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The unconventional machining processes are popular in machining the difficult to cut type complex contour/ profile. The key parameters are to be machined with care as they directly affects the function and non key dimensions are machined with other than consideration of functional aspect, like design, passage. That means accuracy is less important in those dimensions but finish is to be good. So the machining of engineering materials does not always require optimizing parameters based on multiple responses. This investigation focuses on the sensitiveness of Wire EDM of 12X18H10T - Stainless Steel and identifying the parameters contribution and establish mathematical model to predict values without trial. An austenitic alloy 12X18H10T - Stainless Steel exhibits its inherent mechanical properties even when it expose to extremely high temperature. Ithas potential application in aerospace engine components manufacturing. This investigation utilized the Taguchi L9 experiential Design with factors of Pulse off Time, Wire Tension, Pulse on Time, and Wire Feed Rate. This study aims to examine Maximize the rate of machining with Taguchi approach in the process of Wire EDM of 12X18H10T - Stainless Steel and establish a mathematical model to predict the highly influencing parameter(s) for desired rate of machining.

Numerical control electrical discharge machining (NC EDM) is one of the most widely used machining technologies for manufacturing a closed blisk flow path, particularly for three-dimensional (3D) curved and twisted flow channels. In this process, tool electrode design and machining trajectory planning are the key factors affecting machining accessibility and efficiency. Herein, to reduce the difficulty in designing the electrode and its motion path in the closed curved and twisted channels, a heuristic search hybrid optimisation strategy based on channel grids is adopted to realise the initial electrode trajectory design search and optimised size reduction. By transferring the trajectory optimisation constraints from the complex free-form surface to numbered grids, the search is found to be more orderly and accurate. The two trajectory indicators, namely argument angle and minimum distance, are analysed separately for the optimised results of the adaptive learning particle swarm optimisation algorithm, demonstrating that they can meet the actual processing requirements. Experimental results of NC EDM indicate that the motion path generated by this design method can meet the machining requirements of 3D curved and twisted flow channels.

The influence of the surface area by the impact of high temperatures after wire electric discharge machining (WEDM) is a known fact. However, the affected parameters also include a change in microhardness. In order to further investigate this statement, 5 different ferrous and non-ferrous materials were selected, from which three samples were always made with different settings of machine parameters (gap voltage, pulse on and off time, wire feed and discharge current). This examined not only the effect of the machining itself on the material but also whether the change in the microhardness of the material is affected by the setting of the machine parameters. In order to measure the microhardness of the subsurface layer, a metallographic preparation was made from each sample, which enabled accurate measurements always in the same area. Subsequent evaluation revealed that the microhardness may not be affected at all and everything depends only on the type of material being machined. The changes in microhardness affected by setting machine parameters are negligible. Ovlivnění podpovrchové oblasti působením vysokých teplot po elektroerozivním drátovém řezání (WEDM) je známy fakt. Mezi ovlivněné parametry je však zahrnována i změna mikrotvrdosti. Za účelem bližšího zkoumání tohoto tvrzení bylo zvoleno 5 různých kovových a nekovových materiálů, z nichž byly vyrobeny vždy tři vzorky s odlišným nastavením parametrů stroje (gap voltage, pulse on and off time, wire feed and discharge current). Tímto byl zkoumán nejen vliv samotného obrábění na materiál ale také to, zda je změna mikrotvrdosti materiálu ovlivněna nastavením parametrů stroje. Za účelem měření mikrotvrdosti podpovrchové vrstvy byl z každého vzorku vyroben metalografický preparát, který umožnil přesné měření vždy ve stejné oblasti. Následným vyhodnocením bylo zjištěno, že mikrotvrdost nemusí být vůbec ovlivněna a vše závisí pouze na druhu obráběného materiálu. Změny mikrotvrdosti ovlivněné nastavením parametrů stroje jsou zanedbatelné.

Compared with a copper wire electrode, molybdenum wire with a poor conductor is usually used as the electrode in high speed wire-cut electrical discharge machining (HSWEDM), so the resistance of an ultra-fine wire cannot be ignored. To study the differences of discharge characteristics between the ultra-fine wire and the conventional diameter wire, the continuous discharge waveform of two kinds of wire electrodes was compared. It was found that there was a multi-channel discharge phenomenon in the discharge waveform cutting by ultra-fine wire. Through the establishment of a discharge equivalent circuit model and the simulation analysis of the electrostatic field, it was found that the reason why ultra-fine wire is easy to form multi-channel discharge phenomenon is that the potential difference between the wire and the workpiece increased linearly along the axis of the wire. Besides, etching products like metal particles will distort the electric field between the electrodes. Both of them make it easy to form a multi-channel discharge in machining. The results show that the distributions of the equivalent resistance and the peak current are affected by the multi-channel discharge position. Multi-channel discharge can disperse energy and increase effective discharge frequency. Compared with the 0 mm spacing, at a spacing of 100 mm, the machining efficiency increases by 8.7%, the surface roughness decreases by 37.7%, and the average recast layer thickness decreases by 46.6% under the condition of ultra-fine wire-EDM.

In recent decade’s machine tools and cutting tool technology, (EDM) is utmost trending techniques for making factual shape on different material like HSLA, H11, H-13 etc. steels and is maximum endorsed techniques to be ensure for mold & die making. In Electric discharge machining process increases the mechanical and physical properties when used with powder suspension and with assertive composite of electrode materials. Result analysis through the effect of parameters and their level of practically examined least number of experiments trail by during slot cutting by using Taguchi technique identified tool wear. Now a day’s most prominent materials which are largely used in die making & mold casting industries like HSLA, H11 die steel. In the latent research M.R.R and T.W.R examined through the result analysis by the taugchi techniques changes in the level of the selected parameters. Selected parameters like electric current, pulses-on time, graphite and tungsten powders imposed in dielectric by changes the range of different levels with or with-out using magnetic fields. To find out the better result of analysis we followed the ANOVA techniques to optimize and the effects of the parameters at optimum level/range for the M.R.R and T.W.R of the cooper tool.

This paper presents the influence of wire electrical discharge machine (WEDM) cutting parameters on the magnetization characteristics of electrical steel. The demand for electrical steel keeps increases because of the high demand of electrical motor and transformers for electric vehicle and smart grid applications. The magnetization characteristics of the laminated steel used in these machines have dominates the performance of these machines. The cuttings methods and cutting parameters have huge role in deciding the magnetization characteristics. In this work, WEDM is used to cut the electrical steel in to small pieces. The cutting parameters such as current, feed rate and on-time of WEDM are varied by keeping two of these parameters fixed and one varied. From the electrical steel sheet, 18 sample small electrical steel pieces are obtained at various cutting parameters of WEDM. The magnetic field – magnetization characteristics are obtained using vibrating sample magnetometer (VSM). This analysis shows that higher current, lower on-time and higher feed rate is providing higher magnetization.

The Fiber Refinement Polymer Composites (FRPCs) are of great interest nowadays. Composites are employed in diverse areas such as automobiles, aerospace, and the military due to their multiple advantages for better mechanical, thermal, and fracture toughness features. Several researchers have constructed FRPCs using different natural fibers and matrix materials. However, to complete the assembly of the components or pieces, FRPC's actual applications require some secondary activities. Very few scientists discussed the machinability of these FRPCs. The main problems in fiber-reinforced composite plastic machining were discussed in this review concerning the most recent research in this field. In contrast, the unconventional and conventional machining processes were considered, this paper includes annual research in production, traditional machining, unconventional machining, and hybrid MMC machining. The final part of the paper addresses conclusions and future scope.

In any research work, the role of preliminary experimentation to decide the range of various input parameters can never be overlooked. To commence the main experimentation a range of these parameters is selected on the basis of preliminary experiments and an in-depth literature review. The Peak Current (Ip) is considered to be the most predominant input parameter affecting the cryogenically assisted electric discharge machining (CEDM) process. In this paper, the effects of varying the peak current have been evaluated in terms of Material Removal Rate (MRR), Tool Wear Rate (TWR), Surface Roughness (SR), Aspect Ratio (AR) and Out of Roundness and the range of the peak current to be kept during CEDM of AISI D2 has been focused. The electrolytic copper has been used as tool electrode. After conducting the experiments and with the support of literature, it is proposed to keep the range of peak current from 4 A to 12 A, under given machining conditions. The Scanning electron microscope (SEM) analysis of machined workpiece were also performed and CEDM was found to be better than EDM.

Wire electrical discharge machining (WEDM) is often used in the machining of conductive materials when precision is important. The current study looked at wire-cut electric discharge machining of EN31 steel. Taguchi's L27 orthogonal array was used to finish the investigation using various amounts of input parameters. This method was used to determine the optimal parameter combination. The experimental findings show that the machining model is correct, and Taguchi's approach meets the practical requirements. Surfaces having micro cracks and porosity, as well as poor surface quality, are produced by rough machining with WEDM. Finish machining yields a better surface finish (Ra) but at a slower rate (MRR). As a result, the Taguchi approach's purpose is to improve MRR while lowering Ra. To check the performance measures in terms of Surface Roughness, control parameters such as voltage applied, pulse width, pulse interval, and speed were used.

This work investigates the process parameters like peak current, applied voltage, wire feed rate on machining characteristics kerf width and surface roughness of Wire Electrical Discharge Machine (WEDM) while machining AA6351/Rutile composite which is fabricated by powder metallurgy technique. In this experimental work, Taguchi’s L27 orthogonal design is used for conducting experiments. This present research has been intended to optimize the setting of process parameters in order to improve the machining performance by coupling different Multi-Criterion Decision making methods such as Multi-Objective Optimization process on the basis of Ratio Analysis (MOORA) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) with Principal Component Analysis (PCA). When the hybrid MOORA-PCA and TOPSIS-PCA are applied, the results display with a peak current 12 amps, applied voltage 20 V and wire feed rate 5 m/min. When compared these two hybrid methods, MOORA-PCA approach clearly indicates its significance because of its simplicity. The optimised setting obtained canbe further used to produce high quality micro-channels for heat exchangers and heat sinks.

Inconel 617 superalloy is a candidate material for various high temperature components employed in ultra-supercritical power plants. Superalloys are hard to machine materials that easier to process using nontraditional methods such as wire electrical discharge machining. This paper discusses multi performance optimization in machining of Inconel 617 using grey relational analysis and genetic algorithm. The performance characteristics of wire cut EDM are surface roughness, material removal rate, wire wear rate, form and orientation tolerances. Parameters under consideration are pulse on time, pulse off time, current, voltage, flushing pressure, wire tension, table feed and wire speed. The performance measures are consolidated as three performance indices using the grey relational grade. The mathematical models to estimate the performance objectives are developed using regression analysis. Multiobjective optimization is applied through genetic algorithm and a pareto front containing the optimized responses is computed. The optimized parameters are validated experimentally and the results are reported.

Efficient and cost effective utilization of WEDM process is a challenge for leading edge era of manufacturing because of the complex and non-linear behavior of the process. The current study focuses on an experimental inquiry carried out for WEDM of Nitronic-30 to obtain optimum process parameters for improved surface roughness (SR) and material removal rate (MRR), Nitronic-30 is austenitic stainless steel offers high strength with good corrosion resistant property which high potential in applications such as automotive parts, aqueous applications, solid handling equipment. Therefore, multi-response optimization of Nitronic-30 on WEDM is very essential. Experiments were carried out with Taguchi's DoE and a L9 orthogonal series, with machining parameters like pulse on time (Ton), pulse off time (Toff), and peak current (IP). Minitab-17 software was used to evaluate response variables such as material removal rate and surface roughness. Analysis of variance (ANOVA) and SN Ratio plot of GRG indicates that peak current is the most important parameter. Grey Relational Analysis (GRA) provides optimal process parameters like pulse on time 124 machine units, pulse off time 40 machine units and peak current 230A for optimal response variables as 4.019 µm SR and 8.683 mm3/min MRR.

A detailed experimental research study on wire lag phenomena, gap force, and wire lag compensation has been carried out on M2 tool steel material to overcome the error in dimensional accuracy for circular or curved profile job cutting in the wire electrical discharge machining. The design of experimental planning was made based on Taguchi methodology to determine the effect of the WEDM input control parameters on the wire lag related to different machining criteria, as well as the material removal rate, surface finish characteristic in terms of Ra values, spark gap, and specific energy consumption in this research work. The frequency, pulse on time, peak current, wire feed, workpiece height and wire tension, cutting diameter, and the span in between wire guide and job surface are considered as input control parameters for the present study. Parametric analysis shows that wire lag increases with workpiece height and wire lag compensation value increase rapidly with the decrease of job diameter. Parametric analysis is also carried out for MRR, surface roughness, spark gap, and specific energy consumption for optimum output. A further key finding is identified that the energy utilization efficiently increases with larger height job cutting in the WEDM process.

Low processing efficiency and environmental pollution hinder the development of electrical discharge machining (EDM). To address this issue, a sustainable and efficient EDM method under compound field, namely rotating short arc milling, is proposed in this study. The magnetic field and high-pressure flow field of dielectric facilitate the removal of debris from discharge gap. Tap water is used as the dielectric to reduce pollutants generated during processing. Under the compound field, a portion of debris adheres to the machining end of the tool electrode to form a protective layer and participates in the discharge machining as a part of the tool electrode, which can reduce the tool electrode wear. This study describes the principles of this method to achieve high material removal rate (MRR), low tool electrode wear rate (TEWR), and environmentally friendly dielectric. Besides, a series of experiments are conducted to study the motion characteristics and resistance characteristics of rotating short arc, the influence of processing parameters on the machining performance of GH4169 superalloy. The results show that the machining voltage, machining depth, and magnetic field strength are the three most important factors that affect the efficiency and sustainability of rotating short arc milling. Furthermore, the optimal processing parameter combination is obtained by using gray relational analysis method to optimize the machining process in terms of high efficiency and environmental protection.

The coated electrodes with high heat resistant alloy materials can considerably improve the efficiency of electrical discharge machining (EDM) process. In the present study, the influence of Aluminum Chromium Nickel Coated aluminium electrode was investigated on the quality criteria using EDM while machining Titanium alloy (Ti - 6Al-4V). The peak current, gap voltage and pulse-on time were used as input parameters to analyze the material removal rate, tool wear rate and surface roughness under the L16 based Taguchi method and ANOVA method. It was observed that Aluminum Chromium Nickel (AlCrNi) coated electrode could produce higher material removal rate (MRR), lower of tool wear rate (TWR) and surface roughness (Ra) than uncoated electrode. Compared with EDM with uncoated electrodes, the quality indicators in EDM with coated electrode are better, namely 8% higher MRR, the lower TWR and Ra are 8% and 24%, respectively. The better surface finish was also observed with the coated electrode due to its thermal conductivity.

This paper presents a novel piezoelectric-actuated microgripper that mainly consists of a three-stage flexure-based amplification mechanism to achieve a large magnification ratio, a high structural stiffness and a great force output capacity for micromanipulation and assembly. The first two stages are configured as two bridge-type parallelogram amplification mechanisms connected in serial to provide advantages in terms of high structural stiffness and compactness. This configuration is capable of generating large forces to maintain the following connection leverage mechanism and ensure a large displacement output, and also produces a stable amplification ratio insensitive to the input change. The finite element method (FEM)-based simulation has been performed to investigate both static and dynamic characteristics of the designed microgripper. Simulation-enabled structural optimization design has been implemented to further aid and improve the proposed design. The simulation results indicate that the amplification ratio reaches 30.66 with a maximum clamping force of up to 2.32N. The gripper prototype has been fabricated based on the wire electro discharge machining technique, and its performances have been validated through pack-and-place of microbeads experiments. The experimental results have demonstrated its excellent linear amplification performance and they match well with the outcomes from both simulation and theoretical calculation in terms of motion range and amplification ratio.

The Inconel 718 superalloy is widely used in petrochemical, energy, aerospace, nuclear power plants, and many other applications where components are subjected to high temperatures and corrosion environments. This alloy is most used due to its combination of good mechanical properties and relatively low cost compared to other supperalloys. Nevertheless, its mechanical properties and workpieces with very complex geometries are difficult to be manufactured by conventional machining properties. It is observed that notch wear at the cutting tool tip and superabrasive carbides in Inconel 718 promote high abrasive cutting tool wear; high diffusion wear happens at cutting tool, continuous and tough chips cause degradation of the cutting tool, and both high temperature and thermal gradients occur at the cutting tools due to low thermal diffusivity of these alloys. Wire electrical discharge machining is a precision non-traditional machining process that appears as an alternative to the conventional machining process for any hard and electrically conductive material. The objective of this research work is to compare the technological performance of WED-Machining Inconel 718 using a reciprocating molybdenum wire electrode using two types of dielectric fluids (deionized water and 8% emulsion hydrocarbon) under different electrical parameters. Therefore, it presents the investigation of the discharge energy influences for five different levels of discharge durations and varying the wire run-off speed. Technological aspects labeled material cutting rate, kerf width, wire feed rate, and surface integrity were evaluated. The results revealed that the hydrocarbon presented a higher cutting rate than deionized water independent of the discharge energy applied. The hydrocarbon dielectric presented the best results for the wire feed rate compared to water fluid. The largest kerf width was attained for the deionized water, and the surface roughness increase is more pronounced for deionized water than hydrocarbon dielectric.

This research work reports about pattern generation using the photochemical machining (PCM) assisted reverse electro discharge machining (EDM) process on an aluminum 6061 workpiece. A mixture of fi...

Electrical discharge machines (EDM) are widely employed in machining components containing complex profiles of hard-to-cut and machining materials. However, the fabrication-of-tool time for the EDM process is excessively high in the traditional machining method, which significantly affects the machining rate. Therefore, in this paper, a powder metallurgy (PM) technique is employed to fabricate the tool electrode using copper (Cu), titanium carbide (TiC), and zirconium silicate (ZrSiO4) for different combinations. An L18 orthogonal array (OA) is planned using the following input parameters: three types of tools (Cu, Cu90, Cu80), peak current (PC) [A], pulse on time (PT) [µs], and gap voltage (GV) [V]. The performance of EDM is evaluated through the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR). The process parameters are optimized using two different techniques: the technique for order of preference by similarity to the ideal solution (TOPSIS) and grey relational analysis (GRA). TOPSIS and GRA optimization techniques produce the same optimal parametric solution for less TWR, SR, and higher MRR with the combination of the Cu90 tool, E8 APC, 15 µs pulse PT, and 75 V GV. Based on the ANOVA table of TOPSIS, pulse on time plays a major role, contributing 46.8 % of the machining performance; peak current shows the most significant contribution of 39.3 % of the machining performance using GRA values. Furthermore, the scanning electron microscope (SEM) image analyses are carried out on the machined workpiece surface to understand the effect of tools on machining quality.

Precision machining characteristics with high-dimensional accuracy make the material more adaptable towards the applications. The present study employs the powder mixed wire electrical discharge machining process to machine Ti6Al4V alloy material. In spite of limited drawbacks and enhanced output in the powder mixed wire electrical discharge machining process, the present problem has been formulated for improving the machining efficiency of Ti6Al4V. The impact of suspended powder characteristics on responses, that is, material removal rate and surface roughness, is examined throughout the process. The current investigation also focuses on the interaction effect of machining constraints along with Al2O3 abrasive mixed dielectric to achieve economical machining output for the Ti6Al4V material. An effort has been presented to obtain optimal solutions using the different methodologies, namely response surface methodology, grey relation analysis, and particle swarm optimization. The study reveals that discharge energy is deeply influenced by the peak current and pulse off time followed by powder concentration in the powder mixed wire electrical discharge machining process. The maximum material removal rate of 6.628 mm3/min and average surface finish of 1.386 μm are the outcome of the present study for a set of optimal machining settings, that is, pulse off time ( Toff) of 7.247 μs, pulse on time ( Ton) of 30 μs, peak current ( Ip) of 2 A, and powder concentration of 4 g/L. Finally, the proposed model has been verified that the hybrid particle swarm optimization technique has the highest adequate capability to achieve maximum output. Thus, the approach offered an enhancement on performance measures of Ti6Al4V alloy in the powder mixed wire electrical discharge machining process.

Nowadays, special attention is paid to the application of nanoparticles to improve the performance of Electrical Discharge Machining (EDM). In this paper, modeling and optimizing the process parameters of Nanopowder Mixed Electrical Discharge Machining (NPMEDM) is studied. In this study, the effect of aluminum oxide (Al2O3) and silicon oxide (SiO2) nanoparticles on the deionized water dielectric is investigated simultaneously in the process of electrical discharge machining of Ti-6Al-4V alloy. After analyzing the parameters, the discharge current, concentration, pulse on time, and relative composition are considered as input factors. Response Surface Methodology (RSM) using Design-Expert software is employed for the design of the experiments, analysis of the results, and optimization of the parameters. The results show that the best surface morphology is obtained by machining with the addition of nanoparticles in the relative composition of 50%. In this percentage of the composition, the surface of the workpiece has the least value of crack and recast layer. In addition, the maximum value of the material removal rate (MRR) and minimum value of tool wear rate (TWR) can be achieved in the discharge current of 12 A, pulse on-time of 100 μs, and relative composition of 75% Al2O3 – 25% SiO2.

Wire-cut Electrical Discharge Machining (WEDM) is a notable machining process to produce exact and accurate complex shape products. As a high corrosion resistance with high hardness and strength, N...

The present study is designed to study processes occurring during the electrical discharge machining (EDM) of tool steels, the influence of orbiting electrode motion on its accuracy, as well as to justify the application of individual orbiting trajectories and implement these data into production. To that end, a trajectory program was written in machine codes for a Mitsubishi EA-28 die-sinking electrical discharge machine using the CIMCO EDIT software package. Also, a prototype punch and ejector of the blanking die were produced and measured. The standard modes of Mitsubishi EA-28 were used to carry out machining in Blasospark GT 250 dielectric fluid to a roughness of Ra 0.6 in 9 passes. The experiments revealed the influence of electrode geometry on the machining of sharp corners, i.e., the formation of unwanted radii on the workpiece. However, this phenomenon is not observed when the corners are drilled with small diameter holes (0.4–0.6 mm). Depending on the machining process along the inner or outer trajectory, inverse electrode motion is also observed. The production part (punch of the blanking die) was machined using a new orbit adjusted to the geometry of the product. The part was found to be consistent with the requirements and the engineering drawing, thus allowing the assembled die to enter the main production. The results of the performed tests, as well as the study of domestic and foreign experience, were used to develop recommendations on the use of individual orbits in the EDM of tool steels, hard alloys, and other hard-to-machine conductive materials. The method of orbiting motion along a particular trajectory was implemented at Cheboksary Electrical Apparatus Plant (Cheboksary).

The wire-electrical discharge machining method is one of the important modern manufacturing methods and has been widely used especially in the die manufacturing industry. The quality of the surfaces of the tools used in production, such as extrusion dies, punches, which are in contact with the produced product, is very important. The surface roughness of the extrusion die will affect the final product surface quality. In this study, pulse times, pulse pause times, wire feed speeds, and workpiece (die) thicknesses are variable, and their effect on hardness, surface roughness change, and material removal rate were researched. The study was carried out using steel material (cold work tool steel) used in products such as extrusion dies and punch. The effect of the thickness of the workpiece (die) processed by the WEDM method on the surface roughness was investigated, and, unlike the literature, the variation of the surface roughness of the wire entry side and wire exit side on the WEDMed surface was investigated. A slightly higher surface roughness was measured at the wire exit side compared to the wire entry side. In addition, the hardness of the die, which is in constant contact with the product produced, is also very important. The hardness of the die will directly affect the die life. In the study, carbon concentration changes were determined depending on the process parameters on the WEDMed surfaces, and the relationship between carbon concentration and microhardness was revealed. As a result, it was observed that the surface integrity depends on the process parameters, so the process parameters should be selected according to the desired properties of the produced parts.

Machine learning approaches are disseminating very rapidly in manufacturing industry. They emerge out as latent modeling approaches showing a great potential for solving manufacturing-related problems. This study aims to analyze and predict the micro-irregularities on the surface of Inconel 690 superalloy processed by wire electro-spark machining using machine learning approaches. Experimental runs are completed by using the box-Behnken design of response surface methodology. Spark-on time, spark-off time, current and voltage with varying constraints are used as the input process variables, whereas surface integrity is used as the output variable. Support vector machines with two different functions and random forest regression are exercised to predict the machining outcomes with the help of existing models and validate the experimental outcomes. Support vector machine with radial basis function emerged out as the best approach in predicting the process outcomes. It is also perceived that spark-on time is the most dominating input process variable.

Purpose The electric discharge machining (EDM) involves electrons discharged from the electrode and machining progresses due to the removal of the material from the component. This a thermal-based machining process primarily used for hard to machine components with conventional methods. This process is used to make intricate cavities and contours. The fabricated part is the replica of the tool material with high surface finish and good dimensional accuracy. This study aims to evaluate the comprehensive effect of process parameters on electric discharge machining of maraging steel. Design/methodology/approach Multiple criteria Decision making (MCDM) techniques are used to select the best parameters by comparing several responses to achieve the desired goal. There are different MCDM techniques available for optimization of machining parameters. In the current investigation, multi-objective optimization by data envelopment analysis based ranking (DEAR) approach was used for machining Maraging C300 grade steel. Findings The Taguchi L9 runs were planned with process parameters such as current (Amp), Tool diameter (mm) and Dielectric pressure (MPa). The effect of process parameters on the responses, namely, material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) were evaluated. High MRR is found at 15 A current, 14 mm tool diameter and dielectric pressure of 0.2 MPa. Optimum process parameters experiment showed reduced crack density. Originality/value An effort was made successfully to enhance the responses using the DEAR method and establish the decision making of selecting the optimal parameters by comparing the results obtained by machining maraging steel C300 grade.

This paper is focusing on the improvement of the accuracy of WEDM process for machining the precision-die angular stainless-steel parts. The controllable parameters are studied and analyzed by using Response Surface Method technique with respect to the responses of dimensional accuracy and surface quality. Then, these models are optimized by using the multi-objective optimization technique to realize optimal processing parameters. These optimal controllable parameters are ready for WEDM operating technicians’ use.

One of the important non-traditional machining processes is Wire Electrical Discharge Machining, used for machining difficult to machine materials like composites and inter-metallic materials. WEDM involves complex physical and chemical process including heating and cooling. Accompanying the development of mechanical industry, the demand for alloy materials having high hardness, toughness and impact resistance are increasing. The WEDM satisfy the present demands of the manufacturing industries such as better finish, low tolerance, higher production rate, miniaturization etc. The consistent quality of parts being machined in WEDM is difficult because the process parameters cannot be controlled effectively. The problem of arriving at the optimum levels of the operating parameters has attracted the attention of the researcher and practicing engineers for a very long time. The objective of the present study was to experimentally investigate the effects of various Wire Electrical Discharge Machining variables on Surface Roughness and Material Removal Rate of AISI 1045 using ANOVA method. Taguchi’s L18 Orthogonal Array was used to conduct experiments, which correspond to randomly chosen different combination of process parameters: wire type, pulse on time, pulse off time, peak current, servo voltage, wire feed rate, flushing pressure each to be varied in three different levels. The surface roughness and material removal rate were selected as output responses for the present investigation. The effect of all the input parameters on the output responses have been analyzed using analysis of variance (ANOVA). The effect of variation in input parameters has been studied on the output responses. Plots of S/N ratio have been used to determine the best relationship between the responses and the input parameters. In other words, the optimum set of input parameters for minimum surface roughness and maximum material removal rate were determined. It has been found that wire type, pulse on time are most significant factors for surface roughness and wire type, pulse on time, pulse off time, wire feed rate are most significant factors for material removal rate. Keywords: Input Parameters, Wire Electric Discharge Machining, ANOVA, Taguchi

This paper considers the technology of electrical discharge machining of steel friction pairs and reports the results of experimental studies. Analysis of the experimental studies has shown that increasing the "anode-cathode" voltage leads to a sharp decrease in the micro-hardness of the surface layer. The study has also made it possible to determine the characteristic dimensions of the structural elements, the height parameters of surface roughness. The elemental composition of the resulting surface of a steel 15KHGN2TA sample differs from the composition of coatings and the surface layers of samples modified by electrical discharge machining involving various electrodes. Under the "anode-cathode" system operation mode, a thin layer of coating with a stable modified structure forms on the surface of the cathode due to dissipative processes. It is shown that the height of surface irregularities on sections after friction is higher than on the surface sections outside the friction flow, which is associated with the formation of a friction transfer film on the samples' surface. It was established that the interaction of friction of steel samples treated by electrical discharge machining forms a thin film on the surface of friction of steel samples, which leads to a change in the relief of surfaces with an increase in the height of the micro-protrusions, as well as the structuring of the transfer film in the direction of sliding. The effect of machining steel surfaces by electrical discharge on the wear resistance of metal-polymer tribosystem was established. The implementation of the devised technology could provide a significant increase in the wear resistance of metal-polymer tribojunctions

Diamond is a typical super-hard material with very high thermal conductivity. This makes is highly suited to heat dissipation from electronic microchips. The stability of its chemical lattice structure, however, means it has no free-electrons and a high melting point, making machining of diamond difficult. In this study, a micro-energy w-EDM (wire-Electric Discharge Machining) power source with dual-capacitance is designed for using high-frequency spark erosion to precisely cut boron-doped nano-polycrystalline diamond (B-NPD) material. The power source design consists of a dual-capacitance circuit, a programmable logic circuit (PLC), and a metal–oxide–semiconductor field-effect transistor (MOSFET). By utilizing a high-frequency switching dual-capacitance circuit, each capacitor has enough charge/discharge time to create a micro-energy pulse train of uniform iso-pulse on-time (τon) and iso-pulse peak current (Ip). Material removal occurs rapidly so that micro-quantities of diamond are readily removed to reduce the probability of thermal damage and graphitization. The technique allowed successful machining of a highly consistent plate-finned diamond heat-sink array and trapezoid-pillar diamond heat-sink array. Furthermore, manufacturing using the designed low-energy power-source is highly efficient. To estimate machining efficiency in terms of the content of charge per unit volume per unit of time in diamond cutting, “Charge Density (CD)” is proposed and examined as an evaluation criterion. The following are all discussed in detail: work frequency, work capacitance, wire-electrode number and short-circuiting percentage, heat-erosion on fins of different thicknesses, and fin efficiency.

Various novel 3D micro machining technologies were researched and developed for silicon micro mechanical system fabrication. Micro EDM is one of them. The material removal mechanism is thermal sparking erosion and is completely independent with regards to the crystalline orientation of silicon, therefore there is no orientation constraint in processing the complex 3D geometry of silicon wafers. As thermal sparking implied, the process features local area high temperature melting and evaporating, and this characteristic has an adverse side-effect on the sparked surface integrity. One important concern is the generation of micro cracks, which would provide an adverse effect on the fatigue life of the micro feature element made of silicon. For this consideration, in this paper, with the experiment and SEM picture analysis approach, the author explored the micro crack generation characteristics on mono crystalline silicon wafers under micro EDM with available sparking energies and on the different crystal orientation surface machining. The generation of micro cracking is not only related with the sparking energy but also related with the crystalline orientation. The {100} orientation is the strongest surface to resist crack generation. For a strong-doped P type silicon wafer, there exists a maximum crack energy threshold. If single sparking energy is over this threshold, micro cracks unavoidably would be generated on any orientation surface. Two types of chemical etching post processes that can remove cracks on sparked surfaces are also tested and discussed.

This paper studies the application of a path analysis approach to model a wire electrical discharge machining (WEDM) process for investigating the relationships between its different process parame...

In electrical discharge machining, the formation of the modified surface layer depends on the physicochemical properties of the anode and cathode and the machining conditions. Experiments show that the mass transfer and coating thickness decrease with increase in thermal conductivity and decrease in melting point of the anode and cathode. The mass transfer and state of the modified surface are also impaired by increase in energy of the generator pulses and increase in roughness of the machined surface. These data are fundamental in selecting electrode materials and creating metal coatings with specified functional properties.

A comparative heat transfer performance of an internally grooved anodized thermosyphon with eco-friendly refrigerants is presented in this study. Thermosiphons are fabricated with 50 numbers of axial micro-grooves having a width of 500 μm and a depth of 550 μm that is formed using an electrical discharge machining process. The micro-grooved surface was then anodized and characterized using SEM as well as DSA 25 drop shape analyzer. Later, the heat transfer performance of non-anodized grooved thermosyphon is studied by varying fill ratio (20-80 %), inclination angle (0-90°), and heat inputs (5-50 W). The heat transfer coefficient of the thermosyphon is improved by anodization by 20.9 %, 17.2 %, and 18.1 %, respectively, with R717, R134a, and R600a at optimum circumstances (30 % fill ratio and 60° inclination angle). Due to the performance enhancement and zero global warming potential of R717, an anodized surface with the same is recommended for a wide range of heat transfer applications.

High-intensity electrical discharges are used in the unconventional technique known as electrical discharge machining (EDM) to machine metals of any hardness. Due to their extraordinary conductivity and strength, carbon nanotubes (CNTs) have recently been explored in EDM too. However, material removal with CNT yarn (CNTY) has not been studied thoroughly. This work advocates the use of a pristine CNTY as an EDM tool. The feasibility is examined through characterization and material removal experiments. The measurements show that the CNTY ( 100 mu m) multi-ply tools extend tool life and, therefore, machining time by more than 14 s in the air and nearly 2.5 s in the oil. Other factors that restrict machining include intensified discharges and the shielding effect of the carbide layer formed on the workpiece.

This study developed an energy-enhanced (ee)-micro-electric discharge machining (EDM) system for preparing nano-tungsten (nano-W) colloids. This system enables spark discharge using tungsten wires immersed in deionized water, to produce nano-W colloids. Compared with the chemical preparation method, the processing environment for preparing colloids in this study prevented nanoparticle escape. Among the nano-W colloids prepared using the ee-micro-EDM system and an industrial EDM system, the colloid prepared by the ee-micro-EDM system exhibited a more favorable absorbance, suspensibility, and particle size. The colloid prepared by the ee-micro-EDM system with a pulse on time and off time of 10–10 μs had an absorbance of 0.277 at a wavelength of 315 nm, ζ potential of −64.9 mV, and an average particle size of 164.9 nm. Transmission electron microscope imaging revealed a minimum particle size of approximately 11 nm, and the X-ray diffractometer spectrum verified that the colloid contained only W2.00 and W nanoparticles. Relative to industrial EDM applications for nano-W colloid preparation, the ee-micro-EDM system boasts a lower cost and smaller size, and produces nano-W colloids with superior performance. These advantages contribute to the competitiveness of the electrical spark discharge method in the preparation of high-quality nano-W colloids.

Electrically conductive zirconia tungsten carbide composites are attractive materials for manufacturing precision components by electrical discharge machining due to their high strength, toughness and electrical conductivity. In this study, nanocomposite ceramics with a ytterbia samaria co-stabilized zirconia 1.5Yb-1.5Sm-TZP matrix and 24–32 vol.% tungsten carbide dispersion were manufactured by spark plasma sintering (SPS) at 1400 °C for 15 min at 60 MPa pressure. The materials exhibited high strengths of 1300–1600 MPa, a moderate fracture resistance of 6 MPa√m and an ultrafine microstructure with grain sizes in the 150 nm range. Scanning electron microscopy and RAMAN spectroscopy revealed the in situ formation of carbon during the SPS process and carbon formation scales with tungsten carbide content, and this apparently impedes bending strength.

It is well known that electrical discharge machining can be used in the processing of nonconductive materials. In order to improve the efficiency of machining modern engineering materials, existing electrical discharge machines are constantly being researched and improved or developed. The current machining of non-conductive materials is limited due to the relatively low material removal rate and high surface roughness. A possible technological improvement of electrical discharge machining can be achieved by innovations of existing processes. In this paper, a new approach for machining zirconium oxide is presented. It combines electrical discharge machining with assisting electrode and powder-mixed dielectric. The assisting electrode is used to enable electrical discharge machining of nonconductive material, while the powder-mixed dielectric is used to increase the material removal rate, reduce surface roughness, and decrease relative tool wear. The response surface method was used to generate classical mathematical models, analyzing the output performances of surface roughness, material removal rate and relative tool wear. Verification of the obtained models was performed based on a set of new experimental data. By combining these latest techniques, positive effects on machining performances are obtained. It was found that the surface roughness was reduced by 18%, the metal removal rate was increased by about 12% and the relative tool wear was reduced by up to 6% compared to electrical discharge machining with supported electrode without powder.

Electrical discharge machining (EDM) is very essential unconventional electro-thermal machining process to machine the contour profile of hard materials in modern production industries. The liquid dielectric fluid has been replaced by the gas and minimum quantity of liquid mixed with gas (gas-mist) to encourage the green machining processes. The various gases and gas-mist have been used as the working fluid in dry and near-dry EDM respectively. The research-contextual, various dielectric fluids, sustainable and innovative developments, process parameters, machining characteristics, and optimization techniques applied in various dry and near-dry EDM have been illustrated through an extensive literature survey. Future research opportunities in both dry and near-dry EDM have been summarized to promote eco-friendly EDM research activities.

The electrical discharge machining (EDM) process is mostly used in conditions that complex and intricate shapes need to be machined on very hard metals. However, the process leaves behind some undesirable properties such as high surface roughness, rough topography, high residual tensile stresses, micro-cracks, heat-affected zone (HAZ), and recast layer. This paper investigates the effects of different output parameters on the properties listed above. The input parameters studied include current, pulse-on time, and the type of dielectric; and the material being machined is AISI 1045 steel. Results show that the deionized water improved the output variables in EDM. The use of deionized water as the dielectric, not only improved the machined surfaces’ topography but also lowered the micro-cracks and HAZ thickness. The experiments also show how the pulse-on and current time affect the outcome of EDM machining of AISI 1045 steel.

Due to advances in power electronics and high-frequency process control, the technology of electrical discharge machining (EDM) has received a decisive technological boost in the last two decades to increase the achievable removal and cutting rates and to minimize the thermally influenced surface zone. At the same time, wire electrical discharge machining in particular has always been characterized by high achievable geometrical accuracy. In addition, a cup-shaped surface structure is formed in EDM as a result of the individual discharge points, which can offer targeted optimization potential with regard to tribological properties in rolling-sliding contacts. For this reason, the objective of this report is the knowledge of the contact fatigue strength of eroded surfaces in comparison to a ground reference with a focus on tribological contact conditions typical for gears.

In this study, wire electrical discharge machining of aluminium matrix composites has been experimentally investigated. A metal matrix composite Al/Al2O3/22 p has been machined at various combinati...

A substantially developed machining process, namely wire electrical discharge machining (WEDM), is used to machine complex shapes with high accuracy. This existent work investigates the optimization of the process parameters of wire electrical discharge machining, such as pulse on time ( Ton), peak current ( I), and gap voltage ( V), to analyze the output performance, such as kerf width and surface roughness, of AA 4032–TiC metal matrix composite using response surface methodology. The metal matrix composite was developed by handling the stir casting system. Response surface methodology is implemented through the Box–Behnken design to reduce experiments and design a mathematical model for the responses. The Box–Behnken design was conducted at a confident level of 99.5%, and a mathematical model was established for the responses, especially kerf width and surface roughness. Analysis of variance table was demarcated to check the cogency of the established model and determine the significant process. Surface roughness attains a maximum value at a high peak current value because high thermal energy was released, leading to poor surface finish. A validation test was directed between the predicted value and the actual value; however, the deviation is insignificant. Moreover, a confirmation test was handled for predicted and experimental values, and a minimal error was 2.3% and 2.12% for kerf width and surface roughness, respectively. Furthermore, the size of the crater, globules, microvoids, and microcracks were increased by amplifying the pulse on time.

Electrical discharge machining (EDM) is a well-known process, which is distinct from conventional machining methods thermal machining principle not susceptible to materials hardness and therefore is mainly used for difficult-to-cut materials. EDM milling is a relatively new method to machine complex geometries by using standard shape, cylindrical, rotary electrode. This method with some limitations of small radius of corners and edges can be used instead of the complex die-sinking electrodes and exclude electrode milling step from the production chain. Layer-by-layer machining strategy is typically used in EDM milling, while the influence of such a crucial parameter as the layer thickness to the machining conditions is barely addressed in the process optimization. The current work investigates in the wear pattern during EDM milling in order to optimize machining strategy and therefore to achieve higher shape precision and minimized milling time. Correlations in electrode wear pattern are investigated after EDM drilling, EDM milling, and electrode dressing. Geometries of the machined cavities are presented and analyzed. Through all investigations derived the conditions and optimization principles for the thickness of the machining layer. Electrode diameter, electrode type, and the process gap, as an outcome of servo control and open voltage, are considered. Finally, new correlations and machining strategy recommendations are proposed based on the obtained knowledge.

Bacterial contamination is among the major issues that occur in surgical instruments and biomedical implants. Bacterial adhesion to surgical instruments and bioimplants form a biofilm that causes microbial infection. Various surface texturing methods are being developed to change the surface properties for reducing the adhesion and colonization of bacteria. Hierarchical structure with dual-scale (micro-nano) surface roughness over materials counters bacterial growth and its spread. In this investigation, WEDM (wire electrical discharge machining) process is adopted to generate hydrophobic surface over Ti6Al4V due to its wide application in the biomedical field. The objective of this work is to evaluate the wettability and antibacterial property of fabricated curved microarray structure over Ti6Al4V. The obtained result shows that the hierarchical structure with dual-scale surface roughness increases the hydrophobicity as compared to non-hierarchical structure. E-coli was selected for bacterial adhesion investigation because this bacterial strain is very common on surgical instruments and bioimplants. The antibacterial investigation reported that colony-forming unit (CFU) of E-coli reduced from 1200 CFU for as received surface to 96 CFU for curved microarray structure.

This paper develops a new method to restrain the fracture of monocrystalline silicon machining in EDM (Electrical discharge machining) through controlling the topography of single discharge crater....

At present, the production of micro parts and components with characteristic sizes ranging from micron to millimeter mainly relies on micro machining technology, but the dimensional size of micro tools (including micro cutting tools, micro grinding tools, and microelectrodes) involved in micro machining is ultra small and made of super hard material like cemented carbide and polycrystalline diamond, which makes the preparation of ultra small micro tools have become the main bottleneck restricting the development of micro machining technology. The non-contact nature of electrical discharge machining (EDM) process makes it more competent in fabricating micro tools with relatively high efficiency and low cost; especially the wire electrical discharge grinding (WEDG) invented in 1985 provides a new approach and direction to fabricate micro tools; following this trend, numerous new design requirements and theoretical concepts of EDM-based processes utilized in fabricating micro tools have been proposed and studied successively, but, very few studies have been proceed from an integrated perspective. To address the gap, this study provides a comprehensive and well-arranged literature survey of the advancements made in the fabrication of micro tools using various EDM-based methods to date along with an insightful discussion on the science and application of EDM process. The critical factors influencing process performance, different numerical models, limitations, as well as possible future research direction and development in the field of micro tools fabricated by various EDM-based methods are identified and reviewed. This article is expected to help the researchers in identifying the existing gaps and contributing towards making EDM-based processes more competent in catering the trend of parameterized and non-standardized fabrication of ultra small micro tools.