Electro-discharge Machining Machining Research Articles

Minimization of residual stress, surface roughness and tool wear in Electro Discharge Machining of inconel 625

Electro Discharge Machining (EDM) is a well-known non-traditional machining technique which is widely used to make die castings and turbine blades out of difficult-to-cut materials like Inconel 625. The machined part's surface quality and dimensional accuracy are affected by the EDM electrode's wear. Moreover, surface roughness and residual stress augmentation of EDM-machined components can reduce the workpiece's lifespan by decreasing the fatigue life of machined parts. To enhance the precision and durability of EDM machined components, residual stress, tool wear, and surface roughness should be evaluated and minimized. The majority of published research works for the assessment and optimization of EDM machining parameters are based on experimental works which are limited to testing, workpiece materials, and machining conditions. In order to improve the quality of machined surfaces and reduce tool wear and residual stress during Inconel 625 EDM processes, a virtual machining approach has been developed in the research work. To predict the cutting temperature during EDM operations, the modified Johnson Cook model of Inconel alloys is used. The finite element approach is then used to calculate the generated residual stress during the EDM process. The proposed virtual machining approach is also applied in order to predict the surface roughness of EDM machined parts. To minimize the residual stress, tool wear, and surface roughness during EDM operations of Inconel 625, the machining parameters of gap voltage, peak current, pulse-off time, and pulse-on time are optimized using the Taguchi optimization approach. Experiments and simulations are then conducted to verify the developed virtual machining system in the study. So, using the optimal machining parameters, the residual stress, surface roughness of machined items and wear of EDM electrode are minimized by 24.5 %, 25.4 %, and 25.4 % respectively. Thus, the quality and reliability of components made using EDM processes may be enhanced by the suggested virtual machining system.

A Novel Physically Guided Data Fusion Prediction Model for Micro-EDM Drilling

Accurate prediction of Electro-Discharge Machining (EDM) results is crucial for industrial applications, aiming to achieve high-performance and cost-efficient machining. However, both the current physical model and the standard Artificial Neural Network (ANN) model exhibit inherent limitations, failing to fully meet the accurate requirements for predicting EDM machining results. In addition, Micro-EDM Drilling can lead to the distortion of the macroscopic shape of machining pits under different input conditions, rendering the use of only the volume of machining pits as the evaluation index insufficient to express the complete morphological information. In this study, we propose a novel hybrid prediction model that combines the strengths of both physical and data-driven models to simultaneously predict Material Removal Rate (MRR) and shape parameters. Our experiment demonstrates that the hybrid model achieves a maximum prediction error of 4.92% for MRR and 5.28% for shape parameters, showcasing excellent prediction accuracy and stability compared to the physical model and the standard ANN model.

Augmentation of pool boiling performance using Ag/ZnO hybrid nanofluid over EDM assisted robust heater surface modification

Recently, miniaturization has been scaled up tremendously to improve the compactness and aesthetics of devices. Such changes require adequate thermal management for efficient and flawless operation. Pool boiling in such scenarios is preferred as it offers significant amounts of latent heat for transferring thermal energy. The current research looks at augmentations offered using Ag/ZnO hybrid nanofluid concentrations of 0.02%, 0.06%, and 0.1% over heater surfaces modified through electro discharge machining (EDM). The modified surfaces had average surface roughness (Ra) values ranging from 2.96 µm to 8.53 µm for EDMed surfaces (E1, E2, and E3). Amongst all experimental trials, the one with a 0.1% concentration of Ag/ZnO hybrid nanofluid over surface E3 exhibited the highest critical heat flux (CHF) of 225.68 W/cm2 and a heat transfer coefficient (HTC) of 151.63 kW/m2 °C, which are respectively 80.43% and 252.98% greater than the control surface (CS)-DI water combination with a Ra value of 1.61 µm used for comparison. Overall, increased nucleation sites owing to EDM machining and decreased surface contact angle owing to nanoparticle deposition attributed to an augmented pool boiling performance.

Primary research on influence of workpiece cooling on efficiency of Inconel’s 625 alloy elecrodischarge milling in carbon dioxide

Inconel alloys one of the most cost intensive materials to machine with conventional machining methods. It is connected with its mechanical properties, as well as low thermal conductivity and also high material losses during machining. An alternative to conventional machining is electrodischarge machining (EDM), which enables to machine all the materials which are conductors or semi-conductors regardless its chemical composition and mechanical properties. There are three main dielectric types which can be used for EDM machining. The eco-friendly are gaseous ones. It is still hard to use gaseous dielectrics in the industrial applications, however it seems that this dielectrics are the future. The main aim of this research was to determine an influence of EDM milling in carbon dioxide used as dielectric in two configurations – with and without external workpiece cooling with deionized water on the EDM technological parameters (material removal rate, electrode wear) as well as technological surface integrity and surface structure.

A Review on Machinability of Shape Memory Alloys Through Traditional and Non-Traditional Machining Processes: A Review

This review article offers consolidated knowledge on the subject of several traditional and non-traditional procedures that are taking place throughout the years to form shape memory alloys (SMAs). At the primary part of the review, the usage of several shape memory alloys was shown. The dialogue then continued towards numerous traditional techniques of operating followed by the obstacles in the running of SMAs utilizing traditional techniques of operating. Moreover, numerous non-traditional processes of operations such WJM (Water jet Machining), cryogenic, WEDM (Wire Electro Discharge Machining), EDM (Electro Discharge Machining), and electrochemical machining explored. As well, Numerous of outcomes reactions that may occur during the operation procedures have been emphasized such as material removal rate (MRR), rate of tool wear, surface roughness (SR), the surface integrity. A consolidated records of various academics and their findings on this issue has been evaluated. After all, the article has been concluded by suggesting a variety of key points seen throughout the review process.

Thermal error analysis of tauren EDM machine tool based on FCM fuzzy clustering and RBF neural network

A method that combines temperature field detection, adaptive FCM (Fuzzy c-means) clustering algorithm and RBF (Radial basis function network) neural network model is proposed. This method is used to analyze the thermal error of the spindle reference point of the tauren EDM (Electro-discharge machining) machine tool. The thermal imager is used to obtain the temperature field distribution of the machine tool while the machine tool simulates actual operating conditions. Based on this, the arrangement of temperature measurement points is determined, and the temperature data of the corresponding measurement points are got by temperature sensors. In actual engineering, too many temperature measurement points can cause problems such as too high cost, too much wiring. And normal processing can be affected. In order to establish that the thermal error prediction model of the machine tool spindle reference point can meet the actual engineering needs, the adaptive FCM clustering algorithm is used to optimize the temperature measurement points. While collecting the temperatures of the optimized temperature measurement points, the displacement sensors are used to detect the thermal deformation data in X, Y, Z directions of the spindle reference position. Based on the test data, the RBF neural network thermal errors prediction model of the machine tool spindle reference point is established. Then, the test results are used to verify the accuracy of the thermal errors analysis model. The research method in this paper provides a system solution for thermal error analysis of the tauren EDM machine tool. And this builds a foundation for real-time compensation of the machine tool’s thermal errors.

Study of Machine Characteristics During Rotary EDM Machining using Tools Made of Aluminium Alloy 6061

Electro discharge machining (EDM) is an unconventional machining process that uses spark energy to remove material from the workpiece. EDM process is extensively being used in die/mould making industries, automobile industry, aerospace industry etc. for generating complex and intricate shape on hard material. Numbers of research works have been carried out using EDM process in order to improve the performance. Further, different variant of EDM process like dry EDM, orbital EDM, powder mixed EDM, ultrasonic assisted EDM and rotary EDM etc. have also been studied. Rotary EDM process is very promising process that helps to improve surface finish, overcut as well as out of roundness. In the present paper, a extensive review has been presented on rotary EDM process. Significance of several input parameters has been observed on output characteristics like overcut and out of roundness.

Improving the Efficiency of Electrical Discharge Machining of Special-Purpose Products with Composite Electrode Tools.

The article is devoted to increasing the efficiency of electrical discharge machining of special-purpose items with composite electrode tools. The subject of research is the parameter of the roughness of the processed surface and the work of the electro-discharge machining (EDM) of 40Crsteel in various modes of electrical discharge machining. The aim of the work is to increase the efficiency of the process of copy-piercing electrical discharge machining of parts introduced into the composition of a special-purpose product and the use of electrode tools with the introduction of 20% graphite. Experimental studies were carried out using the method of a full factorial experiment with a subsequent regression analysis. The experiments were carried out using a copy-piercing Smart CNC EDM machine, a tool electrode, and a profile composite electrode. Empirical dependencies were established, reflecting the relationship between the processing modes, productivity, and surface roughness parameter after processing. A theoretical model for calculating the roughness parameter was developed, which makes it possible to predict the quality of the processed surface with a reliability of 10–15%. To ensure the required ratios of the quality of the processed surface at the maximum performance indicators, technological recommendations were obtained, as a result of which a 35% reduction in machine time was achieved when processing the “screw” part with the required indicators of surface quality.

Effect of a Rapid Tooling Technique in a 3D Printed Part for Developing an EDM Electrode

The role of rapid tooling (RT) in additive manufacturing (AM) seems essential in improving and spreading out the vista of manufacturing proficiency. In this article, attempts were made to discover the feasibility and the accomplishments of the RT electrode in the field of electro-discharge machining (EDM). Fused deposition modeling (FDM) is one of the AM processes adopted to fabricate the EDM electrode prototype by coating with copper. The copper is deposited on FDM-built ABS plastic component for about 1 mm through thick electroplating. The copper-coated FDM (CCF) and solid copper (SC) electrodes are used to conduct experiments on a die-sinking EDM machine using tool alloy steel as a workpiece. The CCF polymer electrode can be efficiently used in EDM operations as the build time of any complex shape was substantially reduced. However, the material removal rate (MRR) is far less than that of the SC electrode. It is recommended that the CCF electrode is used for semifinishing and finishing operations in which MRR happens to be less. However, CCF can get spoiled as high temperatures are generated on the machining tool, and the plastic core hardly sustains such high temperatures.

The recent trends of EDM applications and its relevance in the machining of aluminium MMCs: A comprehensive review

In the recent few years, owing to the versatility of electro discharge machining, its use hasn’t just been limited to the usual precision material removal process but also extended to the areas of micro machining, micro impressions, machining of difficult-to-machine materials etc. With the development of high hardness advanced materials like metal matrix composites, there is also an increasing research interest developed among the researchers across the globe in non-conventional machining process like EDM (Electro Discharge Machining) on such materials. In this review work, the recent exploration of EDM in various fields of research such as medical implants, food industry, super-alloys, etc. are being discussed and reviewed the process control parameters for EDM machining of aluminium based MMCs (metal matrix composites), reported by some of the researchers across the globe.

Studying the process of electric discharge machining of products obtained by powder laser welding

In modern mechanical engineering, machine parts and mechanisms are made of new materials. These materials are characterized by enhanced mechanical properties. Expensive are products made from them. Deterioration of working surfaces leads to the need to replace the entire part. About 80% of the part is not subject to wear. The method of laser surfacing allows you to restore the part. The operability of the mechanism is returned. Cost-effectiveness is increasing. The processing of deposited surfaces is difficult. The properties of mechanical surfacing increases and cutting with a blade tool is not possible. Electroerosive technologies are beginning to be actively used in the processing of deposited parts. The study of the electro discharge machining (EDM) process of such details is now relevant. After EDM, the formation of the roughness of deposited surfaces has not been fully studied. The aim of the work is an experimental study of the EDM process of such surfaces. It is important to study the effect of EDM modes on the formation of roughness is important. A full factorial experiment was conducted during the study. EcoCut wire-cutting EDM machine selected as experimental equipment. Brass wire d = 0.25 mm is used as an electrode tool. The deposited material titanium VT-01 is selected for the experiment. An empirical model was obtained during the experiment. To establish the relationship between the EDM modes and the quality of the processed surface allows the model. An increase in the stress (U, mm) and the height of the workpiece (N, mm) leads to an increase in the roughness of the treated surface (Ra, μm) when processing titanium was found. The maximum roughness value for Ra = 3.3 μm is achieved at a voltage of U = 25 V, duty cycle q = 3.5, and a workpiece height of 10 mm.

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.

Findings of performance evaluation of EDM for different materials of electrodes and work pieces- a review

EDM (Spark erosion) is non-conventional machining process which uses as removing unwanted material by electrical spark erosion. EDM Machining parameters affecting to the performance and the industries goal is to produce high quality of product with less time consuming and cost. To achieve these goals, optimizing the machining parameters such as pulse on time, pulse off time, cutting speed, depth of cut, duty cycle, arc gap, voltage etc. The performance measure of EDM is calculated on the basis of Material Remove Rate(MRR), Tool Wear Rate(TWR), and Surface Roughness(SR).The main objective of present work is to investigate of the influence of input EDM (Electro Discharge Machining) parameters on machining characteristics like surface roughness and the effects of various EDM process parameters such as pulse on time, pulse off time, servo voltage, peak current, dielectric flow rate, on different process response parameters such as material removal rate (MRR), surface roughness (Ra), Kerf (width of Cut), tool wear ratio(TWR)and surface integrity factors. In this paper few selected research paper related to Die-sinker EDM with effect of MRR, TWR, surface roughness (SR) and work piece material have been discussed.

Parameter Optimization of Electro-Discharge Machining (EDM) in AISI D2 Die Steel using Taguchi Technique

Objectives: To find the important parameters that affects the performance output (i.e.) to boost the Material Removal Rate (MRR) of the workpiece. Methods: Electro–Discharge Machining (EDM) is a thermal based machining process which is used to remove ‘hard to cut materials’ with complex shapes. The principle with the EDM or spark eroding machining is that the unwanted materials are removed with the repeated current discharges between cathode and the anode, separated by a dielectric fluid and is subjected to an electric voltage. Findings: This paper investigates in optimizing the process variables of EDM by employing a traditional technique. The parameters chosen for optimization are pulse on time, pulse off time followed by the current and L9 Orthogonal Array (OA) has been selected to examine the impact of the process variables on the performance i.e. on the material removal rate. The experimental trials have been done on AISI D2 die steel with positive polarity and brass has been chosen as an electrode material. Applications: Mainly, the EDM are employed to machine difficult to cut materials like nickel base super alloys, titanium etc.

Investigation on Machining of Holes and Channels on Borosilicate and Sodalime Glass Using μ-ECDM Setup

Electro Chemical Discharge Machining (ECDM) is a non-conventional machining process used to machine various conducting and non-conducting engineering materials. The non-conventional machining processes, uses some form of energy to machine materials. These some form of energies includes mechanical, thermal, chemical etc. Some of the mechanical machining processes are Water Jet Machining (WJM), Abrasive Jet Machining (AJM), Ultra Sound Machining (USM) etc., thermal machining processes are Electro Discharge Machining (EDM), Ion Beam Machining (IBM), Plasma Arc Machining (PAM), Laser Beam Machining (LBM) etc., and chemical machining processes are Electro Chemical Machining (ECM), Electro Chemical Grinding (ECG), etc. EDM and ECM machining processes are well developed and established commercially. Currently the main focus is on hybrid machining processes to utilize the advantages of one and overcome the disadvantages of others. ECDM is one such process which combines the features of EDM and ECM to machine non-conducting materials. ECDM process is mainly used for machining, scribing hard and brittle non-conducting materials like soda lime glass, borosilicate glass, PMMA material, silicon wafers etc. In the present work, experiments are conducted to machine holes and channels with a developed μ-ECDM setup. Design of Experiments (DOE) is used to plan and conduct the experiments. Optimized combinations of process parameters- voltage, duty factor and electrolyte concentration are obtained for responses- maximum Material Removal Rate (MRR), minimum Tool Wear Rate (TWR) and Radial Over Cut (ROC) are obtained using main effect plots. Repeatable holes and channels are machined using the obtained optimized parameter for maximum MRR. The response- diameter of micro holes of 0.92mm, micro channels of length 14mm, 0.34mm and 0.63mm width are obtained on borosilicate and sodalime glass with tool diameter 0.3mm of tungsten carbide and tungsten copper alloy material.

Multi-Responses Optimization Of Edm Sinking Process Of Aisi D2 Tool Steel Using Taguchi Grey–Fuzzy Method

Rough machining with Electro Discharge Machining (EDM) process gives a large Material Removal Rate (MRR) and high Surface Roughness (SR), while finish machining gives low SR and very slow MRR. In this study, Taguchi method coupled with Grey Relational Analysis (GRA) and fuzzy logic has been applied for optimization of multiple performance characteristics. The EDM machining parameters (gap voltage, pulse current, on time and duty factor) are optimized with considerations of multiple performance characteristics, i.e., MRR and SR. The quality characteristic of MRR is larger-is-better, while the quality characteristic of SR is smaller-is-better. Based on Taguchi method, an L18 mixed-orthogonal array is selected for the experiments. By using the combination of GRA and fuzzy logic, the optimization of complicated multiple performance characteristics was transformed into the optimization of a single response performance index. The most significant machining parameters which affect the multiple performance characteristics were gapvoltage and pulse current. Experimental results have also shown that machining performance characteristics of EDM process can be improved effectively through the combination of Taguchi method, GRA and fuzzy logic.

Parametric Investigation Into the Fabrication of Disk Microelectrodes by Electrochemical Micromachining

In electrochemical micromachining (EMM) of microfeatures using straight cylindrical microtools, sidewalls of the structure tapers as depth increases. Disk microtool electrodes are used to minimize the taper formation during the machining of microfeatures. At present disk microtool electrodes are fabricated by wire electrical discharge grinding, reverse electro discharge machining (EDM), and microwire electro discharge machining method, which needs separate EDM machine as well as fabricated microtools suffer from thermal defects like microcracks on surface, residual stress, deformation, and needs careful handling. To overcome these limitations, new method is proposed to fabricate disk microtool electrode by EMM. Also the influences of EMM process parameters like applied voltage, pulse frequency, duty ratio, electrolyte concentration on shank diameter, material removal rate, and surface quality are investigated. Disk microtool electrode of disk height 70 μm, disk diameter 175 μm, shank diameter 93 μm, and shank height 815 μm have been fabricated from tungsten microrod of 300 μm diameter by proposed method and used to machine microfeatures like cylindrical hole with reduced taper angle, reverse taper hole, taper free microgroove, and 3D microstructure with plane surfaces on stainless steel by EMM. Effects of disk height on machining accuracy during generation of microhole, in the form of taper angle are also presented in the paper. Proposed method of developing disk electrode by EMM will be very useful for fabricating disk microtool electrodes with different disk diameters, disk heights, shank diameter, and shank height with desired surface quality by controlling various process parameters. Disk microtools with lower disk heights are more effective to generate microfeatures with minimum taper.

Surface integrity of moulds for microcomponents manufactured by micromilling and electro-discharge machining

Milling is one of the most important processes to manufacture dies and moulds. However, it cannot machine regions with small sizes and difficult access to the cutting tool. Such regions must be machined by electro-discharge machining (EDM). It is known that EDM can damage the integrity of the machined surface, and also requires long processing time, due to both, the necessity to manufacture the electrode and its low material removal rate. The micromilling process, using high-frequency spindle together with cutting tools smaller than 1 mm of diameter has been emerging as an option for machining small regions in dies and moulds. In this context, this paper aims to help the understanding of the cutting phenomenon to manufacture small areas using both machining techniques, in order to identify the adequacy to replace EDM for micromilling in such circumstances. Machining experiments were carried out on AISI P20 (29HRC) and AISI H13 (45HRC) steels. These materials are commonly used in the mould and die industry. Residual stress on machined surface, surface finishing (2D and 3D), SEM images, microstructure and microhardness were accessed. The residual stress was tensile for the EDM pieces and compressive for the milled parts. The material had more influence on the residual stresses values than the process and H13 had higher values than P20. The surface roughness from the EDM machining pieces was not influenced by the material. The EDM caused white layer and microcracks on both materials, but much more intensely on H13. These occurrences were not found on the milled workpieces. Plastic deformation occurred on the micromilled surfaces, but without phase transformation of the material’s microstructure. Unexpectedly, the roughness on the hardest material (H13) was worse than P20 for the milling experiments. It was attributed to more intense tool deflection when milling H13. In general, roughness obtained in micromilling was about six times lower than that obtained using EDM and it presented a regular surface topography, unlike the EDM specimens.

Multi-objective parametric optimization of powder mixed electro-discharge machining using response surface methodology and non-dominated sorting genetic algorithm

Powder mixed electro-discharge machining (EDM) is being widely used in modern metal working industry for producing complex cavities in dies and moulds which are otherwise difficult to create by conventional machining route. It has been experimentally demonstrated that the presence of suspended particle in dielectric fluid significantly increases the surface finish and machining efficiency of EDM process. Concentration of powder (silicon) in the dielectric fluid, pulse on time, duty cycle, and peak current are taken as independent variables on which the machining performance was analysed in terms of material removal rate (MRR) and surface roughness (SR). Experiments have been conducted on an EZNC fuzzy logic Die Sinking EDM machine manufactured by Electronica Machine Tools Ltd. India. A copper electrode having diameter of 25 mm is used to cut EN 31 steel for one hour in each trial. Response surface methodology (RSM) is adopted to study the effect of independent variables on responses and develop predictive models. It is desired to obtain optimal parameter setting that aims at decreasing surface roughness along with larger material removal rate. Since the responses are conflicting in nature, it is difficult to obtain a single combination of cutting parameters satisfying both the objectives in any one solution. Therefore, it is essential to explore the optimization landscape to generate the set of dominant solutions. Non-sorted genetic algorithm (NSGA) has been adopted to optimize the responses such that a set of mutually dominant solutions are found over a wide range of machining parameters.

Abrasive Assisted EDM & ECM Compound Machining

The rapid development of micro electromechanical systems(MEMS) and the miniaturization trend of products require much higher machining quality for micro structural surfaces such as micro hole,micro groove and micro prism/pyramid and so on.In order to improve the machining quality of micro structural surfaces,a new method of abrasive assisted electro discharge machining(EDM)and electro chemical machining(ECM) compound machining is provided.The machining mechanism is analyzed by its micro machining model.Micro machining equipment is set up.Process parameters are optimized.Blind and through holes are drilled on SUS 304 stainless steel using tungsten electrodes whose diameters are 500 μm and 75 μm separately.The results indicate that abrasive assisted EDM ECM compound machining obtains the highest surface roughness(Ra15 nm) among the three methods of EDM,EDM ECM compound machining and abrasive assisted EDM ECM compound machining.Therefore,this is one of the best methods which can be used to machining micro structural surfaces with high efficiency and high quality.