Showing papers on "Electrical discharge machining published in 2010"

Review of research work in sinking EDM and WEDM on metal matrix composite materials

Abstract: Metal matrix composites (MMCs) are newly advanced materials having the properties of light weight, high specific strength, good wear resistance and a low thermal expansion coefficient. These materials are extensively used in industry. Greater hardness and reinforcement makes it difficult to machine using traditional techniques, which has impeded the development of MMCs. The use of traditional machinery to machine hard composite materials causes serious tool wear due to the abrasive nature of reinforcement. These materials can be machined by many non-traditional methods like water jet and laser cutting but these processes are limited to linear cutting only. Electrical discharge machining (EDM) shows higher capability for cutting complex shapes with high precision for these materials. The paper presents a review of EDM process and year wise research work done in EDM on MMCs. The paper also discusses the future trend of research work in the same area.

Optimization of the EDM parameters on machining Ti–6Al–4V with multiple quality characteristics

Abstract: In this paper, parameter optimization of the electrical discharge machining process to Ti–6Al–4V alloy considering multiple performance characteristics using the Taguchi method and grey relational analysis is reported. Performance characteristics including the electrode wear ratio, material removal rate and surface roughness are chosen to evaluate the machining effects. The process parameters selected in this study are discharge current, open voltage, pulse duration and duty factor. Experiments based on the appropriate orthogonal array are conducted first. The normalised experimental results of the performance characteristics are then introduced to calculate the coefficient and grades according to grey relational analysis. The optimised process parameters simultaneously leading to a lower electrode wear ratio, higher material removal rate and better surface roughness are then verified through a confirmation experiment. The validation experiments show an improved electrode wear ratio of 15%, material removal rate of 12% and surface roughness of 19% when the Taguchi method and grey relational analysis are used.

Optimization of EDM process for multiple performance characteristics using Taguchi method and Grey relational analysis

Abstract: Electrical discharge machining (EDM) is one of the most extensively used non-conventional material removal processes. The Taguchi method has been utilized to determine the optimal EDM conditions in several industrial fields. The method, however, was designed to optimize only a single performance characteristic. To remove that limitation, the Grey relational analysis theory has been used to resolve the complicated interrelationships among the multiple performance characteristics. In the present study, we attempted to find the optimal machining conditions under which the micro-hole can be formed to a minimum diameter and a maximum aspect ratio. The Taguchi method was used to determine the relations between machining parameters and process characteristics. It was found that electrode wear and the entrance and exit clearances had a significant effect on the diameter of the micro-hole when the diameter of the electrode was identical. Grey relational analysis was used to determine the optimal machining parameters, among which the input voltage and the capacitance were found to be the most significant. The obtained optimal machining conditions were an input voltage of 60V, a capacitance of 680pF, a resistance of 500Ω, the feed rate of 1.5μm/s and a spindle speed of 1500rpm. Under these conditions, a micro-hole of 40μm average diameter and 10 aspect ratio could be machined.

Modeling, simulation and parametric optimization of wire EDM process using response surface methodology coupled with grey-Taguchi technique

Abstract: In the present work, quadratic mathematical models have been derived to represent the process behavior of wire electrical discharge machining (WEDM) operation. Experiments have been conducted with six process parameters: discharge current, pulse duration, pulse frequency, wire speed, wire tension and dielectric flow rate; to be varied in three different levels. Data related to the process responses viz. material removal rate (MRR), roughness value of the worked surface (a measure of surface finish, SF) and kerf have been measured for each of the experimental runs; which correspond to randomly chosen different combinations of factor setting. These data have been utilized to fit a quadratic mathematical model (Response Surface Model) for each of the responses, which can be represented as a function of the aforesaid six process parameters. Predicted data have been utilized for identification of the parametric influence in the form of graphical representation for showing influence of the parameters on selected responses. Predicted data given by the models (as per Taguchi’s L27 (3*6) Orthogonal Array (OA) design) have been used in search of an optimal parametric combination to achieve desired yield of the process: maximum MRR, good surface finish (minimum roughness value) and dimensional accuracy of the product. Grey relational analysis has been adopted to convert this multi-objective criterion into an equivalent single objective function; overall grey relational grade, which has been optimized (maximized) by using Taguchi technique. Optimal setting has been verified through confirmatory test; showed good agreement to the predicted value. This indicates utility of the grey-Taguchi technique as multi-objective optimizer in the field of wire EDM. Keywords: Wire EDM; MRR; response surface methodology; Orthogonal Array (OA)

Optimization of wire electrical discharge machining for pure tungsten using a neural network integrated simulated annealing approach

Abstract: This study analyzed variation of cutting velocity and workpiece surface finish depending on wire electrical discharge machining (WEDM) process parameters during manufacture of pure tungsten profiles. A method integrating back-propagation neural network (BPNN) and simulated annealing algorithm (SAA) is proposed to determine an optimal parameter setting of the WEDM process. The specimens are prepared under different WEDM process conditions based on a Taguchi orthogonal array table. The results of 18 experimental runs were utilized to train the BPNN predicting the cutting velocity, roughness average (Ra), and roughness maximum (Rt) properties at various WEDM process conditions and then the SAA approaches was applied to search for an optimal setting. In addition, the analysis of variance (ANOVA) was implemented to identify significant factors for the WEDM process and the proposed algorithm was also compared with respect to the confirmation experiments. The results of proposed algorithm and confirmation experiments are show that the BPNN/SAA method is effective tool for the optimization of WEDM process parameters.

Experimental characterization of material removal in dry electrical discharge drilling

Abstract: Dry electrical discharge machining is one of the novel EDM variants, which uses gas as dielectric fluid. Experimental characterization of material removal in dry electrical discharge drilling technique is presented in this paper. It is based on six-factor, three-level experiment using L 27 orthogonal array. All the experiments were performed in a ‘quasi-explosion’ mode by controlling pulse ‘off-time’ so as to maximize the material removal rate (MRR). Furthermore, an enclosure was provided around the electrodes with the aim to create a back pressure thereby restricting expansion of the plasma in the dry EDM process. The main response variables analyzed in this work were MRR, tool wear rate (TWR), oversize and compositional variation across the machined cross-sections. Statistical analysis of the results show that discharge current ( I ), gap voltage ( V ) and rotational speed ( N ) significantly influence MRR. TWR was found close to zero in most of the experiments. A predominant deposition of melted and eroded work material on the electrode surface instead of tool wear was evident. Compositional variation in the machined surface has been analyzed using EDAX; it showed migration of tool and shielding material into the work material. The study also analyzed erosion characteristics of a single-discharge in the dry EDM process vis-a-vis the conventional liquid dielectric EDM. It was observed that at low discharge energies, single-discharge in dry EDM could give larger MRR and crater radius as compared to that of the conventional liquid dielectric EDM.

Cooling Effect on Electrode and Process Parameters in EDM

Abstract: In electrical discharge machining (EDM), material is removed by a series of electrical sparks that develops a temperature in the range 8, 000°C–12, 000°C between the electrode and the workpiece Due to the high temperature of the sparks, the workpiece is melted and vaporized At the same time, the electrode material is also eroded by melting and vaporization This erosion of the electrode is termed as electrode wear (EW) The EW process is similar to the material removal mechanism as the electrode and the workpiece are considered as a set of electrodes in EDM Due to EW, electrodes lose their dimensions resulting in inaccuracy of the cavity formed by EDM This paper reports on the study of the effect of electrode cooling during the EDM of titanium alloy (Ti-6Al-4 V) Investigation on the effect of electrode cooling on electrode wear was carried out Current, pulse on-time, pause off-time, and gap voltage were considered as the machining parameters while EW is the response Analysis of the influence of ele

Current research trends in variants of Electrical Discharge Machining: A review

Abstract: Present manufacturing industries are facing challenges from these advanced materials viz. super alloys, ceramics, and composites, that are hard and difficult to machine, requiring high precision, surface quality which increases machining cost. To meet these challenges, non-conventional machining processes are being employed to achieve higher metal removal rate, better surface finish and greater dimensional accuracy, with less tool wear. Electric Discharge Machining (EDM), a non-conventional process, has a wide applications in automotive, defense, aerospace and micro systems industries plays an excellent role in the development of least cost products with more reliable quality assurance. Die sinking EDM, Rotating pin electrode (RPE), Wire electrical discharge machining (WEDM), Micro- EDM, Dry EDM, Rotary disk electrode electrical discharge machining (RDE-EDM) are some of the variants methods of EDM. The present paper review the state of the art technology of high-performance machining of advanced materials using Die Sinking EDM, WEDM, Micro-EDM, Dry EDM AND RDE-EDM. The review relies on notable academic publications and recent conference proceedings.

Research Developments in Additives Mixed Electrical Discharge Machining (AEDM): A State of Art Review

Abstract: Electrical discharge machining (EDM) is a well-established modern machining process used to manufacture geometrically complex shapes, process hard materials that are extremely difficult to machine by conventional machining processes. This noncontact machining technique is continuously emerging from a mere tool and dies making process to a microscale machining applications. In recent years, researches have emphasized on increasing machining performance coupled with deliberate surface treatments. Additive mixed electrical discharge machining (AEDM) is a novel innovation for enhancing the capabilities of electrical discharge machining process in this direction. This article presents comprehensive history, mechanism of AEDM process, and reviews research literature in this area. The last part of this article outlines trends for future AEDM research directions.

Effect of single and multi-channel electrodes application on EDM fast hole drilling performance

Abstract: This paper presents a comparative experimental investigation of electrical discharge machining fast hole drilling of aerospace alloys, namely Inconel 718 and Ti–6Al–4V. A series of experiments was carried out using electrical discharge machining process in order to explore the influence of electrode type and material, i.e., single and multi-channel tubular electrodes made of brass and copper materials. The comparisons were made from the results of material removal rate, electrode wear, microhardness, and scanning electron microscope images taken from the machined/drilled hole surfaces. The experimental results reveal that the single-channel electrode has comparatively better material removal rates and lower electrode wear ratio. However, scanning electron microscope images show that multi-channel electrodes produce better surfaces than single-channel electrodes for both aerospace alloys. Microstructural changes while drilling operations for both types of electrodes result in an annealing effect on Inconel 718 and a tempering effect on Ti–6Al–4V alloy. In addition, multi-channel electrodes produce comparatively lower hardness values.

An analysis of the discharge mechanism in electrochemical discharge machining of particulate reinforced metal matrix composites

Abstract: An analysis of the discharge mechanism in electrochemical discharge machining (ECDM) of a particulate reinforced metal matrix composite was undertaken, and a model to reveal the electric field acting on a hydrogen bubble in ECDM process has been established. The model was found capable of predicting the position of the maximum field strength on the bubble surface as well as the critical breakdown voltage for spark initiation, for a given processing condition. A set of experiments was performed to verify the model and the experimental results agreed well with the predicted values. The experimental results also showed that an increase in current, duty cycle, pulse duration or electrolyte concentration would promote the occurrence of arcing action in ECDM. Moreover, by studying the waveform of ECDM and surface craters, it is confirmed that the spark action is in the form of an arc. Compared to EDM, the volume of an arc eroded crater of ECDM was less than that of EDM. An XRD analysis of the phases of the EDM and ECDM specimens showed that the Al 4 C 3 phase was detected on the former but not on the latter.

Determination of material removal rate in wire electro-discharge machining of metal matrix composites using dimensional analysis

Abstract: Wire electro-discharge machining (WEDM) is a vital process in manufacturing intricate shapes. The present work proposes a semi-empirical model for material removal rate in WEDM based on thermo-physical properties of the work piece and machining parameters such as pulse on-time and average gap voltage. The model is developed by using dimensional analysis and non-linear estimation technique such as quasi-Newton and simplex. Predictability of the proposed model is more than 99% for all work materials studied. The work materials were silicon carbide particulate reinforced aluminium matrix composites. The experiments and model prediction show significant role of coefficient of thermal expansion in WEDM of these materials. In addition, an empirical model, based on response surface method, has also been developed. The comparison of these models shows significant agreement in the predictions.

Some studies into wire electro-discharge machining of alumina particulate-reinforced aluminum matrix composites.

Abstract: Non-traditional process like wire electro-discharge machining is found to show a promise for machining metal matrix composites. However, the machining information for the difficult-to-machine particle-reinforced material is inadequate. This paper is focused on experimental investigation to examine the effect of electrical as well as non-electrical machining parameters on performance in wire electro-discharge machining of metal matrix composites (Al/Al2O3p). Taguchi orthogonal array was used to study the effect of combination of reinforcement, current, pulse on-time, off-time, servo reference voltage, maximum feed speed, wire speed, flushing pressure and wire tension on cutting speed, surface finish, and kerf width. Reinforcement percentage, current, and on-time was found to have significant effect on cutting rate, surface finish, and kerf width. The optimum machining parameter combinations were obtained for surface finish, cutting speed, and kerf width separately. Wire breakages were found to pose limitations on the cutting speed in machining of these materials. Wire shifting was found to deteriorate the machined surfaces.

Optimisation of process parameters for multi-performance characteristics in EDM of Al2O3 ceramic composite

Abstract: The advantages of electrical discharge machining (EDM) in machining of complex ceramic components have promoted research in the area of EDM of ceramic composites. The recent developments in ceramic composites are focused not only on the improvements of strength and toughness, but also on possibilities for difficult-to-machine shapes using EDM. One such EDM-machinable ceramic composite material (Al2O3–SiCw–TiC) has been developed recently and has been selected in the present study to investigate its EDM machinability. Experiments were conducted using discharge current, pulse-on time, duty cycle and gap voltage as typical process parameters. The grey relational analysis was adopted to obtain grey relational grade for EDM process with multiple characteristics namely material removal rate and surface roughness. Analysis of variance was used to study the significance of process variables on grey relational grade which showed discharge current and duty cycle to be most significant parameters. Other than discharge current and duty cycle, pulse-on time and gap voltage have also been found to be significant. To validate the study, confirmation experiment has been carried out at optimum set of parameters and predicted results have been found to be in good agreement with experimental findings.

Effect of Deep Cryogenic Treatment on Machinability of Titanium Alloy (Ti-6246) in Electric Discharge Drilling

Abstract: Currently there is a vital need for cost effective machining processes for titanium alloys. Electrical discharge machining (EDM) is used quite extensively in machining titanium alloys due to its favorable features and advantages. This paper investigates the effect of deep cryogenic treatment (DCT) on machinability of Ti 6246 alloy in electric discharge drilling (EDD) by conducting experimental investigations on the production of 10 mm diameter blind holes with electrolytic copper tool. An attempt has also been made to compare the production accuracy of holes drilled in deep cryogenically treated Ti 6246 (DCT Ti 6246) alloy and nontreated Ti 6246 alloy in terms of surface roughness and overcut. The result of study reveals the higher material removal rate (MRR) and wear ratio (WR), lower tool wear rate (TWR) in case of EDD of DCT Ti 6246 alloy workpiece as compared with nontreated Ti 6246 alloy workpiece. Also superior production accuracy of holes is reported while EDD of DCT workpiece.

Technological Advancement in Electrical Discharge Machining with Powder Metallurgy Processed Electrodes: A Review

Abstract: Electrical discharge machining (EDM) is a well-established machining option for processing hard materials with complex geometrical shapes which are extremely difficult-to-machine by conventional machining processes. These hard materials find applications where lower surface cracks, wear resistance, corrosion resistance, etc. are desirable surface properties. In recent years, research has been carried out to determine the possibility of employing electrode as feed stock material in an effort to produce significant surface alloying. These electrodes are generally produced through powder metallurgy (PM) technique in order to achieve necessary combination of operating characteristics. This paper reports state of art related to the usefulness of PM-processed electrodes in imparting desirable surface properties and modification of the machined surface. The final part of the paper outlines the trends for future EDM research using PM-processed electrodes.

The effect of process parameters on machining of magnesium nano alumina composites through EDM

Abstract: The effects of electrical discharge machining (EDM) parameters on drilled-hole quality such as taper and surface finish are evaluated. Microwave-sintered magnesium nano composites (reinforced with 0.8 and 1.2 wt.% of nano alumina) are used as work materials. Experiments were conducted using Taguchi methodology to ascertain the effects of EDM process parameter. The process parameters such as pulse-on time, pulse-off time, voltage gap, and servo speed were optimized to get better surface finish and reduced taper. ANOVA analyses were carried out to identify the significant factors that affect the hole accuracy and the surface roughness. Confirmation tests were performed on the predicted optimum process parameters. Pulse-on time and the servo speed are identified as major response variables. Micro structural changes and the effects of nano particle reinforcement in the drilled hole were studied through SEM micrographs.

Optimization of the WEDM Parameters on Machining Incoloy800 Super alloy with Multiple Quality Characteristics

Abstract: The present work demonstrates optimization of Wire Electrical Discharge Machining process parameters of Incoloy800 super alloy with multiple performance characteristics such as Material Removal Rate (MRR), surface roughness and Kerf based on the Grey–Taguchi Method. The process parameters considered in this research work are Gap Voltage, Pulse On-time, Pulse Off-time and Wire Feed. Taguchi’s L9 Orthogonal Array was used to conduct experiments. Optimal levels of process parameters were identified using Grey Relational Analysis and the relatively significant parameters were determined by Analysis of Variance. The variation of output responses with process parameters were mathematically modelled by using non-linear regression analysis method and the models were checked for their adequacy. Result of confirmation experiments shows that the established mathematical models can predict the output responses with reasonable accuracy.

MRR Improvement in Sinking Electrical Discharge Machining: A Review

Abstract: Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes. EDM process is based on thermoelectric energy between the workpiece and an electrode. Material removal rate (MRR) is an important performance measure in EDM process. Since long, EDM researchers have explored a number of ways to improve and optimize the MRR including some unique experimental concepts that depart from the traditional EDM sparking phenomenon. Despite a range of different approaches, all the research work in this area shares the same objectives of achieving more efficient material removal coupled with a reduction in tool wear and improved surface quality. The paper reports research on EDM relating to improvement in MRR along with some insight into mechanism of material removal. In the end of the paper scope for future research work has been outlined.

A multiprocess machine tool for compound micromachining

Abstract: Compound micromachining is the most promising technology for the production of miniaturized parts and this technology is becoming increasingly more important and popular because of a growing demand for industrial products, with an increased number not only of functions but also of reduced dimensions, higher dimensional accuracy and better surface finish. Compound micromachining processes that combine multiple conventional and non-conventional micromachining processes have the capability to fabricate high aspect ratio microstructures with paramount dimensional accuracy. Such machining should be carried out on the same machine with minimum change of setups. At the same time, on-machine tool fabrication along with on-machine tool and workpiece measurement facilities should also be available for further enhancement of the functionality of the machine and higher productivity. In order to achieve effective implementation of compound micromachining techniques, this research seeks to address four important areas, namely (a) development of a machine tool capable of both conventional micromachining including microturning, micromilling, etc., and non-conventional micromachining including microelectrical discharge machining (micro-EDM), wire-cut electrical discharge machining (WEDM), etc.; (b) process control; (c) process development to achieve the necessary accuracy and quality and (d) on-machine measurement and inspection. An integrated effort into these areas has resulted in successful fabrication of microstructures that are able to meet the miniaturization demands of the industry. This paper presents a few tool-based approaches that integrate micro-EDM, micro-EDG, microturning and microgrinding to produce miniature components on the same machine tool platform in order to demonstrate the capabilities of compound micromachining.

A Study of Multiobjective Parametric Optimization of Silicon Abrasive Mixed Electrical Discharge Machining of Tool Steel

Abstract: In this article, a technique for optimization of abrasive mixed electrical discharge machining (AEDM) process with multiple performance characteristics based on the orthogonal array with grey relat...

Magnetic field-assisted electrochemical discharge machining

Abstract: Electrochemical discharge machining (ECDM) is an effective unconventional method for micromachining in non-conducting materials, such as glass, quartz and some ceramics. However, since the spark discharge performance becomes unpredictable as the machining depth increases, it is hard to achieve precision geometry and efficient machining rate in ECDM drilling. One of the main factors for this is the lack of sufficient electrolyte flow in the narrow gap between the tool and the workpiece. In this study a magnetohydrodynamic (MHD) convection, which enhances electrolyte circulation has been applied to the ECDM process in order to upgrade the machining accuracy and efficiency. During electrolysis in the presence of a magnetic field, the Lorenz force induces the charged ions to form a MHD convection. The MHD convection then forces the electrolyte into movement, thus enhancing circulation of electrolyte. Experimental results show that the MHD convection induced by the magnetic field can effectively enhance electrolyte circulation in the micro-hole, which contributes to higher machining efficiency. Micro-holes in glass with a depth of 450 µm are drilled in less than 20 s. At the same time, better electrolyte circulation can prevent deterioration of gas film quality with increasing machining depth, while ensuring stable electrochemical discharge. The improvement in the entrance diameter thus achieved was 23.8% while that in machining time reached 57.4%. The magnetic field-assisted approach proposed in the research does not require changes in the machining setup or electrolyte but has proved to achieve significant enhancement in both accuracy and efficiency of ECDM.

Modelling and experimental investigation on the effect of nanopowder-mixed dielectric in micro-electrodischarge machining of tungsten carbide

Abstract: Micro-electrodischarge machining (micro-EDM) is one of the most effective methods used in die and mould industries for machining difficult-to-cut tool and die materials such as tungsten carbide (WC). The quality and integrity of the surface finish resulting from the micro-EDM process in die and mould making can have a significant impact on the product performance. The present study intends to investigate the feasibility of improving the surface finish in micro-EDM of WC in a dielectric mixed with graphite (Gr), aluminium (Al), and alumina (Al2O3) nanopowders. The mechanism of powder-mixed micro-EDM is presented theoretically in terms of the effect of additive powder characteristics on the dielectric breakdown and gap width. In addition, the effect of the nanopowders’ mixed dielectric on surface topography, average surface roughness (Ra), peak-to-valley roughness (Rmax), material removal rate (MRR), and electrode wear ratio (EWR) was studied experimentally. It has been shown theoretically that the ...

Electrical discharge machining of submicron holes using ultrasmall-diameter electrodes

Abstract: We have carried out the electrical discharge machining (EDM) of submicron holes using ultrasmall-diameter electrodes. Two types of electrode were used: tungsten electrodes fabricated by the combination of wire electrodischarge grinding and electrochemical machining, and silicon electrodes originally designed as probes for scanning probe microscopes. The diameters of the former and latter were 1 μm or less, and less than 0.15 μm, respectively. Holes were drilled using a relaxation-type pulse generator at an open-circuit voltage of less than or equal to 20 V with the machine's stray capacitance as the only capacitance. Using tungsten electrodes, holes of less than 1 μm in diameter and more than 1 μm in depth were successfully drilled. A 1.3-μm-wide slot was also fabricated by drilling many holes with a small pitch. It was possible to drill holes of approximately 0.5 μm diameter using silicon electrodes because the electrode diameter was less than those of the tungsten electrodes. These holes have the smallest reported diameter for holes drilled by EDM, indicating the possibility of submicron- and nanoscale machining by EDM.

Optimizing surface finish in WEDM using the taguchi parameter design method

Abstract: Wire electrical discharge machining (WEDM) is extensively used in machining of materials when precision is of major factor. Selection of optimum machining parameter combinations for obtaining higher accuracy is a challenging task in WEDM due to the presence of a large number of process variables and complex stochastic process mechanisms. In the present work, WEDM of titanium alloy (Ti6Al4V) is experimentally studied. The behavior of eight control parameters such as Ignition pulse current (A), Short pulse duration(B), Time between two pulses(C), Servo speed(D), Servo reference voltage(E), Injection pressure(F), Wire speed(G) and Wire tension(H) on surface finish was studied using Taguchi parameter design. A mathematical model is developed by means of linear regression analysis to establish relationship between control parameters and surface finish as process response. An attempt is made to optimize the surface roughness prediction model using Genetic Algorithm (GA). Optimum values of control parameters at level A1, B1, C1, D3, E1, F3, G2, H3 for the selected range and workpiece material are obtained.

Pulse train data analysis to investigate the effect of machining parameters on the performance of wire electro discharge turning (WEDT) process

Abstract: This paper aims at giving an insight into the wire electro discharge turning (WEDT) process, by analyzing the effect of machining parameters on material removal rate (MRR), surface roughness and roundness error, using the pulse train data acquired at the spark gap. To achieve this objective a simple and cost effective spindle is developed for the WEDT process. Pulse train data are acquired with a data acquisition system developed in the present work. A pulse discrimination algorithm has been developed for classifying the discharge pulses into open circuit, normal, arc and short circuit pulses. With the help of algorithm the number of arc regions, average ignition delay time, the width of the normal and arc regions in the data acquired can also be obtained. It has been observed that the rotation of the workpiece has significant influence on the type of the discharges occurring at the spark gap. Preliminary experiments conducted to compare the WEDM and WEDT processes disclosed that MRR is less in WEDT and the number of arcs and arc regions are more in WEDT. It has been observed that the surface roughness and roundness error of the WEDT components are influenced by the occurrence of arc regions, width of arc and normal discharge regions and average ignition delay time.

Neuro-fuzzy and neural network-based prediction of various responses in electrical discharge machining of AISI D2 steel

Abstract: In the present research, two neuro-fuzzy models and a neural network model are presented for predictions of material removal rate (MRR), tool wear rate (TWR), and radial overcut (G) in die sinking electrical discharge machining (EDM) process for American Iron and Steel Institute D2 tool steel with copper electrode. The discharge current (I p), pulse duration (T on), duty cycle (τ), and voltage (V) are considered as inputs to the network. A full-factorial design was used to conduct the experiments with various levels of I p, T on, τ, and V. The analysis of variance results reveal that I p is the most influencing factor for MRR and G, having the highest degree of contributions of 87.61% and 81.90%, respectively. In case of TWR, T on has the highest degree of contribution of 46.05% and is the most significant factor. The half of the experimental data set was used to train the networks and was tested for convergence with a different set of data to obtain appropriate number of neurons, epoch, and the fuzzy rule base. The mean square error convergence criteria, both in training and testing, came out very well. The developed models are found to approximate the responses quite accurately. Moreover, the predicted results based on above models have been confirmed with unseen validation set of experiments and are found to be in good agreement with the experimental results. The comparison results reveal that the artificial neural network and the neuro-fuzzy models are comparable in terms of accuracy and speed, and further, the proposed models can be employed successfully in prediction of MRR, TWR, and G of the stochastic and complex EDM process.