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

• 한국안전학회지
• /
• 제19권2호
• /
• pp.21-25
• /
• 2004

This study deals with the characteristics of wire-cut EDM(Electrical Discharge Machining)process in aluminum alloys. Besides 2 series and 7 series of aluminum alloys for aerospace applications, porous aluminum is tested, which is used for sound absorbing matherial and interior and exterior material of building. Jinyoung JW-30 wire cutting machine was used in this experiment. Tap wate passed a filter and ionization was used as the discharging solution. An immerision method was applied as a cooling method because it separates chips effectively and machinability is good even with low value of electric current. The speed of fabrication was estimated by measuring the travel distance of the work piece and time spent for the movement. As pulse-on-time increased the fabrication speed decreased. On the other hand, as peak voltage of peak current increased the fabrication speed increased. In general 7075 aluminum alloy resulted in higher fabrication speed.

• 한국기계가공학회지
• /
• 제14권4호
• /
• pp.100-107
• /
• 2015

Recently, high-efficiency machining in the production of high-value products with a complex shape has constantly been required with the need for hybrid machining. In this study, in addition to the wire-cut E.D.M. and vibration used to present the possibility of a hybrid process by carrying out the aluminum alloy experiment, the hybrid process determines the nature of the surface. The selected experimental parameters are horizontality, waveform, amplitude, peak current, and frequency. The experimental results give guidelines for selecting reasonable machining parameters. The surface roughness was improved by about 20% with increases in the amplitude of the vibration.

• 한국산학기술학회논문지
• /
• 제18권9호
• /
• pp.61-67
• /
• 2017

프레스금형 제작 시 사용목적에 맞는 적합한 소재선택과 빠른 가공방법에 대한 연구는 금형제작시간을 줄이고 금형원가를 절감하는데 절대적으로 필요한 연구분야이다. 특히 장수명 프레스금형을 개발하기 위해선 열에 대한 고찰이 반드시 이루어져야 한다. 일반적으로 프레스금형의 주요부품 소재로는 Cr, W계 저합금 공구강, 고탄소 고크롬강, 고속도강 등 냉간 금형용 합금공구강이 많이 쓰이고 있다. 프레스금형부품을 가공하는 데는 주로 공작기계와 와이어 컷 방전가공을 사용하고 있다. 가공공정에 따라 금형부품의 가공시간 및 수명이 많은 차이가 난다. 밀링가공과 연삭가공으로 제작된 부품의 경우 제작시간과 비용은 많이 드는데 비해 금형의 수명이 길고 밀링가공과 와이어 컷 방전가공을 사용하면 제작시간과 비용은 절감되는 반면 금형수명은 줄어드는 현상이 나타난다. 따라서 본 연구에선 가공시간과 비용이 절감되는 가공방법으로 열처리를 사용하여 금형의 사용수명을 향상시키는 방법에 대해 고찰하고자 한다. 밀링가공-연삭가공, 밀링가공-와이어 컷 방전가공, 밀링가공-와이어 컷-고온템퍼링, 3가지 가공방법으로 시편을 제작하여 가공표면과 중심부를 SEM, EDS분석 및 표면조도분석으로 문제점을 고찰하였고 밀링가공-와이어 컷 방전가공-고온템퍼링의 가공방법으로 밀링가공-연삭가공과 동일한 금형의 수명을 만드는 방법을 도출하였다.

• 소성∙가공
• /
• 제22권1호
• /
• pp.23-29
• /
• 2013

In this study, a micro/nano-random-pattern-structure surface was machined by electric discharge machining (EDM) followed by replicating the EDM surface with a silicone elastomer having low energy and greater hydrophobicity. The variation of hydrophobicity was of prime interest and was examined as a function of the surface roughness of the replicated silicone elastomer. The hydrophobicity was evaluated by the water contact angle (WCA) measured on the relevant surface. For the experiments, the original surfaces were machined by die sinking electric discharge machining (DS-EDM) and wire cutting electric discharge machining (WC-EDM). The ranges of surface roughness were Ra $0.8{\sim}19{\mu}m$ for the DS-EDM and Ra $0.5{\sim}4.7{\mu}m$ for the WC-EDM. In order to fabricate a hydrophobic surface, the EDM surfaces were directly replicated using a liquid-state silicone elastomer, which was thermally cured. The measured WCA on the replicated surfaces for DS-EDM was in the range of $115{\sim}130^{\circ}$ and for WC-EDM the WCA was in the range of $123{\sim}150^{\circ}$. Additionally, the dynamic hydrophobicity was evaluated by measuring an advancing and a receding WCA on the replicated silicone elastomer surfaces.

• 한국기계가공학회지
• /
• 제14권2호
• /
• pp.59-66
• /
• 2015

The production of high value-added products requires efficient processing and this constant demand for complex shape processing has led to the need for hybrid processing. In this study, the surface characteristics of hybrid machining, which combines wire-cut E.D.M and vibration, are examined. The selected experimental parameters are verticality, waveform, amplitude, peak current and frequency. The experimental results provide a guideline for selecting reasonable machining parameters. Surface roughness was improved by increasing the amplitude of the vibration.

• Composites Research
• /
• 제13권6호
• /
• pp.39-46
• /
• 2000

방전가공은 공구와 공작물 사이의 얇은 간극에 전류를 방전시켜 금속을 가공하는 방법이다. 방전 와이어 가공은 전도성 와이어를 사용하는 방전가공의 특수한 예로서, 펀치나 금형제조에 널리 이용되고 있다. 와이어 방전가공에서 와이어는 와이어 가이드 및 외팔보로서 지지되어 있다. 최근 생산성의 증가추세와 더불어 와이어의 이송속도가 증가함에 따라 외팔보의 진동 등으로 인한 기계 정밀도의 저하가 우려된다. 본 논문에서는 정, 동특성이 우수한 방전가공기용 복합재료 외팔보를 설계, 제작하였다. 끼워맞춤길이와 보강 적층수의 변화에 따른 정, 동특성의 변화를 살펴보기 위하여 시편을 제작하여 하중실험을 수행하였다. 또한 유한요소 해석을 수행하여 하중실험의 결과와 상호 비교하였다. 시편실험의 결과로부터 방전가공기용 복합재료 외팔보를 설계, 제작하여 기존의 금속 외팔보와 그 성능을 상호 비교하였다.

• 한국정밀공학회지
• /
• 제21권11호
• /
• pp.171-178
• /
• 2004

This paper presents vibration characteristics of a wire cut discharge machine in which an electro-rheological brake actuator is used to control the wire tension. The ER brake actuator has several advantages including design simplicity, fast response time and real-time controllability. On the basis of the tension level required in the machine an appropriate size of the ER brake actuator is devised. The ER brake actuator is then incorporated with the machine and the field-dependent wire tension is experimentally evaluated. The straightness of the workpiece is also empirically investigated by changing the intensity of the electric field.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
• /
• pp.567-572
• /
• 2000

From the experimental study of W-EDM for alloyed steel, the characteristics such as Hand Drum Form and surface roughness have been observed and evaluated for various conditions. In square hole, the increase of IP as to made condition, the calculate high value of surface roughness. Also compare dimensionless square hole with circle hole' graph, In circle hole, if a value of surface roughness IP 6 in a side of circle it show a 0.4${\mu}{\textrm}{m}$ and in IP 8, 0.6${\mu}{\textrm}{m}$, in IP 10, 0.7${\mu}{\textrm}{m}$, in IP 12, 0.8${\mu}{\textrm}{m}$ higher than before. This figure show the surface roughness is higher than before, because a table move in either X-axis or Y-axis in square hole, on the contrary, in circle there table move in X-axis and Y-axis at the same time. hand drum form getting small when wire tension increase 1000gf to 1500gf, at the same working conditions. The smaller of off time, the maller of hand drum form in same condition and same wire tension. but if you compare square hole with circle hole' graph, hand drum form displayed in maintained term of working condision, on the contrary, in case of square hole variation of hand drum form is more increase than a grow of IP

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.953-956
• /
• 1997

Micro drilling characteristics by EDM method was investigated. In detail, Micro tool electrode for EDM drilling was machined by use of WEDG method and micro hole was drilled using the machined tool electrode in SUS plate. The machining accuracy and time was compared in a different dielectric fluid. As a result, it was convinced that this method could be utilized as a fabrication technology of micro mold or micro 3 dimensional parts.