Removal of Defective Layer after Electrical Discharge Machining

2019 ◽  
Vol 973 ◽  
pp. 157-160
Author(s):  
Stanislav A. Mozgov ◽  
Yuriy A. Morgunov ◽  
Boris P. Saushkin

This study investigates the possibility of electrochemical removal of the defective layer formed on the surface of the product after its electrical discharge machining. A set of experiments was conducted in different electrolytes based on aqueous and aqueous-organic solvents. The experiments were to trace the influence of such settings of electrochemical machining as current density, electrolyte pumping speed, electrolyte temperature, and an electrode gap upon both the dynamics of metal removal and surface quality. Morphology of the obtained surface was examined by an Olympus BX-51Microscope. The dynamics of removing material (stock) from the work piece was inspected. Appropriate adjustments were made to the machining parameters during the machining of 65G steels, and a preferred composition was selected for the working medium. A sufficient design for production tools was proposed. Pitting corrosion was discovered on the surface of the samples in all studied modes of electrolysis. It was observed that switching from aqueous electrolyte to aqueous-organic electrolyte gave lower material removal rate and longer machining time accordingly. At the same time, a reduction in surface roughness was visualized, together with smaller pits and lower density of their distribution. The obtained results may be applied in operation design for electrochemical machining of steels with relatively high carbon contents.

2009 ◽  
Vol 83-86 ◽  
pp. 756-763 ◽  
Author(s):  
P.S. Satsangi ◽  
K.D. Chattopadhyay

The use of thermo-electric source of energy, as in electrical discharge machining (EDM), has greatly helped in machining all types of electrically conductive materials being used in different industrial applications. The present work investigates the different machining characteristics during electrical discharge machining on EN-8 steel with a rotary copper electrode. The effects of three independent machining parameters viz. peak current, pulse on time and rotational speed of tool electrode are chosen as variables for evaluating the output parameters such as metal removal rate, surface finish of work piece. The research focuses on developing empirical models for prediction of metal removal rate and surface finish during rotary electrical discharge machining process with the help of input parameters. The models are developed using linear regression analysis by applying logarithmic data transformation of non-linear equation. Analysis of results using partial and multiple correlation analysis reveals that electrical parameters have more significant effect than the non-electrical parameters on the machining characteristics during electrical discharge machining by a rotary electrode. Furthermore, when high MRR is criterion, high peak current and low RPM with low pulse duration produces better output; whereas, and when smooth surface finish is criterion, low peak current and low RPM with high pulse duration produces better output. In addition, the predictions based on the above developed models are verified with extra experiments and are found to be in good agreement with the experimental verifications.


2015 ◽  
Vol 14 (03) ◽  
pp. 123-148 ◽  
Author(s):  
S. Panda ◽  
D. Mishra ◽  
B. B. Biswal ◽  
P. Nanda

Electrical discharge machining is an alternative process for machining complex and intricate shapes. In this paper, an inter-relationship of various electrical discharge machining parameters, namely discharge current, pulse on and off time and dielectric flow rate on material removal rate (MRR), tool wear rate (TWR), surface finish ( SR a) and dimensional tolerance using a Taguchi–Grey relational analysis. The response surface methodology is used to develop a second order model for MRR, TWR and SR a in terms of process parameters. Finally, a multi-objective optimization problem is formulated by using MRR, TWR and SR a. The multi-objective problem is then optimized through a modified particle swarm optimization (PSO) algorithm to find the optimum level of parameters. In this research, the results of the proposed method are validated through confirmation experiment. The work piece material used for experimentation is stainless steel of S304 grade.


Author(s):  
D Kondayya ◽  
A Gopala Krishna

This paper presents an application of an integrated evolutionary approach for modelling and optimization of a wire electrical discharge machining (WEDM) process. The proposed methodology consists of two parts. In the first part, a novel application of genetic programming (GP) is proposed. GP is an evolutionary modelling algorithm which uses principles similar to genetic algorithms to model highly non-linear and complex processes, resulting in accurate and reliable models. Two important aspects of machining performance of WEDM, namely metal removal rate and surface roughness, are modelled based on experimental data using GP in terms of four prominent input variables. The effect of machining parameters on the performance measures is also reported. In the second part, as the chosen machining performances are opposite in nature, the problem under consideration is formulated as a multi-objective optimization problem and solved using an efficient evolutionary optimization algorithm, non-dominated sorting genetic algorithm-II (NSGA-II). The outcome of Pareto optimal solutions is presented. The work presents a fully fledged evolutionary approach for optimization of the process.


2018 ◽  
Vol 7 (3.12) ◽  
pp. 1161
Author(s):  
Nishant Kumar Singh ◽  
Sandeep Agrawal ◽  
Rajvardhan . ◽  
Yashvir Singh

Hard materials cannot be machined effectively by the individual machining process. In order to machine workpiece made from hard and stiff materials effectively a concept of Hybrid machining process (HMP) is originated. The HMP is an integration of two or more machining process to get the advantage of each individual process. HMP is used to machine  This study focuses on evolving a novel process using both oil and gas as dielectrics to analyse the effect on tool wear rate (TWR) and material removal rate (MRR). The flow of compressed gas through eccentric-hole rotating tool improved the debris removal from inter-electrode gap, hence it improve the flushing competence of the machining process. In this experimental investigation, the workpiece material is Al-20% SiC metal matrix composite (MMC) and the electrode material is copper. The experiments were conducted following the Taguchi method of design experiments. The effect of various machining parameters on MRR and TWR has been studied. The optimization of process parameter has also been done. The results of TWR and MRR are analysed using S/N ratio, ANOVA and main effect plots. The experimental results, revels that discharge current, gap voltage and pulse on time significantly affected MRR, and TWR. The experimental inference reveal that provision of compressed air through eccentric hole rotary tool has a positive effect on machinability of electrical discharge machining (EDM) process.  


2016 ◽  
Vol 854 ◽  
pp. 93-100 ◽  
Author(s):  
B. Sivaraman ◽  
Senthil Padmavathy ◽  
P. Jothiprakash ◽  
T. Keerthivasan

This Aim of this paper is to analyse the effect of machining parameters of wire electrical discharge machining (WEDM) on workpiece material titanium, that were now widely used in many applications because of its technical benefits. Conventional method of machining the material will make the work piece to crack or flaws due to chipping, presence of burrs and cracking. Wire cut Electrical discharge machining techniques have been already tried with some other high strength materials which is complicated to cut. To prove the feasibility of machining the titanium, many experiments were carried out based on RSM. Hence by the head wire electrical discharge machining process is to be used to machining the work piece material (titanium) and the effect of various control parameters on the response parameters were analysed and optimized and the optimal combination of control parameters were found to get higher metal removal rate and surface finish using Response Surface Methodology.


2012 ◽  
Vol 488-489 ◽  
pp. 871-875
Author(s):  
V. Anandakrishnan ◽  
V. Senthilkumar

Copper based metal matrix composite reinforced with Boron Carbide is a newly developed Electrical Discharge Machining (EDM) electrode showing better performance than the conventional copper based electrode. Right selection of machining parameters such as current, pulse on time and pulse off time is one of the most important aspects in EDM. In this paper an attempt has been made to develop mathematical models for relating the Material Removal Rate (MRR), Tool Removal Rate (TRR) and Surface roughness (Ra) to machining parameters (current, pulse-on time and pulse-off time). Furthermore, a study was carried out to analyze thSubscript texte effects of machining parameters on various performance parameters such as, MRR, TRR and Ra. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models, can adequately describe the performance within the limits of the factors being studied. Response surface modeling is used to develop surface and contour graphs to analyze the effects of EDM input parameters on outer parameters.


2015 ◽  
Vol 656-657 ◽  
pp. 335-340 ◽  
Author(s):  
Fang Pin Chuang ◽  
Yan Cherng Lin ◽  
Hsin Min Lee ◽  
Han Ming Chow ◽  
A. Cheng Wang

The environment issue and green machining technique have been induced intensive attention in recent years. It is urgently need to develop a new kind dielectric to meet the requirements for industrial applications. The aim of this study is to develop a novel dielectric using gas media immersed in deionized water for electrical discharge machining (EDM). The developed machining medium for EDM can fulfill the environmentally friendly issue and satisfy the demand of high machining performance. The experiments were conducted by this developed medium to investigate the effects of machining parameters on machining characteristics in terms of material removal rate (MRR) and surface roughness. The developed EDM medium revealed the potential to obtain a stabilizing progress with excellent machining performance and environmentally friendly feature.


Author(s):  
Sandeep Yadav ◽  
Deepak k ◽  
Sarthak Sharma ◽  
Lalit Vashishth

Electrical discharge machining (EDM) is one of the earliest non-conventional method of manufacturing processes. This process based on thermoelectric energy between work piece and electrodeand they must have electrical conductivity to generate the spark. A spark generated between work piece and electrode, and removes the material from work piece through melting and vaporizing. EDM produced various types of products such as dies and moulds. EDM is used to manufacture the parts of aerospace, automotive industry and surgical components. The effect of the machining parameters on surface roughness, metal removal rateand tool wear rate are studied.


2021 ◽  
Author(s):  
Dragan Rodic ◽  
Marin Gostimirovic ◽  
Milenko Sekulic ◽  
Borislav Savkovic ◽  
Branko Strbac

Abstract It is well known that electrical discharge machining can be used in the processing of nonconductive materials. In order to improve the efficiency of machining modern engineering materials, existing electrical discharge machines are constantly being researched and improved or developed. The current machining of non-conductive materials is limited due to the relatively low material removal rate and high surface roughness. A possible technological improvement of electrical discharge machining can be achieved by innovations of existing processes. In this paper, a new approach for machining zirconium oxide is presented. It combines electrical discharge machining with assisting electrode and powder-mixed dielectric. The assisting electrode is used to enable electrical discharge machining of nonconductive material, while the powder-mixed dielectric is used to increase the material removal rate, reduce surface roughness, and decrease relative tool wear. The response surface method was used to generate classical mathematical models, analyzing the output performances of surface roughness, material removal rate and relative tool wear. Verification of the obtained models was performed based on a set of new experimental data. By combining these latest techniques, positive effects on machining performances are obtained. It was found that the surface roughness was reduced by 18%, the metal removal rate was increased by about 12% and the relative tool wear was reduced by up to 6% compared to electrical discharge machining with supported electrode without powder.


Author(s):  
Anshuman Kumar Sahu ◽  
Joji Thomas ◽  
Siba Sankar Mahapatra

Electrical discharge machining (EDM) is a thermo-electrical process that can be conveniently utilized for generating complex shaped profiles on hard-to-machine conductive materials using metallic tool electrodes. In this work, composite tools made of copper-tungsten-boron carbide (Cu-W-B4C) manufactured by powder metallurgy (PM) route are used during machining of titanium alloy (Ti6Al4V). The effect of four input machining parameters viz. current, pulse-on-time, duty cycle and percentage of tungsten and boron carbide on material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra) is studied. A novel meta-heuristic approach such as simple optimization (SOPT) algorithm has been used for single and multi-objective optimization. The pareto-optimal solutions obtained by SOPT have been ranked by VIKOR method to find out the best suitable optimal solution. Analysis of experimental data suggests vital information for controlling the machining parameters to improve the machining performance.


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