Hybrid Electrical Discharge Machining Research Articles

Preface

5th International eConference on Frontiers in Materials Engineering and nanoTechnology [ICF-MET-2023] has been held on May 05 – 06, 2023 by Shri Yashwantrao Patil Science College Solankur India. The aim was to provide the common platform for students, professors, researchers and industrialist to present their recent research in the field of Materials Science; Materials Engineering; Mechanical Engineering; Metallurgy; Nanotechnology; Metals, alloys and compounds; Nanofabrication; Properties of Materials; Synthesis, characterization and applications of Materials; Advances in Nanotechnology. It aims at the interaction of knowledge of current and future innovation in the above mentioned field for societal needs. The pandemic situation has taught human beings a lot and now the time to work towards it with new technological ideas. 5th ICF-MET-2023 provides the bridge to fill up the gaps that were essentially found during the pandemic.The response from the scientific community was excellent. The organizers received 95 abstracts; out of which 25 abstracts were rejected. Remaining authors were called to join the conference and share the knowledge with the peers in the field. The five invited talks were arranged where peers from various well known institutions such as KAUST Saudi Arabia; The New College Shivaji University Kolhapur; The LNM Institute of Information Technology Jaipur; Kathmandu University Nepal; participated and all of the participants gave the oral presentations.On the day first, opening ceremony, keynote speech, invited talk and oral presentations took place. Dr. Gholap Sandeep, Senior Scientific Researcher, King Abdullah University of Science and Technology (KAUST), Catalysis Centre, Saudi Arabia gave the keynote on “Iridium Single Atom Catalyst in Glycerol Conversion to Lactic Acid”. It was then followed by an invited talk by Dr. Yadav JB, Scientific Officer, Shivaji University Kolhapur on “Hydrogen a Green Energy Source: Challenges and Opportunities”. The next invited talk was given by Prof (Dr) Subedi DP, Professor of Physics, School of Science, Kathmandu University, Nepal on “Surface Treatment of Handwoven Fabrics by Atmospheric Pressure Dielectric Barrier Discharge”. Then participants gave the oral presentations as per the schedule.The day second was started with the invited talk by Dr. Ashok Chougale, The New College, Shivaji University Kolhapur, India on “Eco-Friendly Nanomaterials: Advancements in Drug Delivery and Wastewater Treatment”. The next invited talk was held by Dr. Unune Deepak, The LNM Institute of Information Technology, Jaipur on “Machining of difficult-to-cut materials using hybrid electrical discharge machining processes: Variants, Capabilities and Research Prospects”. It was further followed by the oral presentations by the participants. At the end, the valedictory ceremony was taken wherein the best presentation awards were also declared.The organizing committee acknowledge the financial and moral support from the Patrons - Hon. A. Y. Patil – Founder & Secretary, SVSPM Solankur; Hon. R. Y. Patil – Chairman, SVSPM Solankur.Beside, we are grateful to Dr. Ashok Chougale, Dr. Vishal More and Dr. Nilesh Pawar, The New College Kolhapur for their expertise and technical assistance.The organizing committee members have taken lot of efforts for this conference.Chairman – Dr Chougale GG;Convener – Dr Patil RB;Coordinator – Dr Tamboli SH;Secretary – Dr Jatratkar AA.The organizers thank all the participants, committee members, experts, reviewers and institute management authority for their mutual understanding and support during the journey of 5th ICFMET-2023. Finally, we would like to take this opportunity to thank the Editorial of IOP: JPCS for their assistance in publishing this issue.

Surface integrity of Ti-6Al-4V alloy in hybrid electrical discharge machining processes

Titanium alloy is one of the difficult-to-machine materials. The final conditions of the machined surface of this alloy are influenced by electro-discharge machining. High temperatures and thermal cycles in machining operation induce undesirable alterations in the surface quality of Ti-6Al-4V. One of the ways to improve the negative effects of electrical discharge machining is to use hybrid methods. There is no comprehensive research on the effect of hybrid electrical discharge machining process on the surface integrity of the Ti-6Al-4V alloy. In this paper, hybrid electrical discharge machining techniques including ultrasonic-assisted electrical discharge machining, powder-mixed dielectric electrical discharge machining using Al2O3 nanopowders and powder-mixed dielectric combined with ultrasonic-assisted electrical discharge machining, were used for processing of this alloy. The hybrid electrical discharge machining processes were evaluated by basic specifications of surface integrity including surface cracks, heat affected area, residual stress, and corrosion resistance. It was found that in powder-mixed dielectric combined with ultrasonic-assisted electrical discharge machining process, developed microcracks were very low and this process developed a thinner heat-altered layer, compared to traditional electrical discharge machining process, which produced a thicker heat-altered layer. The findings also, demonstrated that ultrasonic waves have reduced residual stresses compared to other methods and its stress diagram was distinct in comparison with the other processes. The corrosion rate of samples machined by electrical discharge machining process was higher than other hybrid processes; in powder-mixed dielectric electrical discharge machining process, the machined samples had the highest corrosion resistance.

A REVIEW ON ELECTRICAL DISCHARGE GRINDING: CURRENT STATUS AND FUTURE PERSPECTIVES

Electrical discharge machining (EDM) is widely applied for machining difficult-to-cut materials in mold and die industries. However, the major limitations associated with the EDM are low productivity and poor surface integrity of the machined surfaces. In recent years, several developments have been applied to overcome such limitations of EDM. Electrical discharge grinding (EDG) is a hybrid machining process that simultaneously involves the spark erosion action of EDM and the mechanical abrasion action of the grinding wheel for the material removal purpose. The rotating motion of the grinding wheel also contributes to the easy removal of debris particles, thereby improving the material removal. It is evident from the literature that the rotating motion of the grinding wheel enhances the flushing mechanism resulting in better performance of the process. This paper aims to present a comprehensive review of the research carried out in EDG, highlighting the result of the experimental, modeling, and optimization techniques applied in this area. Initially, the background of EDM and the need for hybrid EDM processes have been presented. Then, a few hybrid EDM processes have been discussed, addressing their advantages and limitations. Further, the concept of EDG and electrical discharge diamond grinding (EDDG) has been discussed, along with the classification of the EDDG process. Finally, this paper explores the current research status and future research perspective in the area of EDG and EDDG processes.

An insight on Powder Mixed Electric Discharge Machining: A state of the art review

Electrical discharge machining (EDM) is an exigent focus of interest for researchers since its inception. EDM has a wide range of applications due to its non-contact machining process based on the spark erosion method. EDM is a non-conventional machining process with high potential in the recent industrial era. Due to the few limitations of EDM, many hybrid techniques are evolved in recent years. The present review paper elucidates the in-depth mechanism of the material removal process in EDM. Hybrid EDM processes are also reviewed with special attention on powder mixed electrical discharge machining (PMEDM). A detailed comparison between the EDM and PMEDM is presented with a meticulous portrayal of the advancement and evolution of PMEDM. The emphasis is given on significant performance parameters, namely tool wear rate, material removal rate and surface roughness, besides other parameters. In addition, the study also includes different modelling, optimization, and surface analysis techniques on EDM. The paper concludes with the future scope of PMEDM in the fields of manufacturing along with its applications.

Electrical discharge machining of nickel-based superalloys: a comprehensive review

Electrical discharge machining (EDM) is commonly used to machine hard-to-cut materials without physical contact between the workpiece and the tool. It works on a dominant thermal mechanism in which the material is eroded by melting and vaporising through numerous high-energy sparks. This paper presents a thorough literature review about the research findings of ED machining for different grades of nickel-based superalloys. These studies correlate experimental results with theoretical analysis, aiming to improve the performance parameters such as material removal rate, electrode wear rate and surface quality. The work focuses on the various process parameters and their influences on multiple responses. This paper also elaborates on the modelling and simulation techniques used to improve the machining efficiency by optimising the process parameters. This review paper includes the recent developments such as hybrid EDM technology mixing nano-particles in dielectric fluids and also lays forth a scope for future research.

Experimental Study on Indigenously developed Magnetic Force-assisted Powder-mixed EDM Set-up of Al based MMC

ABSTRACT Electric Discharge Machining (EDM) is the most accepted non-contact machining process for machining of newly developed materials, but due to its poor machining quality and productivity, numerous researchers are working hard to modify the machining quality of EDM by using the hybridisation concept. This work is focused on the indigenous development of rotating Magnetic Force-assisted Powder-mixed EDM (MFPEDM) and study the surface quality of Aluminium Titanium Di-boride (Al-Ti-B2) on developed hybrid EDM using One Factor At a Time (OFAT) approach also observed the impact of machining parameters such as Pulse ON-time (Ton), Pulse OFF-Time (Toff), Current (I), and Powder Concentration (PC) on surface roughness. The value of surface roughness obtained by this hybrid set-up has been compared with machining on conventional EDM. The considerable improvement in the roughness value has been recorded by comparison of the machined surfaces obtained by machining on MFPEDM than conventional EDM.

Study of surface crack density and microhardness of Aluminium 6061 alloy machined by EDM with mixed powder and assisted magnetic field

Magnetic field assisted powder mixed electrical discharge machining (MFAPM-EDM) has emerged as hybrid electrical discharge machining (EDM) technique which improves machining performance by the addition of powder in dielectric and under the influence of magnetic field. In the present article, Aluminium 6061 alloy was machined through fabricated MFAPM-EDM set-up considering the one-parameter-at-a-time method. The individual effect of process parameters, namely pulse on duration (PON), pulse off duration (POFF), discharge current (IP), magnetic field strength (MF) and powder concentration (PC) on surface crack density (SCD) and micro hardness (MH) has been studied. Pulse on duration was observed as the most dominating process parameter accompanied by peak current, powder concentration and magnetic field for both SCD and MH. Lower SCD (0. 0063 µm/µm 2 ) and higher MH (188. 21 HV) on machined surface were observed at PON= 90 µsec, POFF=45 µsec, IP=13 A, PC =10 g/l and MF= 0. 3 T. Machining of AA6061 with MFAPM-EDM process revealed 85% and 76% improvement in SCD and MH, respectively. XRD analysis witness an increase in MH due to the presence of oxide as well as carbide layer on machined surface.

Functional grading of surfaces through hybrid ultrasonic, abrasive water jet, and electric discharge machining processing

The present study investigated a hybrid electrical discharge machining (h-EDM) process for producing functionally graded titanium surface. Herein, a stream of hydroxyapatite/titanium oxide abrasive slurry jet has been supplied, through a specially designed tool, to the ionized zone created by the EDM process, and the abrasive particles were finally directed towards the melted region of titanium through ultrasonically produced kinetic energy. The finally produced functionally graded surfaces have been characterized through microscopic analysis to assess the efficacy of the as-produced surfaces. The results highlighted that the abrasive particles have been successfully embedded into the surfaces. The proposed hybrid technology could be used for various engineering applications, including automotive and biomedical sectors.

Electrical Discharge Machining Characteristics of ECAP Copper Electrode

Enormous research work has done on the electrode wear in spark erosion machining such as hybrid electrical discharge machining process, introducing various methods such as ultrasonic vibration in electrode, rotating the electrode, developing new electrode material (alloys and composites) and surface coated electrode etc,. Equal Channel Angular pressing is one such technique which makes tool material harder through grain refinement and ultimately enhances the tool life. The work material is AISI H13. For this research work, two copper electrodes are prepared, out of which one copper electrode has undergone equal channel angular pressing process. The most influencing parameters of spark machining like current, pulse on time and pulses off time are chosen for this study. The experiments are conducted using bare copper electrode and equal channel angular pressed copper electrode based on the box Behnken approach. The observations are analyzed for the machining characteristics in terms of rate of machining, rate of tool erosion and surface coarseness. Finally, it is found that ECAP processed copper electrode has lesser wear rate and better surface finish than bare copper electrode.

Experimental investigation of abrasive assisted hybrid EDM of Ti-6Al-4V

Hybrid electric discharge machining (EDM) has been a promising technique for improving overall machining efficiency for hard-to-cut material. This, to some extent, has been related to the conventional EDM being incompetent for mass production owing to low material removal and reduced surface quality. Hence, the powder mixed electrical discharge machining (PMEDM) hybridized with abrasive jet machining (AJM) has been carried out. The tool wear rate (TWR), material removal rate (MRR) and surface finish study of titanium (Ti-6Al-4V) have been investigated. This hybrid EDM has been performed with and without abrasive jet flushing for evaluation of various eminent responses, namely MRR, TWR and SR, taking into account the input process parameters. Copper electrodes with variable inner hole diameter were used for machining of workpiece in SiCp mixed dielectric fluid. The experiments were planned and analyzed using Taguchi approach. This machining route revealed an appreciable enhancement in MRR when coupled with abrasive jet flushing and enhanced surface finish at the same time. The tool wear was significantly affected by peak current and use of SiC particulates in dielectric. In abrasive mixed flushing technique, an increase in tool erosion was spotted. Moreover, hole size, pulse-off and abrasive mixed dielectric proved to be influential in declining the surface finish of the finished component. The SEM analysis of Ti-6Al-4V samples put forward that pulse-on duration, current and type of dielectric fluid exhibited a vital influence on the topology and microstructure of machined surfaced along with their interactions.

Development and Investigation of Hybrid Electric Discharge Machining Electrode Process

Hybrid Electric Discharge Machining Electrode (HEDME) process is developed by comprising the features of Electric Discharge Machining (EDM) and traditional grinding which occurs alternatively in place of their simultaneous effect as Electric Discharge Grinding (EDG) process. This paper reports the experimental study of HEDME during machining of High Carbon Alloy Steel for material removal rate (MRR), tool wear (TW) and surface roughness (SR). The experiments were carried out on an indigenously developed HEDME attachment on Sparkonix EDM. The effects of main machining parameters such as type of tool, current and machining time have been studied. The effect of the machining on the workpiece surface machined by HEDME has been optimized using Taguchi L9 orthogonal array and results are reported. Experimental study shows that the TW is found to be the least with third design of the electrode and it decrease with the decreasing value of current, also surface finish increases with decrease in current. Moreover, the third design of electrode gives the lowest SR and highest MRR.

A comparative investigation on hybrid EDM for drilling small deep holes

For the use of electrical discharge machining (EDM) to drill small, deep holes, many studies have shown that tool electrode vibration and rotation and pump forced flushing can improve machining efficiency or quality. However, these factors are usually studied separately. In this study, a hybrid, rotary, ultrasonic EDM system was developed that used these three methods simultaneously. A comparative investigation on different combinations of the three methods was conducted for drilling small, deep holes in Inconel 718 and 41Cr4 workpieces. Results showed that, compared with other combinations for precision drilling under low discharge currents, combinations including these three methods simultaneously achieved more stable machining and higher material removal rates. In addition, the applied current greatly influenced hole depth and the effects of ultrasonics. When a high discharge current was applied, the electrode vibration contribution appeared weak.

Investigation of magnetic field-assisted EDM of composites

ABSTRACTThe Electrical Discharge Machining (EDM) technique was performed under the magnetic field influence to determine the material removal mechanism as well as surface roughness (SR) of nonmagnetic material. This study presents an exploration of the hybrid EDM technique assisted by magnetic field, with an aim to improve process performance. Herein, magnetic field intensity, peak current, duration of pulse-on/off, tool electrode material, and SiC percentage distribution were opted as the machining parameters. The chosen parameters were analyzed for their effects on the material removal rate (MRR) and SR while machining of SiC-reinforced aluminum-based metal matrix composites. Taguchi methodology was adopted for optimization of process parameters to achieve better MRR and lower SR. The experimental results witnessed improved surface finish and enhanced material removal ability of the process and also inferred that the magnetic field-assisted EDM facilitated the process stability.

Effects of hybrid electrical discharge machining processes on surface integrity and residual stresses of Ti-6Al-4V titanium alloy

The performance of the produced parts in the electrical discharge machining (EDM) is strongly influenced by the final quality of surface. High thermal gradients in EDM process develop considerable changes in surface integrity of machined samples such as changing the chemical composition of the surface, micro cracks appearance, recast layer, residual stresses, and reduction in fatigue life and corrosion resistance. Ultrasonic-assisted EDM (USEDM) and powder-mixed dielectric EDM (PMEDM) are two techniques in improving EDM efficiency. This paper was an attempt to investigate the effects of USEDM, PMEDM, and powder-mixed dielectric USEDM (PM-USEDM) processes on main characteristics of the surface integrity such as surface roughness, micro cracks, heat-altered metal zone, and residual stress. Scanning electron microscopy (SEM) micrographs were used to analysis micro cracks and heat-altered metal zone, and nanoindentation method was utilized to measure the amount of residual stress of discharged surface. The results indicated that PMEDM process improved surface roughness as well, induced micro cracks in PM-USEDM were very low, and heat-altered metal layer was very thick in traditional EDM comparing to PM-USEDM process which was thinner. The results of the present study also confirmed that the amount of residual stress of ultrasonic-assisted process was partially in lower level and had different profile compared with traditional EDM and PMEDM process.

Machining Characteristics of a Hybrid Process of EDM in Gas Combined with Ultrasonic Vibration and AJM

This study investigated the machining characteristics of a developed hybrid process of electrical discharge machining (EDM) in gas combined with abrasive jet machining (AJM) and ultrasonic vibration (USV). The developed hybrid EDM process was adopted to examine the machining characteristics such as material removal rate (MRR), electrode wear rate (EWR), and surface roughness (SR) for SKD 61 steel through the experimental works. In this study, the compressed dielectric media such as air, oxygen, and argon were employed in the experiments to investigate the effects on material removal efficiency, surface integrity, and thickness of recast layer. The experimental results show that the hybrid EDM process obtained higher MRR. In addition, the oxygen medium could facilitate the reaction within the machining area to increase the exploding and melting effects. Thus, the MRR gained by oxygen has the highest response. The argon was an inert gas that could prevent the oxidation during the process, and the lowest EWR as well as the finest SR could be received using argon as a dielectric media in the hybrid EDM process. The ultrasonic vibration incorporated in the hybrid EDM process could effectively reduce the thickness of recast layer. In general, the different dielectric media supplied into the machining area could create various mechanisms. From the experimental results, the USV and AJM incorporated into the hybrid EDM process could obviously promote the machining efficiency and surface quality.

Experimental study of an electrostatic field–induced electrolyte jet electrical discharge machining process

In this study, a new electrostatic field–induced electrolyte jet electrical discharge machining method has been proposed, which can automatically generate the tool electrode. Then, a series of experiments have been carried out to reveal the machining mechanism and test the machining ability of this method. The continuous observation experiments and the online current detection experiments have demonstrated that the electrolyte jet discharge machining is a pulsing, dynamic and cyclic process. Moreover, the 20-min time long reverse polarity experiments on the silicon surface have revealed that the machining is an electrical discharge machining process during the negative polarity machining; however, in the positive polarity machining, it is a hybrid electrical discharge machining and electrochemical machining process. Furthermore, the craters as small as 2 µm in diameter on stainless steel and silicon are produced by this electrolyte jet electrical discharge machining, which has proved the micro-machining ability of this method.

Study of the Productivity and Surface Quality of Hybrid EDM

The development of new, advanced engineering materials and the need for precise prototypes and low-volume production have made the electric discharge machining (EDM), an important manufacturing process to meet such demands. It is capable of machining geometrically complex and hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, carbides etc. Conversely the low MRR limits its productivity. Abrasive water jet machine (AJM) tools are quick to setup and offer quick turn-around on the machine and could make parts out of virtually any material. They do not heat the material hence no heat affected zone and can make any intricate shape easily. The main advantages are flexibility, low heat production and ability to machine hard and brittle materials. Main disadvantages comprise the process produces a tapered cut and health hazards due to dry abrasives. To overcome the limitations and exploit the best of each of above processes; an attempt has been made to hybridize the processes of AJM and EDM. The appropriate abrasives routed with compressed air through the hollow electrode to construct the hybrid process i.e., abrasive jet electric discharge machining (AJEDM), the high speed abrasives could impinge on the machined surface to remove the recast layer caused by EDM process. The main process parameters were varied to explore their effects and experimental results show that AJEDM enhances the machining efficiency with better surface finish hence can fit the requirements of modern manufacturing applications.

Sintered diamond as a hybrid EDM and grinding tool for the micromachining of single-crystal SiC

Sintered diamond was used as a hybrid tool for micro-scale electrical discharge machining (EDM) and grinding of single-crystal SiC to achieve both high efficiency and surface integrity. Material removal behavior, surface topography, and subsurface damage for both process steps were investigated under various conditions. The results showed that SiC decomposed into Si and C during EDM, creating a very thick recast layer which had remarkably lower hardness than the bulk. Owing to the electrical dressing effect in EDM, diamond grains protrude out of tool surface and grind the recast layer in a ductile manner with low tool wear. An extremely smooth surface (Ra=1.85nm) was obtained.

Machining characteristics of hybrid EDM with ultrasonic vibration and assisted magnetic force

In this investigation, an ultrasonic vibration and an assisted magnetic force are integrated with the electrical discharge machining (EDM) to develop a hybrid process of EDM with ultrasonic vibration and assisted magnetic force (EDMUVAMF), and then the hybrid process is adopted to explore the effects of the main machining parameters on the material removal rate (MRR), electrode wear rate (EWR), surface roughness (SR) and morphologies of the machined surface in machining SKD 61 mold steels. Moreover, the effects on expelling the debris from the machining gap are also studied via evaluating the discharge waveforms, and analyzing the morphology of the machined surface. The bottleneck correlated with large area using EDM process would be overcome when the optimal parameters of the hybrid process of EDMUVAMF is obtained. From the experimental results shown, the hybrid process of EDMUVAMF can improve the machining performance. The MRR was increased significantly and the SR was reduced to ameliorate the machining efficiency and machined surface quality. The hybrid process revealed the potential for the applications in large area via EDM technique.

Past and Current Status of Hybrid Electric Discharge Machining (H-EDM) Processes

A B S T R A C T Electric discharge machining (EDM) process is one of the highly used advanced machining process. The material removal mechanism is melting and evaporation electric discharge in EDM process. EDM process has its advantages and disadvantages. To overcome the disadvantages, many researchers are trying to hybrid this process with other process. So, that the hybrid EDM process clubs the advantages of both processes which can increase performance and efficiency compared to EDM process alone. This paper reviews the past and current status of various hybrid EDM processes.