• Title/Summary/Keyword: Tungsten electrode

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Development of Electrode Guide of Super-drill EDM and Electrical Discharge Machining of Small Hole for High Precision Semiconductor Die (초정밀 반도체 금형 제작을 위한 슈퍼드릴 방전가공기 전극가이드 개발과 미세홀 방전가공)

  • Park, Chan-Hae;Kim, Jong-Up;Wang, Duck-Hyun;Kim, Won-Il
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.4 no.3
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    • pp.32-38
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    • 2005
  • Electrical discharge machining is the method of using thermal energy by electrical discharge. Generally, if the material of workpiece has conductivity even though very hard materials and complicated shape which are difficult to cut such as quenching steel, cemented carbide, diamond and conductive ceramics, the EDM process is favorable one of possible machining processes. But, the process is necessarily required of finish cut and heat treatment because of slow cutting speed, no mirror surface, brittleness and crack due to the residual stress for manufactured goods. In this experimental thesis, the super EDM drilling was developed for high precision semiconductor die steel and for minimization of leadframe width. It was possible to development of EDM drilling machine for high precision semiconductor die with the electrode guide and its modelling and stress analysis. The development of electrode with the copper pipe type was conducted to drill the hole from the diameter of 0.1mm to 3.0mm with the error of from 0.02mm to 0.12mm. From the SEM and EDX analysis, the entrance of the EDM drill was found the resolidification of not only the component of tungsten but also the component of copper.

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Simultaneous Determination of Zinc, Cadmium, Lead and Copper in Tungsten Matrix by Differential Pulse Anodic Stripping Voltammetry (펄스차이 벗김전압전류법에 의한 텅스텐 중 아연, 카드뮴, 납 및 구리의 미량성분 동시분석)

  • Bae, Jun Ung;Lee, Seong Ho
    • Journal of the Korean Chemical Society
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    • v.38 no.2
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    • pp.146-150
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    • 1994
  • The simultaneous determination of Zn, Cd, Pb and Cu in 1.000%(w/v) tungsten matrix by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode has been studied. Tartaric acid(pH=5.00) was used as a supporting electrolyte. Optimum analytical conditions were found that the deposition potential was -1.2 volt(vs. Ag/AgCl), the deposition time was 3 minutes. The linear concentration range of all trace metal ions in 1.000%(w/v) tungsten matrix were 10 to 50 ppb. And the detection limit(3${\sigma}$) of zinc, cadmium, lead and copper were 1.25, 1.02, 1.69, and 1.02 ppb respectively. This method was superior to the ICP-AES method which detection limits(3${\sigma}$) in 1.000%(w/v) tungsten matrix were 8.0, 5.0, 120 and 5 ppb respectively.

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Characteristics and Thermal Stabilities of W-B-C-N Diffusion Barrier by Using the Incorporation of Boron Impurities (Boron 불순물에 의한 W-B-C-N 확산방지막의 특성 및 열적 안정성 연구)

  • Kim, Soo-In;Lee, Chang-Woo
    • Journal of the Korean Magnetics Society
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    • v.18 no.1
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    • pp.32-35
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    • 2008
  • Thermally stable diffusion barrier of tungsten carbon nitride(W-C-N) and of tungsten boron carbon nitride(W-B-C-N) thin films have studied to investigate the impurity behaviors of boron and nitrogen. In this paper we newly deposited tungsten boron carbon nitride(W-B-C-N) thin film for various $W_2B$ target power on silicon substrate. The impurities of the 100nm-thick W-C-N and W-B-C-N thin films provide stuffing effect for preventing the inter-diffusion between W-C-N or W-B-C-N thin films and silicon during the high temperature($700^{\circ}C{\sim}1000^{\circ}C$) annealing process.

AE Characteristics for Weld HAZ in SM 490A Steel (SM 490A 강의 용접 열영향부 음향방출 특성)

  • 이장규;우창기;박성완;김봉각;윤종희;인승현
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2002.11a
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    • pp.257-262
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    • 2002
  • The object of this study is to investigate the effect of compounded welding through the AE (Acoustic Emission) characteristics for weld HAZ (Heat Affected Zone) on static tensile test. This study was carried out a SM 490A, high tension steel using the low hydrogen type E4316 of electronic shield metal arc welding, compound wire of $CO_2$ gas arc welding and tungsten electrode of TIG welding.

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A Carbon Nanotube Sample for the Fabrication of Nanotweezer (나노트위져 제작을 위한 탄소나노튜브 샘플)

  • Choi, Jai-Seong;Lee, Jun-Sok;Kang, Gyung-Soo;Kwak, Yoon-Keun;Kim, Soo-Hyun
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.997-1000
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    • 2004
  • This paper introduces our basic research about a carbon nanotube(CNT) sample for the fabrication of nanotweezer. We have made the nanotweezer through the physical adhesion of multi-walled carbon nanotubes(MWCNTs) on two sharp tungsten tips. Thereby we needed the CNT sample which is proper to this fabrication process. And we applied the dielectrophoretic methods to the fabrication of the CNT sample. During the basic experiment, we used a sharp edged electrode and a flat electrode as electrodes for dielectrophoresis and just a function generator as a voltage source for the generation of electric field.

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Decomposition of CFC-12($CCl_2F_2$) by Discharge Plasma (방전 플라스마에 의한 CFC-12($CCl_2F_2$)의 분해)

  • 강현춘;우인성;황명환;안형환;이한섭;조정국;강안수
    • Journal of the Korean Society of Safety
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    • v.14 no.3
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    • pp.93-100
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    • 1999
  • Decomposition efficiency, power consumption, and applied voltage of CFC(Chlorofluorocatbon) were investigated by SPCP(surface induced discharge plasma chemical processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of CFC-12 with various electric frequencies(5~50kHz). flow rates (100~1,000mL/min), initial concentrations(100~1,000ppm), electrode materials(W, Cu, Al). electrode thickness(1, 2, 3mm) and reference gases($N_2$, $O_2$, air) were measured and the products were analyzed with FT-IR. Experimental results showed that at the frequency of 10kHz, the highest decomposition efficiency of 92.7% for CFC-12 were observed at the power consumptions of 29.6W. respectively, and that decomposition efficiency decreased with increasing frequency above 20kHz and decomposition efficiency per unit power were 3.13%/W for CFC-12. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. Decomposition efficiency was increased with increasing thickness of discharge electrode and the highest decomposition efficiency was obtained for the electrode diameter of 3m. As the electrode material, decomposition efficiency was in order that tungsten(W), copper(Cu), aluminum (Al). Decomposition of CFC-12 in the reference gas of $N_2$ showed the highest efficiency among three reference gases, and then the effect of reference gas on the decomposition efficiency decreased in order of air and $O_2$. The optimum power for the maximum decomposition efficiency was 25.3W for CFC.

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The Effect of Process Parameters on Sealing Quality for Ir-192 Radiation Source Capsule using Resistance Spot Welding (Ir-192 방사선원의 밀봉 용접부 품질에 미치는 저항용접 공정변수의 영향)

  • Han, In-Su;Son, Kwang-Jae;Lee, Young-Ho;Lee, You-Hwang;Lee, Jun-Sig;Jang, Kyung-Duk;Park, Ul-Jae;Park, Chun-Deuk
    • Journal of Welding and Joining
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    • v.27 no.1
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    • pp.65-70
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    • 2009
  • Ir-192 radiation sealed sources are widely employed to the therapeutic applications as well as the non-destructive testing. Production of Ir-192 sources requires a delicate but robust welding technique because it is employed in a high radioactive working environment. A GTA(Gas Tungsten Arc) welding technique is currently well established for this purpose. However, this welding method requires a frequent replacement of the electrode, which results in the delay of the production to take a preparatory action such as to isolate the radiation sources from the working place before getting access to the welding machine. Hence, a resistance welding technique is considered as an alternative method of the GTA welding technique. The advantages of resistance welding are high welding speed and high-rate production. Also it has very long life of electrode comparing to GTA welding. In this study, the resistance welding system and proper welding conditions were established for sealing Ir-192 source capsule. As a results of various experiments, it showed that electrode displacement can be employed as a indicator to predict welding quality. We proposed two mathematical models(linear and curvilinear) to estimate electrode displacement with process parameters such as applied force, welding current and welding time by using regression analysis method. Predicting results of both linear and curvilinear model were relatively good agreement with experiment.

The Effect of Process Variables on Mechanical Properties and Formability in GTA Welds of Commercial Pure Titanium Sheet (순 Ti 박판 GTA 용접부의 기계적 성질 및 성형성에 미치는 공정변수의 영향)

  • Kim, Jee-Hoon;Hong, Jae-Keun;Yeom, Jong-Taek;Park, Nho-Kwang;Kang, Chung-Yun
    • Journal of Welding and Joining
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    • v.28 no.4
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    • pp.73-80
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    • 2010
  • In this work, the effect of welding variables on weldability of gas tungsten arc(GTA) welding was investigated with experimental analysis for a commercial pure(CP) titanium (Grade.1). The GTA welding tests on sheet samples with 0.5mm in thick were carried out at different process variables such as arc length, welding speed and electrode shape. In order to search an optimum arc length with full penetration, bead- on-plate welding before butt-welding were performed with different arc length conditions. From the bead- on-plate welding results, the optimum condition considering arc stability and electrode loss was obtained in the arc length of 0.8mm. Butt-welding tests based on the arc length of 0.8mm were carried out to achieve the optimum conditions of welding speed and electrode shape. Optimum conditions of welding speed and electrode shape were suggested as 10 mm/s and truncated electrode shape, respectively. It was successfully validated by the microstructural observation, tensile tests, micro-hardness tests and formability tests.

Machining Characteristics According to the Thickness Change When Wire-cut Electrical Discharge Machining of Tungsten Carbide (초경합금재 와이어컷 방전가공시 두께변화에 따른 가공 특성)

  • 이재명;김원일;이윤경;왕덕현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.820-823
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    • 2000
  • The characteristics of wire deflection, surface roughness and roundness were observed on changing discharge time for electrical discharge machining(EDM) of tungsten carbide in various conditions of thickness. The wire deflection was decreased as increasing discharge time and wire tension, the gap of deflection was decreased after thickness 60mm and discharge time of 6$\mu\textrm{s}$ due to the changing from fundamental mode to vibration mode. The deflection is the smallest at the water specific resistivity of 7.5 kΩ ㆍcm. The deflection is found to be decreased as increasing dwell time, and the result is due to the vibration of the pressure and the amount of the dielectric. The component of copper(Cu) and zinc(Zn), which is the main material of wire electrode, was observed for rough wire-cutting EDM of STD-11. This phenomena is found to be decreased as the number of EDM is increased. But it will be improved by changing the material and the shape of wire. The roundness of middle is found to be worse than that of upper and it is increased as the thickness of material is increased.

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Beam stability improvement of liquid metal ion source (액체 금속 이온원의 빔 안정도 향상)

  • Hyun J. W.;Yim Youn Chan;Kim Seuong Soo;Oh Hyun Joo;Park Cheol Woo;Lee Jong Hang;Choi Eun Ha;Seo Yunho;Kang Seung Oun
    • Journal of the Korean Vacuum Society
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    • v.13 no.4
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    • pp.182-188
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    • 2004
  • Previous studies on the liquid Gallium ion sources used an electro-chemically etched tungsten wire with a coil-type heater. Such a structure requires excessive power consumption in the course of heating the liquid metal. In this work, a new structure is proposed that replaces the coil-type heater. It uses a Gallium reservoir made of six pre-etched 250$\mu\textrm{m}$ tungsten wires that surround the needle electrode. Gallium trading at the reservoir is observed to be much more stable, resulting in an improved beam stability.