Pulse-on Time Research Articles

Investigation of Electrochemical Dissolution Behavior of Near-α TA15 Titanium Alloy in NaCl Solution with Low-Frequency Pulse Current

TA15 material is a typical near-α titanium alloy and widely used for the aircraft key load bearing components. Electrochemical machining (ECM) is a cost-effective method to machine difficult-to-cut TA15. Due to the high chemical reactivity of titanium, titanium alloy is prone to passivation, which increases the difficulty of ECM, especially for some common ECM methods with low-frequency pulse currents. To investigate the change of surface characteristics of titanium alloy in pulse ECM, the dissolution behavior of TA15 in NaCl solution under the low frequency pulse current was analyzed by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). The results showed that even after removal of initial air-formed oxide film, TA15 would be passivated to form a new passive film during long pulse-off time. Under short pulse-on time, the passive film formed in pulse-off time could not be effectively removed in one pulse-on time, and the passivation effect would be accumulated, resulting in poor machined surface with humps and pits. When the pulse-on time was long enough to completely remove the newly formed passive film, TA15 was dissolved normally to obtain excellent surface with clear crystal structure.

Analysis of machining characteristics in electrical discharge machining of SiC and Al2O3 reinforced AA6061 hybrid metal matrix composites using Taguchi and ANOVA techniques

In this study, the machining behaviour of aluminium alloy (AA6061)/10% aluminium oxide (Al2O3)/10% silicon carbide (SiC) hybrid metal matrix composites was analyzed by Electric Discharge Machining (EDM). The stir casting method was used to fabricate the composite in a volume percentage of 80, 10, and 10 for AA6061, Al2O3 and SiC, respectively. The specimen was prepared in the size of 30 mm in diameter and 12 mm in thickness from the fabricated composite by the Wire-cut Electric Discharge Machining (WEDM) process. The fabricated specimens were machined using EDM by varying the input parameters of pulse-ON time (T–ON) in μs, pulse-OFF time (T–OFF) in μs, and gap current (GC) in amps at three different levels. The design of the experiment by the Taguchi method was used with the L9 orthogonal array. The impact of process parameters on output variables such as Surface Roughness (SR), Machining Time (MT) and Material Removal Rate (MRR) was studied, and an Analysis of Variance (ANOVA) was carried out to identify the most influencing parameter. The GC is observed as the significant input parameter on SR and MT as the percentage contribution of 33% and 47%, respectively. T–ON is identified as more significant than other parameters on MRR as the percentage contribution is 47%. The results show that T–ON time of 12 μs, T–OFF time of 4 μs, and GC of 14 amps yield the least value of 3.304 μm for SR, 12 min for MT, and a higher value of 0.037 mm3 min−1 for MRR.

Parametric Optimization for Quality of Electric Discharge Machined Profile by Using Multi-Shape Electrode.

The electrical discharge machining (EDM) process is one of the most efficient non-conventional precise material removal processes. It is a smart process used to intricately shape hard metals by creating spark erosion in electroconductive materials. Sparking occurs in the gap between the tool and workpiece. This erosion removes the material from the workpiece by melting and vaporizing the metal in the presence of dielectric fluid. In recent years, EDM has evolved widely on the basis of its electrical and non-electrical parameters. Recent research has sought to investigate the optimal machining parameters for EDM in order to make intricate shapes with greater accuracy and better finishes. Every method employed in the EDM process has intended to enhance the capability of machining performance by adopting better working conditions and developing techniques to machine new materials with more refinement. This new research aims to optimize EDM’s electrical parameters on the basis of multi-shaped electrodes in order to obtain a good surface finish and high dimensional accuracy and to improve the post-machining hardness in order to improve the overall quality of the machined profile. The optimization of electrical parameters, i.e., spark voltage, current, pulse-on time and depth of cut, has been achieved by conducting the experimentation on die steel D2 with a specifically designed multi-shaped copper electrode. An experimental design is generated using a statistical tool, and actual machining is performed to observe the surface roughness, variations on the surface hardness and dimensional stability. A full factorial design of experiment (DOE) approach has been followed (as there are more than two process parameters) to prepare the samples via EDM. Regression analysis and analysis of variance (ANOVA) for the interpretation and optimization of results has been carried out using Minitab as a statistical tool. The validation of experimental findings with statistical ones confirms the significance of each operating parameter on the output parameters. Hence, the most optimized relationships were found and presented in the current study.

Multi-Response Optimization of Al2O3 Nanopowder-Mixed Wire Electrical Discharge Machining Process Parameters of Nitinol Shape Memory Alloy

Shape memory alloy (SMA), particularly those having a nickel–titanium combination, can memorize and regain original shape after heating. The superior properties of these alloys, such as better corrosion resistance, inherent shape memory effect, better wear resistance, and adequate superelasticity, as well as biocompatibility, make them a preferable alloy to be used in automotive, aerospace, actuators, robotics, medical, and many other engineering fields. Precise machining of such materials requires inputs of intellectual machining approaches, such as wire electrical discharge machining (WEDM). Machining capabilities of the process can further be enhanced by the addition of Al2O3 nanopowder in the dielectric fluid. Selected input machining process parameters include the following: pulse-on time (Ton), pulse-off time (Toff), and Al2O3 nanopowder concentration. Surface roughness (SR), material removal rate (MRR), and recast layer thickness (RLT) were identified as the response variables. In this study, Taguchi’s three levels L9 approach was used to conduct experimental trials. The analysis of variance (ANOVA) technique was implemented to reaffirm the significance and adequacy of the regression model. Al2O3 nanopowder was found to have the highest contributing effect of 76.13% contribution, Ton was found to be the highest contributing factor for SR and RLT having 91.88% and 88.3% contribution, respectively. Single-objective optimization analysis generated the lowest MRR value of 0.3228 g/min (at Ton of 90 µs, Toff of 5 µs, and powder concentration of 2 g/L), the lowest SR value of 3.13 µm, and the lowest RLT value of 10.24 (both responses at Ton of 30 µs, Toff of 25 µs, and powder concentration of 2 g/L). A specific multi-objective Teaching–Learning-Based Optimization (TLBO) algorithm was implemented to generate optimal points which highlight the non-dominant feasible solutions. The least error between predicted and actual values suggests the effectiveness of both the regression model and the TLBO algorithms. Confirmatory trials have shown an extremely close relation which shows the suitability of both the regression model and the TLBO algorithm for the machining of the nanopowder-mixed WEDM process for Nitinol SMA. A considerable reduction in surface defects owing to the addition of Al2O3 powder was observed in surface morphology analysis.

The Effects of Pulse Shape on the Selectivity and Production Rate in Non-oxidative Coupling of Methane by a Micro-DBD Reactor

The conversion of methane to ethylene has been investigated in a micro-DBD reactor with electrodes containing charge injector parts and excited with a negatively nano-second pulse voltage superimposed on a positive dc voltage. The effect of changing the characteristics of pulsed voltage such as pulse rise time (5–7 ns), total pulse width (12–14 ns), and pulse fall time (5–7 ns) on generation rate and products selectivity of the methane plasma has been studied. The kinetic model includes twenty species (electron, ions, radicals, and neutrals). The results showed that change in input pulse shape changes the generation rate and selectivity of neutral products. The rate of voltage change during pulse on-time significantly changed the instant C2H4 selectivity. With increasing the pulse rise and fall times the ethylene selectivity decreases, while the hydrogen selectivity increases. Results also showed that the electron reactions are dominant conversion channels during pulse on-time, while they had lower contributions in conversion progress during pulse off-time and the conversion process during this period is mainly governed by the radical reactions.

The Performance Prediction of Electrical Discharge Machining of AISI D6 Tool Steel Using ANN and ANFIS Techniques: A Comparative Study

AISI-D6 steel is widely used in the creation of dies and molds. In the present paper, first the electrical discharge machining (EDM) of the aforementioned material is performed with a testing plan of 32 trials. Then, artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) were applied to predict the outputs. The effects of some significant operational parameters—specifically pulse on-time (Ton), pulse current (I), and voltage (V)—on the performance measures of EDM processes such as the material removal rate (MRR), tool wear ratio (TWR), and average surface roughness (Ra) are extracted. To lead the process operators, process plans (i.e., parameter–effect correlations) are created. The outcomes exposed the upper values of pulse on-time caused by higher amounts of MRR and Ra, and likewise lower volumes of TWR. Furthermore, growing the pulse current resulted in upper volumes of the material removal rate, tool wear ratio, and surface roughness. Besides, the higher input voltage resulted in a lower amount of MRR, TWR, and Ra. The estimation models developed by using experimental data recounting MRR, TWR, and Ra. The root means the square error was used to determine the error of training models. Furthermore, the estimated outcomes based on the models have been proven with an unseen validation set of experiments. They are found to be in decent agreement with the experimental issues. The investigation shows the powerful learning capability of an ANFIS model and its advantage in terms of modeling complex linear machining processes.

PARAMETRIC EFFECTS AND ANALYSIS OF ELECTRO-DISCHARGE MACHINING OF TI-6AL-4V TITANIUM ALLOY

The present experimentation focused on investigating electro-discharge machining performance such as material removal rate, surface roughness, electrode wear, overcut, and hardness during machining of biomedical titanium alloy Ti-6Al-4V. Taguchi L25 array is used to determine the process input parameters combination for conducting the experiments. The process input parameters are pulse current, gap voltage, pulse on-time, and pulse off-time. The response surface methodology is used for mathematical modeling. Parameters are selected so uniquely that the properties of the machined components are affected dimensionally significantly less, at the same time rate of production is also reasonably high. The mathematical models are found to be satisfactory. After performing the extensive experimentations, the effect of specific parameters and microstructure was studied and analyzed. Electric-discharge machining of Ti-6Al-4V with precise control over individual response characteristics is simple. However, achieving simultaneous control on all performance characteristics (MRR, SR, EW, OC, and H) is complex. Microstructural analysis reveals that the surface texture of the machined impressions contains a relatively high proportion of black spots. These black spots produce a coarser surface having surface roughness value, Ra = 9.735 µm at 21 Amp pulse current, gap voltage 60 Volt, pulse on-time 350 µs, and pulse off-time 175 µs. However, the material removal rate is maximum at 0.086 mm3/min at these parameters. Dimensional accuracy in overcut OC is 0.118 µm with electrode wear of 0.0006 mm3/min, and alteration in the surface hardness is about 10 VH.

Development of quality microholes by electrical discharge drilling on Al/SiC composite using of Grey-desirability approach

Electric discharge drilling (EDD) is a variant of spark erosion machining and is successfully used for the drilling of quality microholes. In present research, an attempt was made to drill microholes on Al/SiC composite. The drilling on aluminum composite was made at different machining indicators to analyze its effect on drilling rate (DR), electrode wear ratio (EWR), hole overcut (HO) and circularity (C). The input parameters selected in this work are pulse on-time (Ton), peak current (Ip) and pulse off-time (Toff). The experiments were planned as per Taguchi's L9 orthogonal array (OA). It was found that with the increase in Ton value, HO and EWR increases. However, larger values of Ip and Toff decreases the HO and EWR. Due to the combination of different quality characteristics Grey theory along with desirability has been implemented for collective response of output parameters. The optimized setting for multiple performance characteristics is Ton: 40; Ip: 3; Toff: 50. An improvement of 0.0199 is observed in grade value during optimization as compared to the maximum calculated grade value. After the implementation of proposed optimization technique, an improvement of 42.88% in DR, a reduction of 33.59% in EWR, a reduction of 4.54% in HO and 0.68% in C is observed.

Spatial and temporal thermo-physical analysis of Laser-induced plasma assisted ablation (LIPAA) of polycarbonate

High transmissivity of transparent materials in a wide range of wavelength increases its difficulty of machining using lasers. Laser beam passes through the material, producing no thermal effect on the transparent sheet. Conversely, the technique Laser-Induced Plasma Assisted Ablation (LIPAA) is capable of addressing the challenge of machining transparent materials with the aid of laser-induced plasma. This paper reports a three-dimensional nonlinear transient modeling and simulation of the LIPAA process for microchannel fabrication on transparent materials. The merit of the approach lies in simulating simultaneous ablation of both transparent polycarbonate and aluminium metal target during the process. The effect of plasma energy besides input laser irradiation has also been considered to have a realistic approach to the process and consequently, ablation on rear side of polycarbonate is obtained. The developed model has the potential of estimating spatial-temperature distribution along the traverse direction and direction perpendicular to it. The spatial distribution lent a hand in predicting the width and depth of the microchannel. A good correlation between the simulated and the experimental results was achieved on validation. Temporal-temperature distribution for pulse-on and pulse-off time was also explored. It is witnessed that the heating rate during pulse-on time is more than the cooling rate during pulse-off time. Likewise, it is observed that the temperature generated on aluminium is more than on polycarbonate. Substantially, the model can be employed to demonstrate LIPAA for microchannel fabrication on transparent materials irrespective of its transitivity.

EFFECT OF WC–Cu COMPOSITE ELECTRODES ON MATERIAL DEPOSITION RATE, MICROHARDNESS AND MICROSTRUCTURE OF ELECTRICAL DISCHARGE COATED MAGNESIUM ALLOY

Nowadays, coated surfaces have been used in the diverse of applications, such as automobile, aerospace and biomedicals. Different surface modification techniques have been used to improve the surface properties. Electrical discharge deposition (EDD) is an electro-thermal process widely used to deposit the hard composite coating on the workpiece with powder metallurgy electrode. To increase the deposition rate, powder composite electrode plays important role in this EDD process. In this work, tungsten carbide–copper composite coating is developed on ZE41A magnesium alloy surface using EDD. Process parameters used in the study are compaction load, current and pulse-on time, and the responses are material deposition rate (MDR) and microhardness (MH). The effects of process parameters on MDR and MH are studied. MDR and MH increased with increasing current and pulse-on time at low compaction loaded WC70-Cu30 electrode. Compaction load was found as the dominating parameter in the study followed by current and pulse-on time. Layer thicknesses of WC70-Cu30 and WC50-Cu50 electrodes are 92.12 and 72.88[Formula: see text][Formula: see text]m, respectively. MH decreased for the low compaction loaded electrode for both types of electrodes. This could be due to the minimum deposition of the tungsten particles. Uniform depositions with large spherical globules were observed at the surface deposited using WC70-Cu30 electrode. Larger craters were observed at WC50-Cu50 electrode. At the intermediate pulse-on time of WC70-Cu30 electrode, voids were formed which diminished the hardness of the surface.

Numerical and experimental study on WEDM of BN-AlN-TiB2 composite ceramics based on a fusion FEM model

Due to the poor machining performances in the traditional machining process for BN-AlN-TiB2 composite ceramics, this paper investigated the influence of electrical parameters and material composition on the machining performances of wire electrical discharge machining, namely material removal rate (MRR), surface roughness, kerf width, and energy efficiency. To find out the optimal process parameters, a fusion thermo-physical model based on the finite element method was proposed to predict the machining performances of BN-AlN-TiB2 with different weight proportions. Compared with experimental results, the accuracy of the novel model was verified within a relative error of 24.56, 16.16, and 1.87% in MRR, surface roughness, and kerf width, respectively. In addition, a series of experiments were conducted to investigate the effects of process parameters on machining performances for WEDM of different BN-AlN-TiB2 composite ceramics with 6, 8, and 10 wt% TiB2. The experimental results demonstrated that machining performances were proportional to the discharge energy. Moreover, MRR and specific discharge energy increased with increase of discharge current and pulse-on time. Considering the machining performances and energy efficiency, an appropriate parameter range with discharge current of 6–8 A, pulse-on time of 10–30 μs, and pulse-on time of 4–6 μs was recommended, and the BN-AlN-TiB2 composite ceramics with 6 wt% TiB2 exhibit better energy efficiency during the WEDM process.

A comprehensive review on wire EDM performance evaluation

Wire electric discharge machining (WEDM) technique is a fast-growing, advanced manufacturing process which is used for machining of hard materials including various alloys of steel, nickel, tungsten, cubic boron nitride, metal matrix composites (MMC's), superalloys, and ceramic materials. Moreover, it is employed for machining complex profiles and micromachining of hardened materials which are not feasible by various conventional machining processes. Generally, this process is employed to machine electrically conductive materials but during this scenario, it is also being used for machining of electrically low conducting and non-conducting ceramics including silicon carbide, aluminium oxide, silicon nitrate, and zirconium oxide ceramics by modifying the WEDM method with assisted electrode technique or forming composite of conductive and non-conductive materials. This paper presents a comprehensive review on the influence of several WEDM control factors including pulse-on time, pulse-off time, wire feed rate, peak current, wire tension, type of wire (tool) materials, types of base materials and types of powder mixed dielectric fluids on the output responses such as surface roughness (Ra), material removal rate (MRR), width of cut (kerf), wire wear ratio (WWR), wire breakage, microstructural defects, recast layer thickness, and thermal deformation. Moreover, various simulation methods, post processing methods and optimization of WEDM parameters using various techniques were discussed and at last this paper shapes the important recommendations and upcoming developments in WEDM.

Modeling and prediction of electrical discharge machining performance parameters for AA 8081 hybrid composite using artificial neural network

Aluminum matrix composites (AMCs) are gaining increasing attention from various industries due to their lightweight and more excellent wear resistance than conventional materials. Manufacturers embracing that difficulty in machining MMC due to reinforcing particles abrasive nature shorten the tool life. Electro-discharge machining (EDM) is an enormously used non-conventional process to remove material in die making, aerospace, and automobile industries and machine any material with the highest hardness. Hence in the present study, EDM was performed on an aluminium alloy 8081 (AA8081) with reinforcement of 10% SiC, 5% B4C, and 5% Gr particles utilizing an ultrasonic cavitation assisted stir casting process. The machining investigation was carried out adopting face-centered central composite design (CCD) with three parameters such as current, pulse-on time, and pulse-off time to ascertain the effects of two sustainable measures, viz., Material removal rate (MRR) and tool wear rate (TWR) the data were collected. An Artificial Neural Network (ANN) model was developed based on data obtained from experiments. Finally, experimental values are compared with the predicted values of ANN and found high prediction accuracy. The advanced model results are used to approximate the responses fairly precisely. The version features a mean coefficient of correlation of 0.99072. Effects uncovered that the projected version is employed for the prediction of the complex EDM process.

A Soft Computing-Based Analysis of Cutting Rate and Recast Layer Thickness for AZ31 Alloy on WEDM Using RSM-MOPSO.

In the present research, the AZ31 alloy is machined by wire-cut electric discharge machining (WEDM). The experiments were designed according to the Box-Behnken design (BBD) of response surface methodology (RSM). The input process variables, namely servo feed (SF), pulse on-time (Ton), servo voltage (SV), and pulse off-time (Toff), were planned by BBD, and experiments were performed to investigate the cutting rate (CR) and recast layer thickness (RCL). The analysis of variance (ANOVA) was performed to determine the influence of machining variables on response characteristics. The empirical models developed for CR and RCL were solved using Multi-Objective Particle Swarm Optimization (MOPSO). Pareto optimal front is used for the collective optimization of CR and RCL. The optimal solution suggested by the hybrid approach of RSM-MOPSO is further verified using a confirmation test on the random setting indicated by the hybrid algorithm. It is found that the minimum RCL (6.34 µm) is obtained at SF: 1700; SV: 51 V; Toff: 10.5 µs; and Ton: 0.5 µs. However, maximum CR (3.18 m/min) is predicted at SF: 1900; SV: 40 V; Toff: 7 µs; and Ton: 0.9 µs. The error percentage of ±5.3% between the experimental results and predicted solutions confirms the suitability of the proposed hybrid approach for WEDM of AZ31.

An experimental investigation of electro discharge machining parameters effects on ferromagnetic properties of extra-low-carbon steel

Extra-low-carbon steels are becoming increasingly important for their high magnetic permeability, and reasonable price in industrial applications such as magnetic suspension systems, actuators, and sensors. The application of these steels to the aforementioned parts and industries depends on their magnetic properties. The various manufacturing processes used to make equipment and tools based on this kind of steels affect their magnetic properties. In this study, the effect of electro discharge machining (EDM) parameters on the magnetic properties of extra-low-carbon steel has been experimentally extracted, and the optimum levels of the parameters have been determined for optimum magnetic properties. The selected parameters include pulse-on time, pulse-off time, current, and gap voltage, and the design of experiments was done by the Taguchi method. After machining and preparing the specimens, their hysteresis curves were measured using vibrating-sample magnetometer (VSM), and the magnetic properties of the machined extra-low-carbon steels were calculated. The results show that the optimum parameter levels for the lowest magnetic coercive force include the pulse-on time of 160 microseconds, pulse-off time of 60 microseconds, 16 Amps current, and 70 Volts gap voltage. Also, for the lowest remanence magnetization, the pulse-on time, pulse-off time, the current, and gap voltage are 50 microseconds, 60 microseconds, 16 Amps, and 90 Volts, respectively. The optimum parameters for maximum saturation magnetization are 50 microseconds, 90 microsecond, 12 Amps and 80 Volts for the pulse-on time, pulse-off time, the current, and gap voltage respectively.

Microstructural investigation of nickel deposits obtained by pulsed current

Electrodeposited nickel coatings are applied in functional applications to modify or improve corrosion resistance, hardness, wear, magnetic, and other properties. In this work, Nickel deposits were produced by simple pulse electrodeposition using a free-additive Watts bath. It has been shown that pulse current deposition is able to produce coatings with excellent properties in morphology, particle distribution, structure, grain size, hardness and wear resistance. Pulsed techniques present a larger number of variables, so we propose to optimize the parameters which define the pulsed current to obtain deposits with improved properties. The optimization of the conditions of deposition was established and the influence of pulse parameters, namely, pulse on-time, off-time and average current density, on the grain size, surface morphology and crystal orientation was determined. The morphology of the coatings was characterized by observations in scanning electronic microscopy (SEM). X-ray diffraction in symmetric mode was also used to evaluate the structure and principal crystallographic orientations of the deposits. The study showed that pulse current results in better properties of deposits and significantly refined the crystal grain.

WEDM Machining Performance of Al Based Metal Matrix Composites Reinforced with Rice Husk Ash

With the enhancement in science and technology, necessity of complex shapes in manufacturing industries becomes essential for more versatile applications. These lead to demand for light weight and durable materials for applications in aerospace, defence, automotive, as well as sports and thermal management. Due to its high-tech structural, functional applications like defence, automobile, aerospace, thermal sensitive materials. Al-Matrix composites are considered as one of those classes of advanced engineering materials. In the present study, Al-RHA (Rice Husk Ash) composites are prepared by powder metallurgy route using 10% and 15% RHA by weight as reinforcement. Presence of abrasive particles leads to difficulty of conventional machining on Al-RHA composites hence non-conventional machining WEDM (Wire-Electric Discharge Machining) has been investigated. Suitable machining parameters for composites using wire EDM have been tried to get maximum material removal rate and speed. Optimizations of experimental parameters have been studied using Taguchi and Anova to standardize the process parameters for machining. Prime process parameters like servo-voltage, pulse-on time and pulse-off-time have been taken into consideration to study cutting quality of Al-RHA Metal matrix Composite using cutting speed as response parameters while effect of RHA weight fraction addition is also considered for evaluation to understand its influence on affecting the response.

Comparative Study on EDM Parameter Optimization for Adsorbed Si3N4–TiN using TOPSIS and GRA Coupled with TLBO Algorithm

Electrical discharge machining is a thermo-physical-based material removal technique. 25 combinations of process variables were formulated with the aid of Taguchi technique for EDM of adsorbed Si3N4–TiN. Machining variables like pulse current, pulse-on time, pulse-off time, dielectric pressure, and spark gap voltage varied, and impact of each variables on the performance metrics (MRR, EWR, SR, ROC, θ, CIR, and CYL) was assessed. MCDM strategies like grey relational analysis and TOPSIS are utilized to find out the ideal arrangement of machining parameters to achieve most acute productivity of the multitude of reactions. Likewise, metaheuristic algorithm in particular GRA combined with teaching-learning-based optimization algorithm is utilized for getting global optimized input factors. Important factors like pulse current, pulse-on time, and spark gap voltage characteristically affect the outputs. It is recognized that the pulse-on time and the pulse current are the most significant input factors than others. The ideal machining parameters in view of GRA and TOPSIS techniques for acquiring better output factors are I, 12 amps; PON, 7 μsec; POFF, 4 μsec; DP, 12 kg/cm2; and SV, 36 volts.

Experimental examination of the machining characteristics of Nimonic 80-A alloy on wire EDM

Nimonic 80-A alloys are very hard alloys with high-temperature strength having an extensive application in the aerospace industry. Wire Electric Discharge Machining (WEDM) is one of the finest non -conventional machining processes, which due to the material removal taking place using spark erosion with Wire EDM, makes it very easy to machine hard alloys and composites. The accuracy of machining them makes it one of the most advanced non-traditional processes. Kerf width is an important output response during machining on WEDM. The experimental investigation is done to find the optimum machining parameters to minimize the kerf width. The experimental investigation was done using the Taguchi analysis considering input factors peak current, gap voltage, and pulse-on time at three levels for machining on WEDM. Taguchi L27 orthogonal array was applied to generate the required experiments to be performed on WEDM. The output response data kerf width obtained is analyzed using signal-to-noise (S/N) ratio values generated by the Taguchi design methodology. The three main input parameters like peak current (20-80A), gap voltage (30–60 V), and pulse-on time (20–70 μs) are considered within this range. The single response optimization is done of the experimental kerf width data obtained for 27 different settings of input parameters of WEDM. The influence of each of the variables on kerf width is interpreted using the S/N ratio graphs, finding the most appropriate settings to minimize the kerf width. The results were obtained with a specific range of parameters that can be analyzed further with other optimization models, to get a wider range of optimum parameter values. The research on optimizing the output response kerf width for Nimonic 80-A alloy during machining on WEDM has not been reported much in the literature. This new optimized machining data would provide better scope to machine Nimonic 80- A alloy for minimizing the kerf width.

Probabilistic optimization of machining of duplex stainless steel in electric discharge machining with hydroxyapatite nanoparticles mixed dielectric medium

The electric discharge machining has been carried out in the current study for the surface modification of Duplex Stainless Steel (DSS 2205). The machining process is carried out in the hydroxyapatite nanoparticles (Ca5(OH)(PO4)3)(HAP powder) mixed dielectric medium with a copper tungsten electrode in reverse polarity. To determine the optimal machining parameters, the Taguchi L18 orthogonal array approach was employed, and the input machining variables in terms of discharge current, voltage, pulse-on time and pulse-off time were chosen. It has been observed from the results that the discharge current contributing 58.18%, pulse-off time contributing 16.77% and pulse-on time contributing 15.83% were the most significant factors in improving the MRR. The optimum machining parameters for achieving the maximum MRR (0.305 mg/min) with EDM Oil were recognized at discharge current of 16 Amp, pulse-on time of 200 μs, pulse-off time of 60 μs and the applied voltage of 80 V and with nano powder mixed electric discharge machining, the maximum MRR (0.271 mg/min) were observed at discharge current of 16 Amp, pulse on time of 150 μs, pulse off time of 60 μs and voltage 80 V. MRR is reduced by 11% when NPMEDM is used. XRD analysis confirms the modification on the surface of nano powder mixed electric discharge machining demonstrating the formation of several intermetallic compounds.