Electro Discharge Machining Process Research Articles

An experimental study of process parameters on material removal rate in ECDM process

This article highlights on Electro Chemical Discharge Machining (ECDM) process which is an unconventional machining process used to cut several conductive and non-conductive materials. Electro-chemical machining (ECM) and electro-discharge machining (EDM) processes are already developed and are available in market. Presently the emphasis is on developing hybrid machining process to utilize the benefits of both processes. ECDM is a process that combines the features of ECM and EDM processes to machine non-conductive materials like borosilicate glass, soda lime glass, silicon wafers etc. Present work addresses the machining of non-conductive material by drilling hole in Borosilicate glass through the use of stainless steel as tool material and sodium hydroxide (NaOH) as electrolyte. Experiments were conducted as per Taguchi method by selecting different parameters like electrolyte concentration, applied voltage and machining time with three different levels. Material removal rate (MRR) was calculated for all the experiments. In this paper the effect of total machining time on MRR had been studied. From the results it is observed that MRR directly depends on machining parameters; further, the significance of input parameters were analyzed by analysis of variance.

Material Characterization and Parametric Optimization of Unconventional Machining of TiN and TaC reinforced Stir Casted Vitallium Metal Matrix Composite

In this work, influence of machining parameters of the electro discharge machining (EDM) and Abrasive-water jet machining (AWJM) processes on the material removal rate, tool wear rate and surface roughness of the composites were investigated. Titanium nitride and tantalum carbide particles reinforced vitallium composite material was synthesized by stir casting method. The machining characteristics were analyzed through Taguchi and ANOVA methods. The Taguchi optimization technique was used to find the optimal level of parameters while the percentage of contribution for each input parameter on the responses was computed by ANOVA. Scanning electron microscope (SEM) was employed to examine the surface morphology.

Surface modification of aluminium and its parametric optimization using grey relational analysis

This paper describes about the surface modification of aluminium workpiece using tungsten- copper (W-C) powder metallurgical (PM) green compact tool in electro discharge machining (EDM) process. Total nine experiments were conducted based on Taguchi L9 orthogonal array. The major response parameters selected were material transfer rate (MTR), tool wear rate (TWR) and surface roughness (Ra). The corresponding machining parameters were compaction load, peak current and pulse on-time. The experimental results were treated with grey relational analysis (GRA) for multi objective optimization. The highest grey relational grade (Gi) value was found to be 0.79 at the optimal parameter setting of 5 ton of compact load, 4 A of current and 400 µs of pulse on-time. ANOVA for grey relational grade was performed to investigate the effect of relevant process parameters in multi response criteria. The pulse on-time was found to be most influencing parameter having 49.77% of contribution followed by peak current and compact load of percentage 24.95% and 16.27% respectively.

Study of Micro-groove Generation on Titanium Alloy (Ti6Al4V) using Novel WEDM and WECM Sequential Electro Micro Machining (SEMM) Technique

Abstract The micro-part manufacturing can be accomplished by the execution of different micro-machining techniques. The sequential machining is one of the most promising techniques which dictate the structured approach towards the fabrication of highly precise micro-features in sophisticated components. The newly coined Sequential Electro Micro Machining (SEMM) technique has been implemented for the improvement of overall machining efficiency and enhancement in surface characteristics of the part during machining. In the chain of sequential machining, the present research paper has introduced a novel sequential combination of micro Wire Electro Discharge Machining (µWEDM) and micro Wire Electro-Chemical Machining (µWECM) processes. The µWEDM process was carried out on the standard wire cut EDM machine, whereas µWECM was performed on indigenously designed and developed system setup. The micro-grooves on difficult to cut material such as titanium alloy (Ti6Al4V) was initially generated by applying µWEDM process. The µWEDM is a thermal process, where the shaping of micro-groove was accomplished rapidly due to the existence of high-intensity spark discharges. The spark produced also generates recast layer comprising of cracks, micro-pores and numerous micro-craters in the heat affected zone of the machined region. During experimentation, the micro-groove using µWEDM process was cut at different machining voltages. In order to make out the best sequential machining combination, the machining voltage at which the least surface defects occurred on micro-groove was selected for sequencing with the subsequent process. In present experimentation, the least width overcut of the groove was obtained at 10V. The µWECM process was then applied to ameliorate the surface defects and other irregularities imparted to micro-groove during the µWEDM process. The effects of machining process parameters in µWECM, such as applied voltage, machining time and duty ratio on µWEDMed part was investigated. The sequential machining experiments were then conducted by choosing the best input process parameters in both the processes. The experimental results thus obtained after the application of diversified sequential micro-machining processes revealed an improved machining efficiency and high surface quality of micro-groove. Thus the µWEDM process for shaping the groove and µWECM process for finishing the groove was conducted successfully

Analysis of surface integrity and dimensional accuracy in EDM of P91 steels

For any type of machining process, surface integrity and dimensional accuracy is a critical examination for machined material. Electro-discharge machining (EDM) process is the most effective method for surface integrity and dimensional accuracy evaluation of the machined surface. The present research work focused to investigate the influencing of machining parameters (pulse current, pulse on time and duty cycle) on machining of P91 tool steel. During the machining process, quantitively measurement of surface roughness (SR) and surface crack density (SCD) has been considered as surface integrity. Dimensional accuracy is characterized by over cut (OC) in this process of machining. In this study EDM parameters arranged using RSM-based design of experiment, on SCD, SR, and OC and study their individual impact on these response parameters. Pulse current is the most significant factor as compared to other parameters for the machining in EDM. The current work also recommends an optimum setting of system parameters for obtained good dimensional accuracy and surface integrity after P91 tool steel machining with EDM.

An Exploratory Investigation and Optimization of Taper Cutting Operation with Wire Electro Discharge Machining

Taper cutting, a typical application of Wire Electro Discharge Machining process is widely used to produce parts with complex geometry such as cutting and extrusion dies, which finds wide application in tool and die making industry. Taper angle becomes a vital process parameter during taper cutting and is a critical performance measure for the tool and die making industry. The present investigation is initiated with a thought to optimize the different process parameters such as pulse on time (Ton), wire tension (WT), wire feed rate (WFR), taper angle (TA) on the performance measures namely taper error (TE), material removal rate (MRR) and surface roughness (SR) during taper cutting operation utilizing WEDM. Experiments were conducted using Taguchi’s L9 (34) orthogonal array on En-31 tool steel work material using brass wire of 0.25 mm diameter, as electrode material. The parametric multi-objective optimization of the experimental results has been carried out using Taguchi based Grey Relational Analysis (TGRA). The analyzed results uncovers that the pulse on time is the utmost prompting factor for MRR and SR while the taper angle cut on the work material turn out to be a significant factor for taper error.

Multi-objective optimization of EDM process for titanium alloy

Electro-discharge machining (EDM) is a widely used process for manufacturing industries. It is a non-conventional machining process, where material is removed by the thermal energy of the generated electrical sparks between the electrode and workpiece. It is generally used to machine high strength temperature-resistance alloys which are difficult-to-machine. Titanium alloys being a difficult-to-machine alloy, is generally used for parts in aero-space industries, thus its machining should have a higher material removal rate, lower tool wear rate with better surface finish. To achieve these suitable machining responses the process is successfully optimized using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).

A Research on Machinability of Bio Implant by Electric Discharge Machining Process

Increasing demand in industries to manufacturing the complex geometric shape and hard materials parts is extremely difficult to cut by the conventional machining process. The non-conventional machine is used for the manufacturing of 3D complex and geometry shapes without compromise the required specification. Electro discharge machining (EDM) is a non-traditional machining process, which is very widely used in recent days. EDM process is electrical and thermal energy generated between work piece and an electrode. The major applications are dies, moulds, aerospace parts, automotive industry, and surgical components. The human implant materials like Stainless Steel, Titanium and Co-Cr based alloys are widely used in biomedical fields. This paper shows that fundamental studies on electrical discharge machining (EDM), Wire electrical discharge machining (WEDM) and human implant materials with newly developed advance technologies in the current scenario.

Pongamia pinnata Plant Seed Oil as Dielectric Fluid for Electro Discharge Machining Process

Electro Discharge Machining (EDM) is a noticeable machining practice among created unconventional machining procedures for intricate, complex profiles in hard to machine materials, similar to heat-treated steels, composites, superalloys, ceramics, composites, carbides, and so on. In EDM, the material expulsion of the cathode is accomplished through precise controlled electric discharge (the spark), which transforms the metals of two electrodes into melt and vaporize, and due to the breakdown of the dielectric medium. In this research work, the suitability of non-edible plant seed oils from Pongamia pinnata as a dielectric fluid in the EDM process was investigated. Also, the suitability of EDM oil as an alternate dielectric fluid for industrial application was studied. Electrode Wear Rate (EWR), Material Removal Rate (MRR), Surface Roughness (SR), and Tool Wear Rate (TWR) are the key performance features of EDM. The principal goal of EDM is to get higher MRR alongside accomplishing the sensibly good surface quality of the machined workpiece. The parameters that accomplish the most astounding MRR depend on the machining surface, which is related to the workpiece and tool. Dielectric is the most significant variable for obtaining excellent results for the above-stated key features. These investigations showed that Pongamia pinnata oil is a suitable dielectric media; the results are satisfactory comparing with that of EDM oil. The effect of topography of the workpiece and carbon particles dissolving is also checked with SEM analysis for any deviations on work surface.

Effect of Process Parameters on Machining Performances during Machining of Al7075-T6 in Electro-Discharge Machining

In the present study, the machining of Al7075-T6 has been carried out in Electro-discharge machining(EDM) process. Taguchi L9 orthogonal array is used to conduct the experiments with three levels of process parameters.The effect of process parameter like spark gap and pulse off time on the machining performances have been analyzed. The machining performances such as material removal rate (MRR) and tool wear rate (TWR) have been analyzed for both the stationary and rotary tool EDM. Moreover, surface morphology has been studied in both the machining environment. It has been found that MRR is more in the case of rotary tool EDM as compared to stationary tool EDM.

Comparison between different methods for experimental analysis of surface integrity in die-sinking electro-discharge machining processes

Advanced manufacturing techniques such as die-sinking electro-discharge machining have been introduced in different industries such as the naval, automotive and product manufacturing. The surface finish of the parts subjected to these processes is influenced by diverse factors related to geometrical parameters, electric circuit, lubrication system and materials. For that reason, this work is focused on the analysis of the surface morphology of machined part that can be achieved by electro-discharge machining, as a function of some of the main process parameters such as the current intensity and penetration depth. In this work, three different methods for experimental analysis of surface quality, based on the measuring of surface roughness, material profile ratio and crater diameter, were applied and compared. The experimental phase included tests with copper tools on AISI 316 stainless steel workpieces. The surface roughness and accumulated material profile were recorded using measurements made with a profilometer, and for the purpose of measuring the diameter of the craters, scanning electron microscopy technology was used. According to the results, crater diameter can be adopted as a better indicator to characterize the surface quality in electro-discharge machining, because it exhibits a clearer tendency as a function of current intensity and penetration depth.

Effective parametric analysis of machining curvature channel using semicircular curved copper electrode and OHNS steel workpiece through a novel curved EDM process

Electro-discharge machining (EDM) is one of the advanced non-conventional machining techniques used in industries. Most of the EDM research areas are directed towards the linear movement (up-and-down) of the electrode. Through a novel innovation, an innovative way of machining a curvature channel through a semicircular curved copper electrode is possible through curved EDM process. The experimental setup is developed and installed on the Z-axis numerically controlled(ZNC)EDM machine. The oscillating motion of curved electrode on stationary workpiece is obtained by implementing the concept of mechatronics. In this present work, we attempt to investigate the effect of input machining parameters on the output performance characteristics in curved EDM process. During pilot experimentation, critical variables are identified and selected as sparking current, pulse on time, pulse off time and angular sensitivity. Design of Experiment using Taguchi (L9) is used to formulate the planned experiments and to evaluate the effects of input machining characteristics on Material Removal Rate (MRR), Electrode Wear Rate (EWR), Curved Machining Angle (CMA), and Curvature Depth (L). Regression analysis and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are effectively used to validate the model developed for the curved machining. The results obtained after experimentation predicts that the model can be accepted to optimize the quality machining characteristics in curved EDM process. Geometrical analysis and surface roughness are evaluated for the machined curvature through the advance measuring equipment’s. Scanning Electron Microscopy (SEM) is also used for observing the microstructure at higher magnification of workpiece material before and after machining.

Optimization of WEDM process of mould material using Kriging model to improve technological performances

Improving the technical performance of the wire electro-discharge machining (WEDM) process is an effective solution to decrease manufacturing costs. This paper addresses a multi-response optimization to simultaneously improve the cutting area rate CAR and decrease the kerf width AKW, while the average surface roughness ASR is predefined as a constraint. The processing conditions considered include the pulse-on time Ton, the current I, the voltage V and the wire speed S. A WEDM machine was adopted in conjunction with the Box–Behnken matrix to conduct experimental trials for machining of SKD61 steel. Highly nonlinear relationships between machining parameters and technological outputs were developed using the Kriging models. Finally, an archive-based micro-genetic algorithm (AMGA) was used to resolve the trade-off analysis among three responses and determine the optimal values of the processing factors. The results showed that a set of feasible solutions can be determined for the low kerf width as well as the surface roughness and the high cutting area rate. The selection of optimum parameters could help the WEDM operators to save the machining costs and time. The combination of the Kriging model and AMGA could be considered as an intelligent approach for modelling WEDM processes and predicting optimal results.

Modeling of machining parameters for MRR and TWR in EDM characteristics on Al/10 wt.-% TiB2 composites

Abstract This work was undertaken to study the effect of some of the main electro-discharge machining process parameters such as flushing pressure, current, pulse-on-time, and vibration on the tool wear rate (TWR), and metal removal rate (MRR) of Al 6061 alloy with 10 wt.-% TiB2p (titanium boride particulate) composites. The response surface methodology was used to determine the most important criteria to maximize the MRR and minimize the TWR. The experimental procedure was designed based on second-order rotatable central composite design. Sensitivity analysis was used to identify the important criteria and classify them by their order of importance in model validation. Many efforts were made to compare the calculated output of the data obtained. Pulse-on-time sensitivity was found to exert a more significant effect on MRR and TWR than did other criteria. The surface plots were prepared for both MRR and TWR. MRR value increases with an increase in peak current. It occurs in a workpiece that transfers the heat directly to the workpiece, and these functions increase TWR. This occurs because of an increase in MRR and a decrease in TWR.

Effects of electric discharge dressing parameters on polycrystalline diamond micro-tool surface topography and their micro-grinding performances

Polycrystalline diamond (PCD) micro-grinding tools are shaped by using different electro-discharge machining processes, among which wire electro-discharge grinding (WEDG) process is widely accepted due to its capability of producing highly precise, ultra-thin and dimensionally accurate tools. Observing the effects of different WEDG conditions on the tool surface and analyzing the tool's topographic features relevant to micro-grinding are of utmost importance. Current study deals with dressing of polycrystalline diamond tool blanks at different combinations of wire tension and discharge energy to observe the effects of dressing parameters on the tool surface morphology and statistics. Surface roughness, ridge type surface defects and diametrical error in the fabricated tool are analyzed with respect to discharge energy and wire tension. High wire tension produces tools with consistence surfaces and desired diameter. Binder material cobalt is efficiently melted and flushed out from the tool surface at high wire tension, which leads to proper segregation and protrusion of diamond abrasives from the surface. Static abrasive grit density measured by processing the 3D surface data of the tool is found to be ≈165–170 per mm, as compared to theoretically determined value of ≈200 per mm. Micro-slot grinding experiments are carried out on BK7 glass, to quantify the effects of the dressing parameters on the micro-grinding performances of the PCD micro-tools. Cutting forces for all the tools are found to be within 1 N whereas normal force exceeds beyond 1 N. Cutting forces are found to be higher for the tools dressed at high wire tension due to large diameter of the tool as compared to that of undersized tool obtained at low wire tension. Cutting nature is found to be mix of ductile-brittle for the machining conditions adopted in this paper.

Superior advance research in the electro-discharge machining of Ti alloys: Review

Electro Discharge Machining (EDM) known as an advanced machining process that much used for machining material with any hardness and complexity geometry in a high level of the accuracy in the cases of demand of the industrial application. The conception of the EDM process is included in applying electro-thermal energy in the gap, by discharge electrical power on the breaking point of the dielectric without any contact between electrodes. Due to the existing ability for removing debris from the surface, there is a lot of metallurgy defect on it. To improve and optimize EDM performance, the machine’s operating parameters, Input, during& output parameters, need to be optimized. Another handy way to reform of the view metallurgical must take picture sub-structure from the initial and subsequent layer. At the end for catching special status, adjust the technical parameters with metallurgical defects. Studies in case of the EDM have indicated that the appropriate selection of the way to control of the process, material, and operating parameters had considerably improved the process performance and also causing to was better the quality machined surface. This paper made a comprehensive review of the research studies in a different section of the EDM of various grades of titanium and its alloys. This review presents the simulation, experimental and theoretical studies on EDM that helped to improve the process performance, including material removal rate, surface quality, and tool wear rate, the stability of process among others. However, here are collected most of the research are done surrounding of EDM of Ti alloys as the developments of EDM and are seen material for future.

Effects of electro-discharge machining process on ultra-fined grain copper

Copper alloys, due to their proper ductility, proper thermal conductivity and low electrical resistivity, are very applicable in various industries. Ultra-fined grain materials undergo severe plastic deformation processes, in which the microstructure of the material is drastically changed as well as enhancing the level of the energy stored in the grain boundaries. These processes such as equal channel angular pressing, considerably change the material's properties including strength and hardness. Although some specifications of the ultra-fined grain copper obtained via equal channel angular pressing process is improved, the high level of stored energy makes it thermodynamically unstable and susceptible to microstructural changes during secondary thermo-mechanical processes. In the present paper, the effects of the electro-discharge machining on the ultra-fined grain copper alloy has been studied, and the results have been compared with coarse grain copper. The thickness of the recast layer and heat affected zone of the electro-discharge machined samples was investigated as well as the cracks density and the micro-hardness through optical microscopy, scanning electron microscopy and micro-hardness tester. The results show that the ultra-fined grain samples have thicker recast layer and heat affected zone and higher cracks density, comparing to coarse grain samples. However, the micro-hardness of the electro-discharge machined surface of both groups is approximately identical.

Surface characteristics of mild steel using EDM with Cu-MWCNT composite electrode

ABSTRACTThe surface properties of machine components are enhanced by surface modification. The workpiece surface can be modified using electro discharge machining (EDM) process. In this paper, mild steel work surface was modified by EDM operation using copper–multiwalled carbon nanotube (Cu-MWCNT) composite-coated 6061Al electrode. Five different electrodes (uncoated, Cu coated, Cu-MWCNT (0.5, 0.75, and 1 gL−1) composite-coated 6061Al electrode) were used for machining of mild steel work in order to compare the EDMed surface. The microstructure, elemental composition analysis, microhardness, and surface roughness of EDMed surface were investigated. The microstructural and elemental compositional analyses indicated that the MWCNTs were included into the mild steel workpiece during EDM operation. The microhardness (HV) of machined surface was enhanced by 163% compared to the base mild steel. The micro-crack formation on machined surface was significantly decreased by using Cu-MWCNT composite-coated 6061Al electrode.

Harizko elektrohigadura bidezko ebaketa-prozesuko aldagaien azterketa altuera aldakorreko piezak ebakitzeko

Harizko elektrohigadura bidezko ebaketa-prozesua (WEDM) ezinbestekoa da gaur egun, industriak gainazal-akaberen eta dimentsio-perdoien inguruan eskatzen dituen fabrikazio-eskakizun zorrotzak betetzeko. Prozesuari buruzko ezagutzarekin batera softwarearen garapena integratzen duen ingurune batetik abiatuta, makina adimendunaren funtzionamenduaren helburua lortu ahal izango da; hots, makinak bakarrik, fidagarritasunez eta doitasunik galdu gabe funtzionatzea. Baina, horretarako, arazo larrien konponketak optimizatu behar dira; esate baterako, altuera aldakorreko piezak ebakitzeko arazoa. Lan honetan, altuera aldatzen den guneetan ebaketa-prozesuaren aldagairik esanguratsuenen portaera aztertzeko aukera ematen duen industria-sistema bat garatu da. Hau da, aurrea hartu ahal izango zaie arrazoi horrengatik gerta daitezkeen aldaketei, eta, horri esker, haria apurtzea edo prozesuaren harroketa-tasa txikitzea eragin dezaketen ezegonkortasun-arazoak saihestuko dira; hau da, produktibitateak behera egitea eragotz daiteke.

Influence of energy fraction in EDM drilling of Inconel 718 by statistical analysis and finite element crater-modelling

An increase of productivity of electro discharge machining (EDM) is crucial for industrial applications. Energy losses minimisation in plasma-material interaction influences the material removal rate (MRR) in the EDM process. The energy distribution in EDM drilling is the factor that has to be analysed and optimized in order to achieve high-performance machining, reduce costs and increase the quality of the machined parts. In the present work, finite element analysis (FEA) of a single discharge is performed to calculate the energy fraction flowing into the anode. Computational fluid dynamics (CFD) simulations with Marangoni effect and considering the temperature dependent material properties are performed. Inverse FEA is performed in order to calculate the fraction of the energy distributed into the workpiece using a measured crater shape as an input parameter of the model. The model considers as an input the measured current, voltage and final shape of a single crater. The resulting energy fraction is achieved by the fitting of the single discharge modelling parameters to the experiments with various erosion parameters. It is shown that the discharge current is the parameter, which has the biggest impact on the fraction of energy distributed into the workpiece. Longer discharge time increases the fraction of energy distributed into the anode. However, it is proved that longer discharge time is positively correlated with the crater diameter growth. The results of the simulation also showed that the Marangoni effect does not have a significant impact on the removed material, but it affects the shape of the crater. Furthermore, it is proven that in FEA the influence of the temperature dependent material properties in solids and fluids is up to 24% on the estimation of the crater depth.