Effect of impregnated powder materials on surface integrity aspects of Inconel 625 during electrical discharge machining

2016 ◽  
Vol 232 (7) ◽  
pp. 1259-1272 ◽  
Author(s):  
Gangadharudu Talla ◽  
Soumya Gangopadhyay ◽  
CK Biswas
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Surface Integrity ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Inconel 625 ◽  
Powder Materials ◽  
Powder Concentration ◽  
Pulse On Time

In recent times, nickel-based super alloys are widely utilized in aviation, processing, and marine industries owing to their supreme ability to retain the mechanical properties at elevated temperature in combination with remarkable resistance to corrosion. Some of the properties of these alloys such as low thermal conductivity, strain hardening tendency, chemical affinity, and presence of hard and abrasives phases in the microstructure render these materials very difficult-to-cut using conventional machining processes. In this work, an experimental setup was developed and integrated with the existing electrical discharge machining system for carrying out powder-mixed electrical discharge machining process for Inconel 625. The experiments were planned and conducted by varying five different variables, that is, powder concentration, peak current, pulse-on time, duty cycle, and gap voltage based on the central composite design of response surface methodology. Effects of these parameters along with powder concentration were investigated on various surface integrity aspects including surface morphology, surface roughness, surface microhardness, change in the composition of the machined surface, and residual stress. Results clearly indicated that addition of powder to dielectric has significantly improved surface integrity compared to pure dielectric. Among the powders used, silicon has resulted in highest microhardness, that is, almost 14% more than graphite. Lowest surface roughness (approximately 50% less than pure kerosene) and least residual stress were obtained using silicon powder (approximately 8% less than graphite-mixed dielectric). Relative content of nickel was reduced at the expense of Nb and Mo after addition of powders like aluminum and graphite in dielectric during electrical discharge machining.

scholarly journals Electrical Discharge Machining with SiC Powder-Mixed Dielectric: An Effective Application in the Machining Process of Hardened 90CrSi Steel

Machines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 36 ◽  
Author(s):  
Thi-Hong Tran ◽  
Manh-Cuong Nguyen ◽  
Anh-Tung Luu ◽  
The-Vinh Do ◽  
Thu-Quy Le ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Pulse Current ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Powder Concentration ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time ◽  
Edm Process

As a successful solution applied to electrical discharge machining (EDM), powder-mixed electrical discharge machining (PMEDM) has been proposed as an upgrade of the EDM process. The optimization of the process parameters of PMEDM is essential and pressing. In this study, Taguchi methods and analysis of variance (ANOVA) were used to find the main parameters affecting surface roughness in the EDM process with SiC powder-mixed-dielectric of hardened 90CrSi steel. The PMEDM parameters selected were the powder concentration, the pulse-on-time, the pulse-off-time, the pulse current, and the server voltage. It was found that SiC powder exhibits positive effects on reducing surface roughness. The roughness obtained with the optimum powder concentration of 4 g/L was reduced by 30.02% compared to that when processed by conventional EDM. Furthermore, the pulse-off-time was found to be the most influential factor that gave an important effect on surface roughness followed by the powder concentration. The EDM condition including a powder concentration of 4 g/L, a pulse-on-time of 6 µs, a pulse-off-time of 21 µs, a pulse current of 8 A, and a server voltage of 4 V resulted in the best surface roughness.

scholarly journals Surface Roughness Prediction for Steel 304 In Edm Using Response Graph Modeling

2018 ◽  
Vol 14 (4) ◽  
pp. 115-124 ◽  
Author(s):  
Shukry H. Aghdeab ◽  
Nareen Hafidh Obaeed ◽  
Marwa Qasim Ibraheem
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Applied Current ◽  
Graph Modeling ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
The Impact ◽  
Off Time

Electrical Discharge Machining (EDM) is a non-traditional cutting technique for metals removing which is relied upon the basic fact that negligible tool force is produced during the machining process. Also, electrical discharge machining is used in manufacturing very hard materials that are electrically conductive. Regarding the electrical discharge machining procedure, the most significant factor of the cutting parameter is the surface roughness (Ra). Conventional try and error method is time consuming as well as high cost. The purpose of the present research is to develop a mathematical model using response graph modeling (RGM). The impact of various parameters such as (current, pulsation on time and pulsation off time) are studied on the surface roughness in the present research. 27 samples were run by using CNC-EDM machine which used for cutting steel 304 with dielectric solution of gas oil by supplied DC current values (10, 20, and 30A). Voltage of (140V) uses to cut 1.7mm thickness of the steel and use the copper electrode. The result from this work is useful to be implemented in industry to reduce the time and cost of Ra prediction. It is observed from response table and response graph that the applied current and pulse on time have the most influence parameters of surface roughness while pulse off time has less influence parameter on it. The supreme and least surface roughness, which is achieved from all the 27 experiments is (4.02 and 2.12µm), respectively. The qualitative assessment reveals that the surface roughness increases as the applied current and pulse on time increases

Surface Study in a Non-conventional (Electrical Discharge Machining) Process for Grade 6 Titanium Material

2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Md. Ashikur Rahman Khan ◽  
M. M. Rahman
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Machined Surface ◽  
Titanium Material ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time

Electrical discharge machining (EDM) produces complex shapes and permits high-precision machining of any hard or difficult-to-cut materials. The performance characteristics such as surface roughness and microstructure of the machined face are influenced by numerous parameters. The selection of parameters becomes complicated. Thus, the surface roughness (Ra) and microstructure of the machined surface in EDM on Grade 6 titanium alloy are studied is this study. The experimental work is performed using copper as electrode material. The polarity of the electrode is maintained as negative. The process parameters taken into account in this study are peak current (Ip), pulse-on time (Ton), pulse-off time (Toff), and servo-voltage (Sv). A smooth surface finish is found at low pulse current, small on-time and high off-time. The servo-voltage affects the roughness diversely however, a finish surface is found at 80 V Sv. Craters, cracks and globules of debris are appeared in the microstructure of the machined part. The size and degree of craters as well as cracks increase with increasing in energy level. Low discharge energy yields an even surface. This approach helps in selecting proper process parameters resulting in economic EDM machining. 

Influence of Some Factors on Surface Roughness Parameters at Electrical Discharge Machining

2014 ◽  
Vol 657 ◽  
pp. 291-295 ◽  
Author(s):  
Vasile Ciubotariu ◽  
Adrian Câcu ◽  
Ioana Andreea Rotundu ◽  
Marius Marian Cucoş ◽  
Margareta Coteaţă
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Operating Conditions ◽  
Machining Process ◽  
Roughness Parameters ◽  
Power Functions ◽  
Surface Roughness Parameters ◽  
Pulse On Time ◽  
Pulse Off Time

There are various electrical discharge machining techniques and experimental researches could be necessary in order to establish the operating conditions for an optimal machining process. Some theoretical considerations concerning the process of generating the surface asperities as a consequence of the electrical discharge machining process were elaborated. Experimental method was applied in order to evaluate influence exerted by some input factors (pulse on time, pulse off time, average intensity of electric current) on certain surface roughness parameters (Ra, Rz, Ry and Rq). One developed an experimental research by using a copper tool electrode and a workpiece made of high speed steel, in accordance with the requirements specific to a complete factorial experiment with three independent variables at three levels. A ram electrical discharge machine was used as machining equipment. One measured the surface roughness parameters specific to the machined surfaces. Empirical mathematical models of type power functions were established by using the method of least squares.

scholarly journals Surface Analysis of Wire-Electrical-Discharge-Machining-Processed Shape-Memory Alloys

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 530 ◽  
Author(s):  
Rakesh Chaudhari ◽  
Jay J. Vora ◽  
Vivek Patel ◽  
L. N. López de Lacalle ◽  
D. M. Parikh
Keyword(s):  
Surface Roughness ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Surface Integrity ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Wire Electrical Discharge Machining ◽  
Machined Surface ◽  
Edx Analysis

Shape-memory alloys such as nitinol are gaining popularity as advanced materials in the aerospace, medical, and automobile sectors. However, nitinol is a difficult-to-cut material because of its versatile specific properties such as the shape-memory effect, superelasticity, high specific strength, high wear and corrosion resistance, and severe strain hardening. Anunconventional machining process like wire-electrical-discharge-machining (WEDM) can be effectively and efficiently used for the machining of such alloys, although the WEDM-induced surface integrity of nitinol hassignificant impact on material performance. Therefore, this work investigated the surface integrity of WEDM-processed nitinol samples using digital microscopy imaging, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. Three-dimensional analysis of the surfaces was carried out in two different patterns (along the periphery and the vertical plane of the machined surface) andrevealed that surface roughness was maximalat the point where the surface was largely exposed to the WEDM dielectric fluid. To attain the desired surface roughness, appropriate discharge energy is required that, in turn, requires the appropriate parameter settings of the WEDM process. Different SEM image analyses showed a reduction in microcracks and pores, and in globule-density size at optimized parameters. EDX analysis revealed the absence of wire material on the machined surface

Surface integrity of fatigue strength of nickel based super alloy in turning by wire electrical discharge process

2021 ◽  
pp. 095440542110144
Author(s):  
Ebrahim Hosseini ◽  
Shafiqur Rehman ◽  
Ashkan Alimoradi
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Surface Integrity ◽  
Discharge Current ◽  
Electrical Discharge ◽  
Spindle Speed ◽  
Optimum Level ◽  
Discharge Process ◽  
Pulse On Time

In the present work, it is studied how the wire electrical discharge turning factors influence the surface integrity and subsequent fatigue life of Inconel 718. Discharge current, pule on time and spindle speed were taken into account as factors while characteristics to be studied are fatigue life, surface roughness, residual stress, and hardness. It was identified that a sample which is machined by discharge current of 5 A, pulse on time of 600 µs and work rotational speed of 250 rpm yields maximum fatigue life about 14,400 cycles. After finding the optimum level, statistical models of responses were also generated to correlate input-output relationship as well to identify which parameters has the greatest impact on performance measures. It was found from the results that fatigue life and residual stress is majorly influenced by pules current; while the surface roughness and hardness are significantly affected by spindle speed and pulse o time, respectively.

Roughness of Small Diameter External Cylindrical Surfaces Obtained by Ram Electrical Discharge Machining

2015 ◽  
Vol 809-810 ◽  
pp. 411-416 ◽  
Author(s):  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Hans Peter Schulze ◽  
Oana Dodun ◽  
Ciprian Mircescu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Roughness Parameter ◽  
Small Diameter ◽  
Machining Process ◽  
Surface Generation ◽  
Surface Roughness Parameter ◽  
Pulse On Time ◽  
Pulse Off Time

In order to obtain small diameter external surfaces by ram electrical discharge machining from plate workpieces, tubular tool electrodes could be used. In such a case, one can appreciate that the obtained surface is a simple concatenation of cavities appeared as a consequence of electrical discharges developed between the asperities existing initially on the active surface of the tool electrode and surface to be machined of the workpiece. The analysis of the surface generation as a consequence of the electrical discharge machining process showed that due to the surface tensions, a leveling phenomenon could be taken into consideration. An experimental study of influence exerted by some input factors on the surface roughness parameter Ra was designed and achieved. One noticed that the increase of the pulse on time, pulse off time and peak current intensity determines an increase of the surface roughness parameter Ra. By mathematical processing of the experimental results, an empirical model type power function was determined. The examination of the machined surface by means of an optical microscope showed the existence of microcavities generated by the electrical discharge, while the material melted and re-solidified was placed as a bordure of the microcavities.

scholarly journals Optimization of Wire Cut Electro Discharge Machining Process Parameters for Aluminium 6082 by using Taguchi Technique

2021 ◽  
Vol 9 (12) ◽  
pp. 2257-2262
Author(s):  
Mahesh Muley
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Manufacturing Industry ◽  
Metal Cutting ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Research Work ◽  
Machining Process ◽  
Pulse On Time ◽  
Pulse Off Time

Abstract: The manufacturing industry is changing very drastically in all the aspect regarding the manufacturing technology as well as the quality concern as per as the quality is considered. Quality is becoming a significant trend in todays growing automobile industry. In the field of metal cutting operations, the surface roughness is becoming more dominant parameter as per as the quality of the component is considered. Electrical discharge machining is becoming a most powerful non conventional machining which is being widely used in the field of machining. Most specifically our work was conducted on the electrical discharge wire cut machining for achieving the desired surface roughness (Ra) and adequate material removal rate (MRR). The input parameter for our research work were selected as Peak current, pulse on time & pulse off time while the output parameter was selected as MRR and the surface roughness. Aluminum 6082 Grade material is used as a specimen and the research methodology implemented for the research work is taguchi and Anova. Keywords: Wire cut EDM, Taguchi, MRR surface roughness, Anova.

scholarly journals Performance Evaluation of SiC Powder Mixed Electrical Discharge Machining: A Case of Wire Cut Mode with Re-Circulating Molybdenum Wire

2021 ◽  
Author(s):  
Muhammad Qaiser Saleem ◽  
Maham Naqvi ◽  
Sarmad Ali Khan ◽  
Nadeem Ahmad Mufti ◽  
Kashif Ishfaq
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Molybdenum Wire ◽  
Powder Concentration ◽  
Pulse On Time ◽  
Wire Wear

Abstract Review of the available literature on powder mixed electrical discharge machining (PMEDM) indicates, that most of the research has been done for “die sinking machining mode” whereas the “wire cut machining mode” has not received due attention despite being an important process variant. This work employs Silicon Carbide (SiC) powder mixed dielectric fluid for machining of AISI D2 in “wire cut” mode with re-circulating molybdenum wire (an economic and chemically stable proposition as tool). The effect of five process parameters (powder concentration, peak current, pulse on time, nozzle flushing pressure and stand-off distance) have been evaluated on surface roughness, kerf width, material removal rate and wire wear ratio using Taguchi’s approach. It is found that for surface roughness, higher current and low to moderate concentration levels (2 to 4g/l) deteriorate surface quality; higher values of pressure and stand-off distance are also seen to adversely affect it. For material removal rate, pulse on time as well as its interactions with powder concentration and current, are statistically significant. A higher pulse on with smaller and moderate powder concentrations (2g/l and 4g/l) reduces MRR. For wire wear ratio, current is the sole significant factor (PCR of ~ 65%). SEM analysis of the machined workpiece for the maximum MRR condition quantifies recast layer as ~ 19microns. An indirect comparison with the reported values for non-powdered EDM process indicates that for the similar wire (molybdenum), the use of SiC powder maintains the surface roughness and kerf values, for a much harder D2 material used in this work.

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