Influence of Tool Electrode Properties on Machinability in Spark Erosion Machining

2013 ◽  
pp. 130122112650006 ◽  
Author(s):  
T. Muthuramalingam ◽  
B. Mohan
Keyword(s):  
Tool Electrode ◽  
Spark Erosion

scholarly journals Micro Electro Discharge Machining of Nonconductive Ceramic: The Issue of Spalling

2018 ◽  
Vol 7 (3.24) ◽  
pp. 32
Author(s):  
Mohammad Yeakub Ali ◽  
Abdus Sabur ◽  
Md. Abdul Maleque
Keyword(s):  
Electrical Conductivity ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Dimensional Accuracy ◽  
Ceramic Materials ◽  
Tool Electrode ◽  
Laser Applications ◽  
Spark Erosion ◽  
Assisting Electrode

Nonconductive ceramic materials are used in many engineering applications such as car brake, turbine blade, and hip-bone replacement because of its high dimensional accuracy, corrosion and wear resistant, and biocompatibility. These materials are usually processed with diamond grinding and limited laser applications such as cutting, drilling and scribing. Specific shapes and profiles are still difficult and costly to machine using these processes. Electrical discharge machining (EDM), extensively used for various shapes and profiles on conductive materials having minimum electrical conductivity of 0.10 S.cm-1. It is not directly applicable on nonconductive ceramic materials due to its very low electrical conductivity (<10-10 S.cm-1). However, recently EDM is used on nonconductive materials with the aid of assisting electrode to initiate the spark between conductive tool electrode and nonconductive workpiece. The available material removal models of EDM are based on single spark erosion with uniform melting and vaporization of workpiece materials. However, in EDM of nonconductive ceramics, material removal is not uniform because of random spalling due to alternating thermal stress. In addition, it is difficult to create single spark erosion on a nonconductive ceramic workpiece as initial sparks are occurred between tool electrode and assisting electrode attached to workpiece. This paper presents the empirical factor for the estimation of spalling along with melting and vaporization through experimental study. Model of material removal rate as a function of capacitance and voltage are developed in micromachining of nonconductive zirconium oxide (ZrO2) using (R-C) pulse type micro-EDM. The single spark erosion volume is derived from the fundamental principle of melting and vaporization. An empirical correction factor is introduced to compensate random spalling and multi-spark erosion effect.  

Estimation of Residual Stresses and Crater Shape in µ-EDM by Finite Element Method

2012 ◽  
Author(s):  
Jose Mathew ◽  
Allesu K. ◽  
Shravani Srisailam ◽  
K. P. Somashekhar ◽  
Prakash Naidu P. ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Inconel 718 ◽  
Dielectric Fluid ◽  
Tool Electrode ◽  
Workpiece Material ◽  
Electrically Conductive ◽  
3 Dimensional ◽  
Spark Erosion ◽  
Crater Morphology ◽  
Good Agreement

Micro-Electric Discharge Machining (μ-EDM) is the process of machining electrically conductive materials in the form of micro-size craters by using precisely controlled sparks that occur between tool electrode and workpiece in the presence of dielectric fluid. The present paper attempts to predict the accurate model for thermal behavior of the EDM process on commercially available Inconel 718. The temperature gradients are crucial in identifying the zones of high temperature and high residual stresses. 3-Dimensional, transient coupled (structural and thermal) analysis is modeled for Inconel 718 workpiece material to estimate the residual stresses due to spark erosion and also to study the crater morphology. The residual stresses are higher at the centre of the crater and it is decreasing when move far from the centre. The simulated results are compared with the experimental results. Both the experimental and the simulated results are in good agreement.

Investigation the Effect of Negative Polarity of Surface Roughness and Metal Removal Rate During EDM Process

2020 ◽  
Vol 38 (12A) ◽  
pp. 1852-1861
Author(s):  
Shahad A. Taqi ◽  
Saad K. Shatner
Keyword(s):  
Surface Roughness ◽  
Metal Removal ◽  
Removal Rate ◽  
Copper Electrode ◽  
Work Piece ◽  
Tool Electrode ◽  
Metal Removal Rate ◽  
Spark Erosion ◽  
Discharge Machine ◽  
Multiple Variables

The Electro discharge machine that named (EDM) is used to remove the metal from the workpiece by spark erosion. The work of this machining depends on the multiple variables. One of the most influential variants of this machine is the polarity, the material of the electrode, the current and the time pulses. Essentially the polarity of the tool (electrode) positive and the work piece is negative, this polarity can be reversed in this paper was reversed the polarity that was made the tool (electrode) negative and the work piece was positive. The aim of this paper was focused on the influence of reversed the polarity (negative) with changing the electrode metal (copper and graphite) on the surface roughness and metal removal rate by using different parameters (current and pulses of time). Experiments show that:  the copper electrode gives (best surface roughness 0.46 µm when the current 5 Am and Ton 5.5 µs) and (worst surface roughness 1.66 µm when the current is 8 A and Ton 25 µs). And give (best values of the MRR 0.00291 g/min when the current is 8 and Ton 25 µs) and (The lowest values of MRR (0.00054 g/min when current is 5 and Ton 5.5 µs). The graphite electrode gives (best surface roughness 2.07 µm when the current 5 Am and Ton 5.5 µs) and (worst surface roughness 4.17 µm when the current is 8 A and Ton 25 µs). And give (best values of the MRR 0.05823 g/min when the current is...

Effect of Tool Electrode Material on the Spark Erosion of Micro Grooves

2006 ◽  
Vol 526 ◽  
pp. 79-84
Author(s):  
S.H. Yeo ◽  
M. Murali ◽  
S. Balakrishnan
Keyword(s):  
Material Removal ◽  
Electrode Materials ◽  
Removal Rate ◽  
Experimental Investigations ◽  
Tool Electrode ◽  
Micro Edm ◽  
Rough Machining ◽  
Electro Discharge Machining ◽  
Spark Erosion ◽  
Materials Used

Micro electro discharge machining is an important unconventional metal micromachining technology. The performance of micro EDM depends on the combination of the tool and work materials used. In the absence of a comprehensive theoretical model to predict the effect of electrode materials on the performance of EDM, experimental investigations as described in this paper become useful. The work materials studied include ferrous, non-ferrous and exotic material (XW42, Ti6Al4V, WC) and the tool electrode materials include the commonly used EDM tool materials namely tungsten, copper and graphite. It is found that in the microgroove machining by micro EDM using foil electrodes, graphite consistently provides higher material removal rate than tungsten and copper tool electrodes and hence it is useful for the rough machining. On the other hand tungsten tool electrode is preferable for finish machining as it provides the least surface roughness.

Some observations on spark-erosion machining

1972 ◽  
Vol 51 (9) ◽  
pp. 305 ◽  
Author(s):  
S.K. Bhattacharyya ◽  
M. Kettle
Keyword(s):  
Spark Erosion

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 Analysis of Multi-Physics Coupling of Small Holes in GH4169 Alloy by Electrolytic Processing of Tube Electrodes

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 828
Author(s):  
Zhaolong Li ◽  
Ye Dai
Keyword(s):  
Oxide Layer ◽  
Small Hole ◽  
Machining Accuracy ◽  
Tool Electrode ◽  
Metallic Oxide ◽  
Power Sources ◽  
Processing Stability ◽  
Hole Structure ◽  
Gh4169 Alloy ◽  
Small Holes

This paper presents a simulation and experimental study of the structure of small holes in GH4169 alloy electrolytic ally processed by tube electrodes with different characteristic power sources. It analyzes the multi-physical field coupling relationship of flow, temperature, and electric fields within the interstitial space. The results indicate that the tube electrode electrolytic processing of the GH4169 alloy small hole structure with a pulsed power supply has more uniform temperature and current density distribution within the gap, which is beneficial to the processing accuracy and smoothness of the small hole structure. Meanwhile, SEM was used to analyze the microscopic morphology of the electrode end surface during short-circuiting, and it was concluded that as the processing continued, the electrode end surface gradually produced a non-metallic oxide layer, which destroyed the electric field of the gap and affected the processing stability. The use of high-frequency positive and negative pulse power can effectively avoid the generation of a non-metallic oxide layer. Through the combination of simulation analysis and experimental verification, it is concluded that increasing electrolyte pressure in stages can effectively improve machining accuracy and stability. The interstitial current increases as the feed rate of the tool electrode increases, and the diameter of the machined small hole decreases as it increases.

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