Development of EDT Equipment Using Wire Tool Electrode

2016 ◽  
Vol 1136 ◽  
pp. 384-389
Author(s):  
Yasuhiro Takada ◽  
Mitsuru Shinozaki ◽  
Minoru Ota ◽  
Kai Egashira ◽  
Keishi Yamaguchi ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Small Diameter ◽  
High Hardness ◽  
Area Ratio ◽  
Tool Electrode ◽  
Feed Speed ◽  
Feeding System ◽  
Inner Surface ◽  
Cylindrical Parts ◽  
Novel Method

Whirling electrical discharge texturing (WEDT) was developed to process microstructures on the inner surface of cylindrical parts made of high hardness materials. However, the minimum processable diameter of the cylindrical parts was φ 5 mm and the equipment could not feed the new tool electrodes. Therefore, the authors devised a novel method of WEDT using a straight wire tool electrode for a cylindrical surfaces with a small diameter. It was confirmed that microstructures could be created on the inner surface of a cylinder of φ 1.1 mm diameter, and that the texture-area ratio could be controlled by the workpiece feed speed. Moreover, new EDT equipment with a feeding system for a wire tool electrode and a bending system for the tip of a wire tool electrode was developed. As a result, the equipment that can process microstructures on the inner surface of a cylinder with a small diameter and feed a wire tool electrode during texturing was successfully developed.

scholarly journals Micro-Structuring on Cylindrical Inner Surface Using Whirling Electrical Discharge Texturing

2012 ◽  
Vol 565 ◽  
pp. 430-435 ◽  
Author(s):  
Vitchuda Lertphokanont ◽  
Takayuki Sato ◽  
Minoru Ota ◽  
Keishi Yamaguchi ◽  
Kai Egashira
Keyword(s):  
Friction Coefficient ◽  
Electrical Discharge ◽  
Area Ratio ◽  
Crater Depth ◽  
Tool Electrode ◽  
Textured Surface ◽  
Feed Speed ◽  
Total Removal ◽  
Crater Diameter ◽  
Micro Structuring

The authors developed Whirling Electrical Discharge Texturing (WEDT) in order to reduce friction coefficient of cylinder-shaped parts. In previous research, the authors verified fundamental characteristics of WEDT by observation of textured surface. It was found that a crater shape and texture-area ratio can be controlled by WEDT. The texture-area ratio depends on feed speed of tool electrode. In this research, crater depth, crater diameter, texture area ratio and total removal volume of craters were investigated to confirm characteristics of WEDT in detail. In addition, tungsten wire was used as a whirling shaft in order to improve stability of whirling phenomenon. Moreover, a textured surface was finished by lapping-film in order to remove protrusions around craters and reduce friction coefficient. As a result, it was verified that the texture-area ratio slightly increased with decreasing feed speed and it was confirmed that crater depth, crater diameter, and total removal volume of craters were also related to feed speed.

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.

scholarly journals Study on Fe-Based Metallic Glass Micro Hole Machining by Using Micro-EDM Combined with Electrophoretic Deposition Polishing

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 96
Author(s):  
Hai-Ping Tsui ◽  
Shih-Yu Hsu
Keyword(s):  
Metallic Glass ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
High Hardness ◽  
Duty Factor ◽  
Machined Surface ◽  
Inner Surface ◽  
Micro Hole ◽  
Pulse On Time ◽  
Hole Machining

Fe-based metallic glass possesses high hardness and brittleness. It is a hard-to-cut metal material and difficult to machine by conventional methods. Although electrical discharge machining (EDM) has advantages in machining hard-to-cut metal materials, recast layer, pores, and micro cracks will form on the machined surface after machining. The study used a helical tool for the micro electrical discharge drilling (µ-EDD) process on Fe-based metallic glass. The influence of processing parameters, including the pulse on time, gap voltage, duty factor, and spindle rotational speed on the micro hole machining quality characteristics was investigated. The helical tool with SiC electrophoretic deposited (EPD) film was used to polish the inner surface of the electrical discharged micro hole. The findings show that the best micro hole accuracy, tool wear length, and inner surface were obtained at the spindle rotation speed of 1150 rpm, pulse on time of 5 μs, gap voltage of 30 V, and duty factor of 40%. The inner surface roughness can be reduced to 0.018 µm by using EPD tool. The inner surface was polished up to form a mirror surface.

Diminishing Shape Errors at Electrical Discharge Machining of External Cylindrical Surfaces

2013 ◽  
Vol 371 ◽  
pp. 305-309 ◽  
Author(s):  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Lorelei Gherman ◽  
Irina Beşliu ◽  
Miroslav Radovanović ◽  
...  
Keyword(s):  
Experimental Observation ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Cylindrical Tube ◽  
Tool Electrode ◽  
Shape Error ◽  
Machined Surface ◽  
Shape Errors ◽  
Cylindrical Parts ◽  
Experimental Researches

Electrical discharge machining is a method that could be applied in order to detach cylindrical parts from a workpiece made of electroconductive material. If cylindrical tube is used as tool electrode, the machined surface could have a conical shape, due to the presence in the work gap of the electroconductive particles, detached from electrodes. Experimental researches were developed in order to obtain information concerning the shape error of machined surface. As a result of the experimental observation, improved technological solutions were identified and investigated. The experimental results proved certain possibilities of shape error decrease.

scholarly journals Tool electrode wear in electrical discharge of small diameter holes

2017 ◽  
Vol 94 ◽  
pp. 03013
Author(s):  
Laurenţiu Slătineanu ◽  
Oana Dodun ◽  
Iulia Carp ◽  
Margareta Coteaţă ◽  
Irina Beşliu
Keyword(s):  
Electrical Discharge ◽  
Small Diameter ◽  
Tool Electrode ◽  
Electrode Wear

Automatic Stripping of Dielectric-Encased Wire Tool Electrode Used in Electrical Discharge Machining

2007 ◽  
Vol 129 (5) ◽  
pp. 973-978
Author(s):  
Seiji Kumagai ◽  
Naoki Sato ◽  
Koichi Takeda
Keyword(s):  
Control System ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Threshold Value ◽  
Electrode System ◽  
Tool Electrode ◽  
Feed Speed ◽  
Wire Electrode ◽  
Aspect Ratios ◽  
The Wire

A new electrical discharge machining (EDM) system using a wire encased in a dielectric jacket is proposed as an alternative to conventional hole-fabrication EDM systems. The jacket suppresses secondary discharges occurring between the sidewalls of the wire and the fabricated hole, which allows fabrication of holes with higher aspect ratios compared to those formed by a conventional EDM system using naked pipe electrodes. In this new system, the tip of the wire electrode is stripped by displacing the jacket, which produces continuous sparks for workpiece erosion and keeps the bore and shape of the fabricated holes constant. In the present study, we developed a control system to maintain the exposed length of the tip without the need for visual observation and without the assumption that wear is constant over time. The exposed length of the tip of the wire electrode is related to the feed speed (toward the workpiece) of the electrode system. The jacket was displaced when the feed speed of the electrode system exceeded a threshold value, which resulted in slowing of the electrode system feed. The feed speed was kept within the specified range by determining a threshold value, which led to maintenance of a constant exposed length of the tip. This control system was validated in actual drilling tests. Optimizing the threshold feed speed contributed to a higher machining speed.

Monitoring of End-Mill Temperature with Infrared Thermography and Wireless Tool Holder System

2014 ◽  
Vol 1017 ◽  
pp. 624-629 ◽  
Author(s):  
Masatoshi Shindou ◽  
Ryo Matsuda ◽  
Tatsuya Furuki ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
End Milling ◽  
Small Diameter ◽  
Sampling Time ◽  
End Mill ◽  
Monitoring Tool ◽  
Tool Temperature ◽  
Wireless System ◽  
Response Measurement ◽  
Tool Holder ◽  
Novel Method

Nowadays, infrared thermographic technology has been attracting attention in various industrial fields. We therefore focus on it as a novel method for monitoring tool temperature to improve end-milling conditions for difficult-to-cut materials. However, a problem has emerged; it is difficult to measure the tool temperature when there is a coolant because the coolant prevents monitoring of the surface of the end-mill tool. Thus, we developed a wireless tool holder system equipped with a thermocouple in the end mill to monitor the tool temperature under coolant conditions. In this report, we compared the temperature measured by infrared thermographic imagery with that measured by a wireless tool holder system when end milling the stainless steel under dry coolant conditions. The thermocouple, which has a small diameter of 0.12 mm, was used to ensure high response measurement in the proposed wireless tool holder. We obtained the tool temperatures by infrared thermographic imagery and by wireless tool holder equipped with a thermocouple at a sampling time of 1/30 of a second. We confirmed that the temperature measured by the wireless tool holder agrees with that measured by infrared thermographic imagery. As a result, we demonstrated that the developed method with a wireless system is effective to estimate the tool temperature in end-milling processes and makes it feasible to measure it under coolant conditions.

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.

Friction Characteristics with Pin-on-Disc Friction Test on Microstructured Surface Using Whirling Electrical Discharge Texturing

2014 ◽  
Vol 1017 ◽  
pp. 417-422
Author(s):  
Vitchuda Lertphokanont ◽  
Takayuki Sato ◽  
Masahiro Oi ◽  
Minoru Ota ◽  
Keishi Yamaguchi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Electrical Discharge ◽  
Area Ratio ◽  
Mixed Lubrication ◽  
Optimal Conditions ◽  
Friction Test ◽  
Crater Diameter ◽  
Microstructured Surface ◽  
Pin On Disc ◽  
Lubrication Condition

A microstructured surface was created on a steel surface by whirling electrical discharge texturing (WEDT) since it was considered that the microstructures could act as lubricant reservoirs to assist the formation of a lubricating film, resulting in reduced friction. In this study, friction tests under engine oil were carried out over a range of loads and sliding speeds. In addition, the surface characteristics of the microstructured surface were also investigated to optimize the friction characteristics of the textured surface through pin-on-disc friction tests. It was found that under the mixed lubrication condition near the boundary condition, textured surfaces with texture-area ratio of approximately 6% and a mean crater diameter of 35 μm were considered as the optimal conditions for reducing the friction coefficient. However, a texture-area ratio of approximately 4% and a mean crater diameter of 35 μm were considered as the optimal conditions for reducing the friction coefficient under the mixed lubrication condition near the elastohydrodynamic lubrication condition. It was considered that when the normal load decreased, the lubrication region changed from the mixed lubrication condition to the hydrodynamic lubrication condition, which meant that the actual contact surface area decreased. The decrease in the actual contact surface area with decreasing texture-area ratio led to a reduction in the friction coefficient. Finally, it was clarified that the friction coefficient was reduced under the optimized conditions of the microstructured surface through a pin-on-disc friction test.

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