Electro Discharge Machining Operation Research Articles

Approach towards green manufacturing in Maglev EDM using different biodegradable dielectrics at variable discharge conditions

The urge to implement eco-friendly approach for modern manufacturing techniques has assisted in eliminating the hazardous effect of the undesirable byproducts released into the atmosphere. In electro-discharge machining (EDM) process, the hydrocarbon oil degradation releases various toxic gases and non-biodegradable residuals as byproducts. Several bio-dielectrics have been implemented to overcome such setbacks as an economical replacement to conventional hydrocarbon oil dielectrics. The current research demonstrates a green Maglev EDM operation on Ti-6Al-4V alloy using neem oil and canola oil as bio-dielectrics compared with EDM oil. Maglev EDM utilizes novel bipolar linear self-servo strategy for tool positioning which generates consistent machining stability by unique magnetic repulsive force balance action. The performance characteristics of all the dielectrics have been examined through machining rate (MR), tool wear rate (TWR), consumed specific energy (SE), area roughness parameters and surface morphology. The results were compared for respective bio-dielectric at variable discharge voltages (VD) i.e. 22 V, 25 V and 28 V, whereas the discharge current (ID) varied within (220-250 mA). The performance assessment depicts (25 to 28) % lower SE consumption in neem oil and (35 to 37)% in canola oil as compared to EDM oil. The surface morphology assessment portrays lower deformities and better uniformity using bio-dielectrics with huge potential for selective surface modification.

Effect of untreated and deep cryotreated tungsten carbide electrodes on PMEDM performance of AISI 304 stainless steel

Powder mixed electro discharge machining (PMEDM) is the expansion of conventional electro discharge machining (EDM) where powder particles are mixed in the dielectric fluid for acquiring better surface finish and enhancing machining efficiency. Cryotreatment of the electrode is introduced in this study which reduced the tool wear, thus machining cost. In this investigation, SiC powder particles were suspended in kerosene dielectric and the effect of control parameters, cryotreated double tempered (CT2) electrode have been studied on surface crack density (SCD), surface roughness (Ra), material removal rate (MRR) and tool wear rate (TWR). Powder concentration, duty cycle, pulse on time, peak current, and gap voltage were used as control parameters. EDM operation on AISI 304 stainless steel is performed using untreated (UT) and CT2 tungsten carbide (WC) electrodes. It was found that higher material removal rate and superior surface finish obtained in PMEDM over conventional EDM. CT2 electrode gives less TWR and lesser amount of surface cracks than that of UT electrode.

Effect of untreated and deep cryotreated tungsten carbide electrodes on PMEDM performance of AISI 304 stainless steel

Powder mixed electro discharge machining (PMEDM) is the expansion of conventional electro discharge machining (EDM) where powder particles are mixed in the dielectric fluid for acquiring better surface finish and enhancing machining efficiency. Cryotreatment of the electrode is introduced in this study which reduced the tool wear, thus machining cost. In this investigation, SiC powder particles were suspended in kerosene dielectric and the effect of control parameters, cryotreated double tempered (CT2) electrode have been studied on surface crack density (SCD), surface roughness (Ra), material removal rate (MRR) and tool wear rate (TWR). Powder concentration, duty cycle, pulse on time, peak current, and gap voltage were used as control parameters. EDM operation on AISI 304 stainless steel is performed using untreated (UT) and CT2 tungsten carbide (WC) electrodes. It was found that higher material removal rate and superior surface finish obtained in PMEDM over conventional EDM. CT2 electrode gives less TWR and lesser amount of surface cracks than that of UT electrode.

Multi-response optimization of EDM parameters using grey relational analysis (GRA) for Ti-5Al-2.5Sn titanium alloy

PurposeIn this research, electro discharge machining (EDM) of Ti-5Al-2.5Sn titanium alloy is performed taking gap voltage, pulse on time, peak current and duty cycle as process parameters. The purpose of this paper is to find out the optimal process parameters setting for getting higher machining efficiency.Design/methodology/approachFor experimental design, a face-centered central composite design (FCCCD)-based response surface methodology (RSM) is used. Multi-objective optimization like grey relational analysis (GRA) is adopted to achieve the higher machining efficiency by means of lower radial overcut (ROC), surface roughness (Ra), tool wear rate (TWR) and higher material removal rate (MRR). For the statistical study, analysis of variance (ANOVA) has been carried out.FindingsThe result shows that gap voltage, peak current and pulse on time are the most efficient parameters for the responses. An optimal parameter setting has been obtained for achieving higher machining efficiency. For validation of the study, confirmation experiment has been performed at optimal parameters setting.Originality/valueOptimum parameter level for higher machining performance of Ti-5Al-2.5Sn Titanium alloy has been achieved machined by copper electrode during EDM operation.

Machinability of Ti-5Al-2.5Sn for electro-discharge machining: an experimental investigation

Present work attempts to investigate machinability of Ti-5Al-2.5Sn for Electro-Discharge Machining (EDM). Extent of machinability is determined through material removal efficiency, tool wear rate, and surface integrity of the EDMed specimen of Ti-5Al-2.5Sn. Detailed analysis of surface morphology followed by study of surface topographical features including surface roughness, crack density, thickness of the recast layer, foreign material migration, metallurgical phase, residual stress, and micro-indentation hardness are carried out. Disappointing morphology is noticed for EDMed work surface at higher values of peak current as well as pulse-on time values. It is experienced that occurrence of surface cracks depends on recast layer thickness. As compared to ‘as received’ workpiece exhibiting compressive residual stresses, tensile stresses are found induced after performing EDM operation. Similar phenomenon is experienced in case of tool electrode. EDM operation improves microhardness of the machined surface. For Ti-5Al-2.5Sn, such improvement is nearly three times than that of ‘as received’ work material. During EDM operation on Ti-5Al-2.5Sn, titanium carbide is formed over tool as well as work surface. Formation of such hard carbides may degrade machining efficiency.

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.

Effects of Tool Electrode on EDM Performance of Ti-6Al-4V

Due to widespread application of Ti-6Al-4V especially in automotive, aerospace, defense, and biomedical industries; machinability of this alloy is of immense importance. Very low thermal conductivity of Ti-6Al-4V is mainly responsible for its poor machinability. During Electro-Discharge Machining (EDM), conductivity of the workpiece as well as electrode plays a vital role affecting process performance. In this context, choice of electrode also influences the machining efficiency. Therefore, selection of an appropriate electrode to enhance performance of EDM on Ti-6Al-4V alloy is indeed necessary. In the present reporting, an experimental work has been carried out to investigate ease of machining of titanium alloy (Ti-6Al-4V) for electro-discharge machining using Tungsten and Copper (normal and cryogenically treated) electrodes. Experiments have been performed at different values of peak discharge current to study EDM performance on Ti-6Al-4V in terms of material removal efficiency, surface roughness, surface crack density and white layer thickness observed for the EDMed end product prepared from Ti-6Al-4V work material. Influence of peak discharge current on topography of the EDMed work surface has been examined. EDS analysis followed by micro-indentation hardness test has been performed to examine the extent of carbon enrichment onto the machined surface during EDM operation. XRD tests have been carried out to comprehend metallurgical aspects of the EDMed work surface which are supposed to be affected by the thermo-electrical phenomenon of EDM operation. Results obtained thereof, have been analyzed in detail to understand effects of electrode in persuading machinability of Ti-6Al-4V while machining though EDM route. It has been found that among three tool electrodes selected (Tungsten, normal Copper and cryogenically treated Copper), cryogenically treated Copper electrode has been found the most superior in purview of EDM performance.

Electro-Discharge Machining of Inconel 718 Using Square Cross Sectioned Copper Tool Electrode: Studies on Topography and Metallurgical Features of the EDMed Work Surface

A case experimental research towards investigating aspects of Electro-Discharge Machining (EDM) on Inconel 718 super alloy using Copper tool electrode (of square cross section) has been delineated herein. Based on three controllable process variables viz. peak discharge current, pulse-on duration and gap voltage, experiments have been carried out to investigate their effects on influencing various process performance features in relation to surface topography like Surface Crack Density (SCD) and White Layer Thickness (WLT) onto the top surface of the EDMed end product. Additionally, EDAX analysis has been carried out to investigate the extent of carbon enrichment onto the machined surface as affected during pyrolysis of the dielectric fluid whilst executing EDM operation. XRD tests have been carried out to compare metallurgy (various phases/precipitates present in bulk of the matrix material, extent of grain refinement, crystallite size, and dislocation density) of the EDMed work surface with respect to ‘as received’ Inconel 718. Results obtained thereof have been interpreted in detail.

On Electro-Discharge Machining of Inconel 718 Super Alloys: An Experimental Investigation

A case experimental research towards investigating aspects of Electro-Discharge Machining (EDM) on Inconel 718 super alloy using Copper tool electrode (circular cross section) has been delineated herein. Based on three controllable process variables viz. peak discharge current, pulse-on duration and gap voltage, experiments have been carried out to investigate their effects on influencing various process performance features like Material Removal Rate (MRR); Surface Crack Density (SCD) and White Layer Thickness (WLT) onto the top surface of the EDMed end product. Additionally, EDAX analysis has been carried out to investigate the extent of carbon enrichment onto the machined surface as affected during pyrolysis of the dielectric fluid whilst executing EDM operation. XRD tests have been carried out to compare metallurgy (various phases/precipitates present in bulk of the matrix material, extent of grain refinement, crystallite size, strain and dislocation density) of the EDMed work surface with respect to ‘as received’ Inconel 718. Results, thus obtained, have also been compared to that of micro-hardness test data.

Analysis of EDM Pulsed Energy Denoise Process and Its Mutation Characteristic Using Wavelet Packet and S-transform

In this paper, the load of electro discharge machining (EDM) is used to extract the mutation characteristics of pulse energy. In this paper, different wavelet basis functions and thresholds are used to denoise the electrical load characteristics of EDM, and the wavelet denoising function and threshold for different practical situations are obtained, which provide the basis for pulse power quality analysis. What’s more, a method to identify the impulsive power quality mutation information based on S-transform is proposed, which realizes the automatic recognition of power quality during EDM operation, and the extraction accuracy is high.

Electrical Discharge Machining (EDM): A Review

Electro discharge machining (EDM) process is a non-conventional and non-contact machining operation which is used in industry for high precision products. EDM is known for machining hard and brittle conductivematerials since it can melt any electrically conductive material regardless of its hardness. The workpiece machined by EDM depends on thermal conductivity, electrical resistivity, and melting points of the materials. The tool and the workpiece are adequately both immersed in a dielectric medium, such as, kerosene, deionised water or any other suitable fluid. This paper is reviewed comprehensively on types of EDM operation. A brief discussion is also done on the machining responses and mathematical modelling.

Performance analysis of Cu-B<SUB align="right">4C metal matrix composite as an EDM electrode

Performance of electrode materials is one of the important factors that determine the quality of the machined component and the cost involved in the operation of electro discharge machining (EDM) process. Low electrode wear resistance in graphite and copper electrodes necessitated the development of sintered composite electrodes for EDM operation. In this paper, authors attempted to develop a new copper-based metal matrix composite (Cu-B4C) to get an optimum combination of wear resistance, electrical and thermal conductivity. Here the copper-boron carbide composite was developed through powder metallurgy route and EDM experiments were carried out using mild steel specimen. Copper composite with 40% boron carbide reinforcement exhibits better metal removal rate (MRR) and tool removal rate (TRR) compared to conventional copper electrode. SEM and XRD results show the surface modification and formation of boron, B4C reinforced layer on the surface of mild steel work piece when machined with composite electrode.