INVESTIGATION ON CR, MRR AND SR OF WIRE ELECTRICAL DISCHARGE MACHINING (WEDM) ON HIGH CARBON STEEL S50C

2015 ◽  
Vol 76 (6) ◽  
Author(s):  
Bulan Abdullah ◽  
Mohammad Faezeen Mad Nordin ◽  
Muhamad Hafizuddin Mohamad Basir

The purpose of this project is to study the encouragement of three machining parameters on wire electrical discharge machining that consist of peak current (IP), pulse OFF time (OFF) and wire tension (WT) to three machining responses which are cutting rate (CR), material removal rate (MRR) and surface roughness (SR) on high carbon steel (S50C). Brass wire with diameter 0.25 mm was used as the cutting tool for machining a high carbon steel (S50C) using Mitsubishi FX Wire Electrical Discharge Machine (WEDM). The machining parameters such as pulse off time, wire tension and peak current were determined by referring from the guideline in the manual book for Mitsubishi FX Wire Electrical Discharge Machine (WEDM). The calculation of material removal rate and cutting rate were obtained using mathematical equation. The surface roughness was measured using optical measurement “Alicona Infinite Focus” machine. The relationship between material removal rate and surface roughness shows that the optimum machine parameter using brass wire as the electrode is C1. From the spark analysis using brass wire as the machine’s electrode, the deeper the spark occurred, the higher value of the surface roughness. 

Author(s):  
Gaurav Pandey

Abstract: The proper selection of machining conditions and machining parameter is an important aspect, before going to machine a carbon-fiber composite material by Die sinking electrical discharge machining (EDM). Because these conditions will determine such important characteristics as; Material removal rate (MRR), Electrode wears rate (EWR), and Surface roughness (R). The purpose of this work is to determine the optimal values of machining parameters of electrical discharge machine, while machining carbon-fiber-composite with copper electrode. The work has been based on the affect of four design factors: pulse current(Ip) supplied by power supply system of electrical discharge machine (EDM), pulse-on-time(TON), gap voltage(Vg) and duty cycle () on such characteristic like material removal rate (MRR), electrode wear rate(EWR), and surface roughness(Ra) on work-piece surface. This work has been done by means of the technique of design of experiment (DOE), which provides us to perform the above-mentioned analysis with small number of experiments. In this work, a L9 orthogonal array is used to design the experiment. The adequate selection of machining parameters is very important in manufacturing system, because these parameters determine the surface quality and dimensional accuracy of the manufactured part. The optimal setting of the parameters are determined through experiments planned, conducted and analyzed using the Taguchi method. It is found that material removal rate (MRR) reduces substantially, within the region of experimentation, if the parameters are set at their lowest values, while the parameters set at their highest values increases electrode wear rate (EWR). Keywords: EDM, Material removal rate, Surface roughness, Tool wear rate,


Author(s):  
T Jin ◽  
D J Stephenson ◽  
J Corbett

The burn-threshold of high-carbon steel (51CrV4) in the high-efficiency deep-grinding (HEDG) process is investigated. It is found that the burn threshold in HEDG is determined by the wheel-workpiece contact length, material removal rate and wheel speed. A theoretical expression for the burn threshold has been derived, which is based on the thermal modelling for deep grinding and takes account of the grinding parameters, wheel conditions, thermal properties of the workpiece and abrasive grain, and the heat convected away by the coolant and chips. The predicted upper and lower boundaries for occurrence of workpiece burn show good agreements with the experimental observations. It is shown that burn threshold in HEDG is related to the film boiling of process coolant and the critical heat flux increases as the specific material removal rate increases. The experiments were carried out on an Edgetek five-axis computer numerical control (CNC) grinding machine, which is capable of HEDG in a relatively wide range of process parameters.


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 ◽  
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.


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