• Title/Summary/Keyword: Electrochemical machining

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A Study on the Machining Characteristics of the Electropolishing of Aluminum (알루미늄 재의 전해연마 가공특성에 관한 연구)

  • 조규선;박봉진;이은상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.943-946
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    • 1997
  • Electropolishing is the controlled electrochemical removal of surface metal, resultmg in a brilliant appearance andimproved properties. Sometimes described as "reverse plating," the process has a leveling effect, which produces smoothnessand increased reflectivity. Unlike conventional mechanical finishing systems, the electropolishing does not smear, bend,stress or fracture the crystalline metal surface to achieve smoothness. Instead, electropolishing removes metal from thesurface producing a unidirectional pattern that is stress-free, microscopically smooth and often highly reflective. In addition,improved corrosion resistance and passivity are achieved on many ferrous and some non-ferrous alloys. Pure aluminium doesnot electropolish well, if at all, but most other alloys of aluminum electropolish excellently.Therefore, the aim of this study is to determine the characteristics of electropolishing aluminium alloy in term of currentdensity, machining time, temperature, electrode gap and workpiece surface measurementkpiece surface measurement

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A Study for Improving Surface Roughness and Micro-deburring Effect of Nitinol Shape Memory Alloy by Electropolishing (니티놀 형상기억합금의 표면 거칠기 향상 및 미세 버 제거를 위한 마이크로 전해연마의 가공특성 분석)

  • Shin, Min-Jung;Baek, Seung-Yub;Lee, Eun-Sang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.6
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    • pp.49-54
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    • 2007
  • Electropolishing, the anodic dissolution process without contact with tools, is a surface treatment method to make a surface planarization using an electrochemical reaction with low current density. Nitinol is a metal alloy composed of Ni and Ti around 50% respectively which has shape memory effect. Nitinol can be put various applications which require purity and high pricision surface of products. The aim of this study is to investigate the characteristic of electropolishing effect for nitinol workpieces. In order to analyze the characteristics of electropolishing effect, surface roughness and micro-burr size were measured in terms of machining conditions such as current density, machining time and electrode gap. The tendencies about improvement of surface roughness and deburring effect by electropolishing for nitinol workpieces were determined.

Electrochemical Deburring System by the Electroplated CBN Wheel (입방정질화붕소입자 전착지석에 의한 전해디버링 시스템)

  • 최인규;김정두
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.19-23
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    • 1996
  • Deburring and edge finishing technology as the last process of machining operation is required for manufacturing of advanced procesion components, duburring has treated as a difficult problem on going tothe highefficency, automation in the FMS. Removal of butt with various shapes, dimensions and properties coultn't has a standard and has depended on manual treatment. Especially, deburring for cross hole inside owing to passing through out perpendicular to a main hole is more difficult, the electrolytic method is proper as its solution at practical aspects. Therefore, for the high effciency and automation of intermal deburring in the cross hole, development of electrolytic debutting technology is needed. So, the new process in the burr treatment is supposed. In this study, in the eliminating burr inside cross hole, the principle and machining performances of electrochemical deburring by Cubic-Boron-Nitrade abrasive electroplate wheel are investigated, Design and manufacture of CBN electroplated wheel and analysis of characteristics with electrolytic debutting are achieved. Also deburring efficiency and electrolytic performance for cross hole were examined according to electrolytic current and electrolytic deburring condition corresponding to acquired edge quality was found out.

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Improvement of Electrical Discharge Drilling (방전드릴링의 가공특성 향상)

  • Song, Ki-Young;Chung, Do-Kwan;Park, Min-Soo;Chu, Chong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.10
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    • pp.45-51
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    • 2010
  • Electrical discharge drilling (ED-drilling) is a widespread machining method used to bore small holes with a high aspect ratio. This paper presents additional methods by which ED-drilling can improve machining speed, tool wear, and machined surface quality. Firstly, for high machining speed, and low tool wear, a new-type electrode that was ground on one side or both sides of the cylindrical electrodes was suggested to expel debris. The debris which is generated during the machining process can cause sludge deposition and secondary discharge problems: major reasons to decrease machining speed. This new-type electrode also reduced tool wear that was due to the decrease of unstable discharge in a machining gap by helping to expel waste water and debris from the gap. Secondly, to improve the machined surface roughness, an electrolyzation process was included after drilling. This process made the machined surface smooth by means of an electrochemical reaction between an electrode and a workpiece. In this study, the machining speed, electrode wear, and surface roughness were improved by the newtype electrode and the electrolytic process.

Improvement of Geometric Accuracy using Powder Mixed Electro-chemical Discharge Machining Process (전해액 내 혼합된 미세 전도성 입자를 이용한 전해 방전 가공의 형상 정밀도 향상)

  • Han M.S.;Min B.K.;Lee S.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.366-369
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    • 2005
  • Electrochemical discharge machining (ECDM) has been found to be potential fur the micro-machining of non-conductive materials such as ceramics or glass. However this machining process has its own inherent problem that the reproducibility is too low to get the available geometric accuracy fur micromachining applications. One main challenge in reaching this goal is the control of the hydrogen built around the tool-electrode in which happen the discharges. This paper proposes the methods to improve the geometric accuracy using powder-mixed ECDM process. The experimental results show the effects of powder producing improved geometric accuracy by averaging and decreasing the concentration of spark energy.

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Micro Hole Machining by EDM Using Insulated Tool Combined with Ultrasonic Vibration of Dielectric Fluid (가공액의 초음파 진동 및 절연 공구를 이용한 미세방전가공)

  • Park, Min-Soo;Chung, Do-Kwan;Lee, Kang-Hee;Chu, Chong-Nam
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.2
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    • pp.180-186
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    • 2011
  • This paper describes a micro electrical discharge machining (MEDM) technique that uses an insulated tool in combination with ultrasonic vibration to drill micro holes. As the machining depth becomes deeper, the dispersion of debris and circulation of the dielectric fluid are difficult to occur. Consequently, machining becomes unstable in the machining region and unnecessary electrochemical dissolution and secondary discharge sparking occur at the tool side face. To reduce the amount of unnecessary side machining, an insulated tool was used. Ultrasonic vibration was applied to the MEDM work fluid to better remove debris. Through these methods, a $1000\;{\mu}m$ thick stainless steel plate was machined by using a $73\;{\mu}m$ diameter electrode. The diameters of the hole entrance and exit were $96\;{\mu}m$ and $88\;{\mu}m$, respectively. It took only 351s to completely drill one hole.

Low Temperature Interface Modification: Electrochemical Dissolution Mechanism of Typical Iron and Nickel Base Alloys

  • Jiangwei Lu;Zhengyang Xu;Tianyu Geng
    • Journal of Electrochemical Science and Technology
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    • v.15 no.2
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    • pp.220-241
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    • 2024
  • Due to its unique advantages, electrochemical machining (ECM) is playing an increasingly significant role in the manufacture of difficult-to-machine materials. Most of the current ECM research is conducted at room temperature, with studies on ECM in a cryogenic environment not having been reported to date. This study is focused on the electrochemical dissolution characteristics of typical iron and nickel base alloys in NaNO3 solution at low temperature (-10℃). The polarization behaviors and passive film properties were studied by various electrochemical test methods. The results indicated that a higher voltage is required for decomposition and more pronounced pitting of their structures occurs in the passive zone in a cryogenic environment. A more in-depth study of the composition and structure of the passive films by X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy showed that the passive films of the alloys are modified at low temperature, and their capacitance characteristics are more prominent, which makes corrosion of the alloys more likely to occur uniformly. These modified passive films have a huge impact on the surface morphologies of the alloys, with non-uniform corrosion suppressed and an improvement in their surface finish, indicating that lowering the temperature improves the localization of ECM. Together with the cryogenic impact of electron energy state compression, the accuracy of ECM can be further improved.

Fabrication of Microshafts using Electrochemical Process (전해 프로세스를 이용한 미세축 제작)

  • Lim, Young-Mo;Lim, Hyung-Jun;Kim, Soo-Hyun
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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    • pp.169-174
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    • 2001
  • We proposed a new fabrication method using electrochemical process for microshafts. This method is a kind of atomic removal process by chemical reaction. Therefore, it is possible to make thin and long shafts regardless of the stiffness of materials. Because shaping process is simply switched to polishing process by varying process conditions, we can precisely fabricate microshafts with very smooth surface. We also fabricated a very thin shaft with the diameter as small as 10$\mu$m and a microshaft with high aspect ratio.

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Shape and Diameter Control of Microshafts in Electrochemical Process (전해 프로세스에 의한 미세축 가공시 형상 및 직경 제어)

  • Lim, Yung-Mo;Lim, Hyung-Jun;Kim, Soo-Hyun
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.5
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    • pp.50-56
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    • 2001
  • Fabrication methods are shown to produce slender and cylindrical tungsten shafts by electrochemical etching. The shape of microshatf formed by electrochemical etching is determined by the combination of two conflicting factors, i.e., initial shape and diffusion layer. We can obtain a desirable shaft profile by adjusting the thickness gradient of diffusion layer. The diameter of microshaft is controlled by mathematical model based on relation between process parameters and diameter.

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Fabrication of PCD Micro Tool and its Hybrid Micro Machining (다결정 다이아몬드를 이용한 미세 공구 제작과 이를 이용한 미세 복합 가공)

  • Doan, Cao Xuan;Kim, Bo-Hyun;Chung, Do-Kwan;Chu, Chong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.6
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    • pp.694-700
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    • 2011
  • Since polycrystalline diamond (PCD) has high hardness like diamond, it has been used as tool material for lathe and milling of non-ferrite material. A micro tool fabricated from PCD material can be used for micro machining of hard material such as tungsten carbide, glass, and ceramics. In this paper, micro PCD tools were fabricated by micro EDM (electrical discharge machining) and used for micro grinding of glass. Craters generated on the tool surface by EDM spark work as like grits in grinding process. The effects of tool shapes, tool roughness and PCD grain size were investigated. Also studied was a hybrid process combining electrochemical discharge machining (ECDM) and micro grinding for micro-structuring of glass.