scholarly journals Study on the Discharge Characteristics of Single-Pulse Discharge in Micro-EDM

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 55 ◽  
Author(s):  
Qingyu Liu ◽  
Qinhe Zhang ◽  
Min Zhang ◽  
Fazhan Yang
Keyword(s):  
Electrical Discharge Machining ◽  
Short Pulse ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Micro Edm ◽  
Discharge Characteristics ◽  
Discharge Duration ◽  
Positive Ion

To further study the discharge characteristics and machining mechanism of micro-electrical discharge machining (micro-EDM), the variation trends of the discharge energy and discharge crater size with actual discharge duration are discussed based on single-pulse experiments. The polarity effect of micro-EDM was analyzed according to the motion characteristics of electrons and ions in the discharge plasma channel. The results show that the discharge current and voltage of micro-EDM were independent of the discharge width and open-circuit voltage. The energy utilization rate of the short-pulse discharge was relatively high, and the energy utilization rate decreased gradually as the discharge duration increased. Even if the mass of the positive ion was much larger than that of the electron, the kinetic energy of the positive ion was still less than that of the electron when bombarding the surface of the electrode. The acceleration and speed of electrons were very high, and the number of times that electrons bombarded the surface of positive electrode was more than 600 times that of positive ions bombarding the surface of the negative electrode during the same time.

scholarly journals Study on the Time-Varying Characteristics of Discharge Plasma in Micro-Electrical Discharge Machining

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 718 ◽  
Author(s):  
Qingyu Liu ◽  
Qinhe Zhang ◽  
Min Zhang ◽  
Fazhan Yang
Keyword(s):  
Discharge Current ◽  
Electrical Discharge ◽  
Discharge Plasma ◽  
Electrical Discharge Machining ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Expansion Velocity ◽  
Micro Edm ◽  
Micro Electrical Discharge Machining ◽  
Discharge Duration

Micro electrical discharge machining (micro-EDM) has been widely applied in the field of precision machining, but the machining mechanism is still unclear. In this paper, the relationship between the characteristics of discharge plasma and discharge duration is clarified by analyzing the formation and expansion process of the discharge plasma channel under micro-scale discharge conditions. Based on the experimental results, the effects of discharge duration on the discharge current, discharge voltage and discharge crater size are discussed. The results show that the expansion acceleration, internal pressure, temperature, and electron density of the discharge plasma decrease as the discharge duration increase, while the radius and expansion velocity of the discharge plasma increase, and finally the discharge plasma reaches the state of shape–position equilibrium. The resistance of discharge plasma is estimated to fluctuate in the range of 38–45 Ω by the ratio of discharge maintenance voltage to discharge current. The energy utilization rate of micro-EDM is very high when discharge duration is less than 4 μs, and then decreases gradually as the discharge duration increased. There is a positive linear relationship between discharge crater volume and discharge duration. The discharge duration has no significant effect on the discharge crater depth. This study provides a theoretical basis for further study of discharge plasma characteristics in micro-EDM.

Study on Discharge Characteristics of Piezoelectric Self-Adaptive Micro-EDM System

2010 ◽  
Vol 34-35 ◽  
pp. 492-496 ◽  
Author(s):  
Yu Jie Zhu ◽  
Qin He Zhang ◽  
Xiu Zhuo Fu ◽  
Guang Hua Bao
Keyword(s):  
Power Supply ◽  
Electrical Discharge Machining ◽  
New Technology ◽  
Utilization Rate ◽  
Micro Edm ◽  
Micro Machining ◽  
Discharge Characteristics ◽  
Micro Electrical Discharge Machining ◽  
Working Principle ◽  
Self Adaptive

A new technology of piezoelectric self-adaptive micro electrical discharge machining has been developed in this paper according to the characteristics of micro-EDM. Its working principle and the discharge characteristics are introduced, and it has been proved that the new technology can achieve micro machining. Using piezoelectric actuator as micro-feed mechanism, this new technology is simple in structure and can improve the discharging gap effectively. The discharge frequency and effective pulse utilization rate of the power supply is enhanced in machining. Experimental results show that this new technology can achieve good results.

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.

scholarly journals Effect of machining polarity on single discharge characteristics in micro-EDM

2020 ◽  
Vol 191 ◽  
pp. 04004
Author(s):  
Kan Wang ◽  
Yong Liu
Keyword(s):  
Energy Distribution ◽  
Electrical Discharge Machining ◽  
Micro Edm ◽  
Positive Polarity ◽  
Discharge Characteristics ◽  
Micro Electrical Discharge Machining ◽  
Crater Size ◽  
Single Discharge ◽  
Plasma Radius ◽  
The Difference

In micro electrical discharge machining (micro-EDM), polarity effect is attributed to the difference in energy distribution into the anode and cathode. Understanding the effect of machining polarity on energy distribution bears significance in predicting and controlling machining performances. Single discharge experiments were conducted in this study, to explore single discharge characteristics. The plasma radius and energy distribution were calculated by combining the crater size and the electro-thermal model. The results show that the influence of discharge current on crater depth-to-diameter ratio (H/D) is not significant with positive polarity. The plasma radius, fraction of energy transferred to workpiece, and crater size are greater for micro-EDM with negative polarity than positive polarity.

Research on Micro-Size Electrical Discharge Machining Polycrystalline Diamond

2019 ◽  
Vol 943 ◽  
pp. 14-19 ◽  
Author(s):  
Yun Hai Jia ◽  
Jian Mei Guo ◽  
Yan Guo ◽  
Fan Yu
Keyword(s):  
Pulse Duration ◽  
High Efficiency ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Cutting Tools ◽  
Polycrystalline Diamond ◽  
Green Manufacturing ◽  
Single Pulse ◽  
Pit Depth ◽  
Thermal Influence

With the demand of modern cutting technology for ‘high efficiency, precise, flexibility and green manufacturing’, polycrystalline diamond materials as cutting tools have been widely used in automobile, aerospace and non-metal processing. Electro-spark erosion is one of the most effective ways to machine polycrystalline diamond materials. Single pulse discharge is one of the research foundations of micro-EDM. Using 2 micron granularity polycrystalline diamond as experiment material, the influence of single pulse discharge technology on the removal efficiency of materials was studied, such as pit radius, pit depth and radius-depth ratio, etc. The experimental results show that, with the extension of the pulse duration, the radius of the discharge pit begins to increase rapidly, then slowly increases, and finally to slow down; while the radius of thermal influence zone increases rapidly and then continues to increase slowly. With the extension of pulse duration, the ratio of pit depth to radius changes within the range of 0.05 ~ 0.25, which shows a downward trend basically.

Micro Electrical Discharge Machining of Tungsten Carbide with Ultra-Short Pulse

2015 ◽  
Vol 651-653 ◽  
pp. 759-764
Author(s):  
Oliver Kröning ◽  
Mathias Herzig ◽  
Matthias Hackert-Oschätzchen ◽  
Ralf Kühn ◽  
Henning Zeidler ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Pulse Generator ◽  
Electrical Discharge Machining ◽  
Short Pulse ◽  
High Surface ◽  
Micro Edm ◽  
High Surface Quality ◽  
Micro Electrical Discharge Machining ◽  
Metal Machining ◽  
Ultra Short Pulse

Micro EDM (Electrical Discharge Machining) is a known nonconventional process for the machining of hard to cut materials. Due to its ablating nature based on melting and evaporation through heat induced by electrical discharges, it can function independently of the hardness, toughness or brittleness of the workpiece. Thus micro EDM is a possible process to fulfill the requirements of higher precision and high quality in carbide metal machining. Thereby the surface and the roughness of machined carbide metals depend on the discharge energy used. For machining carbide metals with high surface quality pulse generators with ultra-short discharges are required. This paper presents the development of a two-staged pulse generator with the ability to provide ultra-short pulses by using a two-staged pulse. The current and voltage signals of the discharges were recorded and their characteristics were analyzed.

Analysis and Simulation of Micro Electro Discharge Machining Process

2007 ◽  
Author(s):  
Dedong Gao ◽  
Ling Tian
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Machining Process ◽  
Micro Edm ◽  
Analysis Model ◽  
Element Analysis ◽  
Electro Discharge Machining ◽  
Numeric Simulation

Based on the basic thermal conductivity theory and the fact of micro electro discharge machining (micro-EDM), a finite element analysis model of micro-EDM is proposed. Through finite element analysis software ANSYS, the temperature field distribution of the single pulse discharge is simulated under the different heat source condition. It can be seen from the results that the shape of discharge crater is similar to that of molten zone of the temperature distribution. The surface roughness and material removed rate of single pulse discharge are calculated and analyzed by the numeric simulation results.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document