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.

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.  

scholarly journals Effect of Micro-EDM Parameters on Material Removal Rate of Nonconductive ZrO2 Ceramic

2013 ◽  
Vol 465-466 ◽  
pp. 1329-1333 ◽  
Author(s):  
Abdus Sabur ◽  
Abdul Moudood ◽  
Mohammad Yeakub Ali ◽  
Mohammad Abdul Maleque
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Pyrolytic Carbon ◽  
Carbon Layer ◽  
Machining Process ◽  
Machining Parameters ◽  
Micro Edm ◽  
Machined Surface ◽  
Electro Discharge Machining

Micro-electro discharge machining (micro-EDM) technique, an advanced noncontact machining process, is used for structuring of nonconductive ZrO2 ceramic. In this study copper foil as a conductive layer is adhered on the workpiece surface to initiate the sparks and kerosene is used as dielectric for creation of continuous conductive pyrolytic carbon layer on the machined surface. Voltage (V) and capacitance (C) are considered as the parameters to investigate the process capability of machining parameters in continuous micro-EDM of ZrO2. Different voltage pulses are studied to examine the causes of lower material removal rate (MRR) in micro-EDM of nonconductive ceramics. The results showed that in micro-EDM of ZrO2 MRR increases with the increase of voltage and capacitance initially, but decreases at higher values and no significant materials are removed at capacitances higher than 1nF.

Investigating the Micro-EDM Machinability of Bulk Metallic Glass in Micro-EDM Drilling

2019 ◽  
Author(s):  
Chong Liu ◽  
Asif Rashid ◽  
Muhammad P. Jahan ◽  
Jianfeng Ma
Keyword(s):  
Aspect Ratio ◽  
Wear Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Dimensional Accuracy ◽  
Tool Electrode ◽  
Micro Edm ◽  
Tool Wear Rate ◽  
Micro Holes

Abstract Bulk Metallic Glass (BMG) is a solid metallic material with disordered atomic structure, that has the characteristics of high elasticity, hardness, fracture toughness, and superior corrosion resistance. High aspect ratio micro-through holes on BMG has prospective applications in space, nuclear reactor, thermodynamics engineering, biomedical, and electronics industries. In this study, the micro-EDM machinability of BMG (Vit 1b: Zr67Cu10.6Ni9.8Ti8.8Be3.8 (wt%)) is evaluated. The micro-EDM machinability of BMG has been assessed based on the volume of material removal rate (MRR), tool wear rate (TWR), micro-hole surface quality, and dimensional accuracy. The effect of various electrical and non-electrical parameters is studied. It is found that micro-EDM is capable producing high aspect ratio micro-holes on difficult-to-machine BMG. The deposition of resolidified debris around the edge of the micro-holes, both at the entrance and exit side, are found to be a common phenomenon in micro-EDM of BMG. The reduction of capacitance was found to be the effective way for reducing the resolidified debris around the edges. Capacitance was found to be have more pronounced effect, with gap voltage having little effect on the quality of micro-holes. The electrode rotational speed had insignificant effect on the quality of micro-holes. In terms of dimensional accuracy, which was measured by overcut and taper angle, both the gap voltage and electrode rotational speed had little effect. The lower electrode rpm was found to reduce the taperness of the micro-holes, although the material removal rate decreases and tool wear rate increases. Finally, analysis of the composition of tool electrode before and after machining indicates the migration of materials from the dielectric and workpiece to the tool electrode and vice versa.

scholarly journals Micro Electro Discharge Machining of Polymethylmethacrylate (PMMA)/Multi-Walled Carbon Nanotube (MWCNT) Nanocomposites

2008 ◽  
Vol 17 (4) ◽  
pp. 096369350801700 ◽  
Author(s):  
Yi Wan ◽  
Dave (Dae-Wook) Kim ◽  
Young-Bin Park ◽  
Sung-Kwan Joo
Keyword(s):  
Carbon Nanotube ◽  
Material Removal ◽  
Supply Voltage ◽  
Removal Rate ◽  
High Energy ◽  
Material System ◽  
Micro Edm ◽  
Electro Discharge Machining ◽  
Multi Walled Carbon Nanotube ◽  
Mwcnt Loading

This study investigated micro electro discharge machining (micro-EDM) of Polymethylmethacrylate (PMMA)/Multi-Walled Carbon Nanotube (MWCNT) nanocomposites. PMMA/MWCNT nanocomposites were fabricated using solution casting, in which MWCNTs were dispersed in the polymer-solvent solution via high energy sonication, followed by precipitation and hot pressing. MWCNT loading was varied to investigate the effect of electrical conductivity of nanocomposites on the machinability. Micron-size holes were created to study the material removal mechanism in micro-EDM. The electro discharge phenomena may occur between electrically conductive MWCNT and the tungsten electrode during the process. As a result, PMMA/MWCNT nanocomposite samples with 10 to 35 wt% MWNTs were able to be EDMed with proper machining conditions. It was observed that the material removal rate increases with increasing micro-EDM supply voltage and MWCNT loading on the material system. Both optical microscope and scanning electron microscope (SEM) were used to investigate the characteristics of the machined holes and nanocomposite surfaces.

Modeling and process simulation of vibration assisted workpiece in micro-EDM using FEM

2016 ◽  
Vol 13 (3) ◽  
pp. 242-250 ◽  
Author(s):  
Kalipada Maity ◽  
Mayank Choubey
Keyword(s):  
Material Removal ◽  
Removal Rate ◽  
High Strength ◽  
Micro Edm ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Content Type ◽  
Electro Discharge Machining ◽  
Micro Holes ◽  
Strength Material

Purpose Micro-electro discharge machining (EDM) plays an important role in the fabrication of micro holes in an electrically conductive high-strength material. The flushing of debris poses a great challenge in the micro-EDM operation. The vibration of workpiece plays a significant role in the flushing of debris of the workpiece. Design/methodology/approach This study aims that the finite element analysis is performed using ANSYS software to find out the maximum displacement of the workpiece at a different location at different frequencies. For the convergence of this analysis, the natural frequency obtained from ANSYS is validated with some available literature. Findings The continuous up and down vibration of the workpiece results in the formation of vapor bubbles in a low-pressure region that contributes to material removal due to the fracture of bubbles. The vibration-assisted workpiece in the micro-EDM process causes the pressure variation of dielectric between the electrode and workpiece that enhances material removal rate because of cavitation. Originality/value In workpiece vibration-assisted micro-EDM, the selection of correct vibration frequency and displacement is of greater importance because improper frequency selection can cause bending of the wire electrode, affecting machining stability and short circuiting.

scholarly journals Micro Electro Discharge Machining for Nonconductive Ceramic Materials

2018 ◽  
Vol 3 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Mohammad Yeakub Ali ◽  
Abdus Sabur ◽  
Asfana Banu ◽  
Md. Abdul Maleque ◽  
Erry YT Adesta
Keyword(s):  
Removal Rate ◽  
Ceramic Materials ◽  
Micro Edm ◽  
Machined Surface ◽  
Electro Discharge Machining ◽  
Micro Channels ◽  
Spark Erosion ◽  
Copper Material ◽  
Experimental Values ◽  
Assisting Electrode

In micro-electro discharge machining (micro-EDM) of nonconductive ceramics, material is removed mainly by spalling due to the dominance of alternating thermal load. The established micro-EDM models established for single spark erosion are not applicable for nonconductive ceramics because of random spalling. Moreover, it is difficult to create single spark on a nonconductive ceramic workpiece when the spark is initiated by the assisting electrode. In this paper, theoretical model of material removal rate (MRR) as the function of capacitance and voltage is developed for micro-EDM of nonconductive zirconium oxide (ZrO2). It is shown that the charging and discharging duration depend on the capacitance and resistances of the circuit. The number of sparks per unit time is estimated from the single spark duration s derived from heat transfer fundamentals. The model showed that both the capacitance and voltage are significant process parameters where any increase of capacitance and voltage increases the MRR. However, capacitance was found to be the dominating parameter over voltage. As in case of higher capacitances, the creation of a conductive carbonic layer on the machined surface was not stable; the effective window of machining 101 - 103 pF capacitance and 80 - 100 V gap voltage or 10 - 470 pF capacitance and 80 - 110 V gap voltage. This fact was confirmed EDX analysis where the presence of high carbon content was evident. Conversely, the spark was found to be inconsistent using parameters beyond these ranges and consequently insignificant MRR. Nevertheless, the effective number of sparks per second were close to the predicted numbers when machining conductive copper material. In addition, higher percentage of ineffective pulses was observed during the machining which eventually reduced the MRR. In case of validation, average deviations between the predicted and experimental values were found to be around 10%. Finally, micro-channels were machined on nonconductive ZrO2 as an application of the model.

Comparative Assessment of the Laser Induced Plasma Micromachining and the Micro-EDM Processes

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
K. Pallav ◽  
P. Han ◽  
J. Ramkumar ◽  
Nagahanumaiah ◽  
K. F. Ehmann
Keyword(s):  
Electric Potential ◽  
Material Removal ◽  
Removal Rate ◽  
Energy Levels ◽  
Comparative Assessment ◽  
Micro Edm ◽  
Process Technology ◽  
Laser Induced Plasma ◽  
Electro Discharge Machining ◽  
Transparent Dielectric

Micro-electro-discharge machining (micro-EDM) is a well-established micromanufacturing process and has been at the center of research for the last few decades. However, it has its own limitations. The limitations are primarily due to the requirement of a tool and electric potential between the tool and the workpiece. The laser induced plasma micromachining (LIP-MM) is a novel tool-less multimaterial selective material removal type of micromachining process. In a manner similar to micro-EDM, it also removes material through plasma-matter interaction. However, instead of a tool and electric potential, it uses an ultra-short laser beam to generate plasma within a transparent dielectric media and thus circumvents some of the limitations associated with micro-EDM. The paper presents an experimental investigation on the comparative assessment of the capabilities of the two processes in the machining of microchannels in stainless steel. For comparative assessment of their processing capabilities, microchannels were machined by the two processes at similar pulse energy levels, while other process parameters were maintained at their optimal values for their respective process technology requirements. The comparative assessment was based on the geometric characteristics, material removal rate (MRR), effect of tool wear, and the range of machinable materials.

Experimental research on machinability of different electrode materials for SEAM of the nickel-based superalloy GH4169

2018 ◽  
Vol 232 (24) ◽  
pp. 4528-4537 ◽  
Author(s):  
Xuezhi Li ◽  
Jianping Zhou ◽  
Kedian Wang ◽  
Yan Xu ◽  
Tianbo Wu
Keyword(s):  
Experimental Research ◽  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Electrode Materials ◽  
Removal Rate ◽  
Electric Arc ◽  
Tool Electrode ◽  
Nickel Based Superalloy ◽  
Selection Of

The short electric arc machining technology is a technical category of electrical machining in the special machining industry. It further improves machining efficiency (1.92 × 105 mm3/min) in comparison to other electrical machining. In short electric arc machining, the electrode materials directly affect the surface quality of the workpiece, electrode loss, and dimensional accuracy. Therefore, the selection of the electrode material is particularly important. Using the nickel-based superalloy GH4169 machining as the research object, the study aimed to improve the material removal rate, while reducing the electrode loss. The experimental research on the short electric arc machining properties (machining surface quality, inter-polar voltage and current waveform, electrode loss analysis, surface morphology, microstructure, chemical components analysis, etc.) of four types of tool electrode materials (graphite, copper, Q235, and aluminum) separated by two groups was conducted, in the first group: under the certain technological parameter, machining the GH4169 by four kinds of tool electrode materials respectively. In the second group, the influence of different tool electrode materials on the material removal rate was studied by using graphite and copper as the tool electrode materials under the different process parameters of discharge current, pulse time, pulse interval, and air pressure. The results show that the mechanical properties of the electrode materials differed due to the different thermal properties of the electrode materials under the same process parameters. Furthermore, the different physical properties of the electrode material caused different effects on the residual heat, resulting in differences in the material removal rate. Under most of the discharge conditions, MRR occupied a large proportion in the graphite electrode, and the relative mass loss of the electrode was about 16.7% of that of copper, providing a solid theoretical basis for the electrode selection of the short electric arc machining hard surface materials.

Experimental Investigations into the Effect of Process Parameters and Nano-Powder (Fe2O3) on Material Removal Rate during Micro-EDM of Co-Cr-Mo

2017 ◽  
Vol 740 ◽  
pp. 125-132 ◽  
Author(s):  
Nagwa Mejid Elsiti ◽  
M.Y. Noordin
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Machining Process ◽  
Experimental Investigations ◽  
Dielectric Fluid ◽  
Micro Edm ◽  
Cobalt Chromium ◽  
Cobalt Chromium Molybdenum

Cobalt-base alloys are normally applied to materials that require wear, corrosion, and heat resistance. Today, the alloy of cobalt–chromium–molybdenum (Co–Cr–Mo) is employed in aerospace and medical fields. Through the thermal erosion process of Electrical Discharge Machining (EDM), an electrically-produced spark vaporizes materials that are electrically conductive. This paper examines the viability of improvement of material removal rate in the micro-electric discharge machining of cobalt chromium molybdenum (Co-Cr-Mo) using Fe2O3 nanopowder-mixed dielectric fluid. For the purpose of this research, a copper electrode with 300μm diameter and positive polarity was utilized. The performance measures of the machining process were investigated regarding the material removal rate (MRR). For analysis of EDM of the CoCrMo, response surface methodology (RSM) was employed. Two concentrations of nanopowder were added to dielectric (2g/land 4g/l). Findings showed that if Iron oxide nanopowders (Fe2O3) exists in the dielectric, MRRcan be significantly improved. Amongst the two concentrations of powder-mixed micro-EDM, 2 g/l of nanopowder provided higher MRR in comparison with 4g/l and without powder cases.

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.

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