Single Pulse Discharge Channel Expansion Laws of EDM

2016 ◽  
Vol 52 (9) ◽  
pp. 208 ◽  
Author(s):  
Weijie CHANG
Keyword(s):  
Discharge Channel ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Channel Expansion

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 Research on Shape Change of Multimaterial Electrode for EDM

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Wenjian Wang ◽  
Yu Liu ◽  
Wenchao Zhang ◽  
Fujian Ma ◽  
Dapeng Yang ◽  
...  
Keyword(s):  
Material Removal ◽  
Shape Change ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Machining Process ◽  
Die Steel ◽  
Electrode Shape ◽  
Simulation Strategy ◽  
Feed Strategy ◽  
Simulation Results

The shape change law of a multimaterial electrode in EDM was studied, and a cosimulation between ANSYS and MATLAB of electrode shape change of the multimaterial electrode and workpiece was established. Element birth and death in ANSYS was used to obtain the removal volume in a single-pulse discharge, and the electrode feed strategy, material removal, and renewal strategy are considered to establish the shape simulation strategy. Then, a program based on MATLAB software was compiled to simulate the machining process and predict the shape change of the multimaterial electrode of different combinations. The experiments of different multimaterial electrodes were carried out with the die steel as the workpiece. The simulation results were compared with the experimental results to verify the effectiveness of the simulation model.

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.

Comparisons of single pulse discharge crater geometries in EDM and EAM

2016 ◽  
Vol 22 ◽  
pp. 74-81 ◽  
Author(s):  
Min Zhang ◽  
Qinhe Zhang ◽  
Liya Dou ◽  
Qingyu Liu ◽  
Chunjie Dong
Keyword(s):  
Pulse Discharge ◽  
Single Pulse

PACKAGING AND WIDE-PULSE SWITCHING OF 4 MM × 4 MM SILICON CARBIDE GTOs

2009 ◽  
Vol 19 (01) ◽  
pp. 173-181
Author(s):  
HEATHER O'BRIEN ◽  
M. GAIL KOEBKE
Keyword(s):  
Silicon Carbide ◽  
Recovery Time ◽  
Pulse Current ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Electronic Components ◽  
Army Research Laboratory ◽  
Pulse Switching ◽  
Reliable Performance ◽  
High Pulse

The U. S. Army Research Laboratory (ARL) is investigating compact, energy-dense electronic components to realize high-power, vehicle-mounted survivability and lethality systems. These applications require switching components that are low in weight and volume, exhibit reliable performance, and are easy to integrate into the vehicles' systems. The devices reported here are 4 mm × 4 mm silicon carbide GTOs rated for 3000 V blocking. These devices were packaged at ARL for high pulse current capability, high voltage protection, and minimum package inductance. The GTOs were switched in a 1-ms half-sine, single-pulse discharge circuit to determine reliable peak current and recovery time (or Tq). The GTOs were repeatedly switched over 300 A peak (3.3 A/cm2 and an action of 60 A2s) with a recovery time of 20 µs. The switches were also evaluated for dV/dt immunity up to an instantaneous slope of 3 kV/ µs.

Research on a single pulse discharge to discriminate EDM and EAM based on the plasma tunnel and crater geometry

2015 ◽  
Vol 219 ◽  
pp. 248-256 ◽  
Author(s):  
Min Zhang ◽  
Qinhe Zhang ◽  
Haijiao Wang ◽  
Guowei Liu ◽  
Tuodang Guo
Keyword(s):  
Pulse Discharge ◽  
Single Pulse

Research on Micro-Size Electrical Discharge Grinding Polycrystalline Cubic Boron Nitride Based on Single Pulse

2021 ◽  
Vol 1035 ◽  
pp. 778-784
Author(s):  
Yun Hai Jia ◽  
Yan Hua Cia ◽  
Qin Jian Zhang
Keyword(s):  
Boron Nitride ◽  
Pulse Duration ◽  
Electrical Discharge ◽  
High Efficiency ◽  
Pulse Discharge ◽  
Cubic Boron Nitride ◽  
Single Pulse ◽  
Polycrystalline Cubic Boron Nitride ◽  
Corrosion Pit ◽  
Corrosion Pits

Polycrystalline cubic boron nitride (PcBN) was a high temperature and high pressure composite material with high hardness. With its high wear resistance and good chemical stability, it conforms to the basic characteristics of modern advanced cutting technology of "high efficiency, high precision, high efficiency and green". Currently, it was widely used in the field of ferrous metal cutting tools. Electrical discharge grinding was one of the most effective methods for machining polycrystalline cubic boron nitride cutters. It was especially suitable for machining complex shapes and thin edge cutters. Single pulse electrical discharge grinding is the basis of continuous EDG machining and an effective method to study micro-scale electrical discharge grinding. In this study, the morphology of single pulse discharge corrosion pits and the relationship between discharge parameters and material removal rate, such as the deep-diameter ratio of the corrosion pits, the pulse width and the deep-diameter relationship of the corrosion pits, were studied with the polycrystalline cubic boron nitride composite sheet of 2 micron particle size as the test material and the independently developed single pulse discharge power supply as the device. The experimental results show that the radius and heat affected area of the discharge corrosion pit increase rapidly, then slowly, and finally gradually with the extension of pulse duration. The corrosion depth generally varies gently in the range of 0.2 ~ 0.5 micron, and the pulse duration has no obvious effect on the depth of the discharge corrosion pit. With the extension of pulse duration, the ratio of radius to depth of the corrosion pit changed in the range of 13 ~ 20, and the ratio basically declined.

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