Papers by Keyword: EDM

Abstract: Electric Discharge Machining (EDM) is a thermo-electrical disintegration process, utilized to cut hard materials into complex shapes. In EDM, the three vital components are work-piece material, electrode material and dielectric liquid. The significant function of the dielectric fluid is to produce a breakdown voltage for creating a spark between work-piece and electrode. This spark creates ionization by plasma generation and it expels the material from work-piece. In most cases, hydrocarbon-based dielectric liquid is preferred in the EDM process. This kind of dielectric liquid generates hazardous gases which are harmful to people, environment and ecological balances. In this experiment, Canola oil is utilized and the outcomes are compared. The input parameters are Pulse on/off time, current and gap voltage. Copper, Brass and Tungsten-Copper (Alloy) are used as electrodes. The output values from the experiments are Surface Roughness (SR), Electrode Wear Rate (EWR) and Material Removal Rate (MRR). The outcomes demonstrated that Canola oil-based dielectric fluid has comparable properties of conventional based dielectric fluid. This Canola based dielectric gives more prominent MRR value than EDM oil-based dielectric liquid and furthermore higher EWR and SR values are recorded. The proposed Canola oil-based dielectric fluid is biodegradable and has improved suitability in machining.

Abstract: Electric discharge machining (EDM) is a spark erosion process widely used to machine difficult-to-cut material by conventional machining method. The major elements of EDM process are work piece, electrode and dielectric fluid. In this work, an attempt is made to investigate vegetable oil as dielectric fluid and their process performance for machining of Inconel 800 in EDM process. The effects of dielectric fluids are investigated with vegetable oils and conventional dielectric fluid namely Sunflower oil and Kerosene respectively. The important input variables considered in this study are pulse on/off time, current and voltage. Three levels of energy setting are employed for machining with selected dielectric fluids. The output parameters are considered tool wear rate (TWR), material removal rate (MRR) and surface roughness (SR). In the present study effect of vegetable oil as dielectric fluid and the results are compared with conventional dielectric fluid. The result revealed that vegetable oils are successfully employed as dielectric fluids and they are having similar dielectric properties and erosion mechanism compared to conventional dielectric fluid. This proposed vegetable oil based dielectric fluids showed higher MRR than conventional dielectric. It shows vegetable oils have similar dielectric properties compared with conventional dielectric and it is possible to replace as dielectric fluid in EDM process.

Abstract: This paper presents a study on analysis of influences of the surface roughness in Electrical Discharge Machining 90CrSi tablet shape punches with the use of copper electrode. In this paper, 9 experimental runs were designed and conducted by using Taguchi method. In addition, 4 process parameters including the gap voltage, the pulse current, the pulse on time and the pulse off time were investigated. The influences of these input parameters on the surface roughness were evaluated by analysing variance. Also, from the experimental results, optimum values of the input parameters for getting the minimum surface roughness were proposed.

Abstract: Hybrid metal matrix composites (HMMC) are advanced materials which are not simply depicting in improvement of mechanical properties but also on characteristics of machinability for thorny shapes to machine. Electric discharge machining (EDM) shows a potential technique for machining hybrid metal matrix composites. An investigation is done on hybrid metal matrix composite for response parameters like MRR, TWR by conducting a range of experiments with choosing typical process parameters such as peak current, tool lift, pulse-on time and pulse-off time.

Abstract: Electric Discharge Machining (EDM) is used to machine complex geometries of difficult to cut materials in the area of making dies, mould and tools. Currently, hydrocarbon based dielectric fluids are used in EDM and which plays major role for material removal and it emits harmful emission. In this work, vegetable oil is attempted as dielectric fluid and their performance are studied during processing of AISI P20 steel. The effect of pulse on time (P_on) , pulse off time (P_off), and current (A) on Material Removal Rate (MRR), Tool wear rate (TWR) and surface roughness (SR) are analyzed. The result showed that vegetable oils are given good machining performance than conventional dielectric fluids. These proposed dielectric fluids are biodegradable eco friendly and enhance sustainability in EDM process.

Abstract: In this paper, some preliminary experimental investigations have been reported for analysing the machining performance characteristics viz. Material Removal Rate (MRR) & Tool Wear Rate (TWR). Electrical Discharge Machining (EDM) of Inconel-718 alloy via helical threaded cryogenically treated rotary copper tool electrode is conducted. Impact of machining factors viz. peak current (I_p), pulse-on time (T_on), tool rotation (N_t) & hole depth (h) were investigated using Taguchi’s L₉ (3⁴) Orthogonal Array (OA). Optimum arrangements of factors for greatest MRR & least TWR were found in current study. Results predicts that I_p & N_t are two most affecting machining factors that affects MRR. Whereas I_p & T_on are two most affecting machining factors that affects TWR.

Abstract: Inconel-718 is a nickel based super alloy (difficult-to-cut material) used in aerospace industry. Analysis of machining performances viz. Over Cut (OC) & Surface Roughness (SR) for Inconel-718 through rotary Cu-pin tool electrode have been carried out. Peak current (I_p), pulse-on time (T_on), tool rotation (N_t) & hole depth (h) were used as input factors in Electrical Discharge Drilling (EDD) of Inconel-718 work-piece. Effect of input parameters on performance characteristics like OC & SR were found by Taguchi’s L₉ (3⁴) orthogonal array. It is reveals that I_p & h are most affecting factors that affects OC & SR. The Scanning Electron Microscope image was used to measure diameter of hole on work-piece after machining.

Abstract: This research aim to improve the machining properties of the EDM for cemented carbide. The new methods were designed and proposed to use the ultrasonic vibration technique. Two types of USEDM systems were produced. One had a low frequency of 29 kHz with a large vibration amplitude, while the other had a high frequency of 59 kHz with a small amplitude. The Cu-W tool electrode was synchronized with the devised vibration system, and several discharge generation conditions were carried out on the cemented carbide material. The results showed that the highest machining efficiencies were obtained from the ultrasonic low frequency of 29 kHz with a large vibration amplitude. The MRR, TWR and surface roughness of the ultrasonic low frequency with the large vibration amplitude were better than the high frequency system with the small amplitude system. It was clarified that the ultrasonic vibration with the large amplitude could assist the material removal behavior of the discharge.

Abstract: Electrical discharge machining (EDM) process is widely used to process hard materials in the industry. The process of electrical discharge is changed and called PMEDM when alloy powder is added in the oil dielectric. In the current study, the effect of tungsten carbide alloy powder added in the dielectric on the surface roughness (R_a) and the micro hardness of surface (HV) status of the workpiece SKD61 after machining is investigated. Studies show that the surface roughness and the micro hardness of surface obtained by PMEDM is generally better than that by normal EDM. The method can be applied for improving surface quality such as improving strengthening of molds and machine parts.

Abstract: Electrical Discharge Machining (EDM) is a machine for cutting workpieces with thermal energy derived from electrical spark from tool (cathode) to workpiece (anode). As EDM process requires a dielectric fluid in the cutting operation, the characteristics of the dielectric fluid play an essential role for obtaining excellent cutting. Jatropha curcas has been demonstrated for use as a dielectric fluid in EDM process. However, the drawback is that the Rate of Metal Removal (RMR) is lower than that of generally-used dielectric fluid in industry. We consider that the cause is a much higher viscousity of the jatropha curcas. This study was conducted to investigate the characteristics of a new dielectric fluid mixture of jatropha curcas and kerosene. Kerosene was used in the mixture to reduce the viscousity of the jatropha curcas since the kerosene has a much lower viscousity. The measurement of the viscousity of the fluid mixture was performed using an Ostwald viscousimeter. Evidently, when the jatropha curcas mixed with the kerosine the viscousity of the mixture is lower than that of the pure jatropha curcas. The effects of the viscousity of the fluid mixture were investigated by measuring the RMR and Tool Wear Rate (TWR). The RMR and TWR were determined by calculating the difference in the weight of the workpiece and the tool, respectively, before and after the cutting for a certain cutting interval. The measurements were carried out for eleven different concentration of the fluid mixture by varying the current of 15 and 21 Amp, with replication of 3 times. As the result, the energy released during the cutting process affects the values of TWR and RMR. It was also found that in contrast to the effect on TWR, the RMR was not influenced by the viscousity of the mixture.