• 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

• 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.

• 한국분말재료학회지
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• 제14권1호
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• pp.38-43
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• 2007

Cu-Zn alloy nano powders were fabricated by the electrical explosion of Zn-electroplated Cu wire along with commercial brass wire. The powders exploded from brass wire were composed mainly of ${\alpha},{\beta},\;and\;{\gamma}$ phases while those from electroplated wires contained additional Zn-rich phases as ${\varepsilon}$, and Zn. In case of Zn-elec-troplated Cu wire, the mixing time of the two components during explosion might not be long enough to solidify as the phases of lower Zn content. This along with the high vapor pressure of Zn appears to be the reason for the observed shift of explosion products towards the high-Zn phases in electroplated wire system.

• 대한소아치과학회지
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• 제37권4호
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• pp.519-525
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• 2010

이소맹출(ectopic eruption)은 여러 가지 원인들에 의해 치아가 비정상적 위치로 맹출하는 경우를 말하며, 주로 상악 제1대구치, 하악 측절치 그리고 상악 견치에서 발생된다. 이소맹출 한 상악 제1대구치는 정상보다 근심방향으로 맹출하여, 동측상악 제2유구치의 원심협측 치근을 흡수시키며, 결국 상악 제1대구치는 상악 제2유구치 하방에 걸리게 된다. 상악 제1대구치는 저작기능 및 교합에 중요한 역할을 하고 있으므로, 이소맹출 한 상악 제1대구치는 적절한 위치로 이동이 필요하다. 상악 제1대구치를 적절한 위치로 이동하기 위한 치료방법으로는 brass wire 또는 elastic ring을 이용한 separation, 상악 제2유구치의 원심면 삭제, finger spring을 포함한 고정성 또는 가철성 장치, 상악 제2유구치를 발치한 후 공간유지장치 또는 공간회복장치의 이용 등이 있다. 본 증례들은 강릉대학교 치과병원에 내원한 환자들에서 이소맹출 한 상악 제1대구치를 기성금관의 재시적, brass wire의 적용, active plate를 이용하여 적절한 위치로 이동시켜 양호한 교합을 이루었기에 이를 보고하는 바이다.

• 소성∙가공
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• 제15권7호
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• pp.518-523
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• 2006

Wet wire drawing of brass coated steel wire, used for tire reinforcement, is realized with Tungsten Carbide(WC) dies sintered with a cobalt(Co) binder. Dies wear represents an important limitation to the production process and cost savings. Several parameters, such as Co content, WC grain size of tungsten carbide, sintering conditions, and so on, affect on the wear of the drawing die. In this study, the effect of the diamond abrasive particle size on the life of the WC centered dies of the wet wire drawing was investigated. Wet wire drawing experiments were carried out on a wet wire drawing machine. From the experiments, the dies life, dies fracture, wire surface roughness, and wire breaks were investigated. From the results, it was found that the wear of the WC dies increased with the increase in the diamond abrasive particle size.

• 한국정밀공학회지
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• 제20권1호
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• pp.70-78
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• 2003

The purpose of this study was to present the method to choose the optimization machining condition for the wire electric discharge machine. This was completed by examining the ever-changing quality of the material and by improving the function of the wire electric discharge machine. Precision metal mold products and the unmanned wire electric discharge machining system were used and then applied in industrial fields. This experiment uses the wire electric discharge machine with brass wire electrode of 0.25mm. In this experiment, we changed no-node voltage to 7 and 9, pulse-on-time to 6$mutextrm{s}$, 8$mutextrm{s}$ and 10$mutextrm{s}$, pulse-off-time to 8$mutextrm{s}$, 10$mutextrm{s}$ and 13$mutextrm{s}$, and experimented on wire tension at room temperature by 1000gf, 1200gf, and 1400gf, respectively.

• 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

• 한국전자파학회지:전자파기술
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• 제3권2호
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• pp.10-15
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• 1992

The electromagentic characteristics of antennas in the complicated metallic structures were analyzed using the electric field integral equation. The accurancy of computer program was confirmed by comparing the computation result with NELC brass model study. And computation result of antenna characteristics in metallic structures was in good argreement with our measuring result.

• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.816-824
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• 2003

In this study, variations of cutting performance with pulse time, open circuit voltage, wire speed and dielectric fluid pressure were experimentally investigated in Wire Electrical Discharge Machining (WEDM) process. Brass wire with 0.25 mm diameter and AISI 4140 steel with 10 mm thickness were used as tool and work materials in the experiments. The cutting performance outputs considered in this study were surface roughness and cutting speed. It is found experimentally that increasing pulse time, open circuit voltage, wire speed and dielectric fluid pressure increase the surface roughness and cutting speed. The variation of cutting speed and surface roughness with cutting parameters is modeled by using a regression analysis method. Then, for WEDM with multi-cutting performance outputs, an optimization work is performed using this mathematical models. In addition, the importance of the cutting parameters on the cutting performance outputs is determined by using the variance analysis (ANOVA).

• 한국공작기계학회논문집
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• 제13권5호
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• pp.7-15
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• 2004

The purpose of this study was to present the method to choose the optimum machining condition for the wire EDM. This was completed by examining the ever-changing quality of the material and by improving the function of the wire electric discharge machine. Precision metal mold products and the unmanned wire electric discharge machining system were used and then applied in industrial fields. This experiment uses the wire electric discharge machine with brass wire electrode of 0.25mm. To measure the precision of the machining surface, average values are obtained from 3 samples of measures of center-line average roughness by using a third dimension gauge and a stylus surface roughness gauge.