• 제목/요약/키워드: Electro-Discharge energy

검색결과 45건 처리시간 0.055초

금속결합제 연삭숫돌의 방전트루잉에서 기준전류와 절입깊이가 방전에너지에 미치는 영향 (Effect of Reference Current and Depth of Cut on Electro-Discharge Energy in Electro-Discharge Truing Process for Metal-Bonded Grinding Wheel)

  • 신건휘;곽태수;정명원;곽인실
    • 한국정밀공학회지
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    • 제33권6호
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    • pp.485-490
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    • 2016
  • This study focused on developing an electro-discharge truing method for the ELID grinding process using a metal-bonded grinding wheel. The truing process in grinding plays important roles in enhancing the quality of the ground surface. In this study, a reference current in the electro-discharge truing process was confirmed to be a viable solution for efficient truing through performance experiments. Current and voltage variation experiments were carried out and the variation output data were collected with a monitoring program to understand the electrodischarge phenomenon that occurs between metal-bonded grinding wheels and copper electrodes. The experimental results showed that as the reference current decreased, the average electro-discharge energy decreased. Therefore, the reference current can be used as an indicator to estimate the size of the gap between the truer and grinding wheel.

전해 방전법을 이용한 유리 미세 구멍가공 (Micro-hole Fabrication of Glass Using Electro-chemical Discharge Method)

  • 이왕훈;이영태
    • 센서학회지
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    • 제13권1호
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    • pp.72-77
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    • 2004
  • In this paper, we fabricated an apparatus of the electro-chemical discharge drilling for boring narrow through-hole into a glass. In the electrolyte, electro-chemical discharge creates high temperature condition by the electro-discharge energy. Therefore, glass are removed by the accelerated chemical reaction with glasses and chemicals in the high temperature condition. For optimization of the electro-chemical discharge drilling, the process condition was studied experimentally as a function of the electrolyte concentration, supply voltage and process time. The optimum condition was from DC25V to DC30V of applied voltage, 35 wt% NaOH solution.

전기방전소결에 의해 제조된 다공성 및 다공성 표면을 갖는 Ti-6Al-4V 임플란트 : (1) 제조방법 및 기본적 특성 (Fully Porous and Porous Surfaced Ti-6Al-4V Implants Fabricated by Electro-Discharge-Sintering: (1) Fabrication Method and Fundamental Characteristics)

  • 현창용;허재근;이원희
    • 한국분말재료학회지
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    • 제12권5호
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    • pp.325-331
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    • 2005
  • Implant prototypes with various porosities were fabricated by electro-discharge-sintering of atomized spherical Ti-6Al-4V powders. Single pulse of 0.75 to 2.0 kJ/0.7 g-powder, using 150, 300, and $450{\mu}F$ capacitors was applied to produce a fully porous and porous surfaced implant compact. The solid core formed in the center of the compact after discharge was composed of acicular ${\alpha}+{\beta}$ grains and porous layer consisted of particles connected in three dimensions by necks. The solid core and neck sizes increased with an increase in input energy and capacitance. On the other hand, pore volume decreased with increased capacitance and input energy due to the formation of solid core. Capacitance and input energy are the only controllable discharge parameters even though the heat generated during a discharge is the unique parameter that determines the porosity of compact. It is known that electro-discharge-sintering of spherical Ti-6Al-4V powders can efficiently produce fully-porous and porous surfaced Ti-6Al-4V implants with various porosities in a short time less then 400 isec by manipulating the discharging condition such as input energy and capacitance including powder size.

전기방전에 의한 Ti rod의 열처리 및 표면개질 특성에 관한 연구 (Surface Modification and Heat Treatment of Ti Rod by Electro Discharge)

  • 변창섭;오낙현;안영배;천연욱;김영훈;조유정;이충민;이원희
    • 한국재료학회지
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    • 제16권3호
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    • pp.168-172
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    • 2006
  • Single pulse of 2.0 to 3.5 kJ from $150{\mu}F$ capacitor was applied to the cp Ti rod for its surface modification and heat treatment. Under the conditions of using 2.0 and 2.5 kJ of input energy, no phase transformation has been occurred. However, the hardness and tensile strength decreased and the elongation increased after a discharge due to a slight grain growth. By using more than 3.0 kJ of input energy, the electro discharge made a phase transformation and the hardness at the edge of the cross section increased significantly. The Ti rod before a discharge was lightly oxidized and was primarily in the form of $TiO_2$. However, the surface of the Ti rod has been instantaneously modified by a discharge into the main form of TiN from $TiO_2$. Therefore, the electro discharge can modify its surface chemistry in times as short as $200{\mu}sec$ by manipulating the input energy, capacitance, and discharging environment.

Measurement of Energy bands of the MgO Layer in AC-PDPs

  • Jeoung, S.J.;Lee, H.J.;Son, C.G.;Kim, J.H.;Park, E.Y.;Hong, Y.J.;You, N.L.;Lee, S.B.;Han, Y.G.;Jeoung, S.H.;Song, K.B.;Moon, M.W.;Oh, P.Y.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.906-909
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    • 2006
  • The secondary electron emission coefficient $({\gamma})$ of the cathode is an important factor for improving the discharge characteristics of AC-PDPs because of its close relationship to discharge voltage. In AC-PDPs, MgO is most widely used as a surface protective layer. In this experimental, we have investigated the electronic structure of the energy band structure of the MgO layer responsible for the high ${\gamma}$. The MgO layers have been deposited by electron beam evaporation method, where the $O_2$ partial pressures have been varied as 0, $5.2{\times}10^{-5}$ torr, $1.0{\times}10^{-4}$ torr, and $4.1{\times}10^{-4}$ torr, in this experiment. It is noted that work function that is energy gap between surface and first defect level of MgO layer has the lowest value for the highest O2 partial pressure of $4.1^{\ast}10^{-4}$ Torr.

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Hydroxyapatite가 도핑된 Ti-6Al-4V 구형 분말의 전기방전 소결 및 소결체 특성에 관한 연구 (A Study of Electro-Discharge-Sintering of Ti-6Al-4V Spherical Powders Doped with Hydroxyapatite by Spex Milling and Its Consolidation Characteristics)

  • 조유정;김영훈;조예현;김민재;김현수;김승우;박정환;이원희
    • 한국분말재료학회지
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    • 제20권5호
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    • pp.376-381
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    • 2013
  • Spherical Ti-6Al-4V powders in the size range of 250 and 300 ${\mu}m$ were uniformly doped with nano-sized hydroxyapatite (HAp) powders by Spex milling process. A single pulse of 0.75-2.0 kJ/0.7 g of the Ti-6Al-4V powders doped with HAp from 300 mF capacitor was applied to produce fully porous and porous-surfaced Ti-6Al-4V implant compact by electro-discharge-sintering (EDS). The solid core was automatically formed in the center of the compact after discharge and porous layer consisted of particles connected in three dimensions by necks. The solid core increased with an increase in input energy. The compressive yield strength was in a range of 41 to 215 MPa and significantly depended on input energy. X-ray photoelectron spectroscopy and energy dispersive x-ray spectrometer were used to investigate the surface characteristics of the Ti-6Al-4V compact. Ti and O were the main constituents, with smaller amount of Ca and P. It was thus concluded that the porous-surfaced Ti-6Al-4V implant compacts doped with HAp can be efficiently produced by manipulating the milling and electro-discharge-sintering processes.

전기방전소결에 의해 제조된 다공성 및 다공성 표면을 갖는 Ti-6Al-4V 임플란트 : (2) 경도 및 압축강도 (Porous and Porous Surfaced Ti-6Al-4V Implants Fabricated by Electro-Discharge-Sintering : (2) Hardness and Compressive Strength)

  • 현창용;허재근;이원희
    • 한국분말재료학회지
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    • 제12권5호
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    • pp.332-335
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    • 2005
  • Porous and porous surfaced Ti-6Al-4V implant compacts were fabricated by electro-discharge-sintering (EDS) of atomized spherical Ti-6Al-4V powders with a diameter of $100-150\;{\mu}m$, The solid core formed in the center of the compact after discharge was composed of acicular ${\alpha}+{\beta}$ Widmanstatten grains, The hardness value at the solid core was much higher than that at the particle interface or particles in the porous layer, which can be attributed to both heat treatment and work hardening effects induced from EDS, The compressive yield strength was in a range of 19 to 436 MPa which significantly depends on both input energy and capacitance, Selected porous-surfaced Ti-6Al-4V implant compacts with a solid core have much higher compressive strengths compared to the human teeth and sintered Ti dental implants.

기계적 합금화에 의해 제조된 Ti5Si3 분말의 전기방전소결 특성 연구 (Characteristic Studies on Electro-Discharge-Sintering of Ti5Si3 Powder Synthesized by Mechanical Alloying)

  • 천연욱;조유정;강태주;김정열;박준식;변창섭;이상호;이원희
    • 대한금속재료학회지
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    • 제47권10호
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    • pp.660-666
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    • 2009
  • The consolidation of mechanical alloyed $Ti_5Si_3$ powder by electro-discharge-sintering has been investigated. A single pulse of 2.5 to 8.0 kJ/0.34 g was applied to each powder mixture using 300 and $450{\mu}F$ capacitors. A bulk-like solid with $Ti_5Si_3$ phase has been successfully fabricated by the discharge with an input energy of more than 2.5 kJ in less than $160{\mu}sec$. Micro-Vickers hardness was found to be higher than 1350, which is significantly higher than that of a conventional high temperature sintered sample. The formation of $Ti_5Si_3$ and consolidation occurred through a fast solid state diffusion reaction.

전기방전소결을 이용한 Ti-Ni-Zr 준 결정상의 상변화 연구와 Ti, W 다공체 제작 (Phase Transformation of Ti-Ni-Zr Icosahedral Phase and Fabrication of Porous Ti and W Compacts using Electro-Discharge Sintering)

  • 조재영;송기안;이민하;이효수;이원희;김기범
    • 한국분말재료학회지
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    • 제18권2호
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    • pp.149-158
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    • 2011
  • Electro-Discharge Sintering (EDS) employs a high-voltage/high-current-density pulse of electrical energy, discharged from a capacitor bank, to instantaneously consolidate powders. In the present study, a single pulse of 0.57-1.1 kJ/0.45 g-atomized spherical $Ti_{52}Zr_{28}Ni_{20}$ powders in size range of 10~30 and $30\sim50{\mu}m$ consisting of ${\beta}$-(Ti, Zr) and icosahedral phases were applied to examine the structural evolution of icosahedral phase during EDS. Structural investigation reveals that high electrical input energy facilitates complete decomposition of icosahedral phase into C14 laves and ${\beta}$-(Ti, Zr) phases. Moreover, critical input energy inducing decomposition of the icosahedral phase during EDS depends on the size of the powder. Porous Ti and W compacts have been fabricated by EDS using rectangular and spherical powders upon various input energy at a constant capacitance of $450{\mu}F$ in order to verify influence of powder shape on microstructure of porous compacts. Besides, generated heat (${\Delta}H$) during EDS, which is measured by an oscilloscope, is closely correlated with powder size.

Powder Mixed ECDM (Electro-Chemical Discharge Machining)을 이용한 미세구멍가공의 정밀도 개선 (Improvement of Hole Geometric Accuracy by Powder Mixed Electro-chemical Discharge Machining Process)

  • 한민섭;민병권;이상조
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.42-45
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    • 2004
  • Electrochemical discharge machining (ECDM) has been found to be suitable for the micro-hole machining of nonconductive materials such as ceramics or glass compared with existing conventional and also non-conventional machining methods. However this machining process has some problems such as low geometric accuracy and low machining efficiency due to the random spark generation at the end of the electrode. This paper proposes the methods to improve the geometric accuracy of micro-hole using powder mixed ECDM process. The experimental results show the effects of powder producing improved geometric accuracy of machined hole and decreased concentration of spark energy.

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