Thermo-fluid multi-physics modeling and experimental verification of volumetric workpiece material removal by a discharge pulse in electric discharge machining process

2020 ◽  
Vol 53 (39) ◽  
pp. 395501
Author(s):  
Oguz Erdem ◽  
Can Cogun ◽  
Ibrahim Uslan ◽  
Murat Erbas
2010 ◽  
Vol 455 ◽  
pp. 345-349
Author(s):  
B.C. Xie ◽  
Zhen Long Wang ◽  
Yu Kui Wang ◽  
Jing Zhi Cui

In this paper, a thermo-physical model of the electric discharge machining process using finite element method is presented. In this model, parameters such as convection, the latent heat and the thermal properties based on temperature dependent etc. are studied to predict the temperature distribution in the workpiece. The temperature field simulation and experiment were carried out by adopting parameters through optimum pulse curve, and amending the effects of recast layer, the simulation results amended shows a better agreement with experimental results, indicating a theoretical foundation for mechanism of material removal in EDM machining.


Author(s):  
Hardeep Singh ◽  
Anirban Bhattacharya ◽  
Ajay Batish

Powder mixed electric discharge machining (PMEDM) is one of the modern developments in electric discharge machining (EDM) process. In the present work, finite element modeling has been carried out considering randomly oriented multiple sparks during PMEDM. Transient thermal analysis is done to obtain temperature distribution, volume removal, and proportion of volume removed by melting and evaporation at different current, pulse on time and fraction of heat that enters to work piece. Gradually growing spark behavior and Gaussian distribution of heat source is used to simulate multiple craters. Temperature distribution along radial direction shows peak temperature at center of spark and thereafter a gradual decrease with increase in radial distance. Along depth direction temperature sharply decreases that forms wider craters with shallow depth in PMEDM. Peak temperature and volume removal increases with current more rapidly. Volume removal by melting is much higher than evaporation at lower current settings and with higher current almost equal amount of material is removed by melting and evaporation thus reducing the re-solidification of melted material. Current plays a significant role behind the contribution of material removal by evaporation followed by fraction of heat. Increase in pulse on duration increases the total volume of material removal however does not significantly increase the proportion of volume removal by vaporization.


2019 ◽  
Vol 969 ◽  
pp. 715-719
Author(s):  
G. Gowtham Reddy ◽  
Balasubramaniyan Singaravel ◽  
K. Chandra Shekar

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 (Pon) , pulse off time (Poff), 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.


Author(s):  
Yash Pachaury ◽  
Puneet Tandon

In the present study, an attempt has been made to model the electric discharge machining process using the numerical simulation technique. Realistic parameters are added in the model such as variable fraction of heat going to the electrodes, and variation in the plasma flushing efficiency with the process parameters. Gaussian distributed heat flux is applied at the spark location and the two-dimensional heat conduction equation is solved with the help of finite element analysis technique to determine the temperature distribution within the two-dimensional process continuum, using averaged thermo-physical properties of the work material. Melting isotherms are determined and the material removed during a single discharge is obtained from it. Material removal rate is determined using a regression model for the plasma flushing efficiency. Experimental validation is made with the help of highly precise AGIE SIT experimental data. The material removal rate is also compared with state of the art research of other researchers. It has been observed that, at low value of the discharge energies, the proposed model is able to predict the experimental material removal rate better than that of the model proposed by other researchers. However, as the discharge energy increases, the accuracy of prediction decreases. The model can be used for achieving process parameter optimization hence saving both the costs and large lead times associated with determining optimized parameters experimentally.


1983 ◽  
Vol 105 (2) ◽  
pp. 132-138 ◽  
Author(s):  
A. Erden

Electric Discharge Machining process is investigated both theoretically and experimentally to determine the effects of electrode materials on the machining performance. For this purpose a single and isolated spark is physically and mathematically modelled, and its three phases; viz., Breakdown, Discharge and Erosion are investigated. Resolidified electrode materials as suspended particles in the dielectric liquid are found to be the most significant factor in the breakdown phase. Mathematical expressions relating the time lags to particle concentration are given which can be used to determine the effects of particle concentration on the machining performance. Discharge properties are shown to be dependent on the discharge medium which includes vapours of the electrode materials. The polarity effect has been studied both theoretically and experimentally. Some qualitative explanation is given for the erosion phase. Importance of electrical forces is discussed and a simple mathematical expression is given for the erosion phase. It is concluded that optimum machining conditions can only be obtained by proper selection of the tool material, workpiece material and discharge medium since they affect the initiation and development of the discharge and erosion of electrode materials.


2015 ◽  
Vol 813-814 ◽  
pp. 393-397
Author(s):  
Rajinder Kumar ◽  
Neel Kanth Grover ◽  
Amandeep Singh

Electric Discharge Machining (EDM) is one of the most commonly used non-traditional machining processes. Complex geometries can be easily manufactured using EDM. Material removal is achieved by producing continuous spark occurring between well shaped tool electrode and work piece. EDM does not involve direct contact of tool and work piece. Machining process involves a number of input variables like, current, voltage, pulse on/off which in turn affect the machining efficiency of EDM. These process parameters must be optimized to attain high material removal rate and low tool wear rate. The present paper presents theoptimization of tool wear rate of copper and brass electrode on machining of EN-47 using Response Surface Methodology (RSM).


Author(s):  
M. Kalayarasan ◽  
M. Murali

Silicon Nitride-Titanium Nitride ceramic composites are newly advanced material having the properties of high hardness, strength, toughness and low density. These kinds of materials are challenging to machine by conventional machining process because it causes severe tool wear due to its properties. Since the materials can be machined by non-conventional machining process like laser cutting and water jet, but these processes are limited. Electric discharge machining shows higher capability for cutting complex shapes with high accuracy. The present work focuses to optimize the process parameter for maximum material removal rate and minimum electrode wear rate. The experimental studies were conducted under varying pulse on time, pulse off time, dielectric pressure and discharge current. Taguchi L9 orthogonal array was used to design the experiments. Grey relational analysis and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was used to optimize the process parameter and the results were validated by the confirmation tests. Thus the machining parameter for electric discharge machine was optimized to achieve higher material removal rate and lower rate on electrode. The result shows that the proposed technique is being effective to optimize the machining parameter for electric discharge machining process.


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