG fluid of 1.04 g/L.

Micro ultrasonic machining hemispherical mold for MEMS resonator gyroscope using a novel ultraprecise ceramic entire-ball tool

The manufacture of inertial-grade and tactical-grade diamond micro electro mechanical systems (MEMS) hemispherical resonator gyroscopes is limited by the manufacturing accuracy of the monocrystalline silicon hemispherical concave mold, on which the gyroscope shell is formed. To solve this problem, this paper presents a new method for micro-ultrasonic machining of microhemispherical molds for resonator gyroscopes using an ultraprecise ceramic entire-ball tool (UCET). To study the wear mechanism of the UCET and the influence of tool wear on the surface integrity and form accuracy of the microhemispherical mold, a mathematical model for the tool wear of micro-ultrasonic machining of microhemispherical molds with UCET is established and verified by experiments. The micro-ultrasonic amplitude, the abrasive material and the abrasive size is found to have significant influences on the tool wear of the UCET. The wear rates of tungsten carbide and silicon nitride ceramic tools are 2.22% and 3.64%, respectively, which are far less than the wear rate of 8.03% of bearing steel. The wear condition agrees with the theoretical model. The machining experiment shows that the radius change, ΔR, is 6.47 µm of the microhemispherical mold processed by UCET, which is much better than 32 µm of the micromold processed by micro-electro discharge machining at one time. After 10 continuous machining runs, the deviation rate of the form accuracy of the micromold is 1.71%, 3.71% and 24.21%, due to the wear of tungsten carbide, silicon nitride and bearing steel, respectively. It can be seen that micro-ultrasonic machining of microhemispherical molds using UCET has the characteristics of a high initial form accuracy, low wear rate, high integrity and form accuracy. This is a potentially effective method to obtain micromolds with high accuracy and surface integrity.

Microelectro Discharge Machining: Principles and Applications, by Ajay M. Sidpara and Ganesh Malayath

<i>Microelectro Discharge Machining: Principles and Applications</i>, by Ajay M. Sidpara and Ganesh Malayath

Machining and Characterization of Micro-Channels Generated on Phosphor Bronze Using μ-EDM

Micro-Electro Discharge Machining ([Formula: see text]-EDM) is one of the nonconventional micro-machining processes in which electrical discharges are produced between the micro-sized electrodes — tool and workpiece immersed in dielectric fluid. The electrical discharges thus produced remove the workpiece material through melting and vaporization process and results in the creation of micro-craters. This paper focuses on machining of micro-channels on copper alloy — phosphor bronze plate using [Formula: see text]-EDM. Various micro-channels have been machined on phosphor bronze with input parameters: voltage, capacitance and pulse on-time varied at four levels. The experimental layout plans were designed with robust design technique — Taguchi-based L[Formula: see text] orthogonal array and the process parameters were optimized using optimization technique — Grey Relational Analysis (GRA). The dimensional aspects — depth, width, profile and surface roughness of machined channels were selected as output responses. The experimental results show that the parameters have individual and combined effect on responses. Analysis of Variance (ANOVA) technique has been used to explore the effect of parameters on responses. Detailed surface morphology of the machined features has also been analyzed using scanning electron microscope (SEM) and noncontact optical profiler images. As an extension of machining channels, Y-shaped channel has been machined on copper alloy which can be used for micro-fluidic applications.

Carbon nanofibre assisted micro-electro discharge machining (μEDM) of Ti-6Al-4V alloy

Titanium alloys have found growing applications in aerospace, biomedical and marine industry. However, extreme hardness and strength cause difficulty in machining of titanium alloys. This is further complicated by the requirements of micro-features on hard to machine alloys. Micro-electro discharge machining (micro-EDM) is being investigated to match the requirement. However, slower removal rates and thermal effects are the issues in thermal erosion-based EDM process. In this work, we have investigated the efficacy of using carbon nanofibres (CNFs) mixed with the dielectric fluid for micro-machining of Ti-6Al-4V using micro-EDM. It is observed that the addition of CNFs not only improves electro-discharge frequency, material removal rate but also improves the surface roughness. Added nanofibres lowered the material migration and increased spark gap. We noted a significant influence of mixing CNFs in the dielectric fluid for enhancing machining performance characteristics in μEDM during micro hole generation on Ti-6Al-4V alloy.

Effect of different dielectric fluids on material removal rate, surface roughness, kerf width and microhardness

In microelectro discharge machining, dielectric plays prime role in the machining performance. The performance of machining is highly affected by dielectric fluid used in the micro-EDM. This paper discusses the influence of various different dielectric fluids such as demineralised (DM) water, oxygenated DM water, mixture of ethylene glycol and DM water, alumina suspension in DM water, alumina suspension in oxygenated DM water and alumina suspension in mixture of ethylene glycol and oxygenated DM water on the performance criteria such as material removal rate (MRR), surface roughness, kerf width and microhardness during the machining of stainless steel. The results show that the use of DM water as a dielectric gives high MRR. Also when non-conducting alumina powder is mixed with dielectric, the MRR is decreased. Surface roughness is best for DM water. Surface roughness is found to increase with other dielectric fluids. Kerf width is improved after mixing alumina powder and ethylene glycol to DM water. A comparative study for microhardness has also been done for different dielectric fluids. Further study is done using microscope to analyze the microstructure. Further investigation is performed on surface integrity in each type of dielectric with the help of microstructure. Hence, micro-EDM is performed on stainless steel with different dielectric fluids. It is noticed from the results that there is significant impact of mixing non-conducting alumina powder and oxygen in DM water which increased the kerf width and microhardness of machined surface in micro-EDM of stainless steel.

A comparative study between a miniaturized liquid junction built in a capillary gap and semi-open capillaries for nL sample infusion to mass spectrometry

This study introduces a novel design for a microfluidic element used in a high-throughput screening mass spectrometer autosampler. The original design of the sampler consists of a liquid bridge formed in a micrometer gap between two capillaries. This liquid bridge is used to receive the sample, which is later ionized and analyzed by mass spectrometry. However, this liquid bridge is difficult to establish and maintain for long time periods, making the screening of large libraries of compounds a tedious task. The improvement described here consists in replacing the liquid bridge by a single pierced capillary, called “semi-open capillary”. The fabrication of semi-open capillaries is explained. To achieve an optimum structure, two different machining methods were tested, laser ablation and electro-discharge micromachining. The advantages of this design over the previous one include reduction of the dead volume and that of the sample dilution, as well as higher stability. Characterizations of the repeatability and the limit of detection (LOD) show that the optimized semi-open capillary leads to nearly twofold lower LOD when compared to the original liquid bridge.

Micro-holes EDM of superalloy Inconel 718 based on a magnetic suspension spindle system

Micro-electro discharge machining (EDM) plays an important role in fabrication of micro-parts and structures such as micro-holes. However, due to the micro-discharge gap between workpiece and electrode, debris in the gap cannot be flushed away effectively during machining process. Debris accumulation could cause a poor machining stability and low production efficiency for micro-EDM. To address these issues, in this study, a magnetic suspension spindle system (MSSS) EDM possessed high response frequency was proposed to machine micro-holes in superalloy Inconel 718. The objective of this experimental work is to study effects of machining parameters on discharge percentage, material removal rate (MRR), electrode wear rate (EWR), and recast layer with high response frequency MSSS EDM. Experimental results reveal that compared to micro-holes machined by conventional EDM, discharge percentage increased by at least 30%, and arc percentage decreased by at least 11%. Hence, MRR increased by at least 23% and EWR decreased by at least 43%. The inlet and outlet diameters of the micro-holes were improved further and the recast layer significantly decreased by MSSS EDM. The experimental results demonstrate that compared to conventional EDM, MSSS EDM can be used to fabricate micro-holes on Inconel 718 with a higher efficiency and quality.