• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.735-738
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• 2000

The characteristics of wire electrical discharge machining (WEDM) are governed by many factors such as the power supply type, operating condition and electrode material. This work deals with the effect of wire electrode materials on the machining characteristics such as, metal removal rate, surface characteristics and surface roughness during WEDM A wire's thermal physical properties are melting point, electrical conductivity and vapor pressure. One of the desired qualities of wire is a low melting point and high vapor pressure to help expel the contaminants from the gap. They are determined by the mix of alloying elements (in the case of plain brass and coated wire) or the base core material(i.e. molybdenum). Experiments have been conducted regarding the choice of suitable wire electrode materials and influence of the properties of these materials on the machinability and surface characteristics in WEDM, the experimental results are presented and discussed from their metallurgical aspect. And the coating effect of various alloying elements(Au, Ag, Cu, Zn, Cr, Mn, etc.) to the Cu or 65-35 brass core on them was reviewed also. The removal rate of some coated wires are higher than that of 65-35 brass electrode wire because the wire is difficult to break due to the wire cooling effect of Zn evaporation latent heat and the Zn oxide on the surface is effective in preventing short circuit. The removal rate increases with increasing Zn content from 35, 40 and Zn coated wire

• 공업화학
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• 제21권2호
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• pp.205-210
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• 2010

본 연구에서는 기체방전관의 과전압 보호 성능과 수명에 미치는 절연파괴 특성을 알아보기 위하여 황동전극을 이용하여 기체방전관을 제조하였다. 황동전극을 이용한 기체방전관의 절연파괴 특성은 인가전압의 기울기와 방전관 내부의 질소기체 압력을 통하여 알아보았다. 방전관 인가전압의 기울기가 증가할수록 절연파괴 전압과 방전 시 소비되는 에너지량이 크게 상승되었고, 절연파괴 시간은 감소되었다. 방전관 내부 질소기체의 압력이 감소할수록 절연파괴 전압과 절연파괴 소요시간, 방전 소비에너지량이 크게 감소되었다. 결과적으로, 방전관의 과전압 보호 성능 및 수명을 증진시키기 위해서는 절연파괴 전압과 절연파괴 소요시간, 방전 시 소비되는 에너지량이 감소되어야 함을 알 수 있었다. 한편, 방전관 내부 질소기체 압력이 방전관의 자체 수명 및 과전압 보호 성능에 영향을 미침을 알 수 있었다.

• 한국수소및신에너지학회논문집
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• 제34권6호
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• pp.785-791
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• 2023

Copper sulfide (Cu_xS) has been extensively utilized as a counter electrode (CE) material for quantum dot solar cells (QDSCs) due to its exceptional catalytic activity for polysulfide electrolytes. The typical fabrication method of Cu₂S CEs based on brass substrate is dangerous, involving the use of a highly concentrated hydrochloric acid solution in a relatively high temperature. In contrast, electroplating presents a safer alternative by employing a less acidic solution at a room temperature. In addition, the electroplating method increases the probability of obtaining CEs of consistent quality compared to the brass method. In this study, the optimized electroplating cycle for CuS CEs in QDSCs has been studied for the highly efficient photovoltaic performances. The QDSCs, featuring electroplated CuS CEs, achieved an impressive efficiency of 7.18%, surpassing the conventional method employing brass CEs, which yielded an efficiency of 6.62%.

• Corrosion Science and Technology
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• 제14권2호
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• pp.85-92
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• 2015

An on-line corrosion rate measurement system was developed using a personal computer, a data acquisition board and program, and a 2-electrode corrosion probe. Reliability of the developed system was confirmed with through comparison test. With this system, the effect of sodium nitrite ($NaNO_2$) as a corrosion inhibitor were studied on iron and aluminum brass that were immersed in sodium chloride (NaCl) solution. Corrosion rate was measured based on the linear polarization resistance method. The corrosion rates of aluminum brass and iron in 1% NaCl solutions were measured to be 0.290 mm per year (mmpy) and 0.2134 mmpy, respectively. With the addition of 200 ppm of $NO{_2}^-$, the corrosion rates decreased to 0.0470 mmpy and 0.0254 mmpy. The addition of $NO{_2}^-$ caused a decrease in corrosion rates of both aluminum brass and iron, yet the $NO{_2}^-$ acted as a more effective corrosion inhibitor for iron. than aluminum brass.

• 한국기계가공학회지
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• 제11권5호
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• pp.88-93
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• 2012

This paper describes the machinability of the sintered carbide and tool-die steel(STD-11) by electric discharge drilling with various tubular electrodes which have multi-holes. Various types of electrode which have different diameters and materials are used with the application of continuous direct current and axial electrode feed. Inner part of electrodes are inserted with smaller tubes or Y-channel or bar. In ED-Drilling, the dielectric flushed down the interior of the rotating tube electrode, in order to remove machining debris from the hole. As result of experiments, the bigger the diameter of the electrode is, the lower the material removal rate is. Machinability of copper electrode is higher than that of brass. In machining of sintered carbide, to use oil is better than distilled water as dielectric.

• 한국생산제조학회지
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• 제6권4호
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• pp.130-137
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• 1997

The demand for wire-cut EDM is increasing rapidly in the die and tool making industry. In this study machining characteristics such as machining rate, surface roughness, hand drum form and hardness of machined material are investigated experimentally under the conditions varing pulse on time, pulse off time, peak voltage, wire tension after fixing other conditions in SKD 11 and brass and brass workpiece. It was found that various operating conditions had significant influences on machining characteristics. But the hardness of workpiece was uneffected by operating conditions. Also it was obtained experimentally that brass workpeice had better machinability than SKD 11 one.dition according to the current(Ip) in an electric spark machine : 1) Electrode is utilized Cu and Graphite. 2) Work piece is used the material of carbon steel. The condition of experiment is : 1) Current is varied 0.7(A) to 50(A) and the time of electric discharging to work piece in each time is 30(min) to 60(min). 2) After the upper side of work piece was measured in radius(5$\mu$m) of stylus analyzed the surface roughness to ade the table and graph of Rmax by yielding data. 3) Electro wear ratio is : \circled1Cooper was measured ex-machining and post-machining by the electronic balance. \circled2The ex-machining of graphite measured by it, the post-machining was found the data from volume $\times$specific gravity and analyzed to made its table and graph on ground the data. 4) In order to keep the accuracy of voltage affected to the work piece was equipped with the A.V. R and the memory scope was sticked to the electric spark machine. 5) In order to preserve the precision of current, to get rid of the noise occured by internal resistance of electric spark machine and to force injecting for the discharge fluid , it made the fixed table for a work piece to minimize the work error by means of one's failure during the electric discharging.

• E2M - 전기 전자와 첨단 소재
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• 제11권11호
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• pp.17-21
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• 1998

The surface potential distribution on insulating polymers was measured by scanning of the probe of an electrostatic voltmeter. The measurements were done for two measured by scanning of the probe of an electrostatis voltmeter. The measurements were done for two cases. In the first case, it was measured on the free surface of insulating films which had been inserted between plane electodes after the removal of the upper brass disk electrode. In the second case, we measured the charging region between a circular and its opposing concentric ring electrodes after the removal of dc ramp voltage in air and nitrogen gas.

• 한국정밀공학회지
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• 제21권2호
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• pp.177-185
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• 2004

The machining performance of wire electrical discharge machining(WEDM), such as cutting speed, surface roughness and straightness depend on the electrode, and the machining parameters are diverse and affect each other. Therefore operator must have a lot of experiences of the parameter for the better machining performance in WEDM. An approach to minimize the time for determining of parameters setting is proposed. Based on the Taguchi method, the significant factors affecting the machining performance are determined. Types of electrodes are arranged at inner array in tables of orthogonal arrays so that we can estimate machining performances of each electrode. Coating wire shows better performances than brass wire in cutting speed but it produces poor surface roughness, and two wires shows similar performance in straightness

• Environmental Engineering Research
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• 제23권2호
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• pp.164-174
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• 2018

Corrosion of copper alloys (copper, bronze and brass) in soil was evaluated at ambient temperature using various methods such as electrochemical impedance spectroscopy (EIS), polarization curves and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy microanalysis measurements. Three equivalent circuits were separately used to interpret the obtained impedance spectra. The EIS measurements indicated that the polarization resistance of all electrodes increases with increasing the immersion time. SEM showed a presence of three layers of corrosion products with various composition and morphology covering each electrode. In addition, it was found that at 20% of moisture content the $R_p$ values and the current density of all electrodes in the studied soil give the following order: copper > bronze > brass. Good consistency between the data obtained from EIS and PP measurements was observed.

• 한국기계가공학회지
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• 제19권4호
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• pp.65-70
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• 2020

While the demand for robots in the manufacturing industry has dramatically increased, the industrial robots' functionality is mainly determined by the effector attached to the end of their arms. They need a flexible gripping system that can act as a human hand and easily grasp a variety of objects, which requires resilient sensors. This study clarifies the electrical output characteristics of elastic tactile sensors according to contact terminals because the output characteristics of the tactile sensors vary greatly, depending on the contact material and the method of contact with the conductive wire. Our research considers the Three Roll Mill and Paste Mixer as the dispersion medium, and a nickel- and gold-plated brass electrode as the contact terminal.