scholarly journals Prediction and analysis of EDM performances considering random multiple-pulse discharges based on geometric optimization modeling

2021 ◽  
Author(s):  
Qin Ni ◽  
Yan Zhang ◽  
Kebing Zhou ◽  
Guoqian Wang ◽  
Lei Ji ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Surface Roughness ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Numerical Models ◽  
Removal Rate ◽  
Pulse Discharge ◽  
Recast Layer ◽  
Geometric Optimization ◽  
Theoretical Research

Abstract Continuous electrical discharge machining (EDM) is characterized by random discharge positions, uncertain discharge energy, extremely short discharge time, extremely narrow tool-workpiece gaps, etc. Theoretical research into the mechanisms leading to thermal erosion of material and the associated surface morphology has become urgent to allow the continued development and application of EDM technology. Firstly, multi-pulse theory and geometric optimization are utilized to derive an expression for the material removal rate and surface roughness in multi-pulse EDM. Secondly, Based on the characteristics of multi-pulse discharge, a multi-pulse numerical simulation model was established to predict the material removal volume, surface roughness and thickness of recast layer. Finally, the results predicted by the geometric and numerical models are compared with the experimental results. Experimentally, 0.176 mg of material is removed in the multi-pulse EDM; the theoretical calculation and numerical simulation of the same produce errors of 5.11% and 11.36%, respectively. The analogous results for the surface roughness are 1.623 µm, 8.93%, and 1.23%. The experimentally determined thickness of the recast layer was 5.31 µm, which corresponds to an error in the simulation error of 7.53%.

scholarly journals The Effect of Discharge Current and Pulse-On Time on Biocompatible Zr-based BMG Sinking-EDM

2020 ◽  
Vol 10 (1) ◽  
pp. 401-407
Author(s):  
Yanuar Rohmat Aji Pradana ◽  
Aldi Ferara ◽  
Aminnudin Aminnudin ◽  
Wahono Wahono ◽  
Jason Shian-Ching Jang
Keyword(s):  
Surface Roughness ◽  
Metallic Glasses ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Hardness ◽  
Recast Layer ◽  
Surface Evaporation ◽  
Pulse On Time

AbstractThe machinability information of Zr-based bulk metallic glasses (BMGs) are recently limited but essential to provide technological recommendation for the fabrication of the medical devices due to the material’s metastable nature. This study aims to investigate the material removal rate (MRR) and surface roughness under different current and pulse-on time of newly developed Ni- and Cu-free Zr-based BMG using sinking-electrical discharge machining (EDM). By using weightloss calculation, surface roughness test and scanning electron microscopy (SEM) observation on the workpiece after machining, both MRR and surface roughness were obtained to be increased up to 0.594 mm3/min and 5.50 μm, respectively, when the higher current was applied. On the other hand, the longer pulse-on time shifted the Ra into the higher value but lower the MRR value to only 0.183 mm3/min at 150 μs. Contrary, the surface hardness value was enhanced by both higher current and pulse-on time applied during machining indicating different level of structural change after high-temperature spark exposure on the BMG surface. These phenomena are strongly related to the surface evaporation which characterize the formation of crater and recast layer in various thicknesses and morphologies as well as the crystallization under the different discharge energy and exposure time.

Surfactant and graphite powder–assisted electrical discharge machining of titanium alloy

2016 ◽  
Vol 231 (4) ◽  
pp. 641-657 ◽  
Author(s):  
Murahari Kolli ◽  
Adepu Kumar
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Graphite Powder ◽  
Recast Layer ◽  
Dielectric Fluid ◽  
Recast Layer Thickness

Surfactant and graphite powder–assisted electrical discharge machining was proposed and experiments were performed on titanium alloy in this investigation. Analysis was carried out to observe changes in dielectric fluid behaviour, material removal rate, surface roughness, recast layer thickness, surface topography and energy-dispersive X-ray spectroscopy. It was found out that the addition of surfactant to dielectric fluid (electrical discharge machining oil + graphite powder) improved the material removal rate and surface roughness. It was noticed to have reduced the recast layer thickness and agglomeration of graphite and sediment particles. Biface material migrations between the electrode and the workpiece surface were identified, and migration behaviour was powerfully inhibited by the mixing of surfactant. Surfactant added into dielectric fluid played an important role in the discharge gap, which increased the conductivity, and suspended debris particles in dielectric fluid reduced the abnormal discharge conditions of the machine and improved the overall machining efficiency.

Effect of SiC-Cu Electrode on Material Removal Rate, Tool Wear and Surface Roughness in EDM Process

2020 ◽  
Vol 38 (9A) ◽  
pp. 1406-1413
Author(s):  
Yousif Q. Laibia ◽  
Saad K. Shather
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Material Removal Rate ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
304 Stainless Steel ◽  
Tool Electrode ◽  
Pulse Time ◽  
Edm Process

Electrical discharge machining (EDM) is one of the most common non-traditional processes for the manufacture of high precision parts and complex shapes. The EDM process depends on the heat energy between the work material and the tool electrode. This study focused on the material removal rate (MRR), the surface roughness, and tool wear in a 304 stainless steel EDM. The composite electrode consisted of copper (Cu) and silicon carbide (SiC). The current effects imposed on the working material, as well as the pulses that change over time during the experiment. When the current used is (8, 5, 3, 2, 1.5) A, the pulse time used is (12, 25) μs and the size of the space used is (1) mm. Optimum surface roughness under a current of 1.5 A and the pulse time of 25 μs with a maximum MRR of 8 A and the pulse duration of 25 μs.

scholarly journals Investigation an assisting electrode powder mixed electrical discharge machining of nonconductive ceramic

2021 ◽  
Author(s):  
Dragan Rodic ◽  
Marin Gostimirovic ◽  
Milenko Sekulic ◽  
Borislav Savkovic ◽  
Branko Strbac
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Metal Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Positive Effects ◽  
Assisting Electrode

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.

scholarly journals Processing Characteristics of Micro Electrical Discharge Machining for Surface Modification of TiNi Shape Memory Alloys Using a TiC Powder Dielectric

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1018
Author(s):  
Ziliang Zhu ◽  
Dengji Guo ◽  
Jiao Xu ◽  
Jianjun Lin ◽  
Jianguo Lei ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Modification ◽  
Shape Memory ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Recast Layer ◽  
Powder Concentration ◽  
Micro Electrical Discharge Machining ◽  
Machining Properties

Titanium-nickel shape memory alloy (SMA) has good biomedical application value as an implant. Alloy corrosion will promote the release of toxic nickel ions and cause allergies and poisoning of cells and tissues. With this background, surface modification of TiNi SMAs using TiC-powder-assisted micro-electrical discharge machining (EDM) was proposed. This aims to explore the effect of the electrical discharge machining (EDM) parameters and TiC powder concentration on the machining properties and surface characteristics of the TiNi SMA. It was found that the material removal rate (MRR), surface roughness, and thickness of the recast layer increased with an increase in the discharge energy. TiC powder’s addition had a positive effect on increasing the electro-discharge frequency and MRR, reducing the surface roughness, and the maximum MRR and the minimum surface roughness occurred at a mixed powder concentration of 5 g/L. Moreover, the recast layer had good adhesion and high hardness due to metallurgical bonding. XRD analysis found that the machined surface contains CuO2, TiO2, and TiC phases, contributing to an increase in the surface microhardness from 258.5 to 438.7 HV, which could be beneficial for wear resistance in biomedical orthodontic applications.

Influence of Machining Parameters on Surface Roughness in WEDM Titanium Alloy

2013 ◽  
Vol 701 ◽  
pp. 349-353 ◽  
Author(s):  
J.B. Saedon ◽  
Paul J.R. Ding J.R. ◽  
M.S.M. Shawal ◽  
H. Husain ◽  
M.S. Meon
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Feed Rate ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Machining Parameters ◽  
Thermo Electric ◽  
Peak Current ◽  
Wire Tension

Wire electrical discharge machining (WEDM) is a material removal process of electrically conductive materials by the thermo-electric source of energy .This kind of machining extensively used in machining of materials with highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using wire electro-discharge machining with brass wire diameter 0.25mm.The objective of this work is to study the influence of three machining parameters namely peak current (IP), feed rate (FC) and wire tension (WT) to material removal rate and surface roughness followed by suggesting the best operating parameters towards good surface finish. A full factorial experimental design was used with variation of peak current, feed rate and wire tension, with results evaluated using analysis of variance (ANOVA) techniques. Parameter levels were chosen based on best practice and results from preliminary testing. Main effects plots and percentage contribution ratios (PCR) are included for the main factors and their interactions. Peak current was shown to have the greatest effect on surface roughness (33% PCR).

A Comparative Study of Machining Parameters on Die-Sinking Electrical Discharge Machining (EDM) using Copper and Aluminium Electrodes on Hard Steels

2016 ◽  
Vol 3 (1) ◽  
pp. 22-44 ◽  
Author(s):  
Ashwani Kharola
Keyword(s):  
Surface Roughness ◽  
Discharge Current ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Die Steel ◽  
The Relationship

This paper considers effect of variation in value of Discharge current on different process parameters of Die Sinking EDM. The parameters considered were Material removal rate (MRR), Tool removal rate (TRR), Surface roughness (Ra) and Time (for machining required depth of cut). A total of 32 experiments were conducted on four different hard steels i.e. Die steel D3, En-8, En-19 and Stainless steel (SS-AISI-440C). The Copper and Aluminium electrodes brazed with mild steel were used for machining. The four different values of current i.e. 6A, 9A, 12A and 15A were considered for the study. The experimental results shows the relationship between MRR, TRR, Ra and Time with variation in magnitude of discharge current. This study also illustrates the relationship among different process parameter considered in the study. The results are shown with the help of graphs and tables.

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