Electrode Wear Ratio Research Articles

Improving Machining Performance for Deep Hole Drilling in the Electrical Discharge Machining Process Using a Step Cylindrical Electrode

The performance of electrical discharge machining for drilling holes decreases with machining depth because the conventional flushing and electrode cannot completely eliminate debris particles from the machining area. In this study, a modified electrode for self-flushing in the electrical discharge machining process with a step cylindrical shape was designed to improve machining performance for deep hole drilling. The experimental results of the step cylindrical electrode showed that the material removal rate increased by approximately 215.7%, 203.8%, and 130.4%, and the electrode wear ratio decreased by approximately 47.2%, 63.1%, and 37.3%, when compared with a conventional electrode for the diameters of 6, 9, and 12 mm, respectively. In addition, the gap clearance and concavity of the side wall of the drilled hole was reduced with the step cylindrical electrode. The limited high flank of the electrode led to an increase in the escape area of the debris that was partially removed from the machining area, and the limited secondary spark on the side wall of the electrode resulted in a reduction in machining time.

Variation of electrode materials and parameters in the EDM of an AA7075-TiO2 composite

Abstract The present study was carried out to analyze the effect of process parameters during EDM machining of AA7075-10 wt.-% TiO2 aluminum matrix composite (AMC). The composite was produced through stir casting. The EDM process parameters such as the electrode material (Cu, Br, EN-8), pulse current (5, 10 and 15 A), pulse ON time (300, 600 and 900 μs) and pulse OFF time (30, 60 and 90 μs) were chosen to study the effects on material removal rate, surface roughness and the electrode wear ratio. The experiment was carried out as per L27 orthogonal array based on Taguchi’s design of experiments. Signal-to-noise ratio and analysis of variance were used to identify the contribution of each input parameters on the output responses of the EDM process. The experimental results shows that pulse ON time and pulse current are the most significant factors for the material removal rate; pulse ON time and electrode material are the most influencing parameters for surface roughness and the electrode wear ratio.

Effects of Side Flushing and Multi-Aperture Inner Flushing on Characteristics of Electrical Discharge Machining Macro Deep Holes

This research investigates the effect of machining parameters on material removal rate, electrode wear ratio, and gap clearance of macro deep holes with a depth-to-diameter ratio over four. The experiments were carried out using electrical discharge machining with side flushing and multi-aperture flushing to improve the machining performance and surface integrity. The machining parameters were pulse on-time, pulse off-time, current, and electrode rotation. Response surface methodology and the desirability function were used to optimize the electrical discharge machining parameters. The results showed that pulse on-time, current, and electrode rotation were positively correlated with the material removal rate. The electrode wear ratio was inversely correlated with pulse on-time and electrode rotation but positively correlated with current. Gap clearance was positively correlated with pulse on-time but inversely correlated with pulse off-time, current, and electrode rotation. The optimal machining condition of electrical discharge machining with side flushing was 100 µs pulse on-time, 20 µs pulse off-time, 15 A current, and 70 rpm electrode rotation; and that of electrical discharge machining with multi-aperture flushing was 130 µs, 2 µs, 15 A, and 70 rpm. The novelty of this research lies in the use of multi-aperture flushing to improve the machining performance, enable a more uniform GC profile, and minimize the incidence of recast layer.

Tool wear and energy consumption optimization in EDM of chromium tool steel

The machining feasibility of high chromium tool steel using the EDM process has been studied. An attempt has been made to optimise the EDM process, concerning eco-friendly aspects like relative electrode wear ratio, process energy consumption along with machining parameter, that is process time. The four control factors: Peak current, Pulse duration, Flushing pressure and Dielectric level were selected to minimize the output responses. The Taguchi approach was used to optimise the process parameters. It was observed that the output responses were greatly influenced by the peak current and the dielectric level, but least affected by pulse duration.

Development of Mathematical Model for Predicting the Electric Erosion Behavior of TiO2 Filled Al-Zn-Mg-Cu (AA7075) Alloy Composite Using RSM-DFA Method

This work aims to develop a mathematical model and predict the machining performance characteristics of electric discharge machining (EDM) process using response surface methodology (RSM) coupled with desirability function approach (DFA). The effect of various factors, such as electrode material, pulse current, pulse ON time and pulse OFF time were selected as input process parameters with an objective to maximize the material removal rate (MRR), minimize the surface roughness (SR) and electrode wear ratio (EWR). The machining was conducted on Al-Zn-Mg-Cu (AA7075) alloy composite reinforced with 10[Formula: see text]wt.% TiO2 particulates produced by stir casting route. The experimental work was planned as per L27 orthogonal array using design of experiments through RSM. Experimental results show that, pulse current and pulse ON time are the most significant factors for MRR and SR while electrode materials and pulse current have notable effect on EWR. Finally, multi-response optimization was performed to predict the EDM parameters by using DFA. The optimum combination of parameters were identified as electrode material (Br), pulse current (15 amps), pulse ON time (900[Formula: see text][Formula: see text]s) and pulse OFF time (30[Formula: see text][Formula: see text]s).

Classification and comparative study of EDM pulse generators

Electrical discharge machining (EDM) is a non-conventional machining technique that requires pulse generators to create sparks between the tool and the workpiece. Classical texts describe only two types of EDM pulse generators (EPGs), although there are several different types. This work presents a classification and detailed comparative study of 13 important EPG topologies from the power electronics perspective. The operation of each topology is explained using simulation studies for EDM load with spark current of 10 A and pulse repetition frequency of 1 kHz. Control schemes of each topology are explained from the viewpoint of mechanical performance parameters, viz. material removal rate, surface finish, and tool electrode wear ratio. A general analytical methodology to compute efficiency based on machining duty is illustrated considering the existence of two distinct switching frequencies. Overall comparison between EPG topologies is presented considering control aspects, size, efficiency, voltage stresses and suitability for any required application. As an example, a case of investigation of cutting silicon ingots with wire EDM is considered and experimental results are provided for the same. This work can be used as a guideline to understand and develop EPG based on particular target specifications.

Application of multi-criteria decision-making (MCDM) methods on a meso-scale electrical discharge drilling (EDD) process

Multi/Multiple-criteria decision-making methods or multiple-criteria decision analysis (MCDA) have a useful contribution to determine the optimal or the best experimental condition for a process. One of the objectives of the presented research is the observation of the effects of the electrical parameters on the material removal rate (MRR) and the electrode wear ratio (EWR) in a meso-scale EDD. The examined electrical parameters are pulse-on/off time, duty cycle/factor and capacitance. Machining results have been investigated by analysis of variance and graphically depending on their main effects. While pulse-on time and duty cycle have statistically significant effect on MRR, pulse-on time, capacitance and duty cycle have significant effect on EWR for the EDD processes. VIKOR, TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and GRA (Grey Relation Analysis) were used as MCDM methods to determine the optimum machining result in terms of maximum MRR and minimum EWR. MCDM results have been monitored by graphically. Since an inconsistency has been seen between the MCDM results, a second supplementary analysis has been done by Weighted of Sum and Weighted of Product methods. By this way, a better consistency has been provided. Consequentially, it has been seen that the results of the second modifier analysis and the results of VIKOR were closer to each other in terms of specifying the optimal condition for the process. Hole formations were also observed by scanning electron microscopy images in this work. As a result, it has been decided that the minimum pulse-on time and pulse off-time with 50% duty cycle and minimum capacitance inputs gives an optimum output for MRR and EWR in the meso-scale EDD process.

Increasing Wear Resistance of Copper Electrode in Electrical Discharge Machining by Using Ultra-Fine-Grained Structure

Tool electrode wear is a severe problem in electrical discharge machining (EDM) which significantly affects the efficiency of the machining process and dimensional accuracy. In this paper, ultra-fine-grained (UFG) structures due to their unique and unusual properties are used to alleviate the wear problem of tool electrode. Equal-channel angular pressing (ECAP) is a novel severe plastic deformation metal forming process which can produce ultra-fine to nanoscale grains in bulk materials. Commercially pure copper was ECAP-ed to produce UFG microstructures and then used as tool electrode in EDM. The performance parameters in the EDM process, which have been studied, are material removal rate (MRR), volumetric electrode wear (VEW) and electrode wear ratio (EWR). For UFG and coarse-grained electrodes, the MRR, VEW and EWR obtained in EDM process have been compared. The results show that VEW and EWR decrease when UFG copper tool electrodes are used. But with increasing machining time, VEW and EWR of UFG copper electrodes approach those of the coarse-grained copper electrode.

Multi-Objective Optimization of Electrical Discharge Machining Parameters for 2024 Aluminum Alloy Using Grey-Taguchi Method

This paper focused on Grey relational analysis (GRA) to optimize EDM parameters through multi-objective optimization for Al2024 aluminum and electrode graphite ISO-63 was used as a cutting tool. The process parameters pulse on time, duty factor, pulse current and open voltage. Performance characteristics examined included material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (SR). Taguchi’s 27 experimental designs, often called an orthogonal array (OA), was utilized to ignore interaction and concentrate on main effect estimation. GRA was performed to optimize input parameters levels. Results were that MRR increased from 35.00 to 35.11 mm3/min, EWR decreased from 11.63 to 10.89 mm3/min, and SR decreased from 5.01 to 4.97 μm. Taguchi and GRA resulted in clear improvements in MRR, EWR, and SR.

Electric discharge drilling with gas-assisted multi-hole slotted tool

This paper proposes the use of a novel electrode containing modified design explicitly intended to promote gas-assisted tool rotation-induced debris removal. The proposed tool was observed to be efficient in dispensing the accumulation of eroded materials from the discharge gaps. In this work, the influence of process parameters like discharge current, tool speed, gas pressure, pulse duration, and duty cycle has been investigated on output responses: material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR). A comparative study of the output responses was made with a solid rotary tool and the gas-aided multi-hole slotted tool. The outcome reveals that the application of the multi-hole slotted tool increased the MRR in AAEDD by 40-80%. Besides this, the EWR decreased in AAEDD by 17–25% compared to REDD. Moreover, the SR of the AAEDD process was comparatively higher (9-15%) than that of the REDD process. It has been found less surface crack, micro pores and recast layers on specimens machined by the AAEDD process in comparison to the REDD process. The present work proposed a novel method for improving the machining performance by improving the flushing efficiency of the machining gap on the way to improve the material removal mechanism.

Havacılık Malzemelerinde Mikro Delik Delinmesi ve Regresyon Analizi

In this study, Electrical Discharge Micro Hole Drilling process applied to specific aerospace material of Ti-6Al-4V. Although Hole-EDM drilling uses the same principles as other EDM methods, a rotated hollow electrode and pumping of dielectric coolant fluid through the electrode tube are the two distinct features. This process has alternatively used for producing fuel injectors, holes in turbine blades and Wire-EDM starter points. In this experimental study, surface observation and the effects of machining parameters of arc on-time (Ton), arc off-time (Toff) and current (I) on performance parameters were studied. Experimental works applied with single channel, cylindrical, brass, tabular electrode. Deionized water was used for coolant where was pumping inside the electrode at high pressure. The performance parameters chosen as surface roughness (Ra), material removal rate (MRR), electrode wear ratio (EWR) which occurred under the influence of the machining parameters were analysed. The purpose of analysing, Taguchi method consulted to design of experiments. Regression mathematical model was developed and analysis of variance (ANOVA) implemented to figure out of the reliability of mathematical model results. The experimental results reveal that the 500µm brass electrode has comparatively better MRR and lower EW. According to ANOVA reliable mathematical models were developed with 0,9643, 0,9827 and 0,9201 R-sq.% for Ø500µm successfully.

Experimental investigation and statistical modeling of air-assisted EDM of Al–SiC composite with an improvised tool

The present paper deals with the electrical discharge machining of Al–SiC composite using an air-assisted multi-hole rotary slotted tool. The slot was fabricated on the tool surface to provide easy removal of debris from the inter-electrode gap. The compressed air passed through the multi-hole slotted tool produced a high amount of turbulence and cavitation and directly increased the material removal rate. The influence of process factors such as peak current, tool rotation, discharge air pressure, pulse duration, and duty cycle was investigated by considering them as input parameters with output response, electrode wear ratio and material removal rate (MRR). A comparative analysis of the output response with the solid rotary tool and the air-assisted multi-hole rotary slotted tool was presented. The result shows that the use of the air-assisted multi-hole rotary slotted tool increased the MRR in air-assisted rotary electric discharge drilling (AAEDD) by 40–70%. Moreover, the EWR decreased in AAEDD by 15–25% compared to rotary electric discharge drilling (REDD). The emergence of fewer recast layers and surface cracks in the AAEDD process has been identified compared to the REDD process. A genetic algorithm was utilized to achieve optimal process factors by optimizing the AAEDD for maximizing the MRR and minimizing the EWR.

Parametric optimization of EDD using RSM-Grey-TLBO-based MCDM approach for commercially pure titanium

PurposeElectric discharge drilling (EDD) is used to drill quality microholes on any conductive materials. EDD process parameters play a crucial role in the drilling. Depending upon the material characteristics, the cost of drilling also changes. Therefore, a suitable method is required to control the process parameters and drill quality microholes.Design/methodology/approachThe input process parameters in the present work are peak current (Ip), pulse on-time (Ton) and pulse off-time (Toff). The trials were intended in accordance to central composite face-centered design of response surface methodology (RSM). The output responses, namely drilling rate (DR) and electrode wear ratio (EWR), were converted into a single response, that is, grade using Grey relational analysis (GRA). The grade value is further modeled by regression analysis. The empirical model was figured out using teaching–learning-based optimization (TLBO). The RSM-Grey-TLBO-based multicriteria decision-making (MCDM) is used to investigate the optimized process parameter setting.FindingsThe RSM-Grey-TLBO-based MCDM approach suggests that the optimized setting for DR and EWR is Ip: 3A; Ton: 40 µs; Toff: 42 µs. The percentage errors for the predicted and experimental results are 8.1 and 7.5% in DR and EWR, respectively.Originality/valueThe parametric optimization of EDD using RSM-Grey-TLBO-based MCDM approach while machining commercially pure titanium is still underway. Thus, this MCDM approach will give a path to the researchers working in this direction.

Evaluation of technical feasibility and environmental impact of Calophyllum Inophyllum (Polanga) oil based bio-dielectric fluid for green EDM

• The research explores new bio-dielectric i.e Calophyllum inophyllum (polanga). • 3 productivity & process quality aspects (MRR,TWR,REWR,SR,SH,ROC/RUC) are assessed. • Significant improvement in output responses were found in the comparison process. • Environmental impact with aerosol emission rate for PBD is lower by 17.33% in comparison to HC dielectric. • Current study will be more helpful in opening path for more in-depth research in GREEN EDM. In a global scenario, energy conservation with eco-sustainable manufacturing is a major challenge for engineers. Motivation and stringent implementation of sustainable manufacturing practices is one significant way to insure the green environment for future. Alarming needs at present is innovative green methods of non-conventional manufacturing processes to be globally competitive. So, in the present investigation, authors have assessed the operational feasibility of transesterified Calophyllum Inophyllum (Polanga) based non-edible oil as possible alternative bio-dielectric for EDM applications and compared the response patterns of the new bio-dielectric fluid with hydrocarbon based EDM oil. OFAT (one factor at a time) design algorithm was utilized using peak current, duty cycle, pulse-on time, and gap voltage as control parameters to evaluate the response pattern for material removal rate, electrode wear rate, relative electrode wear ratio, surface texture and aerosol emission rate. The study confirms that Polanga bio-dielectric contributes to higher productivity and better process quality parameters like enhancement in mean MRR by 0.86 times, better surface finish by 16.64%, surface hardness by 6.46% as well as refined microstructure quality as compared to traditional hydrocarbon dielectric. Assessment of environmental impact through aerosol emission rate confirms 17.33% reduction with Polanga bio-dielectric use. Results and performance evaluation reveal that new bio-dielectric fluid can be a primary dielectric choice for green EDM replacing conventional hydrocarbon, water and synthetic based dielectric fluids. Findings also confirms that it can greatly contribute for establishing a family of vegetable-based bio dielectrics in the area of green manufacturing thus removing obstacles like reduction of toxic emissions, operator’s health hazards, fire hazards and enhancement of environmental sustainability in future.

Mathematical Modelling of Electric Discharge Machining of Al (6351)-SiC-B4C Hybrid Composite

The Electric Discharge Machining (EDM) has emerged as one of the major machining method for the machining of hard-to- machine materials and composites. This paper aims at creating a mathematical model for the machining of the Al(6351)-SiC-B4C composites based on the experimental data and compare the same to identify the level of errors between the mathematical model and the experimental results. This paper was aimed as an attempt to develop a mathematical model for the output parameters viz. Electrode Wear ratio and Surface roughness based on the input parameters viz. current, pulse-on-time, pulse duty-factor and gap voltage.

Processing of heat-treated steel by arc discharge machining

ABSTRACTArc discharge machining was an efficient method in machining difficult-to-cut materials. However, there was a serious overcutting phenomenon during machining, causing serious machining errors. In order to improve the machining accuracy, this paper presented a novel kind of arc discharge milling technology, which was based on the arc driving mechanism using the controllable non-uniform flow field around the tubular electrode. The control system changed the distribution of the non-uniform flow field in real time according to the machining path, driving the arc to extend in a controlled direction and reducing the repeated erosion of the specific machining surface. Compared with the annular flow field, the non-uniform flow field could reduce the overcutting by 52.15%, while obtaining similar relative electrode wear ratio (REWR) and material removal rate (MRR). The effects of non-uniform flow field, peak current of pulse generator, and pulse width on machining accuracy, REWR, and MRR were investigated. The result shows that the non-uniform flow field can significantly improve the accuracy of arc discharge machining.

Investigation and wear analysis of Al-SiC<SUB align="right">p nano composites and study of its machinability using electro discharge machining

The present research work has been given the importance on proper distribution of silicon carbide nano particles with different volume fractions of 1%, 1.5% and 2% in the aluminium metal matrix. The paper also deals with the wear analysis of the developed Al-SiCp nano composite by using dry sliding wear test with pin on disc machine. XRD analysis of the Al-SiCp nano composite work material has been performed to determine the purity and grain size of the sample. The present work also focuses on metal matrix nano composites during electric discharge machining (EDM) process using brass, aluminium and copper as tool electrodes. Electrode wear ratio (EWR) of the tool as well as material removal rate (MRR) of the workpiece has been determined and it was found that copper is the best and preferable electrode followed by aluminium and brass electrodes due to its higher MRR and lower EWR.

EDM of Nickle and Titanium Alloy Sheets aided by Vibration

Nickel and titanium alloys are widely used as aero-engine blade materials due to their excellent properties such as high strength, light weight and resistance to high temperature. There are many methods available to machine materials to the required dimensions and with high blade accuracy. Electrical chemical machining (ECM) is one of them. However, the complexity of flow field and electric field on the leading and trailing edges of the blade during ECM results in large dimensional and shape errors. The edges must be dressed to the required dimensions and accuracy. Electric discharge machining (EDM) has the ability to remove any electrically conductive material regardless of its strength and hardness. In this paper, EDM aided by vibration is used to roughly dress the leading and trailing edges of the blade. To optimize machining parameters such as peak current, pulse on-time, amplitude and frequency of vibration, extensive experiments are carried out based on orthogonal method. Thin sheets of nickel and titanium alloys with cross section of 29 mm × 0.5 mm are cut off 2mm in length. The optimal machining parameters were verified by confirmation experiments. It was found that under optimal conditions and using graphite electrode, machining time of nickel alloy was 1.62 minutes and machining time of titanium alloy was 2.12 minutes. The corresponding electrode wear ratio and heat affected zone were analysed.

Investigation and wear analysis of Al-SiC<SUB align="right">p nano composites and study of its machinability using electro discharge machining

The present research work has been given the importance on proper distribution of silicon carbide nano particles with different volume fractions of 1%, 1.5% and 2% in the aluminium metal matrix. The paper also deals with the wear analysis of the developed Al-SiCp nano composite by using dry sliding wear test with pin on disc machine. XRD analysis of the Al-SiCp nano composite work material has been performed to determine the purity and grain size of the sample. The present work also focuses on metal matrix nano composites during electric discharge machining (EDM) process using brass, aluminium and copper as tool electrodes. Electrode wear ratio (EWR) of the tool as well as material removal rate (MRR) of the workpiece has been determined and it was found that copper is the best and preferable electrode followed by aluminium and brass electrodes due to its higher MRR and lower EWR.

Experimental investigation and effects of process parameters on EDM of Al7075/SiC composite reinforced with magnesium particles

Abstract The recent paper presents the experimental investigation on material removal rate (MRR) and electrode wear ratio (EWR) of hybrid metal matrix composite of Aluminium 7075 reinforced with 10% by wt. Silicon carbide particles and nanoparticles of magnesium (Al 7075/10%SiC/Mg). Magnesium metal matrix composites are of significant importance nowadays because of the increasing demand of light weight structural material in aerospace and automotive applications. Stir casting process has been used for fabrication of hybrid metal matrix composite. The effect of process parameters on responses such as MRR and EWR are evaluated during conventional EDM and rotary EDM. The pulse duration, peak current, duty cycle, and tool speed are selected as machining parameters. A comparative analysis of conventional EDM and rotary EDM of hybrid composite has been done. Experimental results indicated that the rotation of the tool enhances the flow of dielectric and effective evacuation of the debris from the gap between the workpiece and tool. The result shows increased MRR and reduced EWR with rotary EDM as compared to conventional EDM. This work seems to be of novelty and the findings can be useful for aerospace and automotive industry.