Electrical Discharge Research Articles

The effect of graphene solution on mixed powder electrical discharge milling of Ti6Al4V

Abstract Ti6Al4V is the most widely used materials in aerospace, medical, nuclear power and other fields. However, due to its unique properties such as low thermal conductivity, titanium alloy poses challenges in machining processes. Electrical discharge milling (EDM) is a machining method that utilizes the electrical corrosion phenomenon of pulsed spark discharge between two electrodes to remove materials, which is highly suitable for the machining of Ti6Al4V. This paper investigates a mixed powder EDM approach for titanium alloy using a graphene solution medium known for its green and sustainable characteristics. Compared to conventional deionized water medium processing which without powder particles, the material removal rate can be increased by 50%, the surface hardness after processing was 2.5 times higher than that of the substrate, the electrode wear rate could be reduced by 40%, the surface roughness values were reduced by more than 20%. Besides that, the micro-cracks and micro-pores on the workpiece surface can be significantly reduced. Subsequently, single factor experiments and orthogonal experiments were conducted using material removal rate, electrode wear rate, and surface roughness as process indicators. The influence of processing parameters on process indicators was investigated based on optimal selection method and analysis of variance (ANOVA). Finally, the optimized parameters in graphene solution mixed powder EDM for Ti6Al4V were obtained. When using the process combination A3B3C1D2, the maximum MRR can be obtained.

Enhancing Risk Management: Leveraging the Likelihood/Severity Matrix for Effective Risk Assessment and Mitigation in the Electrical and Electronic Sector

This paper presents the basic concept of risk and reviews commonly applied tools and techniques for risk assessment. Generally, risk assessment is a completely experiential decision-making process based on experience and knowledge of risk assistants. This paper emphasises one quantitative/qualitative technique, namely the likelihood/severity matrix approach, which aims to direct the organisation’s attention towards risks that have the highest potential to have a negative effect. This paper’s main contribution lies in introducing a proposed model that utilises the likelihood/severity matrix approach to categorise risks into ‘regions’ and subsequently rank them. This process supports risk managers in making informed decisions to reduce risks effectively. A likelihood/severity matrix was examined through a case study belonging to the electrical and electronic sector to find the critical risks that hinder the assembly line of personal computers. Results showed that the ‘Breaking parts during assembly’, ‘Shocking the components from static electricity discharge’ and ‘Using wrong compatible parts’ risks had the maximum risk score, with values of 10–15 as the most critical risks. These results can influence decision makers in developing actions to mitigate these highlighted risks.

Optimization of electrical discharge machining parameters for enhanced performance on inconel 718 using Cu-Ni-B4C nanocomposite electrodes and advanced modeling techniques

Abstract This paper investigate into the complex field of electrical discharge machining (EDM) to improve material removal rate (MRR), electrode wear rate (EWR), and surface roughness (SR) for the machining of Inconel 718, a difficult-to-machine superalloy. The effects of discharge current, pulse duration, and pulse interval on machining performance were assessed through experiments. Response surface methodology (RSM) and artificial neural network (ANN) models, such as RNN, LSTM, and CNN, were used to optimize. Twenty runs of confirmation experiments were used to confirm the optimal process parameters found by the created models for better machining. For Inconel 718, the novel Cu-Ni-B4C nanocomposite electrode greatly enhanced EDM performance. The ideal configuration increased MRR while decreasing wear and surface roughness. Machined surfaces were inspected using SEM and EDAX analysis. With optimal settings of 50 μs pulse duration and 90 μs pulse interval, increasing current to 8 Amps increased MRR to 0.0118 g min−1, reducing EWR to 0.001 g min−1 and SR to 3.108 μm. Compared to the RNN, LSTM, and RSM models, the CNN model had the greatest R-squared (R2) score of 0.9999, suggesting greater MRR, EWR, and SR prediction.

Assessment of process parameters on modified 316L SS surfaces prepared via hybrid powders mixed EDM

This study aims to assess the influence of hybrid powders (hydroxyapatite, manganese, copper, and carbon nanotube) mixed electric discharge machining (EDM) and coating process on 316L stainless steel (SS). An efficiently machined, hydrophilic, thin, and microporous surface is produced using variable discharge energies and powders weighted percentage suspended in the dielectric medium. The research outcome indicates that the hybrid powders mixed-EDM process synthesised a coating that substitutes the base elements with foreign elements of calcium (Ca), phosphorous (P), copper (Cu), carbon (C), oxygen (O), and manganese (Mn). The surface wettability response of the coating displays a hydrophilic nature with a contact angle of 51.5° and surface energy of 52.9 mJ m−2. The coated surface exhibited a roughness value of 3.201 μm, which is expected to promote osseointegration, and the material removal rate has been enhanced to an optimal value of 100.32 mg/min. The Taguchi design demonstrated that the powder mixing ratio, current intensity, and spark time are the most influential factors in the hybrid powders mixed EDM process. This study determines a novel multiple additives-assisted EDM method to synthesise a coating on 316L SS with potential benefits for biomedical applications.

РЕГУЛЮВАННЯ ХАРАКТЕРИСТИК ЗАРЯДНОГО КОЛА ЄМНІСНОГО НАКОПИЧУВАЧА ЕНЕРГІЇ ЗМІНЕННЯМ ЙОГО ПОЧАТКОВОЇ НАПРУГИ ПРИ АПЕРІОДИЧНОМУ ЗАРЯДЖАННІ ВІД ДЖЕРЕЛА ПОСТІЙНОЇ НАПРУГИ

An analysis of the transient processes during aperiodic charging of the capacitive energy storage (CES) of the electri-cal discharge installation (EDI) from the source of direct voltage (SDV) of the USDV was carried out under the condition of changing the initial voltage of the CES at the time of the start of charging. The dependences of energy characteristics (dose of energy that powers the capacitor, energy losses and efficiency) on the magnitude and sign (polarity) of the ini-tial voltage CES were obtained. The energetically appropriate CES charge modes were determined. It is substantiated that increasing the initial voltage of the capacitor leads to an increase in the charging efficiency. The analysis of the ratio between the dose of energy that powers the CES during one charge cycle W*C and the energy of losses W*losses showed that the ratio W*C / W*losses increases with a change in the voltage U0C from –USDV to + USDV due to the fact that the energy of losses W*losses decreases faster than the dose of energy that powers the CES. Ref. 11, fig. 3, table.

Electrochemical survey of electroactive microbial populations in deep-sea hydrothermal fields

Electric discharge in deep-sea hydrothermal fields leads us to expect the existence of electroactive microbial ecosystems in the environments. Electrochemical properties such as electric field distribution on the seafloor and electrical conductivity of the rock can be useful indicators of searching electroactive microbial community in natural environments. We performed electric field measurements in deep-sea hydrothermal fields and collected rock samples by a remotely operative vehicle (ROV) operation. Several spots on the seafloor with strong electric fields were detected, which included both active hydrothermal vent areas and inactive sulfide deposits far from the vents. The electrical conductivity of the rock samples was correlated with the copper and iron sulfide content. Microbial community compositions of the rock samples were characterized by small subunit (SSU) rRNA gene amplicon sequencing analysis. The abundance of several microbial components, which are highly related to electroactive microorganisms such as Geobacteraceae and Thiomicrorhabdus, was affected by the electrical properties of rock samples. The results suggested that electrochemical properties on the seafloor would be related to the abundance of possible electroactive microbial populations, and that the electrochemical survey may be a powerful tool for exploring electroactive ecosystems.

Electrical insulation properties in a cold plasma of alumina coating for the in-vessel stabilizing shell of the RFX-mod2 fusion device

This paper presents the results of experimental tests on samples made of copper coated with alumina layer, performed to assess the reliability of its dielectric properties for applications in the low temperature plasma at the edge of a fusion device. The cue of the study was related to the plasma facing components of the RFX-mod2 fusion device (Marrelli et al., 2019, Peruzzo et al., 2023, Peruzzo et al., 2019), devoted to the experimental study of the magnetic confinement of fusion plasmas in a variety of configurations, including the reversed-field pinch and the tokamak. In RFX-mod2 an in-vacuum copper shell for the passive stabilization of MHD modes will surround the plasma. To avoid potentially harmful electrical discharges, which could be induced by rapid transients of the plasma current, this structure must be covered with an electrically insulating layer. For RFX-mod2 an alumina coating was chosen, whose dielectric properties have been tested both in air and in the presence of weakly ionized plasma. Electrical tests, conducted on copper samples with alumina deposits of about 100μm thickness, revealed that the ceramic layer has a high electrical resistance value in air (>1GΩ), but electrical discharges can occur in presence of a weakly ionized plasma, depending on compactness and porosity of the alumina layer, causing local melting of the alumina and expulsion of copper droplets from the substrate. Scanning Electron Microscope (SEM) analyses revealed that in the failed samples the ceramic layer was irregular and rough, with interconnected cavities and cracks, which could reduce its effective thickness and explain the dielectric breakdown at relatively low voltages (<400V). The analyses also showed that samples with a more compact layer present a higher dielectric strength in the presence of the plasma, highlighting that compactness and porosity play crucial roles in ensuring good insulation for materials in a plasma. This study led the definition of the requirements for the insulating coating of the plasma facing components of the RFX-mod2 fusion machine, however the results can be useful for other fusion and non-fusion plasma applications requiring electrical insulation, which can span from industrial devices to spacecrafts.

Enhancing Mild Steel Surface Characteristics through Electrical Discharge Coating with Titanium Dioxide Suspension

In this research, surface modification of mild steel was carried out by using electric discharge coating (EDC) with titanium dioxide (TiO2) powder suspension. The concentrations of TiO2 powder were varied and their effect on the surface roughness and deposited element were investigated. The results showed that elements such as titanium, carbon, copper, oxygen, zinc and iron were successfully coated on the mild steel surface. Aside from that, the weight % of the titanium element increased with an increase of TiO2 powder concentration. The surface roughness was also reduced 62.9% by using 5 g/l TiO2 powder when compared to the pure kerosene oil.

Prediction of circularity of the holes in electrical discharge machining of inconel alloy using machine learning technique

Prediction of circularity of the holes in electrical discharge machining of inconel alloy using machine learning technique

Precisely regulating thermal deformation behavior of wire electrical discharge machining thin-wall fin via pulsed laser-induced shockwave

The thermal deformation in the process of thin-walled metal fin processed by wire electrical discharge machine (WEDM) is almost unavoidable, which restricts the application of wire electrical discharge machining in the precision machining of thin-walled parts. In this study, a new process of thermal bending deformation regulation by laser-induced shockwave of wire electrical discharge machining thin-wall fin was proposed to obtain low/no deformation thin-wall parts. The thermal deformation of thin-wall In718 metal processed with different wire electrical discharge machining parameters was calibrated, and the law between the thermal bending and the process parameters was obtained. The thermal ablation and laser shock thermal deformation regulation model was established to accurately describe the stress distribution and deformation behavior of thin walls. For In718 thin-wall fin with different thicknesses, the thermal bending deformation could be regulated by laser-induced shockwave. After adjustment, the warpage of all thin walls was only −0.174μm at the lowest, and the thermal deformation could be reduced by 98.35 % at the highest. Laser shock improved the surface integrity of thin walls, increased the surface hardness to 433.9HV, increased by 46.84 %; laser shock also reduced the surface roughness of thin walls to a maximum of 2.67μm, a decrease of 33.58 %. In addition, laser shock could reduce the number of large-size grains, increase the number of twins, refine the impact surface grains to a certain extent, and the particle size was reduced to 7.64μm, which was reduced by 45.62 %.

Dynamic Electric Discharge Paths in Liquid Metal Marble Arrays.

Electric discharge occurs ubiquitously in both natural and engineered systems, where the discharge paths provide critical information. However, control and visualization of discharge patterns is a challenging task. Here arrays of liquid metal marbles, droplets of a gallium-indium eutectic alloy with a copper-doped ZnS luminescent coating, are designed for pixelated visualization of electric discharge paths at optical imaging length-scales. The ZnS particles embed themselves into the surface of liquid metal droplets and are anchored by a self-limiting gallium oxide layer. The operation is achieved by generating spark discharges at inter-marble air gaps and reduced voltage drop across highly conducting liquid metal droplets. By taking advantage of the malleability of soft liquid metal marbles, the dynamic visualization platforms allow the manipulation of discharge path selections in configurable marble arrays and the embedding of artificial defect features. The systems are further integrated for characterizing dynamic changes in granular and soft systems, and for enabling logic computing and information encoded display. This demonstration holds promises for creating new-generation electric discharge-based optoelectronics.

Enhancing the Longevity and Structural Stability of Humidity Sensors: Iron Thin Films with Nitride Bonding Synthesized via Magnetic Field-Assisted Sparking Discharge.

Developing long-lasting humidity sensors is essential for sustainable advancements in nanotechnology. Prolonged exposure to high humidity can cause sensors to drift from their calibration points, leading to long-term accuracy issues. Our research aims to develop a fabrication method that produces stable sensors capable of withstanding the environmental challenges faced by humidity sensors. Traditional iron-based nanoparticles often require complex treatments, such as chemical modification or thermal annealing, to maintain their properties. This study introduces a novel, one-step synthesis method for iron-based thin films with exceptional stability. The synthesized films were thoroughly characterized using X-ray photoelectron spectroscopy (XPS) to evaluate their phase stability and nitride formation. The method proposed in this study employs an electrical sparking discharge process within a pure nitrogen atmosphere under a 0.2 T magnetic field, producing thin films composed of nanoparticles approximately 20 nm in size. The resulting films demonstrate superior performance in humidity sensing applications compared to conventional methods. This straightforward and efficient approach offers a promising path toward robust and sustainable humidity sensors.

A Simple Window Screen to Create Electric Discharges for Repelling and Exterminating Stable Flies and Houseflies in Cattle Barns

A Simple Window Screen to Create Electric Discharges for Repelling and Exterminating Stable Flies and Houseflies in Cattle Barns

Novel machine learning-driven multi-objective optimization method for EDM trajectory planning of distorted closed surfaces

Highly distorted closed surfaces pose significant challenges for machining trajectory planning due to their intricate surface constraints and closed structures. Despite these challenges, components with such features are prevalent in industries like aerospace. This paper presents a machine learning-driven multi-objective optimization method for electrical discharge machining (EDM) trajectory planning of highly distorted closed surfaces. The method transforms the structural design of forming electrodes and trajectory planning into a multi-objective decision problem. And a discrete point trajectory planning method, guided by surface average curvature, is employed to determine the optimal position and orientation of the electrode. Additionally, an elite dataset, generated using the Monte Carlo method and Arena's Principle, is utilized to train an artificial neural network (ANN). This network predicts hyperparameters for the nonlinear optimization problem. Based on the proposed method, a multi-objective optimization model is formulated for an integral shrouded blisk, considering minimization of iteration count, axial motion, and maximization of machining surface quality. The Pareto front is utilized to obtain the optimal EDM trajectory. Experimental results demonstrate a 17.38 % reduction in the overall machining cycle duration using this trajectory, and the surface roughness and profile accuracy satisfy the design specifications, which proves the effectiveness of this method.

An experimental investigation on copper square electrode wear in electric discharge machining of Hastelloy B2

Hastelloy B2 is a high-performance nickel-molybdenum alloy and has been used in micro reactor, pump, pipe, and corrosion-resistant equipment. Square holes are required in the above application components. Although square holes are easily produced by spending more electrodes wear in Electrical Discharge Machining (EDM). Moreover, the square hole with small electrode wear achieved is a challenging task in thermal machining. Hence, in this work, the effects of EDM process parameters on electrode taper angle, electrode radius, electrode wear length and cutting time of Hastelloy B2 are studied. Taguchi based VišekriterijumskoKompromisnoRangiranje (VIKOR) method is used to find the optimum process parameters and compared with Taguchi based Grey Relational Analysis (GRA) method for validation. The results showed that current and pulse duration greatly affects the electrode wear out surface and edges. The square electrodes with sharp edges and surfaces are fully transformed into hemispherical shapes at electrode ends due to an unstable spark with diffusion of heat. Also, the VIKOR method provides an alternative multi-criteria optimization method that enhances the process performance over the grey relational analysis due to comparability, uniqueness, assessment and prediction.

Investigation of process parameters for modeling of ceramic composite SiSiC IN dry EDM (DEDM) cutting

The manufacturing industry is currently grappling with issues related to energy dissipation and product quality, both of which significantly impact productivity. In addressing this pertinent concern, this study endeavours to identify the key indicators that contribute a crucial role in machining process. The Dry EDM (DEDM) emerges as a novel technology, wherein environmentally friendly gases serve as an alternative dielectric medium instead of liquid EDM approaches. In conventional EDM process, hydrocarbon oils release toxic emissions while the gases used in Dry EDM process don’t produce harmful emissions and hence make the DEDM process sustainable.An investigation has been carried out to observe the influence of different gases like O2, N2 and Air on Siliconized Silicon-Carbide plate (SiSiC) of ø50mm*2 mm under Dry Electrical Discharge Machining. Effect of different tools is also observed using varying shapes of electrodes like plane Cu electrode of ø6 mm diameter with 60 mm length and tubular shape with outer diameter ø6mm and inner diameter ø5.1 mm with a length of 60 mm. The three gases are one by one supplied through a nozzle in the presence of plane Cu electrode to make the holes in SiSiC plate. The same process is executed with tubular Cu electrode. Modified Taguchi Orthogonal Array is applied to analyze the effect of control factors such as gap voltage, discharge current and pulse on-time through a series of experiments. Effect of different shape of tools and different gases is observed for the material removal rate (MRR) and surface roughness (SR) of specimen.In this paper, a latest DEDM process of swirl assisted flushing is proposed which provides a new technique to solve the problems of low MRR and poor surface integrity. Swirl assisted flushing works on Decay Law and also microscopic investigation justifies its validity. It is concluded by this research that current and Pulse on time are more contributing factors about 53.3 % and 27 % respectively. Furthermore, it is noted that DEDM increases MRR 19.5 % and lowers Ra approximately 2/3 than traditional machining. The MRR of O2 is about 3.1 times more than Air and N2 comes at least position while N2 creates better quality of surface due to formation of an inert nitride layer. Empirical relations are established for SR and MRR using Minitab 18 Software to develop a robust model. Confirmation test is performed to check the validity of developed mathematical model. The Novelty of this research is also extended by introducing a new method SAF. The results are finally evaluated by ANOVA.

Research on the key techniques of composite processing of EDM and vibration ultrasonic drilling

PurposeUtilizing electrical discharge machining (EDM) to process micro-holes in superalloys may lead to the formation of remelting layers and micro-cracks on the machined surface. This work proposes a method of composite processing of EDM and ultrasonic vibration drilling for machining precision micro-holes in complex positions of superalloys.Design/methodology/approachA six-axis computer numerical control (CNC) machine tool was developed, whose software control system adopted a real-time control architecture that integrates electrical discharge and ultrasonic vibration drilling. Among them, the CNC system software was developed based on Windows + RTX architecture, which could process the real-time processing state received by the hardware terminal and adjust the processing state. Based on the SoC (System on Chip) technology, an architecture for a pulse generator was developed. The circuit of the pulse generator was designed and implemented. Additionally, a composite mechanical system was engineered for both drilling and EDM. Two sets of control boards were designed for the hardware terminal. One set was the EDM discharge control board, which detected the discharge state and provided the pulse waveform for turning on the transistor. The other was a relay control card based on STM32, which could meet the switch between EDM and ultrasonic vibration, and used the Modbus protocol to communicate with the machining control software. FindingsThe mechanical structure of the designed composite machine tool can effectively avoid interference between the EDM spindle and the drilling spindle. The removal rate of the remelting layer on 1.5 mm single crystal superalloys after composite processing can reach over 90%. The average processing time per millimeter was 55 s, and the measured inner surface roughness of the hole was less than 1.6 µm, which realized the micro-hole machining without remelting layer, heat affected zone and micro-cracks in the single crystal superalloy.Originality/valueThe test results proved that the key techniques developed in this paper were suite for micro-hole machining of special materials.

High-speed cutting performance characteristics of Ti(C, N)–W cermet tools against S32750 super-duplex stainless steel round bars

In this study, TiC0.5N0.5–60 wt% W and TiC0.5N0.5–70 wt% W cermet cutting tool specimens consisting of Ti(C, N) core, W-rich Ti(C, N) rim, and W-based alloy phases with much higher strengths than conventional heat-resistant tool materials at temperatures above 1673 K were fabricated by spark plasma sintering, electric discharging, and polishing. The cutting performance characteristics of the cermet cutting tool specimens were then examined and compared with those of commercially available NX2525, JX1, and HTi10 cutting tool specimens when cutting S32750 super-duplex stainless steel round bars under dry condition at a cutting speed of 800 m/min. The NX2525, JX1, and HTi10 specimens were TiC–Ni-based cermet containing Mo, Nb, and Co, WC–Al2O3-based composites, and WC–Co cemented carbide, respectively. The TiC0.5N0.5–70 wt% W and TiC0.5N0.5–60 wt% W cermet cutting tool specimens exhibited the first and second longest lifetimes among all the noncoated cutting tool specimens. The lifetime of the TiC0.5N0.5–70 wt% W cermet cutting tool specimen was extended by coating it with TiAlN film by physical vapor deposition. In contrast, the TiC0.5N0.5–60 wt% W and TiC0.5N0.5–70 wt% W cermet specimens exhibited compressive strengths much higher than those of the NX2525, JX1, and HTi10 specimens at 1973 K, whereas all the specimens exhibited similar compressive strengths at room temperature.

Aging assessment of silicone rubber materials under corona discharge accompanied by humidity and UV radiation

Abstract High voltage (HV) outdoor insulators are subjected to both electrical and environmental stresses, which may lead to their failure. Among the causes, corona discharge, humidity and UV radiation are considered to be the most damaging factors. Efforts are therefore underway to investigate new materials for improving the performance of insulating systems. In this research work, silicone-based room temperature vulcanized samples filled with alumina trihydrate (ATH), silicon dioxide and magnesium hydroxide (MH) were prepared and exposed to AC corona discharge for a duration of 110 h. The electric discharge was also accompanied by UV radiation and two different humidity levels. Following aging of the test samples, diagnosis was conducted to assess their integrity. Measurements based on determining the static contact angle demonstrated the loss of hydrophobicity of all the materials, while hydrophobicity recovery phenomena revealed that ATH-doped materials demonstrated a comparatively higher increase in the contact angle than in samples filled with silicone dioxide (silica) and MH. Scanning electron microscopy analysis revealed deep cracks and block-like structures on their surfaces. Similarly, energy-dispersive X-ray analysis indicated the signs of surface oxidation of the aged samples. However, the data of elemental composition exhibited the loss of filler contents as well as that of carbon from the base matrix. The overall assessment showed that resistance to suppress aging is influenced by both the filler type and its concentration in the investigated composites. The ATH-filled composites exhibited outstanding performance when exposed to the rigors of corona discharge and other environmental stresses. This research contributes to materials science and HV engineering by addressing the development of composites for enhanced insulator performance, with future aspects lying in the utilization of nano-composites for advanced functionality and durability.

Dielectric Fluids for the Electrical Discharge Machining: A Review

An extensive examination of the effect of dielectric properties of the Electrical Discharge Machining (EDM) operation machining variables is being done in the present study. Irrespective of the material's hardness, an EDM is an unconventional thermo-erosion machining procedure. It gave the workpiece a better and more detailed surface topography. Dielectric is an essential EDM component that typically affects the operation's high material removal rate and surface integrity. The dielectric fluid acts as a medium that modulates electrical sparks and traps energy due to the operation. It cleans up the trash and cools the workpiece. Whenever powders like Ti, Si, graphite, Cu, Al2O3, and others are added to the dielectric fluid, the fluid's conductivity increases the micro-hardness of the substance. For executing studies in EDM, choosing a proper dielectric from the number of fluids now offered is crucial. Adopting different additives in the dielectric fluid impacts the optimization of machining parameters and related characteristics are addressed in this study in light of existing research. The studies show the effect on various output parameters.