Study on Gap Phenomena Before and After the Breakout Event of Fast Electrical Discharge Machining Drilling

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Weiwen Xia ◽  
Yaou Zhang ◽  
Mo Chen ◽  
Wansheng Zhao
Keyword(s):  
Fluid Flow ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Deep Understanding ◽  
Tool Electrode ◽  
Machining Efficiency ◽  
Short Period ◽  
Before And After ◽  
Flush Fluid ◽  
Side Gap

Abstract Fast electrical discharge drilling is broadly used to manufacture small holes on molds, dies, filters, and automobile and aerospace components. Breakout is the event when the tool electrode reaches the opposite surface of the workpiece. When a breakout happens, the machining efficiency drops sharply and the process becomes unstable. To gain a deep understanding of the breakout process, this paper observed the gap phenomena before and after the breakout with cameras through a quartz glass flake. Experiments were conducted on the workpiece tilted to 45 deg. From the observation, it was found that the deformation of the electrode was not negligible. The electrode would vibrate or shake before and after the breakout. Side-gap sparks were common in the process, and even more were observed after the breakout. The fluid flow in the discharge gap and the side gap did not vanish immediately when a breakout happened and could still evacuate debris for a short period. The debris gradually accumulated as the fluid flow in the gap vanished. A series of simulations were conducted to study the fluid flow and debris movement after the breakout. And simulations were also performed to find the influence on electrode vibration of high-pressure flush fluid and discharge location. The results of simulations agreed well with the observed phenomena. From the observation and simulation results, the deformation or vibration of the electrode and the accumulation of debris were found to be the main factors that led to the low machining efficiency after the breakout.

Machining Characteristics of IN718 by EDM with Cooled Electrode and Vibration of the Workpiece

2020 ◽  
Vol 996 ◽  
pp. 131-136
Author(s):  
Yao Li ◽  
Cheng Cui ◽  
Bengang Lin ◽  
Li Li
Keyword(s):  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Cryogenic Cooling ◽  
Tool Electrode ◽  
Machining Efficiency ◽  
Electrical Erosion ◽  
Machining Characteristics ◽  
Edm Process ◽  
Process Material

Inconel718 has been widely used in various fields for its good performance, but it is difficult to machine with traditional machining methods. Electrical discharge machining is an alternative competitive process to machine Nickel-based alloys by electrical erosion. In order to improve reduce the electrode loss and improve the machining efficiency, the horizontal ultrasonic vibration of the workpiece and the cryogenic cooling of the tool electrode were applied into the EDM process. Material removal efficiency, surface roughness, surface topography, and microhardness have been characterized.

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.

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.

Study on the improvement of the surface integrity and efficiency of electrical-discharge-machined TC4 titanium alloy via abrasive flow machining

2020 ◽  
pp. 095440542097109
Author(s):  
Ze Yu ◽  
Dunwen Zuo ◽  
Yuli Sun ◽  
Guohua Li ◽  
Xuemei Chen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Surface Quality ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Small Hole ◽  
Machining Process ◽  
Machining Efficiency ◽  
Abrasive Flow Machining ◽  
Tc4 Titanium Alloy

To simultaneously optimize the surface quality and machining efficiency of the electrical discharge machining (EDM) processes used to produce titanium alloy quadrilateral group small hole parts, a combined “EDM + AFM” machining technology is proposed in this paper as an efficient and high-quality machining approach. In the proposed method, TC4 titanium alloy is first machined using the EDM process with graphite electrodes and the abrasive flow machining (AFM) process is then used to finish the machined surface. The effects of various electrical parameters on EDM-derived surface quality and improvements in EDM-derived quality under the application of AFM were assessed and, using the final surface roughness as a constraint condition, the effects of various combinations of EDM and “EDM + AFM” on efficiency were studied. The results revealed that the thickness and surface roughness of the superficial recast layer of the TC4 titanium alloy increase with both current and pulse width; in particular, increasing these parameters can increase the surface roughness by two to three grades. Following AFM, the alloy has a more uniform hardness distribution and the surface stress state changes from tensile to compressive stress, indicating that the combined “EDM + AFM” machining scheme can significantly enhance the surface quality of EDM-produced titanium alloy quadrilateral small group holes. The combined scheme achieves a balancing point beyond which increasing the roughness or the number of machining holes enhances either the machining efficiency or the machining surface quality. In the case of typical titanium alloy quadrilateral group small hole parts, the combined machining process can improve the finishing efficiency and total machining efficiency by 71.2% and 25.36%, respectively.

State of the art in processing of shape memory alloys with electrical discharge machining: A review

2020 ◽  
pp. 095440542095877
Author(s):  
Ranjit Singh ◽  
Ravi Pratap Singh ◽  
Rajeev Trehan
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Real Life ◽  
Orthopedic Implants ◽  
Industrial Applications ◽  
Future Research ◽  
Tool Electrode ◽  
Micro Tools

Shape memory alloys (SMAs) have been well known for their superior and excellent properties which makes them an eligible candidate of paramount importance in real-life industrial applications such as; orthopedic implants, actuators, micro tools, stents, coupling and sealing elements, aerospace components, defense instruments, manufacturing elements, bio-medical appliances, etc. In spite of their exceptional properties, the effective processing of these alloys is always seen as a challenge by researchers around the globe. The present article has been therefore attempted to explore the numerous studies conducted to process these alloys by employing the principles of electrical discharge machining (EDM) and its allied approaches. The NiTi-based SMAs have been revealed to be explored majorly among the several types SMAs. The several investigations carried out in the domain of EDM, Wire-EDM, and some conventional processing of various types of SMAs have also been critically reviewed and reported. It also highlights the numerous experimental, theoretical, modeling, and optimization-based researches attempted in EDM of SMAs. It was also reported that the proper selection of process variables, tool electrode, and the dielectrics can substantially improve the overall process effectiveness. Among the various accessible EDM variants used for the processing of SMAs, attempted by the umpteen investigators, the wire-cut EDM process has been revealed as the most explored one for cutting SMAs than the other allied processes such as: die-sinking EDM and powder-mixed EDM. The micro-machining applications of EDM have also been deliberated briefly. The last section of the article reports about the opportunities and the challenges for future research.

Research on Electrical Discharge Machining for Injection Mold of Automotive Connector

2012 ◽  
Vol 522 ◽  
pp. 17-20
Author(s):  
Wei Min Pan ◽  
Ke Ke Shi ◽  
Xian Qing Lei
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Tool Electrode ◽  
Injection Mold ◽  
Workpiece Material ◽  
Electrode Tool ◽  
Mating Surface ◽  
Plastic Components

Electrical discharge machining (EDM) processing is generally applied on the area of molding plastic component or mating surface required high accuracy. The areas determine the quality of the plastic components. The principle of EDM is based on the material vaporization of high potential difference across the workpiece and Tool electrode. Tool electrode and workpieces are discontiguous when the EDM processes. Because there is no mechanical contact, Hardness and strength of the workpiece material have minimal effect on the material removal rate .The application of EDM technology on injection mold of automotive connector is focused on in this paper. Processing of the complex cores is researched. The design and processing of the tool electrode have been completed in the meantime.

Electrical Discharge Machining of Submicron-Diameter Micropins

2010 ◽  
Vol 447-448 ◽  
pp. 238-241 ◽  
Author(s):  
Hiromitsu Ueno ◽  
Yuki Kono ◽  
Kai Egashira
Keyword(s):  
Electrical Discharge ◽  
Tungsten Wire ◽  
Open Circuit Voltage ◽  
Pulse Generator ◽  
Electrical Discharge Machining ◽  
Open Circuit ◽  
Tool Electrode ◽  
Stray Capacitance ◽  
Finish Machining ◽  
The Wire

The wire electrodischarge grinding (WEDG), which is one of the electrical discharge machining (EDM) methods, of submicron-diameter zinc micropins was attempted using a relaxation-type pulse generator. Tungsten wire of 30 µm diameter was employed as the tool electrode. The open-circuit voltage was set at lower than or equal to 15 V in the finish machining step. The electrostatic capacitance of the pulse generator was its stray capacitance only. As a result, a micropin of 0.3 µm diameter was processed. They are the smallest-diameter micropins fabricated by EDM, to the best of our knowledge.

Small Diameter External Cylindrical Surfaces Obtained by Ram Electrical Discharge Machining

2014 ◽  
Vol 611-612 ◽  
pp. 650-655 ◽  
Author(s):  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Hans Peter Schulze ◽  
Oana Dodun ◽  
Irina Besliu ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Process Analysis ◽  
Electrical Discharge Machine ◽  
Small Diameter ◽  
Machining Process ◽  
Dielectric Fluid ◽  
Tool Electrode ◽  
Electrical Discharges ◽  
Pulse On Time

Electrical discharge machining uses the pulse electrical discharges generated between the closest asperities existing on the workpiece surface and the active surface of the tool electrode in dielectric fluid. Essentially, some distinct electrical discharge machining schemas could be used in order to obtain cylindrical external surfaces; within this research, one preferred a machining schema based on the use of a cooper plate in which there were small diameter holes, by taking into consideration the existence of a ram electrical discharge machine. The results of the machining process analysis were presented. A thin copper was considered to be used as tool electrode, in order to diminish the spurious electrical discharges, able to generate shape errors of the machined surface. Some experimental researches were developed by changing the sizes of the process input parameters. As output factors, the test piece and tool electrode masses decreases were considered. Power type empirical mathematical models were determined, in order to highlight the influence exerted by the pulse on time, off time and machining process duration on the output parameters values.

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