• Title/Summary/Keyword: Electro-chemical machining

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Relationship between Shape Recovery Characteristics & Electro Chemical Machining of Ni-Ti Shape Memory Alloy (Ni-Ti 형상기억합금의 전해가공과 형상복원 특성의 관계)

  • 최영수;박규열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.1097-1100
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    • 2001
  • In this paper, the electro-chemical-machining characteristics of Ni-Ti Shape Memory Alloy(SMA) was investigated. From the experimental results, the optimal electro chemical machining conditions for satisfying the machining quality(fine surface & high recovery stress) might be confirmed. And it was concluded that optical electro chemical condition for Ni-Ti SMA could be obtained at approximately 100% current efficiency and high frequency pulse current.

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ECM Characteristics of Ni-Ti Shape Memory Alloy (Ni-Ti 형상기억합금의 전해가공의 특성)

  • 김동환;강지훈;박규열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.955-958
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    • 2000
  • In this paper, the electro-chemical-machining characteristics of Ni-Ti Shape Memory Alloy(SMA) was investigated. From the experimental results, the optimal electro chemical machining conditions for satisfying the machining quality(fine surface & high recovery stress)might be confirmed. And it was concluded that optical electro chemical condition for Ni-Ti SMA could be obtained at approximately 100% current efficiency and high frequency pulse current.

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Relationship between Machining Characteristics & Current Efficiency in Electro Chemical Machining of Ni-Ti Shape Memory Alloy (Ni-Ti 형상기억합금의 전해가공에서 전류효율과 가공특성의 관계)

  • 김동환;강지훈;박규열
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.320-325
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    • 2000
  • This study was performed to investigate the electro-chemical-machining (ECM) characteristic of Ni-Ti Shape Memory Alloy (SMA). From the experimental results, we could gain optimal electro-chemical conditions to bound with lesser machining effect and better surface roughness than any other machining methods to workpiece at the same time. At these conditions, current efficiency was, for especially ECM working of Ni-Ti SMA, approximately 100% and high frequency pulse current was detected.

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Micro-shaft and Micro-hole Machining for Micro Punching (마이크로 펀칭용 미세축, 미세구멍의 가공)

  • Ryu S. H.;Cho P. J.;Lee K. H.;Chu C. N.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.239-244
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    • 2002
  • In this study, we developed the manufacturing technology of micro-hole and micro-shaft for micro punching system using micro electrical discharge machining and micro electro chemical machining. Micro punching dies of tungsten carbide with $55\;{\mu}m\;and\;110\;{\mu}m$ diameter and $250\;{\mu}m$ depth were made by micro electrical discharge machining. The form accuracy and surface roughness of die hole were pretty good and it was shown that the punched hole quality was fine. WC micro-shaft with $30\;{\mu}m$ diameter was made by the multistep micro electro chemical machining. The developed technologies can be effectively used in precision manufacturing of micro punching die and mass production of micro-shaft.

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Localized Electro-chemical Micro Machining Using Ultra Short Pulses (초단펄스 전해 국부화를 이용한 미세 가공)

  • Ahn, Se-Hyun;Choi, Se-Hwan;Ryu, Shi-Hyoung;Cho, Deok-Ki;Chu, Chong-Nam
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1052-1058
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    • 2003
  • The possibility of micro/nano machining through electro-chemical process is discussed in this research. Electro-chemical dissolution region is localized within 1 ${\mu}m$ by applying ultra short pulses with tens of nanosecond duration. The effects of voltage, pulse duration, and pulse frequency on the localization distance are investigated. Localization distance can be manipulated by controlling the voltage and pulse duration, and various hole shapes are produced including stepped holes and taper free hole. High quality micro-hole with 8 ${\mu}m$ diameter with 20 ${\mu}m$ depth and micro-groove with 9 ${\mu}m$ width with 10 ${\mu}m$ depth are machined on 304 stainless steel.

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Localized Electro-chemical Micro Drilling Using Ultra Short Pulses (초단펄스 전해 국부화를 이용한 미세구멍 가공)

  • 안세현;류시형;최덕기;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.8
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    • pp.213-220
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    • 2003
  • By the localization of electro-chemical dissolution region, we succeeded in a few micrometer size hole drilling on stainless steel with the radial machining gap of about 1 ${\mu}{\textrm}{m}$. Tens of nanosecond duration voltage pulses were applied between WC micro-shaft and stainless steel in the 0.1 M $H_2SO_4$ solution. Pt balance electrode was used to drill the high aspect ratio micro-hole without generation of Cr oxide layer on the machined surface. The effects of applied voltage, pulse duration, and pulse period on localization distance were investigated according to machining time. We suggested the taper reduction technique especially brought up on blind-hole machining. High quality micro-holes with 8 ${\mu}m$ diameter with 20 ${\mu}m$ depth and 12 ${\mu}m$ diameter with 100 ${\mu}m$ depth were drilled on 304 stainless steel foil. The various hole shapes were also produced including stepped holes and taper free holes.

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

  • 한민섭;민병권;이상조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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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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A Study on the Performance Evaluation of a Voice Coil Actuator for Electro-Discharge Micro-Drilling Machine (보이스코일 액츄에이터로 이송되는 미세구멍 가공용 방전 가공기의 작동특성 연구)

  • Yang, Seung-Jin;Baek, Hyeong-Chang;Kim, Byeong-Hui;Jang, In-Bae
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.12
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    • pp.152-158
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    • 2001
  • In this paper, we have developed an electro discharge machine for micro drilling driven by a voice coil actuator. Because the voltage signal of the electro-discharging circuit shows a lot of peaks and valleys, the active type low-pass filtering technique is adopted to get the average of the signal. Since the motion of the voice coil is precisely controlled by the error value between the object voltage value and the measured one, it is possible to prevent the mechanical contact between the rotating electrode and the workpiece and to maintain the appropriate machining conditions during the process. The electro-chemical machining technology was also adopted to make small diameter electrodes. Pure water is used as a dielectric. The machining procedure is performed to verify the feasibility of the developed system. It takes about 10 seconds to drill the ${\phi}m$100${\mu}m$ hole to the 100${\mu}m$ thickness stainless steel plate. The machining time depends on the values of the resister and the capacitor. There may exist the optimal values of time constant and the tendency is displayed In the appendix.

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Fabrication of Tungsten Probe using Electro-Chemical Etching (전기화학적 에칭을 이용한 텅스텐 미세 탐침 가공)

  • In, Chi-Hyun;Kim, Gyu-Man;Chu, Chong-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.2
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    • pp.111-118
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    • 2001
  • Tungsten probe is the most important part of a probe card, which is widely used for the performance test of wafer chips. Electro chemical etching becomes an exclusive choice for mass production of the tungsten probes. In the mass production, not only the shape of the probe but also the shape distribution of machined probes is important. A new method is proposed for the mass production of the tungsten probes. Tungsten wires are separated by a distance, and dipped into electrolyte. The dipping rate is controlled to shape the probes. Several experimental tests are performed to study the machining characteristics. From the test results, machining parameters including electrical conditions and anode position showed significant influences on the shape, repeatability, precision and quality of sharp tips.

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A Study on Micro-Hole Drilling by EDM (미세구멍의 방전가공에 관한 연구)

  • 윤재웅;양민양
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1147-1154
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    • 1990
  • Micro-hole drilling by EDM and production of fine rods for the tool electrode or other purpose have become very important in industry. This paper suggests a new method for production of very fine rods by ultrasonic-assisted chemical machining and describes the machining characteristics of micro-hole drilling by EDM. For fine rods, copper wires of initial diameter of 250.mum are used and successfully machined into a diameter of less than 30.mum with good repeatability. The ultrasonic agitation not only accelerated the material removal rate uniformly, but also produced smooth surfaces of fine rods. To drill the micro-hole, kerosene and pure water is used as a dielectric. From the experiment, water is superior to kerosene with respect to surface roughness of inlet and outlet of hole and machined surface as well as electrode wear. However, due to the electrochemical reaction of water, small pits are remained on the workpiece surface.