Study on Single-Pulse Discharges under Special Flushing Conditions

2012 ◽  
Vol 504-506 ◽  
pp. 1183-1188 ◽  
Author(s):  
Markus Munz ◽  
David Sternkopf ◽  
Rüdiger Haas
Keyword(s):  
Electrical Discharge ◽  
Plasma Channel ◽  
Single Pulse ◽  
Tool Electrode ◽  
Narrow Gap ◽  
Gap Flow ◽  
Computational Fluid Dynamics Analysis ◽  
Flow Speeds ◽  
Electrical Discharge Drilling ◽  
Dielectric Flushing

Investigations on the special flushing conditions with an electrical discharge drilling machine were done to analyze single discharges. While flushing speeds in electrical discharge drilling are quiet higher as in electrical discharge sinking, the craters are influenced by the strong flushing. The topography of the craters in terms of depth, length and volume were analyzed. Crater depth and crater length are increasing with higher flushing speeds. Under a dielectric flushing the removed material on the tool electrode is less than on the workpiece. If the volume flow is high enough, the whole plasma channel is pushed in the direction of the flow. A computational fluid dynamics analysis was done to simulate the flow speeds in the narrow gap. Flow speeds above 500 m/s were simulated in the gap.

Computational Fluid Dynamics Analysis of Working Fluid Flow and Machining Debris Movement in End Electrical Discharge Milling and Mechanical Grinding Compound Machining

2012 ◽  
Vol 621 ◽  
pp. 191-195 ◽  
Author(s):  
Ren Jie Ji ◽  
Yong Hong Liu ◽  
Chao Zheng ◽  
Fei Wang ◽  
Yan Zhen Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Electrical Discharge ◽  
Great Influence ◽  
Working Fluid ◽  
Tool Electrode ◽  
Process Performance ◽  
Mechanical Grinding ◽  
Gap Flow ◽  
Computational Fluid Dynamics Analysis

The working fluid flow and the machining debris movement in the machining gap exercise a great influence on the process performance in end electrical discharge milling and mechanical grinding compound machining. In this paper, the working fluid flow and the machining debris movement in the machining gap are modeled based on the liquid-solid two-phase flow theory. The gap flow field is calculated with the software of Fluent, and the velocity field and the pressure field are analyzed. The results show that in the gap flow field of the compound machining, the working fluid flow can be accelerated, and the machining debris can be ejected timely by the rapid rotation of the tool electrode, so the compound process performance can be enhanced.

Analysis of Dimensional Accuracy (Over Cut) and Surface Quality (Roughness) in Electrical Discharge Machining of Inconel-718 Alloy

2019 ◽  
Vol 969 ◽  
pp. 644-649
Author(s):  
Rakesh Kumar ◽  
Anand Pandey ◽  
Pooja Sharma
Keyword(s):  
Inconel 718 ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Dimensional Accuracy ◽  
Work Piece ◽  
Tool Electrode ◽  
Affecting Factors ◽  
Inconel 718 Alloy ◽  
Electrical Discharge Drilling ◽  
Pulse On Time

Inconel-718 is a nickel based super alloy (difficult-to-cut material) used in aerospace industry. Analysis of machining performances viz. Over Cut (OC) & Surface Roughness (SR) for Inconel-718 through rotary Cu-pin tool electrode have been carried out. Peak current (Ip), pulse-on time (Ton), tool rotation (Nt) & hole depth (h) were used as input factors in Electrical Discharge Drilling (EDD) of Inconel-718 work-piece. Effect of input parameters on performance characteristics like OC & SR were found by Taguchi’s L9 (34) orthogonal array. It is reveals that Ip & h are most affecting factors that affects OC & SR. The Scanning Electron Microscope image was used to measure diameter of hole on work-piece after machining.

An Experimental Study of the Phenomenon of Surface Alloying by EDM Process Using Inconel Tool Electrode

2013 ◽  
Author(s):  
Sanjeev Kumar
Keyword(s):  
Experimental Study ◽  
Surface Properties ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Plasma Channel ◽  
Machining Process ◽  
Tool Electrode ◽  
Electrode Wear ◽  
Surface Alloying ◽  
Machining Conditions

Electrical Discharge Machining (EDM) has emerged as a very important machining process due to its numerous advantages. It is extensively used by the die and toolmaking industry for the accurate machining of complex internal profiles. Although EDM is essentially a material removal process, it has been used successfully for improving the surface properties of the work materials after machining. As the dissolution of the electrode takes place during the process, some of its constituents may alloy with the machined surface under appropriate machining conditions. Additive powders in the dielectric medium may form part of the plasma channel in the molten state and produce similar alloying effect. The breakdown of the hydrocarbon dielectric under intense heat of the spark contributes carbon to the plasma channel. Sudden heating and quenching in the spark region also alters the surface properties. This paper reports the results of an experimental study into electrical discharge machining of H13 hot die steel with Inconel (an alloy of chromium, nickel and iron) tool electrode under machining conditions favouring high electrode wear. The results show improvement in micro-hardness after machining by as much as 88%. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis of the machined surfaces show transfer of chromium and nickel from the tool electrode. Both these elements form intermetallic compounds as well as solid solution with iron and strengthen it. It was found that percentage of chromium increased from 5.39% to 6.52% and that of nickel increased from 0.19% to 4.87%. The favourable machining conditions for surface alloying were found to be low value of peak current, shorter pulse on-time, longer pulse off-time and negative polarity of the tool electrode.

scholarly journals Research on Ultrasonic Vibration Assisted Electrical Discharge Machining SiCp/Al Composite

2021 ◽  
Author(s):  
Xiang Gao ◽  
Jucai Li ◽  
Qixuan Xing ◽  
Qinhe Zhang
Keyword(s):  
Surface Roughness ◽  
Flow Field ◽  
Ultrasonic Vibration ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Pulse Interval ◽  
Tool Electrode ◽  
Gap Flow ◽  
Al Composite

Abstract In this paper, ultrasonic-vibration assisted electrical discharge machining (UEDM) is used to process SiCp/Al composite materials in order to achieve a higher material removal rate (MRR) and lower surface roughness, width overcut, and relative tool wear rate (RTWR). FLUENT software was used to simulate the gap flow field. The simulation results of the gap flow field show that the ultrasonic vibration of the tool electrode is conducive to the removal of chips, which makes the discharge more stable and improves the machining efficiency. Based on the single factor experiment, the effects of peak current, reference voltage, pulse width, and pulse interval on MRR, surface roughness, width overcut, and RTWR of the workpiece are studied. Then, based on the orthogonal experiment, the grey relational analysis method was used to optimize the process parameters, and the order of the influence of the 4 process indicators on the comprehensive performance and the optimal processing parameter combination was obtained. The reliability of the process optimization was verified with experiments.

scholarly journals Sub-Microstructure of Surface and Subsurface Layers after Electrical Discharge Machining Structural Materials in Water

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1040
Author(s):  
Sergey N. Grigoriev ◽  
Marina A. Volosova ◽  
Anna A. Okunkova ◽  
Sergey V. Fedorov ◽  
Khaled Hamdy ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Structural Materials ◽  
12Kh18n10t Steel ◽  
Mean Deviation ◽  
Water Medium ◽  
Tool Electrode ◽  
Marquardt Algorithm ◽  
Subsurface Layers ◽  
Electrical Wear

The material removal mechanism, submicrostructure of surface and subsurface layers, nanotransformations occurred in surface and subsurface layers during electrical discharge machining two structural materials such as anti-corrosion X10CrNiTi18-10 (12kH18N10T) steel of austenite class and 2024 (D16) duralumin in a deionized water medium were researched. The machining was conducted using a brass tool of 0.25 mm in diameter. The measured discharge gap is 45–60 µm for X10CrNiTi18-10 (12kH18N10T) steel and 105–120 µm for 2024 (D16) duralumin. Surface roughness parameters are arithmetic mean deviation (Ra) of 4.61 µm, 10-point height (Rz) of 28.73 µm, maximum peak-to-valley height (Rtm) of 29.50 µm, mean spacing between peaks (Sm) of 18.0 µm for steel; Ra of 5.41 µm, Rz of 35.29 µm, Rtm of 43.17 µm, Sm of 30.0 µm for duralumin. The recast layer with adsorbed components of the wire tool electrode and carbides was observed up to the depth of 4–6 µm for steel and 2.5–4 µm for duralumin. The Levenberg–Marquardt algorithm was used to mathematically interpolate the dependence of the interelectrode gap on the electrical resistance of the material. The observed microstructures provide grounding on the nature of electrical wear and nanomodification of the obtained surfaces.

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.

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