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High electrical conductivity and low thermal conductivity are beneficial for the electrical discharge machining performance of ceramics. In this work, B 4 C–TiB 2 composites were prepared by spark plasma sintering of B 4 C–TiC–B powder mixture. The chemical reaction between TiC and B, together with subsequent selective matrix grain growth, expelled small in-situ generated TiB 2 grains to form conductive interlayers around large B 4 C grains. The unique microstructure significantly enhances the electrical conductivity of B 4 C–TiB 2 composites, especially at low TiB 2 content, while the ultrafine in-situ formed TiB 2 grains endow the composites with low thermal conductivity. The effects of TiB 2 content on the microstructure, mechanical properties, thermal & electrical conductivity of the composites were investigated. B 4 C–20 vol% TiB 2 composite exhibits excellent comprehensive performance, including a relative density, Vickers hardness, flexural strength, fracture toughness, room electrical and thermal conductivity of 98.6%, 28.15 GPa, 656 MPa, 5.46 MPa⋅m1/2, 1.08 × 105 S/m and 19.37 W/m⋅K, respectively. [ABSTRACT FROM AUTHOR]

Electrode wear (EW) during the electrical discharge machining (EDM) process determines surface topography accuracy. In this paper, an automatic evaluation method is proposed by integrating image segmentation and three-dimensional (3D) registration (IS-3DR) to evaluate the EW more accurately. First, the original two-dimensional (2D) image and the 3D point cloud were derived from a laser microscope image, and the 2D worn area was determined by automatic recognition and segmentation. Then, 3D registration between the 3D point cloud and the 2D worn area was utilized to qualitatively define the 3D EW area. Finally, the 3D EW volume was obtained quantitatively through micro-element calculation based on the 3D EW area and the shape fitting of the original electrode. The results showed that the intersection over union (IOU) of image segmentation was higher than 97.5%, compared with the manually labeled image segmentation method. Compared with IS-3DR, the random error of the two-dimensional evaluation method could reach 27.08%, indicating higher reliability and stability of IS-3DR. The EDM experiment was carried out to investigate the effect of parameters on EW. The experimental results showed that the effects of current and servo voltage were most significant, followed by pulse width. [ABSTRACT FROM AUTHOR]

In electrical discharge machining (EDM), it is a much more effective method to improve working characteristics by changing the input process of pulse energy. However, it has not been investigated enough whether pulse form is the most adequate or not. In this study, the effect of superimposed pulse current waveform and its parameter on surface integrity was investigated. The surface topography, roughness, microstructure, white layer thickness, and residual stress were analyzed and discussed. Moreover, the material removal rate was also tested and compared. The results show that with the backward movement of the superimposed pulse current, the material removal rate and surface roughness decrease, while the white layer thickness, residual stress, and surface defects increase. The current waveform has little influence on microstructure. Under the same pulse discharge energy and pulse-on time, the samples processed by superimposed pulse current waveform instead of rectangular current waveform can obtain a thinner white layer, lower residual stress, fewer surface defects, and high surface roughness. With the increase of superimposed pulse-on time and current, the surface integrity becomes worse due to the increase of pulse energy. This paper provides a guide to the development and selection of EDM discharge current waveforms in EDM. [ABSTRACT FROM AUTHOR]

The exploration of Electrical Discharge Machining (EDM) with coated electrodes represents a relatively novel research avenue, thereby yielding limited published research outcomes. The choice of coating material plays a pivotal role in the EDM machining process, and alterations in coating materials can directly influence the adjustment of technological parameters in EDM. Consequently, research dedicated to optimizing these technological parameters for EDM employing coated electrodes is of paramount importance, and it promises to advance the practical implementation of this cutting-edge technique. In this study, we systematically investigate the technological parameters for EDM employing a copper-coated aluminum electrode in the context of Ti-6Al-4V machining. Our research outcomes are framed within a multi-objective optimization paradigm, with a focus on Material Removal Rate (MRR) and Surface Roughness (SR) as vital quality indicators. To address the intricate multi-objective optimization challenge, we have harnessed the combined power of the Taguchi methodology and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The amalgamation of these techniques enables us to navigate the complexities of EDM parameter optimization effectively. Our findings reveal that the most favorable process parameters entail a configuration of U=40V, I=40 A, Ton=1000μs, resulting in an MRR of 0.028mg/min and an SR of 7.56μm. These optimized parameters exemplify a substantial enhancement in machining efficiency and surface quality when utilizing coated electrodes. Moreover, our study scrutinizes the quality of the machined surface under optimal conditions with coated electrodes. We employ the TOPSIS method as a proficient solution for this endeavor, offering a straightforward approach to this intricate calculation process. [ABSTRACT FROM AUTHOR]

This study investigates the performance of deep cryogenically treated brass (CuZn25Al5) electrodes in the die-sink EDM process. Two different cryogenic treatment durations, 6 h and 12 h, were applied to 8 mm diameter electrodes, and their effects were compared to untreated electrodes. The machining tests were conducted under moderate and aggressive conditions. In the machining tests, the 6-h cryo-treated electrode exhibited a 16.8% increase in material removal rate (MRR) under moderate conditions and a 19.7% increase under aggressive conditions compared to the reference electrode. The 12-h cryo-treated electrode showed similar MRR values to the reference electrode but improved tool wear resistance by 9.4% under moderate conditions. The kerf angle was minimized, indicating better hole verticality, in the 6-h cryo-treated electrode group. The improvement in machining performance was attributed to the enhancement in electrical conductivity of the electrodes, which increased by 28% for the 6-h cryo-treated electrode and 20% for the 12-h cryo-treated electrode. X-ray diffraction (XRD) analysis revealed shifts in peak positions and possible phase transformations due to cryogenic treatment. Surface roughness measurements showed improved surface conditions in the cryo-treated electrodes under aggressive conditions. The results indicate that cryogenic treatment enhances MRR, reduces tool wear, and improves surface quality in die-sink EDM. These improvements are attributed to increased electrical conductivity and changes in the internal structure of the brass electrode. [ABSTRACT FROM AUTHOR]

Electrical discharge drilling of blind holes has been a challenging task due to the inherent difficulties in removing debris from the discharging gap. This paper investigates the working mechanism and effects of new stepped electrodes which are used in conjunction with injection flushing in drilling deep blind holes. A series of theoretical simulations and comparative experiments were conducted using cylindrical electrodes and two types of stepped electrodes. Pulse waveforms were captured to analyse the discharge status. Surface topography and machining quality were analysed using scanning electron microscope (SEM) images. The machining performance was evaluated by studying the material removal rate (MRR) and tool wear ratio (TWR). Experiment results show that internal flushing caused the debris to circulate in the machining zone and led to abnormal discharges, disrupting the formation of the plasma channel. The MRR was increased by 75% and 82% when using cylindrical electrodes with pressures of 120 psi and 40 psi, respectively. In contrast, the MRR with injection flushing was about 80% of that without injection flushing when using stepped electrodes. Regardless of the type of electrode, the application of injection flushing resulted in the increase in the maximum effective machining depth. [ABSTRACT FROM AUTHOR]

Micro electrical discharge drilling (ED-drilling) is a machining method used to make micro holes in hard-to-cut materials. The RC-discharge generator is often used because it creates a short and strong discharge spark. However, this method has issues such as current oscillation between tool electrode and workpiece, causing polarity changes that increase tool wear, and a low material removal rate due to long spark delay time. Furthermore, micro ED-drilling results in a large taper angle due to second discharge sparks created by debris in the narrow gap. To address these issues, the effect of adding graphite powder to the working fluid was studied. The graphite powder in kerosene created a bridge effect that reduced tool wear and taper angle, while improving MRR and surface roughness. The electrical conditions were not changed, and the machining process was improved by only altering the working fluid without modifying the existing system. [ABSTRACT FROM AUTHOR]

A global manufacturing community is dedicatedly striving to implement the concept of NetZero in precision cutting of difficult-to-machine materials, specifically, Inconel 617 (IN617) with due consideration to environmental protocols. The fast strain hardening issue of the said alloy during conventional processing rationalizes the application of electric discharge machining (EDM). However, EDM has been criticized for its high energy consumption and limited cutting efficiency. Moreover, conventional dielectric (kerosene) employed in EDM has drastic environmental and operator health concerns. To address the abovementioned issues, waste cooking oil (WCO) has been employed in this study which enhances the reusability of resources and minimizes the cost of the dielectric. Making the process sustainable is imperative along with continuously escalating scarcity of engineering resources. Therefore, the potential of shallow and deep cryogenically treated electrodes (SCT and DCT) has been comprehensively examined against nanofilled WCO to achieve the aforementioned objective. Three different concentrations of powder (Cp) and surfactant (Cs) to uplift the machining responses are investigated through a detailed parametric experimental design. Core machining factors such as material removal rate (MRR), surface roughness (SR), and specific energy consumption (SEC) are examined through optical and electron microscopy studies and 3D surface profilometry. Hereafter, machining factors are modelled using the artificial neural network (ANN) technique. An exceptional improvement of 80%, 25.3%, and 75.16% has been achieved in MRR, SR, and SEC respectively using nanopowder-mixed WCO against SCT brass compared to the responses' values obtained against conventionally used kerosene. Furthermore, compared to kerosene, the maximum CO2 reduction of 79.97 ± 11.2% is achieved with WCO. [ABSTRACT FROM AUTHOR]

This research paper explores the impact of electrical discharge machining process parameters, including current, pulse‐on time (Ton), and pulse‐off time (Toff), on the material removal rate (MRR) and surface roughness (SR) during the fabrication of aluminum silicon dioxide (Al7075–SiO2) composites. The Al7075–SiO2 composites were produced through stir casting, incorporating 10% by weight of SiO2 reinforcements with an average particle size of 54 µm. To systematically investigate the process parameters' effects, Taguchi's L9 orthogonal array was implemented in the design of experiments. Subsequently, the experimental data underwent analysis of variance (ANOVA) for thorough analysis. The response table for MRR and SR demonstrated that the current significantly influenced both responses (MRR and SR). The ANOVA results provided valuable insights into the percentage contribution of each parameter to the responses. Through the analysis, the optimal control variable settings for achieving the highest MRR were identified as a current of 3 A, a pulse‐on time of 1500 µs, and a pulse‐off time of 1 µs. Conversely, to attain the lowest SR, the ideal control variable settings were determined to be a current of 1 A, a pulse‐on time of 500 µs, and a pulse‐off time of 1 µs. Results also suggest that the error was within admissible range of 5% and the percentage contribution of the current (70.19%) had the largest effect on MRR. [ABSTRACT FROM AUTHOR]

Dense silicon carbide (SiC) composites with 0–30 vol% (ZrN-TiB 2) were fabricated by using liquid phase spark plasma sintering at a relatively lower sintering temperature (1800 °C) and shorter holding time (5 min). The effects of co-addition of ZrN and TiB 2 on densification, mechanical properties, and electrical conductivity of SiC ceramics were investigated. The reinforcement significantly enhanced density of sintered composites, while the phase analysis and microstructure confirm the suppression of β→α phase transformation in the SiC matrix. The fracture toughness ranged from 4.1 to 4.6 MPa·m0.5, hardness from 19.5 to 20.3 GPa, and electrical conductivity from 4.85 ×101 to 1.25 ×103 (Ω·cm)−1. Incorporating conductive reinforcements and nitrogen additives enhanced electrical conductivity. Successful wire-EDM cutting of SiC-ZrN-TiB 2 composites demonstrate the feasible alternative to conventional machining of non-oxide ceramics with a maximum material removal rate of 8.54 mm2/min. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding and optimizing mechanical manufacturing processes is essential for sustainable industrial development. Among unconventional machining methods, electrical discharge machining (EDM) distinguishes itself by its capability to remove material through successive electrical discharges submerged in a dielectric fluid. EDM encompasses intricate phenomena influenced by machine parameters, dielectric choice, and the materials involved. Unlike conventional machining, EDM operates with the tool electrode in close proximity to, but not in physical contact with, the workpiece, achieving material removal through localized overheating. This study focuses on monitoring EDM phenomena during the machining of AISI H13 steel, exploring variations in machining parameters and electrode materials (electrolytic copper and graphite). Acoustic emission (AE) signals and machine learning (ML) are employed for experimental characterization and data analysis. Spectral entropy is applied to AE signals, quantifying inherent signal uncertainty. The findings reveal remarkable accuracy (97.7%) and underscore the superior control achieved with graphite electrodes in managing machining phenomena compared to electrolytic copper electrodes. [ABSTRACT FROM AUTHOR]

When utilizing electrical discharge machining (EDM) for processing, the processing efficiency and quality will be significantly impacted, if the electrocorrosion residues in the gap flow field cannot be discharged in time. Numerical simulation is considered an effective means to simulate the flow field of EDM gaps. Based on simulation, this study investigates the processing time, depth, current, and dielectric (kerosene, water, and sunflower seed oil), on the movement of electrocorrosion residues within the dielectric. The simulation results demonstrate that an increase in processing time, current, or depth leads to a decrease in the escape rate of corrosion residues from the discharge gap. Compared with kerosene and sunflower seed oil, water has a higher residue escape rate, but the actual processing effect is not ideal. The escape rate of sunflower seed oil at any time was higher than that of kerosene,the highest was higher than 25%, and the average was higher than 22.21%. Sunflower seed oil can be used as a renewable dielectric to replace kerosene. Subsequently, verification experiments are conducted based on simulation results that demonstrate that the discrete phase model (DPM) fluid simulation exhibits excellent coupling with actual processing conditions. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) and electrochemical machining (ECM) are two typical unconventional processing methods for fabricating difficult-to-cut materials. Surfaces machined by EDM generally contain recast layers, whereas ECM owns low machining accuracy. EDM–ECM hybrid machining can suppress their shortcomings and combine their advantages. The working fluid is vital to realizing the combination of EDM and ECM. Conventional EDM–ECM hybrid machining commonly adopts water-based fluid, which can meet the requirements of hybrid micro-, small-hole, and milling machining. However, water-based fluid hardly maintains the stable sinking EDM that possesses a relatively large machining area and a closed machining gap; thus, it is unsuitable for hybrid sinking machining. The lack of appropriate fluid seriously hinders the promotion and application of EDM–ECM hybrid sinking machining. Here, a novel bi-characteristic fluid water-in-oil (W/O) nanoemulsion that combines electrical insulation and conductive properties is proposed, and an electrical discharge and electrochemical hybrid sinking machining (EDCSM) using W/O nanoemulsion is developed. The composition parameters (salt concentration, water content) of the W/O nanoemulsion and electric parameters (open voltage, pulse frequency) are investigated. Material removal mechanisms are also discussed. Results show that the material removal mechanisms and the strength of EDM and ECM in EDCSM can be manipulated by adjusting the investigated crucial parameters. EDCSM using W/O nanoemulsion can achieve a high-quality machined surface and good machining accuracy, demonstrating its superiority and potential in the field of sinking machining. [ABSTRACT FROM AUTHOR]

The electrode is an important component of electrical discharge machining (EDM), playing an important role in machining efficiency, surface quality and geometric accuracy. In this work, a new method combining equal channel angular pressing (ECAP), deep cryogenic treatment (DCT) and aging treatment (AT) was proposed. The ultrafine-grained Cu-0.5%Cr electrode has high strength and high electrical conductivity through this process, so as to improve the machining characteristics in EDM. The surface roughness (Ra), the workpiece corner sharpness (WCS), and the electrode wear rate (EWR) were investigated. The results showed that the treatment of the electrode with 4 passes of ECAP + DCT (12h) + AT (550℃ × 1h) can reduce the EWR and WCS by 63.6% and 49.7%, respectively. It also contributed to the enhancement of electrical conductivity and microhardness of the Cu-0.5%Cr electrode by ECAP + DCT + AT. Meanwhile, it revealed that the processing of the Cu-0.5%Cr electrode resulted in the excellent machined surface quality (Ra was reduced by 53.5%) which was confirmed by the results of the scanning electron microscopy (SEM). The ultrafine-grained Cu-0.5%Cr electrode with an excellent combination of strength and electrical conductivity has an outstanding EDM performance. [ABSTRACT FROM AUTHOR]

Surface formation in electrical discharge machining (EDM) involves melting, evaporation, re-solidification and crater overlapping. However, almost all existing models concerning surface formation in EDM only consider the thermal process and ignore hydrodynamic phenomena during machining. Herein, a novel three-dimensional thermo-hydraulic coupling model incorporating the arbitrary Lagrangian–Eulerian scheme was developed to address the above problem. The model comprehensively considered the surface deformation caused by melt flow, temperature-dependent material properties, phase changes and the effects of practical forces on melt pools to simulate surface formation on an anodic workpiece at a discharge current of 2 A. Simulation results demonstrate that during single-pulse discharge, molten material flowed radially to the crater periphery. The radial melt flow was driven by evaporation recoil pressure and thermocapillary force. The effect of evaporation recoil pressure on melt flow was gradually counteracted by that of surface tension after discharge ignition, and thermocapillary force became the dominant factor that maintained the existence of bulges around craters. During multiple discharges, the bulges generated by different discharges underwent superposition owing to the flow of molten material and subsequently formed surface peaks. The simulation results also provide the measurements of crater diameter, surface roughness and recast layer thickness, which are consistent with experimental results. The proposed modelling method can provide a useful reference for further investigations on surface integrity in EDM with minimal computing resource requirements. • A novel 3D thermo-hydraulic coupling surface formation model for EDM was proposed. • The effects of evaporation recoil pressure and thermocapillary force on melt pool dynamics in EDM were investigated. • Simulation results of multiple discharges show good consistency with experiment results concerning surface properties. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) method is an innovative method for the fabrication of structured array surfaces on binderless tungsten carbide (WC) which is a typical embossing mold material, compared to traditional machining methods. To improve the convenience of electrode replacement and the fabrication efficiency of the structured array, a novel self‐assembly ball electrode is innovatively developed. The feasibility of machining binderless WC with a self‐assembly ball electrode was studied and its effect on profile deviation analyzed. Furthermore, the discharge condition's effect on surface roughness, material removal rate (MRR), and tool wear ratio (TWR) was investigated. The microstructure, phase structure, and element distribution of binderless WC caused by EDM were characterized by Raman spectroscopy, scanning electron microscopy, and energy dispersive x‐ray spectroscopy. The results indicated that the maximum profile deviation of the different random structured arrays was about 3.7 μm. The surface roughness of all structured arrays was below 1 μm. The maximum TWR was about 0.008 mm3/min. Besides, the binderless WC surface after EDM presented strong D and G carbon peaks, which means the precipitation and transformation of the WC phase during the discharge process. Finally, different kinds of self‐assembly ball electrodes are developed and used to fabricate the lens array structures on binderless WC. The fast fabrication of the micro‐lens array surfaces in different arrangements sheds some light on the design and manufacturing of other functional structured surfaces. [ABSTRACT FROM AUTHOR]

Electrical discharge machining is a versatile machining technology that uses precisely directed sparks within the range of the dielectric fluid and between the electrodes to make electrically conductive products. The influence of different processing parameters on diverse metal matrix composites, including new reinforcing elements (silicon carbides, aluminium oxides and nitrides), and the modifications that occur as a consequence of each of these components are discussed in this article. As a result, new reinforcing materials and ways for optimising performance have emerged. The goal of this study is to provide analysts with research data that will allow them to effectively use EDM principles and, more particularly, to investigate process characteristics in order to enhance the process of advanced PMEDM operation. [ABSTRACT FROM AUTHOR]

The titanium alloy Ti6Al4V ELI (grade 23) is widely used in biomedical industry because of its engineering attributes. However, it requires surface modifications and has processing challenges because it is difficult to machine nature. Therefore, powder-mixed electric discharge machining process is commonly applied to simultaneously machine the material and carry out surface treatment. The performance of the process is limited by both low cutting efficiency and the formation of a rough surface. In this regard, the current study evaluates SiC powder-mixed electric discharge machining of Ti6Al4V ELI using a range of tool materials such as copper, brass, graphite, and aluminum along with a comprehensive list of process parameters. The surface roughness parameters involving arithmetic roughness, the average peak-to-valley distance, and the highest peak-to-deepest valley distance along with material removal rate are comprehensively studied. Taguchi design of experiments L16 orthogonal array is used to study the process performance with parametric effect analysis, parametric significance analysis, and surface morphological analysis with a scanning electron microscope. Furthermore, the experimental results are optimized against a multi-response optimization matrix using grey relational analysis approach. An optimal compromise between surface attributes and cutting efficiency is identified by Al electrode, pulse current of 14 A, pulse on time of 75 µs, pulse off time of 75 µs, and negative polarity parametric conditions. [ABSTRACT FROM AUTHOR]

Metallic glass offers several advantages, including high strength, corrosion resistance, and low coercivity. In precision machining fields like optical devices, medical devices, and micro-electromechanical systems, Ti-based metallic glass offers more advantages than Fe- and Zr-based metallic glass. However, its current machinability poses a challenge in meeting the requirements of precision metallic glass parts. To obtain the best machining performance, a thermophysical model of the EDM drilling process was established to simulate the temperature distribution on the surface of metal glass workpiece during EDM drilling. In addition, a new systematic method is utilized to calculate the characteristics of important machining holes, such as inlet and outlet overcut and inlet and outlet edge deviation. In this investigation, the maximum relative overcut and edge deviation are 8.59% and 7.23%, respectively, relative to the electrode radius. To improve the machining quality and machining stability, the slit width should be kept at an ideal value. Therefore, the recommended discharge current is 4–5 A, pulse duration is 50 μ s, and pulse duty ratio is 0.2 - 0.3 when EDM drilling of amorphous alloy. Based on this, the EDM drilling analysis method by numerical and experimental investigation for titanium-based metallic glass is put forward, which provides scientific theoretical guidance for the EDM of drilling it. [ABSTRACT FROM AUTHOR]

This work aims to optimize the machining parameters and study the effect of powder-mixed dielectric fluid on the electrical discharge machining (EDM) process. The TOPSIS method of optimization is adopted to identify the optimal machining parameters. HCHCr die steel is preferred as a machining material. Due to their hard and ductile nature, Ni, Zr, and Ni+Zr were selected as powder inclusion in dielectric fluid. An L9 array Taguchi DOE is preferred to perform the experiments with parameters like peak off time, pulse off time, and pulse current. TOPSIS study revealed that the third level of powder dielectric fluid (Ni+Zr), 7A peak current, 9 µs pulse on time, and 2 µs pulse off time were specified as the optimal condition. Pulse on time (Ton) significantly impacted metal removal rate and surface roughness while machining operation on HCHCr die steel. SEM analysis was done to find the effect of powder-mixed dielectric fluid, while EDAX analysis was done to ensure the presence of powder inclusion. [ABSTRACT FROM AUTHOR]

Aluminum alloys with 40 to 50 wt.% silicon content are potential material candidates for the manufacturing of satellite components. These materials have excellent thermal and mechanical stabilities, but machining complex components from these alloys is facing many challenges. The present study was performed on an aluminum-high silicon alloy (50–50 wt.%) with the main aim of investigating the evolution of the microstructure with particular attention to surface and subsurface damage as a result of Electrical Discharge Machining (EDM). For this purpose, the microstructure was characterized by optical and Scanning Electron Microscopes (SEM) as well as Energy Dispersive Spectroscopy (EDS) of the machined samples. The results show the existence of melted and re-solidified zone with much finer silicon particles located in a zone on the top of the machined surface where cracks were also observed. Moreover, SEM examinations showed that the cracking damage concern the primary silicon particles. Possible mechanisms, such as the thermal shock produced by rapid cooling rate of the primary silicon particles and the presence of porosities, formed during the manufacturing process, are discussed. [ABSTRACT FROM AUTHOR]

Due to different characteristics of ceramic coatings and superalloy substrates, it is impossible to balance surface quality and machining efficiency of thermal barrier coated superalloys by using constant parameters in electrical discharge machining. In this paper, an adaptive control (AC) method is studied, which can adaptively adjust discharge parameters in real time according to the change of material types. A short circuit detection method based on statistics of the duration of the current falling edge is proposed. And by combining it with voltage detection, discharge states of high resistance and low resistance can be both identified. Based on statistics and analysis of discharge waveforms under various discharge states, a detection method is studied to distinguish metals from insulating ceramics. An adjustment strategy of parameters that has higher sensitivity to insulating ceramics is proposed. It can ensure the real-time conversion of parameters and reduce the number of high-energy pulses acting on the ceramic surface. The waveforms of discharge gap measured with an oscilloscope show that the AC method can realize the conversion between low energy pulses and high energy pulses. The experimental results show that the AC method has much shorter machining time (5.1 min) compared with the method of small energy parameters (52 min) and has smaller maximum damage distance (58.4 μm) than the method of large energy parameters (89 μm). [ABSTRACT FROM AUTHOR]

Arc plasma is the heat source in electrical discharge machining (EDM), it affects the material removal and discharge crater formation directly, so it is necessary to clarify its characteristics. However, it is challenging to understand the physical mechanisms behind each pulse discharge through experimental methods, as it is a transient, multi-physical process that occurs in a very short time and small gap. In this paper, a two-temperature model was proposed to investigate the characteristics of the arc plasma and the energy distribution considering the multi-physics fields in the steady state. In this model, the electrons and the heavy species of the arc plasma were considered separately in the energy conservation equations, so that the temperature of the electrons and heavy species can be calculated separately. Besides, the velocity distribution, pressure distribution, electrical potential distribution, and diameter of the arc plasma, as well as the heat flux distribution and the energy distribution into the anode and cathode were analyzed. Then the variations in arc plasma properties and energy distribution with different discharge conditions were studied. The results showed that, at a lower discharge current, the electron temperature was higher than the heavy species temperature, which means that the arc plasma did not reach a local thermodynamic equilibrium (LTE) state under these discharge conditions. To validate the simulation results, the arc plasma was observed with a high-speed camera, and the diameter of craters on the surface of both the cathode and anode was measured with single-pulse discharge experiments. The experiment results were consistent with the simulation results. • A two-temperature model was established to study the arc plasma in EDM. • The temperature of electrons and heavy species of arc plasma was obtained. • The arc plasma did not reach the local thermodynamic equilibrium state under the given simulation conditions. • The energy distribution ratio into the anode, cathode, and dielectric were calculated, respectively. • The arc plasma characteristics and the energy distribution under different discharge conditions were studied. [ABSTRACT FROM AUTHOR]

Multiwall carbon nanotube buttressed aluminium 7075 metal matrix composite was synthesized through an amended liquid metallurgy method, which consisted semisolid stirring, ultrasonic treatment and squeeze casting. Aim was to investigate its machinability and surface morphology during electrical discharge machining. Variable machining factors were peak current, pulse‐on time and gap voltage, whereas the responses under investigation were electrode wear rate, material removal rate and average surface roughness. Results revealed electrode wear rate, material wear rate and average surface roughness increased on increasing peak current and pulse‐on time, but all these responses behaved inversely with the increase of gap voltage. Average surface roughness reduced by around 44 % on reducing the peak current from 10 A to 4 A and increasing gap voltage from 55 V to 80 V at constant pulse‐on time of 300 μs; however, it increased by around 25 % on reducing the gap voltage from 80 V to 55 V and increasing the pulse‐on time from 100 μs to 300 μs at constant peak current of 10 A. Significance of the process parameters were verified, regression models were developed and morphology of the machined surfaces was studied. Finally, multiple response optimization was conducted following grey relational approach. [ABSTRACT FROM AUTHOR]

In this study, a novel hybrid additive and subtractive manufacturing method using pulsed arc plasma (PAP-HASM) was developed to better integrate additive and subtractive processes. The PAP-HASM process is based on the flexible application of pulsed arc plasma. In this PAP-HASM method, wire arc additive manufacturing using pulsed arc plasma (PAP-WAAM) and dry electrical discharge machining (EDM) milling were used as additive and subtractive techniques, respectively; both are thermal machining processes based on pulsed arc plasma, and both are dry machining techniques requiring no working fluids. The PAP-HASM can be easily realized by only changing the pulsed power supply and tool electrodes. A key technological challenge is that the recast layer on the part surface after dry EDM milling may have a detrimental effect on the component fabricated by PAP-HASM. Here, the hybrid manufacturing method developed in this study was validated with commonly used 316L stainless steel. Preliminary experimental results showed that the PAP-HASM specimens exhibited excellent tensile properties, with an ultimate tensile strength of 539 ± 8 MPa and elongation of 46 ± 4%, which were comparable to the PAP-WAAM specimens. The recast layer on the surface after dry EDM milling has no significant detrimental effect on the mechanical properties of the parts fabricated by PAP-HASM. In addition, compared with components fabricated by PAP-WAAM, those fabricated by PAP-HASM showed significantly better surface roughness. [ABSTRACT FROM AUTHOR]

The superior engineering properties and excellent biocompatibility of titanium alloy (Ti6Al4V) stimulate applications in biomedical industries. Electric discharge machining, a widely used process in advanced applications, is an attractive option that simultaneously offers machining and surface modification. In this study, a comprehensive list of roughening levels of process variables such as pulse current, pulse ON time, pulse OFF time, and polarity, along with four tool electrodes of graphite, copper, brass, and aluminum are evaluated (against two experimentation phases) using a SiC powder-mixed dielectric. The process is modeled using the adaptive neural fuzzy inference system (ANFIS) to produce surfaces with relatively low roughness. A thorough parametric, microscopical, and tribological analysis campaign is established to explore the physical science of the process. For the case of the surface generated through aluminum, a minimum friction force of ~25 N is observed compared with the other surfaces. The analysis of variance shows that the electrode material (32.65%) is found to be significant for the material removal rate, and the pulse ON time (32.15%) is found to be significant for arithmetic roughness. The increase in pulse current to 14 A shows that the roughness increased to ~4.6 µm with a 33% rise using the aluminum electrode. The increase in pulse ON time from 50 µs to 125 µs using the graphite tool resulted in a rise in roughness from ~4.5 µm to ~5.3 µm, showing a 17% rise. [ABSTRACT FROM AUTHOR]

The study was performed to determine the optimum flushing condition for electrical discharge machining (EDM) of functional material titanium VT6 obtained by plasma cladding with a thermal cycle. Copper is used as an electrode tool (ET) to machine functional materials. The optimum flushing flows are analyzed theoretically by using ANSYS CFX 20.1 software which is also validated by an experimental study. It was observed that while machining the functional materials to adepth of 10 mm or more, the turbulence fluid flow dominates when nozzle angles are 45° and 75°, consequently drastically affecting the quality of flushing and the performance of the EDM. For the highest machining performance, the nozzles should be at an angle of 15° relative to the tool axis. The optimum flushing at deep hole EDM process minimizes the occurrence of debris deposition on tool electrodes, thus facilitating stable machining of functional materials. The adequacy of the obtained models was confirmed experimentally. It has been established that EDM of a hole with a depth of 15 mm, an intense accumulation of sludge, is observed in the processing zone. There arebuild-ups exceeding 3 mm in cross-section after EDM. This build-up leads to a short circuit and a reduction in surface quality and productivity. It has been proven that not correct flushing leads to intensive wear of the tool and a change in its geometric shape and, accordingly, to a decrease in the quality of EDM. [ABSTRACT FROM AUTHOR]

This study investigates the effect of electrolytic plasma processing on the degree of defective layer removal from a damaged layer obtained after manufacturing operations. Electrical discharge machining (EDM) is widely accepted in modern industries for product development. However, these products may have undesirable surface defects that may require secondary operations. This work aims to study the die-sinking EDM of steel components followed by the application of plasma electrolytic polishing (PeP) to enhance the surface properties. The results showed that the decrease in the roughness of the EDMed part after PeP was 80.97%. The combined process of EDM and subsequent PeP makes it possible to obtain the desired surface finish and mechanical properties. In the case of finishing EDM processing and turning, followed by PeP processing, the fatigue life is enhanced without failure up to 109 cycles. However, the application of this combined method (EDM + PeP) requires further research to ensure consistent removal of the unwanted defective layer. [ABSTRACT FROM AUTHOR]

In recently, titanium and its alloys have been used in a large number of medical implants due to their excellent biological qualities. However, infections brought on by their biological inertness have emerged as a challenging issue for clinicians across a range of specialties. On the other hand, improper use of antibiotics has increased bacterial resistance, which has made the issue of infections brought on by titanium implants worse. The preparation of implants with antimicrobial capabilities has emerged as a key research area in the effort to address this issue at its source. However, present techniques for preparing antimicrobial surfaces are pricy, ineffective, and harmful to the environment, thus cannot be used extensively in industrial manufacturing. In this study, the bionic shark skin's antibacterial rhombic surface was prepared in a single step using the WEDM processing. The samples were then described, and the outcomes were examined using XRD, FE-SEM, and EDS. By using the plate coating method and SBF immersion assays, the samples' bioactivity and antibacterial capacity were assessed. Due to the high temperature produced during the WEDM process, which enables the tool electrode to melt and metallurgically link with the titanium alloy substrate surface, the primary crystalline phase of the antibacterial surface is CuTi 2. After 1 h of incubation on the sample surface, the samples' antibacterial rate was 93%. The antibacterial property of the sample also attained an ideal 98.4% when acid etching was carried out using a 20%wt HNO 3 solution. The Ti on the sample surface had no discernible impact on the effectiveness of the antibacterial. Additionally, the simulated liquid immersion findings demonstrated that the sample pieces made using this approach exhibited good bioactivity. [ABSTRACT FROM AUTHOR]

2 wt.% TiB2 (mean particle size: 400 nm) reinforced Al 7075 metal matrix composites (MMCs) fabricated through mechanical stirring and ultrasonic agitation integrated squeeze casting process were subjected to electrical discharge machining (EDM) after determining the physical and mechanical properties. EDM was conducted with Cu electrode tools to investigate influence of machining factors, i.e. peak current (IP), pulse on time (TON) and gap voltage (VG) on the tool wear rate (TWR), material removal rate (MRR) and average surface roughness (ASR) of the machined surfaces. All the three responses increased on increasing IP and TON, but reduced on increasing VG. The machined surfaces were studied through scanning electron microscope (SEM). Significance of the EDM parameters on the individual responses were studied using analysis of variance (ANOVA) and regression models for the responses were developed using response surface method (RSM). The responses under consideration were optimized simultaneously using Taguchi embedded weighted principal component analysis (WPCA), which resulted the parametric combination of 4A (current), 100 µs (pulse duration) and 75V (voltage) was the optimal setting for the multi-criteria decision problem. Finally, the result of optimization was validated by conducting some confirmatory experiments. [ABSTRACT FROM AUTHOR]

Traditional electric discharge machining (EDM) uses a Cu electrode to machine polycrystalline diamond (PCD), but it is hampered by poor machining efficiency and quality. During this study, a Cu-Ni electrode was used to machine PCD with graphene power suspended in the dielectric. The surface properties and machining mechanism of PCD under different parameters were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The surface quality and machining efficiency were analyzed by quantifying the surface roughness (SR) and material removal rate (MRR). The results demonstrated that the MRR of the Cu-Ni electrode increased by 65% when compared with that of Cu electrode at low discharge parameters, with the MRR of Cu-Ni electrode improved by a further 87% when graphene was added to the dielectric. Raman spectroscopy and XRD analysis showed that graphitization of PCD diamond processed by the Cu-Ni electrode was greater than that of the Cu electrode, and the addition of graphene further facilitated this process. The machining efficiency and quality of PCD in EDM can be greatly improved with the use of Cu-Ni electrode and graphene suspended in the dielectric. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is widely applied for machining difficult-to-cut materials in mold and die industries. However, the major limitations associated with the EDM are low productivity and poor surface integrity of the machined surfaces. In recent years, several developments have been applied to overcome such limitations of EDM. Electrical discharge grinding (EDG) is a hybrid machining process that simultaneously involves the spark erosion action of EDM and the mechanical abrasion action of the grinding wheel for the material removal purpose. The rotating motion of the grinding wheel also contributes to the easy removal of debris particles, thereby improving the material removal. It is evident from the literature that the rotating motion of the grinding wheel enhances the flushing mechanism resulting in better performance of the process. This paper aims to present a comprehensive review of the research carried out in EDG, highlighting the result of the experimental, modeling, and optimization techniques applied in this area. Initially, the background of EDM and the need for hybrid EDM processes have been presented. Then, a few hybrid EDM processes have been discussed, addressing their advantages and limitations. Further, the concept of EDG and electrical discharge diamond grinding (EDDG) has been discussed, along with the classification of the EDDG process. Finally, this paper explores the current research status and future research perspective in the area of EDG and EDDG processes. [ABSTRACT FROM AUTHOR]

The efficiency and accuracy of conventional electrical discharge machining (EDM) are limited by the stability of the voltage between the poles. To improve the efficiency of EDM, this paper presents a machining method that combines a self-developed 5-degree-of-freedom (5-DOF) controllable magnetic levitation actuator with a conventional EDM machine tool. The stability of the interpole voltage is improved by actuator microadjustment of the electrodes of the EDM machine tool. First, an EDM control system with local current feedback and decoupling control elements is designed based on the EDM servo drive principle to improve the response speed and positioning accuracy of the actuator. Second, the actuator is connected to the spindle of a conventional EDM machine tool, and machining experiments are carried out. The experimental results show that the EDM machine tool connected to the actuator can control the electrode position more quickly, adjust the discharge state quickly, and increase the number of discharges per unit time. The average machining speed increases from 1.108 to 3.925 µm/s, which is 3.54 times as fast as conventional EDM. Finally, complex shape machining experiments are carried out, and the machining results showed that by adjusting the target value of the radial direction of the actuator, the various trajectories of the electrode can be controlled to depict arbitrary shapes. [ABSTRACT FROM AUTHOR]

Inconel 625 superalloy and stainless steel 304 are known for their significant corrosion resistance along with their high hardness and strength. Therefore, they are used in a wide range of industries, including oil and gas and nuclear. Electrical discharge machining is among the most widely used processes for machining of these metals. However, this process has limitations, such as low material removal efficiency, high surface roughness, and the formation of a recast layer. Therefore, in this study, the effective parameters on increasing the material removal efficiency and reducing recast layer thickness are investigated. These parameters include the dielectric fluid, electrode material, discharge current, and pulse duration. After performing the test matrix, the effect of each of the input parameters on the material removal rate, surface roughness, and thickness of the recast layer is evaluated using the ANOVA method. The results of this analysis showed that the type of dielectric fluid and the presence of silver oxide nanoparticles have a significant effect on output variables. When using sunflower oil fluid containing nanoparticles and the silver electrode, the recast layer and surface roughness are reduced, while the average material removal rate increases by 40% compared to the traditional mode. Also, due to the biodegradability of deionized water and sunflower oil fluids, the environmental sustainability of the process in this study is increased and while increasing productivity, it leads to the sustainable development of the EDM process. [ABSTRACT FROM AUTHOR]

Creating systems for monitoring technology processes based on concentrated energy flows is an urgent and challenging task for automated production. Similar processes accompany such processing technologies: intensive thermal energy transfer to the substance, heating, development of the melting and evaporation or sublimation, ionization, and expansion of the released substance. It is accompanied by structural and phase rearrangements, local changes in volumes, chemical reactions that cause perturbations of the elastic medium, and the propagation of longitudinal and transverse waves in a wide frequency range. Vibrational energy propagates through the machine's elastic system, making it possible to register vibrations on surfaces remotely. Vibration parameters can be used in monitoring systems to prevent negative phenomena during processing and to be a tool for understanding the processes' kinetics. In some cases, it is the only source of information about the progress in the processing zone. [ABSTRACT FROM AUTHOR]

Amorphous alloys are a new type of multi-functional advanced material with the properties of general metal materials and glass, which are also called metallic glasses. They have good comprehensive properties, such as a wide application range, low cost, and high reusability. Using reasonable process parameters, non-traditional machining can not only realize the machining of complex amorphous parts, but also avoid the crystallization and oxidation of amorphous alloys, realizing tasks that cannot be accomplished by traditional machining. Therefore, this review systematically summarizes the research status and development potential of amorphous alloys fabricated using non-traditional machining methods. First, we introduce the principles of laser machining, ultrasonic machining, electrical discharge machining, electrochemical machining, and other non-traditional machining methods for amorphous alloys. Subsequently, the influence of the machining parameters and other external conditions on the machining effect is summarized. The machining cost, machining efficiency, and environmental impact of these non-traditional machining methods were compared. Finally, non-traditional machining technology for amorphous alloys is summarized and discussed. • The processing principles of non-traditional machining methods are summarized. • The influences of processing parameters on the machining effect are reviewed. • Costs, effects, and pollution of non-traditional machining are compared. • The limitations or shortages of non-traditional machining methods are summarized. [ABSTRACT FROM AUTHOR]

Micro-liquid floated gyroscopes are widely used in nuclear submarines, intercontinental missiles, and strategic bombers. The machining accuracy of micro-ball sockets determined the motion accuracy of the rotor. However, it was not easily fabricated by micro-cutting because of the excellent physical and chemical properties of beryllium copper alloy. Here, we presented a linear compensation of tool electrode and a proportional variable thickness method for milling micro-ball sockets in C17200 beryllium copper alloy by micro-electrical discharge machining. The machining parameters were systematically investigated and optimized to achieve high-precision micro-ball sockets when the k value was 0.98 and the initial layer thickness was 0.024 mm. Our method provided a new way to fabricate micro-ball sockets in C17200 with high efficiency for micro-liquid floated gyroscopes. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is a nonconventional machining process that involves the formation of a plasma in an interelectrode gap filled with a dielectric that melts and vaporizes the electrodes (tool and workpiece) when a voltage is applied across them. This work models the plasma discharge in the EDM process to describe plasma characteristics such as electron density, heavy species densities, plasma potential, and plasma temperature using chemical kinetics, fluid flow, and heat transfer mechanisms in a 1D domain in the direction of the gap. The 1D domain allows the model to utilize surface reactions on the electrode walls necessary for sustaining the plasma reactions. The domain also provides a perspective of the plasma characteristics near the workpiece. Temperature results are compared with the experimental data obtained from spectrometer measurements. Additionally, an estimate of the plasma diameter is made and compared with actual high-speed camera images. The effect of EDM parameters such as supply voltage and interelectrode gap size on plasma characteristics is studied. The model predicts the incumbent heat flux on the workpiece electrode for small gaps which could have applications in the development of melt-pool models of EDM. Finally, the model provides a physics-based understanding of the mechanisms of plasma generation in the EDM process. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is a nonconventional machining process that involves the formation of a plasma in an interelectrode gap filled with a dielectric that melts and vaporizes the electrodes (tool and workpiece) when a voltage is applied across them. This work models the plasma discharge in the EDM process to describe plasma characteristics such as electron density, heavy species densities, plasma potential, and plasma temperature using chemical kinetics, fluid flow, and heat transfer mechanisms in a 1D domain in the direction of the gap. The 1D domain allows the model to utilize surface reactions on the electrode walls necessary for sustaining the plasma reactions. The domain also provides a perspective of the plasma characteristics near the workpiece. Temperature results are compared with the experimental data obtained from spectrometer measurements. Additionally, an estimate of the plasma diameter is made and compared with actual high-speed camera images. The effect of EDM parameters such as supply voltage and interelectrode gap size on plasma characteristics is studied. The model predicts the incumbent heat flux on the workpiece electrode for small gaps which could have applications in the development of melt-pool models of EDM. Finally, the model provides a physics-based understanding of the mechanisms of plasma generation in the EDM process. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is a nonconventional machining process that involves the formation of a plasma in an interelectrode gap filled with a dielectric that melts and vaporizes the electrodes (tool and workpiece) when a voltage is applied across them. This work models the plasma discharge in the EDM process to describe plasma characteristics such as electron density, heavy species densities, plasma potential, and plasma temperature using chemical kinetics, fluid flow, and heat transfer mechanisms in a 1D domain in the direction of the gap. The 1D domain allows the model to utilize surface reactions on the electrode walls necessary for sustaining the plasma reactions. The domain also provides a perspective of the plasma characteristics near the workpiece. Temperature results are compared with the experimental data obtained from spectrometer measurements. Additionally, an estimate of the plasma diameter is made and compared with actual high-speed camera images. The effect of EDM parameters such as supply voltage and interelectrode gap size on plasma characteristics is studied. The model predicts the incumbent heat flux on the workpiece electrode for small gaps which could have applications in the development of melt-pool models of EDM. Finally, the model provides a physics-based understanding of the mechanisms of plasma generation in the EDM process. [ABSTRACT FROM AUTHOR]

Shape Memory Alloys (SMAs) have various applications in the field of medical science due to its superior properties such as pseudoplasticity, shape memory effect, biocompatibility, high specific strength, high corrosion resistance, high wear resistance and high anti fatigue property. The machining of TiNi shape memory alloys by traditional processes is very crucial due to poor thermal conductivity, poor surface finish and burr formation. Hence, to overcome these problems the non-conventional machining process viz. water jet machining, electrical discharge machining, laser beam machining, etc. are more suitable to machine SMAs. The appropriate non-conventional machining process EDM/wire EDM, provides better machining and surface characteristics during machining of SMAs. The objective of the current work is to identify the research gap for SMAs during their machining by the EDM and Wire EDM process and to identify the future prospective of SMAs for different applications in the field of biomedical. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) is a well-known manufacturing process that is reported for several times as an effective technique for cutting of nickel-based superalloy of Inconel 718 (IN718). A majority of existing researches in EDM of Inconel 718 are focused on machinability of material considering production rate, tool wear, surface roughness and dimensional tolerances. To the best of author's knowledge, corrosion resistance EDMed Inconel 718 has hardly been taken into consideration. In the present work, an experimental study was made to understand how the electrical discharge machining parameters, viz. pulse current, pulse on time and rotational motion of the tool electrode, influence the corrosion properties of IN718. Technique of potentiodynamic polarization curve was utilized to measure IC and EC of the samples. A number of seven samples were machined using single-factor experiments design, and the effect of EDM parameters on foresaid corrosion indices was studied. Surface roughness, surface morphology, hardness and residual stress distributions were taken into account for justification of the variations. It was obtained from the results that as a result of increase in current from 5 to 15A, the corrosion rate increases, where the current density increases from 0.15 to 0.28 μA/cm2, and corrosion potential decreases from 0.51 to − 2.49 VSCE. In addition, it was found that less value of pulse on time, i.e., 600 μs, results in best corrosion properties where increase up to 800 μs results in increase in corrosion density from 0.11 to 0.19 μA/cm2 and also reduction of corrosion potential from −0.34 to −1.13 VSCE. It was further found that increase in tool rotational speed from stationary condition up to 200RPM results in enhancement of corrosion resistance; here, the current density reduces from 0.4 to 0.088 μA/cm2 and increase in corrosion potential from − 1.89 to 0.11 VSCE. [ABSTRACT FROM AUTHOR]

The electrical discharge machining (EDM) is an extremely effective manufacturing process to create deep and three-dimensional complex cavities. In EDM, machining occurs due to the generation of thermoelectric energy between the work piece and an electrode. EDM widely engaged for cutting superalloy material that are having high strength to wear ratio, corrosion resistance, etc. In this work, Inconel 825 material, which is nickel–chromium based superalloy, is opted due to its outstanding mechanical and thermal properties. We considered various important EDM input parameters, i.e. spark gap (Sg), gap voltage (Vg), pulse on time ( T on ), pulse off time ( T off ), peak current ( I p ), servo feed (Sf), depth of cut (Dc) and difficulty index (Di) with Taguchi L 2 7 orthogonal array for optimizing output responses, i.e. tool wear rate (TWR), material removal rate (MRR) and surface crack density (SCD) in multi-objective optimization (MOO) realm. Undertaking repeated experimental runs are very expensive, tedious, time consuming and economically unjustified. Hence, we have robustly introduced a novel integrated computational Taguchi based grey relational analysis (TGRA) accompanied with Taguchi based technique for order of preference by similarity to ideal solution (T-TOPSIS) to optimize the EDM process. This research represents that the pulse on time is the chief significant factor and the p value is found as 0.002 for both TGRA and T-TOPSIS. Experimentally, it has been confirmed that the optimum settings yielding an improvement of 0.01627 and 0.28071 in TGRA and T-TOPSIS score, respectively. The comparative analysis for the methodologies is fruitfully discussed and the results clearly present the effective parametric combinations to be implicated for optimizing MOO framework. Investigation of surface topography is fruitfully presented and the effects of the pulse on time, gap voltage and pulse off time on heat affected layers, machining debris and surface cracks were also discussed. Validation tests were carried out and show closer relationship with the experimental results. [ABSTRACT FROM AUTHOR]

Atomic Diffusion Additive Manufacturing (ADAM) is an innovative Additive Manufacturing process that allows the manufacture of complex parts in metallic material, such as copper among others, which provides new opportunities in Rapid Tooling. This work presents the development of a copper electrode manufactured with ADAM technology for Electrical Discharge Machining (EDM) and its performance compared to a conventional electrolytic copper. Density, electrical conductivity and energy-dispersive X-ray spectroscopy were performed for an initial analysis of both ADAM and electrolytic electrodes. Previously designed EDM experiments and optimizations using genetic algorithms were carried out to establish a comparative framework for both electrodes. Subsequently, the final EDM tests were carried out to evaluate the electrode wear rate, the roughness of the workpiece and the rate of material removal for both electrodes. The EDM results show that ADAM technology enables the manufacturing of functional EDM electrodes with similar material removal rates and rough workpiece finishes to conventional electrodes, but with greater electrode wear, mainly due to internal porosity, voids and other defects observed with field emission scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Modern industry is focused on looking for new and effective technologies to manufacture complex shapes from alloys based on nickel and chromium. One of the materials widely used in the chemical and aerospace industry is Hastelloy C-22. This material is difficult to machine by conventional methods, and in many cases, unconventional methods are used to manufacture it, such as electrical discharge machining (EDM). In the EDM process, the material is removed by electrical discharges between a workpiece and a tool electrode. The physical and mechanical properties of the tool electrodes have a direct impact on the process efficiency, machining accuracy, and surface roughness. Currently, there has been a significant increase in the use of graphite as a material for tool electrodes due to the low purchase cost of the raw material, good machinability, and high sublimation temperature. In this work, an experimental investigation of the influence of the grain size of the graphite tool electrode on material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra) of Hastelloy C-22 was carried out. Two POCO graphite tool electrodes with a grain size of 1 µm (AF-5) and 10 µm (S-180) were used. Based on the experimental studies, empirical models describing the influence of machining parameters on technological indicators and the condition of the surface texture were determined. The research indicates that graphite with a larger grain provides higher process efficiency with high relative wear of the tool electrode. The lowest surface roughness was obtained for graphite with a smaller grain size (AF-5). The analysis of the machining parameters proves that the discharge current and pulse duration are the main factors determining the MRR and Ra values for both AF-5 and S-180 graphite. The time interval is the dominant parameter with regard to the relative wear of the graphite electrode. [ABSTRACT FROM AUTHOR]

The study and development of the technological foundations for creating a textured surface using an electrode tool obtained by the method of additive manufacturing are the purpose of the work. Methods for obtaining textured surfaces and for creating a tool electrode for electrical discharge machining are considered in this work. The modeling of the electrodetool, analysis of internal stresses during its manufacture by the selective laser melting method, and the manufacture of electrodes are considered. A Realizer SLM 50 laser machine was used to create the electrode tool. Ti6Al4V metal powder with an average particle size of 30 µm was chosen as the material for manufacturing. The experiments were carried out on a copy-piercing electrical discharge Smart CNC machine. The material of the workpiece is corrosion-resistant, heat-resistant, high-alloy steel 15Cr12H2MoWVNNB. An Olympus GX 51 light microscope (Olympus Corporation, Shinjuku-ku, Japan) at 100× magnification was used to visually evaluate the texturing results and measure dimensions. The possibility of using electrodes obtained by the selective laser melting method for texturing surfaces was studied. [ABSTRACT FROM AUTHOR]

Recent developments in material science have concentrated not only on the improvement in mechanical properties, but also on the machinability that was difficult for system profiles. The present research explains the machinability assessment of the part of the sintered powder metallurgy using an electric discharge machining. The ferrous clay matrix preparations are constructed from iron–carbon–copper material and bentonite clay. The selected input parameters for the measurement of machinability are wt. % of clay, current (A), pulse on time (µs) and voltage (V), whereas the electrode wear rate, material removal rate and surface roughness (Ra) are considered as performance features. Results show that the performance parameters have been optimized at three different parametric conditions. Further, to obtain single optimum condition the hybrid GRA-TOPSOS methodology has been implemented for maximum MRR with minimum EWR and low surface roughness. The single optimum condition has been found at 5% clay, current 7 A, voltage 49 V and pulse on time 400 µs. The study of micro-structure and chemical composition of machined surfaces has been carried out using scanning electron microscopy with X-ray diffraction and energy-dispersive spectrometry analysis, respectively. The SEM exposes the less recast layer and micro-cracks during electrical discharge machining of ferrous clay composite. [ABSTRACT FROM AUTHOR]

In the electrical discharge machining process (EDM), quantities of discharge craters randomly scatter the workpiece surface. However, the formation mechanism of the discharge crater has not been fully understood, which affects the application of EDM technology. In the paper, a thermal-fluid coupling model was proposed to elucidate the crater formation dynamics process utilizing COMSOL Multiphysics software. The temperature distribution, fluid flow velocity, and more changes in the crater were analyzed, aiming to deepen the understanding of the formation mechanism of the discharge crater in the EDM process. Through the comparison of experimental results and numerical simulation results, it was found that a little of the material is eroded by vaporization, while a lot of material is eroded mainly by melting. In addition, the material removal process is continuously eroded after the end of discharge due to the residual heat and the flow of molten material. Moreover, the effect of pulse on-time and peak current on the temperature field and flow field was solved. Through the experiments and numerical simulations, it was shown that the simulation results are consistent with the experimental results, verifying the applicability of the thermal-fluid coupling model in demonstrating the mechanisms of crater formation in the EDM process. [ABSTRACT FROM AUTHOR]

Electrical discharge grinding technology (EDGT) is an efficient and high precision method for machining RB-SiC ceramic materials. In this paper, the mechanism of material removal in EDGT is deeply analyzed, and the formation mechanism of surface topography under different material removal regimes affected by grinding depth is discussed. A three-dimensional heat conduction analysis model in the process of single pulse discharge was established, and the temperature field distribution in RB-SiC ceramic material under different discharge energy was obtained by numerical calculation. It is found that the simulated crater radius and depth increase with the increase of the discharge time, and the material removal amount gradually increases, but the growth rate gradually decreases. In order to give full play to the advantages of EDGT, the discharge energy and grinding depth were optimized according to the material removal mechanism. Finally, RB-SiC ceramic machining experiments were carried out using the optimized machining parameters, and a smooth surface with few discharge craters was obtained. It is found that the grinding scratches on the material surface are mainly plastic grinding, and the material surface roughness is 0.443 μm. The research results of this paper can provide guidance for engineering practice of ductile grinding RB-SiC ceramic materials. [ABSTRACT FROM AUTHOR]

This study investigated the machinability of AISI H13 hot work tool steel with a hardness of 54 HRC, which has been deep cryogenically treated using the electro-erosion machining technique, one of the unconventional manufacturing methods. The machinability parameters used in the study were determined as current (4, 8 and 12 A), pulse time (200, 300 and 400 µs) and three different electrodes (Copper, Graphite and Tuncop). The experimental design was designed according to the Taguchi L 27 model, and machinability tests were carried out to examine the results obtained from the experimental study both experimentally and statistically. When the literature was examined, it was seen that cryogenic treatment was generally applied to electrode materials, and only surface roughness and material wear amounts were examined as output parameters. The original value of the study is the interpretation of the results by applying cryogenic treatment to the test material and exploring the surface roughness and material wear amount, as well as the hole diameters and criterion diameters formed on the treated surfaces after the EDM process. As a result of the study, it was observed that the surface roughness value, the hole diameter, the amount of material wear, and the crater diameter increased with the increase in ampere and impact time. The lowest surface roughness value was 2.266 µm in the graphite electrode material at 4 amps and 200 µs impact time and the highest wear amount was realized as 0.555 g in the copper electrode material 12 amps and 400 µs impact time. The smallest hole diameter was 12.254 mm with a tuncop electrode with a pulse duration of 4 amps and 200 µs, and the lowest crater diameter was 127.301 µm with a graphite electrode at a current of 4 amps and a pulse duration of 200 µs. When the signal-to-noise ratios were examined, the optimum machining parameters for surface roughness, hole diameter, material wear amount, and crater diameter were determined as A 2 B 1 C 1 , A 1 B 3 C 3 , A 3 B 1 C 1 , and A 3 B 1 C 1 , respectively. When the ANOVA results are examined, it is determined that the most effective parameter for the surface roughness is of the current value with 86.54%, the most effective parameter for the hole diameter is the electrode material with 85.20%, the most effective parameter for material wear amount is the electrode material with 45.67% and the most effective parameter for the crater diameter is current value with 75.35%. [ABSTRACT FROM AUTHOR]