scholarly journals A Mathematical Model to Assess the Material Removal Rate during Gas-Assisted Electrical Discharge Drilling Process

Author(s):  
Nishant Kumar Singh ◽  
Yashvir Singh ◽  
Abhishek Sharma

This research work investigates the use of Gas-Assisted Electrical Discharge Drilling (GAEDD) of high carbon-chromium die steel. The poor material removal rate (MRR) is one of the profound drawbacks of the traditional Electrical Discharge Drilling (EDD) process. Hence, over the years researchers have been feeling the requisite to develop an advanced strategy that can enhance the MRR. This study has examined the utilization of compressed gas in conventional EDM under the constraint state to assess MRR. The impact of procedure parameters likedischarge current, pulse on time, duty cycle, electrode speed, and discharge gas pressure, on MRR, has been explored too. In addition, Variance Analysis (ANOVA) was performed to determine the significant parameters affecting the MRR. During the examination, a mathematical model was established MRR employing Buckingham π-theorem while the GAEDD was being applied. The experiment and anticipated values of the model show a noteworthy impact of the coefficient of thermal expansion in GAEDD of high carbon-chromium steel. In addition, the Response Surface Method (RSM) model has also been evolved. The comparative analysis of the models developed shows considerable agreement in anticipation. Moreover, the semi-empirical model appears to be even more adaptable especially in comparison to the RSM-based model. In fact, the conclusion of this work is that the dimensional analysis model is an effective and reliable strategy to precise EDD response prediction.

Author(s):  
Arun Kumar Rouniyar ◽  
Pragya Shandilya

Magnetic field assisted powder mixed electrical discharge machining is a hybrid machining process with suitable modification in electrical discharge machining combining the use of magnetic field and fine powder in the dielectric fluid. Aluminum 6061 alloy has found highly significance for the advanced industries like automotive, aerospace, electrical, marine, food processing and chemical due to good corrosion resistance, high strength-to-weight ratio, ease of weldability. In this present work, magnetic field assisted powder mixed electrical discharge machining setup was fabricated and experiments were performed using one factor at a time approach for aluminum 6061 alloy. The individual effect of machining parameters namely, peak current, pulse on time, pulse off time, powder concentration and magnetic field on material removal rate and tool wear rate was investigated. The effect of peak current was found to be dominant on material removal rate and tool wear rate followed by pulse on time, powder concentration and magnetic field. Increase in material removal rate and tool wear rate was observed with increase in peak current, pulse on time and a decrease in pulse off time, whereas, for material removal rate increases and tool wear rate decreases up to the certain value and follow the reverse trend with an increase in powder concentration. Material removal rate was increased and tool wear rate was decreased with increase in magnetic field.


2015 ◽  
Vol 14 (03) ◽  
pp. 189-202 ◽  
Author(s):  
V. Vikram Reddy ◽  
P. Madar Valli ◽  
A. Kumar ◽  
Ch. Sridhar Reddy

In the present work, an investigation has been made into the electrical discharge machining process during machining of precipitation hardening stainless steel PH17-4. Taguchi method is used to formulate the experimental layout, to analyze the effect of each process parameter on machining characteristics and to predict the optimal choice for each electrical discharge machining process parameters namely, peak current, pulse on time and pulse off time that give up optimal process performance characteristics such as material removal rate, surface roughness, tool wear rate and surface hardness. To identify the significance of parameters on measured response, the analysis of variance has been done. It is found that parameters peak current and pulse on time have the significant affect on material removal rate, surface roughness, tool wear rate and surface hardness. However, parameter pulse off time has significant affect on material removal rate. Confirmation tests are conducted at their respective optimum parametric settings to verify the predicted optimal values of performance characteristics.


Mechanika ◽  
2021 ◽  
Vol 27 (6) ◽  
pp. 483-491
Author(s):  
Jayaraj JEEVAMALAR ◽  
Sundaresan RAMABALAN ◽  
Jayaraj JANCIRANI

In order to achieve higher productivity and product quality, the investigation of machining parameters on Electrical Discharge Drilling and surface characteristic analysis are most critical for manufacturing industries. The intention of this article is to assess the impact on performance matrices including Material Removal Rate, and Surface Roughness of input factors of peak current, pulse-on and off duration while drilling with a rotary hollow copper tool on Inconel 718 under Tungsten powder suspended kerosene. Analysis of Variance has been implemented using MINITAB release 18 software to identify the most significant input factors. An Artificial Neural Network was used for validating the experimental results of the drilling process. The additional intention of this research is to discover the significance of influencing input parameters and analyze the quality surface of the workpiece were observed by microscope tests. The experimental results indicated that the peak current and pulse-on period have an effect on the performance of the drilling process considerably.


Author(s):  
R Rajeswari ◽  
MS Shunmugam

Electrical discharge machining is used in the machining of complicated shapes in hardened molds and dies. In rough die-sinking stage, attempts are made to enhance material removal rate with a consequential reduction in cycle time. Powder mix and ultrasonic assistance are employed in the electrical discharge machining process to create gap conditions favoring material removal. In the present work, experiments are carried out on hardened D3 die steel using full-factorial design based on three levels of voltage, current and pulse on time. The gap phenomena in graphite powder-mixed and ultrasonic-assisted rough electrical discharge machining are studied using a detailed analysis of pulse shapes and their characteristic trains. Two new parameters, namely, energy expended over a second ( E) and performance factor ( PF) denoting the ratio of energy associated with sparks to total discharge energy, bring out gap conditions effectively. In comparison with the conventional electrical discharge machining for the selected condition, it is seen that the graphite powder mixed in the dielectric enhances the material removal rate by 20.8% with E of 215 J and PF of 0.227, while these values are 179.8 J and 0.076 for ultrasonic-assisted electrical discharge machining with marginal reduction of 3.9%. Cross-sectional images of workpieces also reveal the influence of electrical discharge machining conditions on the machined surface. The proposed approach can be extended to different powder mix and ultrasonic conditions to identify condition favoring higher material removal.


Author(s):  
Vikas Gohil ◽  
Yogesh M Puri

Electrical discharge turning is a unique form of electrical discharge machining process, which is being especially developed to generate cylindrical forms and helical profiles on the difficult-to-machine materials at both macro and micro levels. A precise submerged rotating spindle as a work holding system was designed and added to a conventional electrical discharge machine to rotate the workpiece. A conductive preshaped strip of copper as a forming tool is fed (reciprocate) continuously against the rotating workpiece; thus, mirror image of the tool is formed on the circumference of the workpiece. The machining performance of electrical discharge turning process is defined and influenced by its machining parameters, which directly affects the quality of the machined component. This study presents an investigation on the effects of the machining parameters, namely, pulse-on time, peak current, gap voltage, spindle speed and flushing pressure, on the material removal rate (MRR) and surface roughness (Ra) in electrical discharge turning of titanium alloy Ti-6Al-4V. This has been done by means of Taguchi’s design of experiment technique. Analysis of variance as well as regression analysis is performed on the experimental data. The signal-to-noise ratio analysis is employed to find the optimal condition. The experimental results indicate that peak current, gap voltage and pulse-on time are the most significant influencing parameters that contribute more than 90% to material removal rate. In the context of Ra, peak current and pulse-on time come up with more than 82% of contribution. Finally, the obtained predicted optimal results were verified experimentally. It was shown that the error values are all less than 6%, confirming the feasibility and effectiveness of the adopted approach.


2021 ◽  
Vol 1018 ◽  
pp. 91-95
Author(s):  
Tran Thi Hong ◽  
Nguyen Hong Linh ◽  
Bui Thanh Danh ◽  
Le Hong Ky ◽  
Vu Thi Lien ◽  
...  

This paper aims to find the impact of Electric Discharge Machining (EDM) factors on material removal rate (MRR) for 90CrSi alloy steel. Five three-level factors including pulse on time (Ton), pulse off time (Toff), pulse current (IP), server voltage (SV), and diameter of work-piece (dw) are investigated to explore their contribution on MRR by using Taguchi method in twenty-seven experiments based on an orthogonal array L27 (35). The findings realize that MRR is the most affected by the pulse current while the effect of the dw is the smallest. Based on ANOVA analysis, an optimal model of MRR has been developed and verified by comparing with the experiment result. The applicability of this proposed method can be used for further studies in EDM process.


2015 ◽  
Vol 1115 ◽  
pp. 3-6 ◽  
Author(s):  
M.A. Moudood ◽  
Abdus Sabur ◽  
Mohammad Yeakub Ali ◽  
I.H. Jaafar

Electrical discharge machining (EDM) is a non-conventional machining technique which can be used to machine non-conductive ceramics. This technique removes materials from the workpiece by thermal energy exerted from series of electrical sparks. Using copper foil as assisting electrode (AE), machining of Al2O3 is done successfully. In this investigation, experiments were performed to study the effect of gap voltage and pulse-on time on material removal rate (MRR) for EDM of Al2O3. The results showed that the lowest and the highest values of gap voltage were 12 V and 14 V, respectively, with a fixed peak current of 1.1 A and pulse-on time of 8 μs. Beyond these two voltage values, material cannot be removed due to insufficient pyrolytic carbon layer generation. Similarly, pulse-on time is varied from 6 μs to 8 μs when gap voltage is fixed at 14 V and peak current at 1.1 A. MRR, in this case, is increased almost 20 times from a lowest value of 0.006 mm3/min to a highest value of 0.119 mm3/min for the specified gap voltage and pulse-on time.


2018 ◽  
Vol 1 (2) ◽  
Author(s):  
SHUBHRATA NAGPAL

In the present work, an attempt has been made for material removal rate and surface roughness by response surface optimization techniques in Electrical discharge machining. Electrical discharge machining, commonly known as EDM, is a process that is used to remove metal through the action of an electrical discharge of short duration and high current density between the work piece and too. This work presents the results of a mathematical investigation carried out to the effects of machining parameters such as current, pulse on time, pulse off time and lift time on material removal rate and surface roughness in electrical discharge machining of 17-4 PH steel by using copper electrode. Response surface methodology and ANOVA techniques are used for data analysis to solve the multi-response optimization. To validate the optimum levels of the parameter, confirmation run was performed by setting the parameters at optimum levels. Material Removal Rate during the process has been taken as productivity estimate with the objective to maximize it. With an intention of minimizing surface roughness is been considered as most important output parameter. It is found that the good agreement of that current is most significant parameter for material removal rate and less for surface roughness followed by pulse on time and lift time.


Author(s):  
Rouhan Rafiq

Abstract: One of the important non-traditional machining processes is Wire Electrical Discharge Machining, used for machining difficult to machine materials like composites and inter-metallic materials. WEDM involves complex physical and chemical process including heating and cooling. Accompanying the development of mechanical industry, the demand for alloy materials having high hardness, toughness and impact resistance are increasing. The WEDM satisfy the present demands of the manufacturing industries such as better finish, low tolerance, higher production rate, miniaturization etc. The consistent quality of parts being machined in WEDM is difficult because the process parameters cannot be controlled effectively. The problem of arriving at the optimum levels of the operating parameters has attracted the attention of the researcher and practicing engineers for a very long time. The objective of the present study was to experimentally investigate the effects of various Wire Electrical Discharge Machining variables on Surface Roughness and Material Removal Rate of AISI 1045 using ANOVA method. Taguchi’s L18 Orthogonal Array was used to conduct experiments, which correspond to randomly chosen different combination of process parameters: wire type, pulse on time, pulse off time, peak current, servo voltage, wire feed rate, flushing pressure each to be varied in three different levels. The surface roughness and material removal rate were selected as output responses for the present investigation. The effect of all the input parameters on the output responses have been analyzed using analysis of variance (ANOVA). The effect of variation in input parameters has been studied on the output responses. Plots of S/N ratio have been used to determine the best relationship between the responses and the input parameters. In other words, the optimum set of input parameters for minimum surface roughness and maximum material removal rate were determined. It has been found that wire type, pulse on time are most significant factors for surface roughness and wire type, pulse on time, pulse off time, wire feed rate are most significant factors for material removal rate. Keywords: Input Parameters, Wire Electric Discharge Machining, ANOVA, Taguchi


2021 ◽  
Author(s):  
Muhammad Qaiser Saleem ◽  
Maham Naqvi ◽  
Sarmad Ali Khan ◽  
Nadeem Ahmad Mufti ◽  
Kashif Ishfaq

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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