Papers by Keyword: EDM

Abstract: This paper describes a development of Electrical Discharge Machining (EDM) system for biomedical application. In general, the mechanism of EDM comprises of mechanical structure and electronic control system. This laboratory scale of the EDM system has a capability to accommodate the machining of hip implant which employs low power generator. The holder for the workpiece is created to accurately position the hip implant, ensuring that the machining angle of the implant directs the micro-pits precisely toward the workpiece. A traditional linear x-y-z axis setup (Cartesian coordinate system) is utilized, along with two types of spherical coordinates (swing-swing and swing-rotate configurations). By the results of performance test, the Swing Motor behaves differently to the common servo motor. The Swing Motor is affected by unbalanced load and gravity in which the Ziegler-Nichols PID optimization method has been altered from the conventional model. The average of absolute error is 0.2308 degrees. However, optimized PI controller by Ziegler-Nichols method is able to eliminate the effect in term of final achieved position (steady state condition) and fulfil the objectives.

Abstract: Machining of extremely hard materials with complex shapes are very difficult in traditional processes due to which Electro Discharge Machining (EDM) is being used in many industries mainly aerospace, medical, automotive etc. EDM uses a series of sparks generated between tool-electrode and workpiece-anode to erode materials. These sparks are generated continuously inside the dielectric fluid and produce extreme heat which melt and vaporize the material. Pumping action of the dielectric fluid helps in removing excess material from machined surface. In this experimental work, the impact of input parameters namely current, pulse on time and voltage on two performance features like material removal rate (MRR) and surface roughness (Ra) have been investigated. Incoloy 800HT is used as work-piece and copper as tool material. Incoloy 800HT is an iron-nickel-chromium-based superalloy known for its ability to retain mechanical properties at high temperatures and its exceptional resistance to oxidation, carburization, and corrosion. Taguchi based grey analysis is used the multi-criterion decision-making (MCDM) method for optimization. From the analysis it is revealed that current has the most significant influence on both material removal rate (MRR) and surface roughness (SR), with higher current increasing MRR but deteriorating Ra. Micrograph analysis of machined surface is performed using scanning electron microscope (SEM).

Abstract: Commercial applications for Ti 6Al 4V, an alloy composed of titanium, aluminium, and vanadium, are possible. The features of titanium alloy include: Lightweight, non-magnetic, high melting point, outstanding fatigue strength, superior specific strength, great corrosion resistance, and biocompatibility. Reviewing the electro-discharge machining of titanium alloy (Ti 6Al 4V) as a workpiece, silicon carbide particle combined with EDM oil, and coated tungsten carbide electrode, this research examines this process. Dielectric fluid's impact on microhardness, surface finishing, TWR, and MRR. MRR is raised by silicon particles and coated tungsten carbide electrodes with EDM fluid. According to the study, the most important input parameters for determining TWR, MRR, surface finishing, and micro-hardness are voltage, current, pulse on time (Tonne), and pulse off time (Toff).

Abstract: 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.

Abstract: Composites are being used since decades and imparting excellent properties comparatively. It may be used in numerous industries because of its light weight and specific strength. Machinability of these materials is a concerned aspect. Conventional and The composites have been machined using unconventional machining techniques. Conventional methods are less suitable than non-conventional quoting the best surface finish and ability to machine complex parts. This article investigates the suitability of thermo-electric process for the machining of composites for higher surface quality and material removal. It includes the study of machining by die sinking, wire cut, powder mixed electric discharge machine in different matrix based composites along with the variation of reinforcement. Electric Discharge Machining (EDM) finds its suitability in machining of different metal matrix composites (MMC) more than the Polymer Matrix Composite (PMC) and Ceramic Matrix Composites (CMC). Variation in input parameters listed as Pulse duration, Voltage, Peak Current and Polarity is studied to obtain the optimum resulting parameters as Material Removal Rate (MRR), Surface Roughness (SR), Electrode Wear Rate (EWR) and Kerf Width. Material removal in PMC is 16% more in parallel fibre direction than with perpendicular. Low electrical conductance and high hardness of CMCs limits the use of EDM while natural ceramics are found more suitable for machining. Gap voltage, pulse on time and current are found most crucial in machining MMCs while quantifying material removal and surface roughness.

Abstract: The Al-B₄C composites are exclusively applicable in the structural components of automobiles and aerospace. It is also termed a hard-to-cut material. Hence, the Machining of such materials with firm design and close tolerance is a key concern in the present era of the manufacturing world, particularly through the conventional machining process. The prime motive of this paper is to evaluate the Machinability performance in terms of MRR and SR of the AA7050-7.5% B4C-T6 Composite using die-sinking EDM. The Taguchi L9 DOE was employed for the execution of experiments to assess the machinability performance of the composite in terms of MRR and Ra, with the simultaneous effect of input parameters such as Ip, Ton, and sand parking voltage (Sv). Further, the parameters were optimized using the Taguchi Analysis. ANOVA analysis was performed to evaluate the significance and contribution of the input parameters toward performance measures.

Abstract: Due to outstanding material qualities such as higher strength to weight ratio, resistance to corrosion and resistance to fatigue, titanium alloys (Ti-6Al-4V) are widely applied in aerospace industries. Such a challenging to machine and necessary expensive convenctional machinery materials can cut using Electrical Discharge Machining (EDM). This work involves the study of influence of process characteristics on the performance quality of EDM during machining of Ti-6Al-4V. The process characteristics that are considered in this study are Current (9-15amps) or Input power (I.P. of 3-5 kVA), pulse on (60-80 μsec) and pulse off (20-40μsec) times, the pressure of dielectric fluid (6-10 MPa). The effectiveness of the EDM is measured using rate of tool wear (TWR) and rate of material removal (MRR) during machining, taper angle and surface roughness (SR). Dry brass multi hole tool electrode is used along with deionized water as the dielectric medium. Taguchi L18 orthogonal design is used for experimentation. The optimal combination of process characteristics is determined.

Abstract: In the last few decades, non-traditional machining has increased the efficiency of the machining process. One of the most prevalent non-traditional methods of milling is through the use of an EDM process. Traditional machining methods can't easily machine materials with a complicated profile or hardness that EDM can handle. The industrial sector makes extensive use of EDM. Cryogenically treated copper electrodes and regular copper electrodes were used to conduct an experiment on an EN24 material using varied input parameters, such as electrode rotation, gap voltage, and discharge current. Electric discharge machining was used in a study. The Taguchi method is used to design experiments. Three input parameters were employed in an orthogonal L16 array to find an optimal value for each of the three components. OC (overcut), TWR (Tool wear rate), and Ra (surface roughness) are the three output variables. The S/N ratio can be used to determine the best values and relative relevance of each of these factors using a statistical analysis of variance (ANOVA) table. Additionally, the overcut, tool wear rate, and surface roughness of traditional and non-traditional EDM are examined. For the deep cryogenic and non-traditional machining method, conventional and non-traditional electric discharge machining methods were found to have optimal or dominant factors for the TWR and Ra.

Abstract: The dry-EDM process is environmentally neutral and enables to obtain good machining accuracy and relatively good surface quality. On the other hand, the application of dry-EDM is limited due to problems with the effective dissipation of heat from the machining zone and instability of material removal. The machining of Inconel 625 alloy was carried out in the carbon dioxide as a dielectric supplied to the machining gap through the channel in the working electrode, in the milling kinematics. In one of the investigated variants, the workpiece was submerged additionally in the deionized water during machining. The main aim of this research was to determine an influence of EDM milling in carbon dioxide with and without external workpiece cooling on the workpiece technological surface integrity ie. roughness, morphology and microhardness. The pulse time, current amplitude and gas pressure were selected as investigated parameters. Obtained results indicate significant differences in surface layer properties for both investigated machining variants.

Abstract: This paper emphasises the effect of the surfactant in the PMEDM process. The preparation of nanofluid is done by mixing and sonicating thoroughly into the deionised water is discussed. The effect of varying the graphene nanopowder concentration into the dielectric is also discussed. Also, the effect of surfactant SDS and CTAB in the machining process is elaborated at 0.1 and 0.2g per 800ml concentration. MRR improved by 21.27% and roughness by 18.91% at 0.2g and 8µs, 2A and 50V in 800ml deionised water. SDS provide better MRR and low roughness compared to CTAB at higher peak current and higher pulse on time Simultaneously, the addition of surfactant into the dielectric medium reduces the performance of the EDM process. The MRR varies from 21mg/min at 0g graphene to 45mg/min at 0.2g and then 31.81mg/min at 0.2g with 0.1g SDS, 43mg/min at 0.2g SDS, 28.33mg/min at 0.1g CTAB and 30mg/min at 0.2g CTAB. Debris size also varies with the input parameters.