Analysis of recast layer thickness and martensitic layer thickness in wire electrical discharge machining

2021 ◽  
Author(s):  
Khuvendra Yadav ◽  
Sharad K. Pradhan
Keyword(s):  
Layer Thickness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Recast Layer ◽  
Wire Electrical Discharge Machining ◽  
Recast Layer Thickness

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.

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.

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.

Surfactant and graphite powder–assisted electrical discharge machining of titanium alloy

2016 ◽  
Vol 231 (4) ◽  
pp. 641-657 ◽  
Author(s):  
Murahari Kolli ◽  
Adepu Kumar
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Graphite Powder ◽  
Recast Layer ◽  
Dielectric Fluid ◽  
Recast Layer Thickness

Surfactant and graphite powder–assisted electrical discharge machining was proposed and experiments were performed on titanium alloy in this investigation. Analysis was carried out to observe changes in dielectric fluid behaviour, material removal rate, surface roughness, recast layer thickness, surface topography and energy-dispersive X-ray spectroscopy. It was found out that the addition of surfactant to dielectric fluid (electrical discharge machining oil + graphite powder) improved the material removal rate and surface roughness. It was noticed to have reduced the recast layer thickness and agglomeration of graphite and sediment particles. Biface material migrations between the electrode and the workpiece surface were identified, and migration behaviour was powerfully inhibited by the mixing of surfactant. Surfactant added into dielectric fluid played an important role in the discharge gap, which increased the conductivity, and suspended debris particles in dielectric fluid reduced the abnormal discharge conditions of the machine and improved the overall machining efficiency.

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.

scholarly journals Study on Recast Layer Thickness of Microstructures Machined in micro-EDM with Different Electrodes

2021 ◽  
Author(s):  
Shenggui Chen ◽  
Man-qun Lian ◽  
Xiao-yu Wu ◽  
Jian-guo Lei ◽  
Hang Zhao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Layer Thickness ◽  
Electrical Discharge Machining ◽  
Negative Polarity ◽  
Copper Electrode ◽  
Recast Layer ◽  
304 Stainless Steel ◽  
Micro Edm ◽  
Tungsten Electrode ◽  
Recast Layer Thickness

Abstract Functional-surface microstructures are widely used in industrial practice. During the fabrication of microstructures in micro-electrical discharge machining (micro-EDM), the thermal and physical characteristics of both workpieces and electrode materials at room temperature and high temperatures have an important influence on surface quality and distribution of recast layer. In order to study the influence of different electrode material characteristics on the surface integrity of microstructures machined using micro-EDM, red copper, brass, copper-tungsten and tungsten electrode were used to perform micro-EDM on both Ti-6Al-4V alloy and 304 stainless steel. In the experiment, electrode with groove arrays featuring high copying accuracy and surface quality was designed to carry out powder mixed electrical discharge machining (PMEDM) on Ti-6Al-4V alloy, and the machining results were evaluated based on four indicators: microstructure morphology, tool electrode wear (TEW), material removal rate (MRR), and recast layer thickness (RLT). Simultaneously, the surface morphology and recast layer thickness changes of 304 stainless steel workpieces machined using the above four types of electrodes, using both normal polarity and negative polarity micro-EDM were quantitatively analyzed. The results showed that copper-tungsten electrode is recommended to machine Ti-6Al-4V alloy because it has a smaller TEW (139 µm), the highest MRR (255.39 mm3/min), and a thinner recast layer thickness (3.35 µm). This was followed by copper electrode, which featured good machining performance and machinability. When machining 304 stainless steel with negative polarity, the TEW of copper electrode and tungsten electrode was the smallest, and the thickness of recast layer was able to be effectively reduced to about 3 µm.

Sign in / Sign up

Export Citation Format

Share Document