Effect of Discharge Condition on Cavitations Behavior by Single Pulse Discharge

2012 ◽  
Vol 523-524 ◽  
pp. 951-956
Author(s):  
Yoshiaki Akematsu ◽  
Kazuro Kageyama ◽  
Naotake Mohri ◽  
Hideaki Murayama
Keyword(s):  
Optical Fiber ◽  
Discharge Current ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Optical Fiber Sensor ◽  
Single Pulse ◽  
Vibration Sensor ◽  
Work Piece ◽  
Discharge Condition

This paper describes some experimental results on a fundamental phenomenon of the single pulse discharge. In electrical discharge machining (EDM), processing accuracy was effected by behaviors of fused material. Pressure was important for removing fused material. So, it was needed to clarify that the mechanism of pressure occurrence by electrical discharge. In this study, it was investigated that effect of discharge condition on cavitations behavior by single pulse discharge. Gap region medium viscosity was changed by medium and temperature. Electrical discharge current was changed by applied voltage. The optical fiber vibration sensor is located on an aluminum work-piece (cathode) plate. Pressure was measured by optical fiber sensor during single pulse discharge. As the results, burst acoustic emission (AE) wave was occurred during single pulse discharge. The occurrence of several times burst AE wave was caused by cavitations behavior. The condition on which bubble does not collapse has become apparent. It was found that cavitations behavior was mainly depended on discharge current except for the condition on which bubble does not collapse.

Effect of Arc Discharge Pressure on Discharge Current in EDM

2008 ◽  
Vol 381-382 ◽  
pp. 451-454
Author(s):  
Atsutoshi Hirao ◽  
S. Tai ◽  
H. Takezawa ◽  
Naotake Mohri ◽  
Kazuro Kageyama ◽  
...  
Keyword(s):  
Discharge Current ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Arc Discharge ◽  
Vibration Sensor ◽  
Work Piece ◽  
Tool Electrode ◽  
Discharge Pressure ◽  
Current Behavior

In electrical discharge machining (EDM), an electrical discharge occurs between a tool electrode and a work-piece, and removal of materials is carried out by vaporized explosion between the electrode and the work-piece. However, the mechanism of material removal in EDM is not well understood. In order to clarify this issue, the acoustic emission (AE) method has been applied to examine the force of explosion, and the Schlieren visualization method has been applied to observe the explosion. In this study, we investigate the effect of discharge current behavior on the occurrence of the AE waves by means of an optical fiber vibration sensor.

Measurement of Acoustic Emission Wave by Using Optical Fiber Sensor during Microsecond Discharge

2008 ◽  
Vol 381-382 ◽  
pp. 399-402 ◽  
Author(s):  
Yoshiaki Akematsu ◽  
Atsutoshi Hirao ◽  
H. Takezawa ◽  
Kazuro Kageyama ◽  
Naotake Mohri ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Electrical Discharge ◽  
Optical Fiber Sensor ◽  
Electrical Current ◽  
Vibration Sensor ◽  
Fiber Sensor ◽  
Work Piece ◽  
Force Direction ◽  
Discharge Duration ◽  
Current Behavior

In this study, we investigate the effect of discharge current on the occurrence of burst AE wave caused by microsecond discharge. Electrical discharge duration was changed from about 1µs to 8µs by using condenser circuit. Effect of current behavior was estimated by comparing with experimental signal and simulation one. AE wave was detected by optical fiber vibration sensor. The optical fiber vibration sensor is located on an aluminum work-piece (cathode) plate. Simulation was carried out with MSC. Marc. As the results, it was found that AE wave was occurred by a force depending on electrical current behavior. The force direction was machining direction. The force has been occurred during microsecond discharge.

Shifting Secondary Discharge as the Expulsion Mechanism in EDM

2008 ◽  
Author(s):  
Y. F. Luo ◽  
Jia Tao
Keyword(s):  
Energy Distribution ◽  
Driving Force ◽  
Electrical Discharge ◽  
Metal Removal ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Complex Surface ◽  
Apparent Difference ◽  
Reversed Polarity

A new understanding of the expulsion mechanism in electrical discharge machining (EDM) is discussed in this investigation. The shifting secondary discharge inside a cathodic root is revealed as the major driving force for metal expulsion in EDM. A typical electrode couple of steel for cathode and copper for anode is used in all the experiments and discussions. Micro graphs of discharge craters are taken from the complex surface directly after a continual discharging process while either normal or reversed polarity is applied. The apparent difference in crater morphologies on anode and cathode indicates the unique expulsion mechanism, namely secondary discharges, which only take place inside the cathodic root. The compliance of secondary discharges with long-disputed phenomena, such as the discrepancy between energy distribution and metal removal, is demonstrated through the applications of the mechanism to the phenomena. The applied methods and results are more realistic since single pulse discharge among other process changes is prohibited. Such a more reliable understanding can correlate the complex metal removal mechanisms to better future process developments.

Simulation and Analysis of RC Type Relaxation Power Generator for Electrical Discharge Machines (EDM) in Laplace Transform

2016 ◽  
Vol 818 ◽  
pp. 112-116
Author(s):  
Fatemeh Karimi Pour ◽  
Mahrokh Bavandi ◽  
Azli Yahya
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Pulsed Power ◽  
Work Piece ◽  
Machining Processes ◽  
Power Generator ◽  
Generator Circuit ◽  
Simulation Based ◽  
Pulsed Power Generator

Electrical discharge machining (EDM) is one of the earliest non-traditional machining processes and controlled process where pulsed electrical discharge is used to erode metal in a workpiece. EDM pulsed power generator applies voltage pulse discharge occurs in a small gap between the work piece and the electrode and removes the unwanted material from the parent metal through melting and vaporization. The essential requirement for EDM system is to obtain the output waveform similar to the ideal EDM waveform. This paper seeks to discuss on the design and simulation based on RC (resistance-capacitance) power generator circuit. Based on the findings of the study, from the equation gained, the simulation is constructed through using electrical model in Matlab Simulink software and circuit analysis in Lapels transform in EDM system process. Also this procedure simulated in Matlab software.

Modeling and Simulation of Surface Topography Evolution in Electrical Discharge Machining (EDM)

2014 ◽  
Vol 1017 ◽  
pp. 764-769
Author(s):  
Tian Feng Zhou ◽  
Li Zheng Ma ◽  
Zhi Qiang Liang ◽  
Xi Bin Wang
Keyword(s):  
Surface Topography ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Fem Simulation ◽  
Single Pulse ◽  
Machining Parameters ◽  
Workpiece Material ◽  
Material Erosion ◽  
Gauss Distribution

This paper aims to quantify the effects of the machining condition on the surface topography in electrical discharge machining (EDM), including pulse current, pulse duration and so on. Firstly, the heat source of a single electrical pulse is defined by Gauss distribution, and the thermal effects of machining parameters on the workpiece material erosion are simulated by Finite Element Method (FEM) package ANSYS. Then, the crater size of a single pulse is numerically simulated based on the thermal model of a single pulse discharge. Furthermore, the superposition of multiply craters created by continuous pulse discharges in a random distribution is calculated by MATLAB software program, so that the evolution of the surface topography can be obtained with the combination of FEM simulation and topology calculation. In this way, the surface roughness is quantitatively calculated from the specified EDM parameters.

Design and Model Analysis of Pulse Generator in Electrical Discharge Machines (EDM) System Using in the Laplace Transform

2016 ◽  
Vol 818 ◽  
pp. 106-111
Author(s):  
Fatemeh Karimi Pour ◽  
Azli Yahya ◽  
Mahrokh Bavandi ◽  
Ronia Tavakkoli ◽  
Dana Dehghani
Keyword(s):  
Electrical Discharge ◽  
Pulse Generator ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Work Piece ◽  
Machining Processes ◽  
Power Generator ◽  
Generator Circuit ◽  
Pulse Power Generator ◽  
Edm Process

One of the latest non-traditional machining processes and controlled process is presented as Electrical Discharge Machining (EDM) that the pulsed electrical discharge is used to erode metal in a work piece. The voltage pulse discharge occurs when EDM pulsed power generator is applied on a workpiece. The discharge happens in a small gap between the work piece and the electrode. The important function of EDM is to obtain the output waveform parallel with the ideal EDM waveform. Additionally, the EDM design is according to the transistor kind pulse power generator circuit. The present paper seeks to discuss on the current modeling and voltage gap waveform intended for the system in EDM process. Based on the derived equation, the simulation is done using electrical model in Matlab Simulink software and circuit analysis in Lapels transform in EDM process.

Detection of acoustic emission wave by using optical fiber sensor during single pulse discharge

2006 ◽  
Author(s):  
Yoshiaki Akematsu ◽  
Kazuro Kageyama ◽  
Naotake Mohri ◽  
Hideaki Murayama ◽  
Masako Matsuo
Keyword(s):  
Acoustic Emission ◽  
Optical Fiber ◽  
Pulse Discharge ◽  
Optical Fiber Sensor ◽  
Single Pulse ◽  
Fiber Sensor

Manufacture Probe with EDM Single Pulse Discharge Research

2011 ◽  
Vol 291-294 ◽  
pp. 3069-3072 ◽  
Author(s):  
Lan Chen
Keyword(s):  
Electrical Discharge ◽  
Tungsten Wire ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Tungsten Electrode ◽  
Negative Pole ◽  
Tungsten Microelectrode ◽  
Measurement Devices ◽  
Fabrication Time

This paper presents a new method to fabricate tungsten microelectrode in a single pulse electrical discharge. The electrode material, diameter and polarity affect the shape of probe. The 80μm diameter tungsten wire between 500 and 600μF capacitance can be fabricated in 1μm tungsten electrode probe tip. The experiment use different material such as W, Cu and Mo. Finally, in the condition of “negative pole machining”, only tungsten can be used to make probe. It can greatly shorten the microelectrode fabrication time and effectively improve the reliability of the microelectrode and can fabricate a nanometer level tip in general electrical discharge machining (EDM) machine tool not add any other apparatus. The fabricated microelectrode can be used as a probe for scanner and measurement devices.

Gap Phenomena of Ultrasonic Vibration Assisted Electrical Discharge Machining in Gas

2008 ◽  
Vol 375-376 ◽  
pp. 500-504
Author(s):  
Qin He Zhang ◽  
Jian Hua Zhang ◽  
Shu Peng Su ◽  
Qing Gao
Keyword(s):  
Ultrasonic Vibration ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Environment Pollution ◽  
Dielectric Fluids ◽  
Simple Tool ◽  
Spark Plasma

Ultrasonic vibration aided electrical discharge machining (UEDM) in gas is a new machining technology developed in recent years. This technology uses air or oxygen as dielectric and ultrasonic vibration is applied to the workpiece during machining. UEDM in gas can avoid environment pollution, the most serious disadvantage of conventional EDM in kerosene-based oil or other dielectric fluids, and it is environmental-friendly. The technology also has virtues of wide applications, high machining efficiency, and simple tool electrodes and so on. In this paper, the formation and transformation of the spark plasma and the mechanism of material removal during a single pulse discharge are introduced.

Research on the influence of the discharge breakdown process on the crater formation during EDM

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wenchao Zhang
Keyword(s):  
Mathematical Model ◽  
Discharge Channel ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Crater Formation ◽  
Content Type ◽  
Breakdown Process ◽  
Positive Ions ◽  
Fluid Coupling

PurposeThis paper aims to study the breakdown, oscillation and vanishing of the discharge channel and its influence on crater formation with simulation and experimental methods. The experiment results verified the effect of the oscillating characteristics of the discharge channel on the shape of the crater.Design/methodology/approachA mathematical model that considers the magnetohydrodynamics (MHD) and the discharge channel oscillation was established. The micro process of discharging based on magnetic-fluid coupling during electrical discharge machining (EDM) was simulated. The breakdown, oscillation and vanishing stage of the discharge channel were analyzed, and the crater after machining was obtained. Finally, a single-pulse discharge experiment during EDM was conducted to verify the simulation model.FindingsDuring the breakdown of the discharge channel, the electrons move towards the center of the discharge channel. The electrons at the end diverge due to the action of water resistance, making the discharge channel appear wide at both ends and narrow in the middle, showing the pinch effect. Due to the mutual attraction of electrons and positive ions in the channel, the transverse oscillation of the discharge channel is shown on the micro level. Therefore, the position of the discharge point on the workpiece changes. The longitudinal oscillation in the discharge channel causes the molten pool on the workpiece to be ejected due to the changing pressure. The experimental results show that the shape of the crater is similar to that in the simulation, which verifies the correctness of the simulation results and also proves that the crater generated by the single pulse discharge is essentially the result of the interaction between transverse wave and longitudinal wave.Originality/valueIn this paper, the simulation of the discharge breakdown process in EDM was carried out, and a new mathematical model that considers the MHD and the discharge channel oscillation was established. Based on the MHD module, the discharge breakdown, oscillation and vanishing stages were simulated, and the velocity field and pressure field in the discharge area were obtained.

Sign in / Sign up

Export Citation Format

Share Document