scholarly journals Influence of Energy Parameters on Plasma Radius, Energy Fraction and Plasma Flushing Efficiency for a Single Discharge in EDM

2021 ◽  
Author(s):  
Bibeka Nanda Padhi ◽  
Sounak Kumar Choudhury ◽  
Ramkumar Janakarajan
Keyword(s):  
Layer Thickness ◽  
Discharge Current ◽  
Electrical Discharge ◽  
Recast Layer ◽  
Energy Fraction ◽  
Energy Parameters ◽  
Recast Layer Thickness ◽  
Plasma Radius ◽  
Plasma Flushing Efficiency ◽  
Pulse On Time

Abstract An electrical discharge forms a crater on the workpiece surface. The crater morphology estimates the performance parameters of the electrical discharge machining process. The energy parameters (gap voltage, discharge current and the pulse on time), the plasma channel radius and the energy fraction coming to the workpiece determine the molten cavity radius and depth. The plasma flushes away a portion of material from the molten cavity forming a crater and resolidification of the remaining molten material forms a recast layer. The plasma flushing efficiency determines the crater’s radius and depth. Few researchers have successfully expressed the plasma radius, energy fraction and plasma flushing efficiency in relation to two of the energy parameters, namely, discharge current and pulse on time but not as a gap voltage function. This work attempted to develop a thermo-physical model to express plasma radius, energy fraction and plasma flushing efficiency as a function of all three energy parameters, such as gap voltage, discharge current and pulse on time. Plasma flushing efficiency was calculated and plasma radius and energy fraction were estimated by inverse finite element method from the measured values of crater radius, crater depth and recast layer thickness. The expressions for plasma radius, energy fraction and plasma flushing efficiency were found out from the regression equations obtained from the designed data set using the Taguchi method. Validation shows that the modeled and experimental values of crater radius, crater depth, and recast layer thickness agree well.

Experimental investigations on surface integrity issues of Inconel-690 during wire-cut electrical discharge machining process

2016 ◽  
Vol 232 (4) ◽  
pp. 731-741 ◽  
Author(s):  
M Sreenivasa Rao ◽  
N Venkaiah
Keyword(s):  
Surface Roughness ◽  
Layer Thickness ◽  
Process Parameters ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Recast Layer ◽  
Machining Process ◽  
Micro Hardness ◽  
Recast Layer Thickness ◽  
Inconel 690

Nickel-based alloys are finding a wide range of applications due to their superior properties of maintaining hardness at elevated temperatures, low thermal conductivity and resistance to corrosion. These materials are used in aircraft, power-generation turbines, rocket engines, automobiles, nuclear power and chemical processing plants. Machining of such alloys is difficult using conventional processes. Wire-cut electrical discharge machining is one of the advanced machining processes, which can cut any electrically conductive material irrespective of its hardness. One of the major disadvantages of this process is formation of recast layer as it affects the properties of the machined surfaces. In this study, experimental investigation has been carried out to study the effect of wire-cut electrical discharge machining process parameters on micro-hardness, surface roughness and recast layer while machining Inconel-690 material. Interestingly, hardness of the machined surface was found to be lower than that of the bulk material. The micro-hardness and recast layer thickness are inversely related to the variation of process parameters. Recast layer thickness, surface roughness and hardness of the wire-cut electrical discharge machined surfaces of Inconel-690 are found to be in the range of 10–50 µm, 0.276–3.253 µm and 122–171 HV, respectively, for different conditions. The research findings and the data generated for the first time on hardness and recast layer thickness for Inconel-690 will be useful to the industry.

scholarly journals A Soft Computing-Based Analysis of Cutting Rate and Recast Layer Thickness for AZ31 Alloy on WEDM Using RSM-MOPSO

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 635
Author(s):  
Kapil K. Goyal ◽  
Neeraj Sharma ◽  
Rahul Dev Gupta ◽  
Gurpreet Singh ◽  
Deepika Rani ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Hybrid Approach ◽  
Optimal Solution ◽  
Az31 Alloy ◽  
Recast Layer ◽  
Response Characteristics ◽  
Recast Layer Thickness ◽  
Cutting Rate ◽  
Pulse On Time ◽  
Pulse Off Time

In the present research, the AZ31 alloy is machined by wire-cut electric discharge machining (WEDM). The experiments were designed according to the Box-Behnken design (BBD) of response surface methodology (RSM). The input process variables, namely servo feed (SF), pulse on-time (Ton), servo voltage (SV), and pulse off-time (Toff), were planned by BBD, and experiments were performed to investigate the cutting rate (CR) and recast layer thickness (RCL). The analysis of variance (ANOVA) was performed to determine the influence of machining variables on response characteristics. The empirical models developed for CR and RCL were solved using Multi-Objective Particle Swarm Optimization (MOPSO). Pareto optimal front is used for the collective optimization of CR and RCL. The optimal solution suggested by the hybrid approach of RSM-MOPSO is further verified using a confirmation test on the random setting indicated by the hybrid algorithm. It is found that the minimum RCL (6.34 µm) is obtained at SF: 1700; SV: 51 V; Toff: 10.5 µs; and Ton: 0.5 µs. However, maximum CR (3.18 m/min) is predicted at SF: 1900; SV: 40 V; Toff: 7 µs; and Ton: 0.9 µs. The error percentage of ±5.3% between the experimental results and predicted solutions confirms the suitability of the proposed hybrid approach for WEDM of AZ31.

Correlation of surface roughness and recast layer thickness in electrical discharge machining

2015 ◽  
Vol 231 (3) ◽  
pp. 414-424 ◽  
Author(s):  
Yakup Yildiz ◽  
Murali M Sundaram ◽  
Kamlakar P Rajurkar ◽  
Ahmet Altintas
Keyword(s):  
Surface Roughness ◽  
Layer Thickness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
Processing Technique ◽  
Recast Layer ◽  
Image Processing Technique ◽  
Recast Layer Thickness ◽  
Two Parameters

Electrical discharge machining (EDM) is an extensively used method in the machining of electrically conductive materials. Recast or white layer formation is undesirable, but inevitable, result of EDM and needs to be understood and accurately determined to efficiently perform post-treatment processes for removing the recast layer caused by EDM process. In this study, recast layer thickness and surface roughness data obtained from experimental study were analyzed and a correlation between these two parameters has been established. Image-processing technique has been used for obtaining of recast layer thickness data. It was observed that the correlation between recast layer thickness and surface roughness increases remarkably with the increase of working current and pulse time. The correlation obtained in this study has the potential to predict the recast layer thickness on spark-eroded surfaces from simple surface roughness values instead of using the prevailing time-consuming and tedious etching and polishing method. The possible approximation of the recast layer thickness using a thermal model is also discussed.

Investigation on material removal rate, surface and subsurface characteristics in wire electro discharge machining of Ti50Ni50-xCux shape memory alloy

2015 ◽  
Vol 232 (2) ◽  
pp. 164-177 ◽  
Author(s):  
M Manjaiah ◽  
S Narendranath ◽  
S Basavarajappa ◽  
VN Gaitonde
Keyword(s):  
Shape Memory ◽  
Layer Thickness ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Recast Layer ◽  
Phase Changes ◽  
Machined Surface ◽  
Recast Layer Thickness ◽  
Pulse On Time

TiNiCu shape memory alloys have superior properties as compared with NITINOL due to their greater ductility, reduced hysteresis temperature range, and quick actuation response. The present article investigates the surface and subsurface modifications occurring due to wire electro discharge machining of Ti50Ni50-xCux shape memory alloy. The machining experiments were performed considering the pulse on time, pulse off time, and servo voltage as the process parameters. The influence of these parameters was studied on the material removal rate, surface roughness, recast layer thickness, microhardness, and phase changes in the machined surface. Longer pulse on time causes greater discharge energy, hence leading to higher material removal rate, surface roughness, and recast layer thickness. The machined surface hardness increased up to 900 Hv, which is about 59% increase with respect to the base material for longer pulse on time due to the recast layer thickness and the formation of oxides. A phase change on the machined surface was observed to cause the shape recoverability of the alloy. The microstructure, composition through EDAX, and the phase changes of the machined surface are also discussed in the article.

Evaluation of Recast Layer Thickness of Electrical Discharge Machined AISI 202 Stainless Steel with Various Pulse Generators

2015 ◽  
Vol 766-767 ◽  
pp. 518-522 ◽  
Author(s):  
S. Vignesh ◽  
B. Mohan ◽  
T. Muthuramalingam ◽  
S. Karthikeyan
Keyword(s):  
Stainless Steel ◽  
Layer Thickness ◽  
Electrical Discharge ◽  
Pulse Generator ◽  
Electrical Discharge Machining ◽  
Recast Layer ◽  
Machining Process ◽  
Pulse Generators ◽  
Recast Layer Thickness ◽  
Energy Pulse

Many of the recent developments in the fields such as aerospace, automobile and nuclear engineering industries are partly due to the increasing usage of difficult-to-machining materials. The machining of these materials is very tedious and time consuming process. Electrical discharge machining process has been developed to overcome these difficulties. It is very important to reduce the recast layer thickness of the machined workpiece using EDM process for improving the surface integrity. In the present study, an attempt has been made to study the effect of conventional transistor pulse generator and modified iso current pulse generator on recast layer thickness. In this study, machining experiments have been conducted on AISI 202 stainless steel with transistor pulse generator and iso energy pulse generator in electrical erosion process. The effects of these pulse generators on recast layer have been evaluated and analyzed. From the experimental results, it has been detected that the iso energy pulse generator has produced lower thickness of recast layer than conventional transistor pulse generator.

Tool wear estimating model considering modeling improvement factors in electrical discharge machining process based on physical properties of tool electrodes

2016 ◽  
Vol 231 (5) ◽  
pp. 850-866
Author(s):  
Mohammadhasan Joudivand Sarand ◽  
Mohammadreza Shabgard ◽  
Mohammad Jodari Saghaie ◽  
Laya Joudivand Sarand
Keyword(s):  
Finite Element ◽  
Heat Conduction ◽  
Tool Wear ◽  
Finite Element Model ◽  
Element Model ◽  
Recast Layer ◽  
Inverse Heat Conduction ◽  
Energy Fraction ◽  
Recast Layer Thickness ◽  
Plasma Flushing Efficiency

A comprehensive numerical model is introduced in this article for estimating the tool wear based on finite element model and inverse heat conduction techniques considering the interactive and direct effects of the experimental factors of recast layer thickness, anode energy fraction and plasma flushing efficiency. The individual and interactive effects of the major thermo-physical and electro-physical parameters have been modeled to improve the introduced tool wear estimation procedure. Comparison of the numerical results with the experimental observations indicated that the developed finite element model and inverse heat conduction process was capable of predicting the tool wear with high accuracy. Additionally, application of analysis of variance technique showed that the introduced mathematical models for estimating anode energy fraction, plasma flushing efficiency and recast layer thickness are statistically significant and adequate which means that the proposed equations can be used for a variety of physical, electrical and thermal variables’ combinations.

scholarly journals The Effect of Discharge Current and Pulse-On Time on Biocompatible Zr-based BMG Sinking-EDM

2020 ◽  
Vol 10 (1) ◽  
pp. 401-407
Author(s):  
Yanuar Rohmat Aji Pradana ◽  
Aldi Ferara ◽  
Aminnudin Aminnudin ◽  
Wahono Wahono ◽  
Jason Shian-Ching Jang
Keyword(s):  
Surface Roughness ◽  
Metallic Glasses ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Hardness ◽  
Recast Layer ◽  
Surface Evaporation ◽  
Pulse On Time

AbstractThe machinability information of Zr-based bulk metallic glasses (BMGs) are recently limited but essential to provide technological recommendation for the fabrication of the medical devices due to the material’s metastable nature. This study aims to investigate the material removal rate (MRR) and surface roughness under different current and pulse-on time of newly developed Ni- and Cu-free Zr-based BMG using sinking-electrical discharge machining (EDM). By using weightloss calculation, surface roughness test and scanning electron microscopy (SEM) observation on the workpiece after machining, both MRR and surface roughness were obtained to be increased up to 0.594 mm3/min and 5.50 μm, respectively, when the higher current was applied. On the other hand, the longer pulse-on time shifted the Ra into the higher value but lower the MRR value to only 0.183 mm3/min at 150 μs. Contrary, the surface hardness value was enhanced by both higher current and pulse-on time applied during machining indicating different level of structural change after high-temperature spark exposure on the BMG surface. These phenomena are strongly related to the surface evaporation which characterize the formation of crater and recast layer in various thicknesses and morphologies as well as the crystallization under the different discharge energy and exposure time.

scholarly journals Analysis, predictive modelling and multi-response optimization in electrical discharge machining of Al-22%SiC metal matrix composite for minimization of surface roughness and hole overcut

2020 ◽  
Vol 7 ◽  
pp. 20 ◽  
Author(s):  
Subhashree Naik ◽  
Sudhansu Ranjan Das ◽  
Debabrata Dhupal
Keyword(s):  
Surface Roughness ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Discharge Current ◽  
Metal Matrix ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Parameters ◽  
Response Optimization ◽  
Pulse On Time

Due to the widespread engineering applications of metal matrix composites especially in automotive, aerospace, military, and electricity industries; the achievement of desired shape and contour of the machined end product with intricate geometry and dimensions that are very challenging task. This experimental investigation deals with electrical discharge machining of newly engineered metal matrix composite of aluminum reinforced with 22 wt.% of silicon carbide particles (Al-22%SiC MMC) using a brass electrode to analyze the machined part quality concerning surface roughness and overcut. Forty-six sets of experimental trials are conducted by considering five machining parameters (discharge current, gap voltage, pulse-on-time, pulse-off-time and flushing pressure) based on Box-Behnken's design of experiments (BBDOEs). This article demonstrates the methodology for predictive modeling and multi-response optimization of machining accuracy and surface quality to enhance the hole quality in Al-SiC based MMC, employing response surface methodology (RSM) and desirability function approach (DFA). Finally, a novel approach has been proposed for economic analysis which estimated the total machining cost per part of rupees 211.08 during EDM of Al-SiC MMC under optimum machining conditions. Thereafter, under the influence of discharge current several observations are performed on machined surface morphology and hole characteristics by scanning electron microscope to establish the process. The result shows that discharge current has the significant contribution (38.16% for Ra, 37.12% in case of OC) in degradation of surface finish as well as the dimensional deviation of hole diameter, especially overcut. The machining data generated for the Al-SiC MMC will be useful for the industry.

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