Single Discharge Finite Element Simulation of EDM Process

2015 ◽  
Vol 14 (02) ◽  
pp. 75-89 ◽  
Author(s):  
Rohit Rajendran ◽  
S. P. Vendan

The energy distribution in the electric discharge machining process influences the material removal rate, relative wear ratio and the surface roughness of the machined surface and the effective energy is the part of energy which is distributed toward workpiece to be machined. The theoretical modeling of the process is based upon the heat transfer equations and one of the important parameter is fraction of energy transferred to the workpiece. The model first calculates the temperature distribution in the workpiece material using ANSYS Finite element coding and then volume removed due to single spark is estimated from the temperature profiles. Theoretical material removal rate at different input parameters are compared with the experimental results, making it possible to determine the portion of energy that enters AISI H13 tool steel workpiece. The effect of input parameters (discharge current, voltage, pulse on time) on temperature distributions along the radius and depth of the workpiece has been reported.

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.


2013 ◽  
Vol 393 ◽  
pp. 246-252 ◽  
Author(s):  
A. Sabur ◽  
Mohammad Yeakub Ali ◽  
M.A. Maleque

Electro discharge machining (EDM) technique, a noncontact machining process, is applied for structuring nonconductive ZrO2 ceramic. A conductive layer of adhesive copper is applied on the workpiece surface to initiate the sparks. Kerosene is used as dielectric for creation of continuous conductive pyrolytic carbon layer on the machined surface. Experiments are conducted by varying the peak current (Ip), pulse-on time (Ton), pulse-off time (Toff) and gap voltage (Vg). Correlating these variables a mathematical model for material removal rate (MRR) is developed using Taguchi method. The optimized parametric conditions are determined for higher MRR through ANOVA and signal to noise (S/N) ratio analysis. The results showed that the Ip and Ton are the significant parameters of MRR in EDM for nonconductive ZrO2 ceramic. The model also showed that MRR increases with the increase of Ip and Ton, but the process is controlled by Ip as a whole.


Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 125 ◽  
Author(s):  
Lei Guo ◽  
Xinrong Zhang ◽  
Shibin Chen ◽  
Jizhuang Hui

Ultraviolet-curable resin was introduced as a bonding agent into the fabrication process of precision abrasive machining tools in this study, aiming to deliver a rapid, flexible, economical, and environment-friendly additive manufacturing process to replace the hot press and sintering process with thermal-curable resin. A laboratory manufacturing process was established to develop an ultraviolet-curable resin bond diamond lapping plate, the machining performance of which on the ceramic workpiece was examined through a series of comparative experiments with slurry-based iron plate lapping. The machined surface roughness and weight loss of the workpieces were periodically recorded to evaluate the surface finish quality and the material removal rate. The promising results in terms of a 12% improvement in surface roughness and 25% reduction in material removal rate were obtained from the ultraviolet-curable resin plate-involved lapping process. A summarized hypothesis was drawn to describe the dynamically-balanced state of the hybrid precision abrasive machining process integrated both the two-body and three-body abrasion mode.


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.


2011 ◽  
Vol 189-193 ◽  
pp. 1393-1400 ◽  
Author(s):  
M.M. Rahman

Electrical discharge machining (EDM) is relatively modern machining process having distinct advantages over other machining processes and able to machine Ti-alloys effectively. This paper attempts to investigate the effects of process parameters on output response of titanium alloy Ti-6Al-4V in EDM utilizing copper tungsten as an electrode and positive polarity of the electrode. Mathematical models for material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) are developed in this paper. Design of experiments method and response surface methodology techniques are implemented. The validity test of the fit and adequacy of the proposed models has been carried out through analysis of variance. It can be seen that as the peak current increases the TWR decreases till certain ampere and then increases. The excellent surface finish is investigated in this study at short pulse on time and in contrast the long pulse duration causes the lowest EWR. Long pulse off time provides minimum EWR and the impact of pulse interval on EWR depends on peak current. The result leads to wear rate of electrode and economical industrial machining by optimizing the input parameters. It found that the peak current, servo voltage and pulse on time are significant in material removal rate and surface roughness. Peak current has the greater impact on surface roughness and material removal rate.


Electro discharge machining is a non-traditional machining process used for machining hard-to-machine materials, such as various grades of titanium alloys, heat-treated alloy steels, composites, tungsten carbides, and so forth. These materials are hard to machine with customary machining procedures like drilling, milling and hence electro-discharge machining is used to machine such materials to get better quality and efficiency. These materials are generally utilized in current industries like die making industries, aeronautics, nuclear industries, and medical fields. This type of machining is thermalbased, and machining takes place due to repetitive electric sparks that generate between workpiece and tool. Both tools and workpieces are inundated in a dielectric liquid, which has two primary functions. In the first place, it behaves like a medium between the work metal and the tool. Second, it is a flushing agent to expel the machined metal from the machined zone. Machining parameters like a pulse on time, current, wire feed the tool and gap voltage affect the output responses like surface roughness and material removal rate. The material removal rate is a significant parameter that determines machining efficiency. Surface roughness is also a vital parameter that decides machining quality. A lot of research has been conducted to determine the optimum parameters for obtaining the best results. In the present work, a comprehensive review of different types of EDM and the effect of various machining parameters on the surface roughness, material removal rate, and other response parameters has been done.


2018 ◽  
Vol 28 ◽  
pp. 55-66 ◽  
Author(s):  
Kuldeep Singh ◽  
Khushdeep Goyal ◽  
Deepak Kumar Goyal

In research work variation of cutting performance with pulse on time, pulse off time, wire type, and peak current were experimentally investigated in wire electric discharge machining (WEDM) process. Soft brass wire and zinc coated diffused wire with 0.25 mm diameter and Die tool steel H-13 with 155 mm× 70 mm×14 mm dimensions were used as tool and work materials in the experiments. Surface roughness and material removal rate (MRR) were considered as performance output in this study. Taguchi method was used for designing the experiments and optimal combination of WEDM parameters for proper machining of Die tool steel (H-13) to achieve better surface finish and material removal rate. In addition the most significant cutting parameter is determined by using analysis of variance (ANOVA). Keywords Machining, Process Parameters, Material removal rate, Surface roughness, Taguchi method


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.


2011 ◽  
Vol 110-116 ◽  
pp. 1683-1690 ◽  
Author(s):  
Vishal Parashar ◽  
A. Rehman ◽  
J.L. Bhagoria

In this paper, statistical and regression analysis of material removal rate using design of experiments is proposed for WEDM operations. Experimentation was planned as per Taguchi’s mixed orthogonal array. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, pulse OFF time, wire feed and dielectric flushing pressure. Stainless Steel grade 304L was selected as a work material to conduct the experiments. From experimental results, the material removal rate was determined for each machining performance criteria. Analysis of variance (ANOVA) technique was used to find out the variables affecting the material removal rate. Assumptions of ANOVA were discussed and carefully examined using analysis of residuals. Variation of the material removal rate with machining parameters was mathematically modeled by using the regression analysis method. The developed model was validated with a set of experimental data and appeared to be satisfactory. Signal to noise ratio was applied to measure the performance characteristics deviating from the actual value. Finally, experimental confirmation was carried out to identify the effectiveness of this proposed method.


2011 ◽  
Vol 487 ◽  
pp. 238-242 ◽  
Author(s):  
Min Li ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Jing Fu Chai

Method of compound machining is used to process single crystal silicon and SrTiO3 ceramic substrates, and the factors on effects of compound machining are studied such as magnetic field intensity, processing time, rotating speed of lapping plate and lapping pressure. The results show that the roughness of work pieces processed by compound machining are smaller than that by lapping based on cluster MR effect and polyurethane pad polishing process, while the material removal rate is higher than polyurethane pad polishing process, therefore, compound machining shows its synergistic effect between lapping based on cluster MR effect and polyurethane pad polishing process. The type and properties of workpiece material, and machining parameters both have a significant impact on the roughness and material removal rate of compound machining process of polyurethane polishing pad and cluster abrasive brush based on MR effect.


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