• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.105-110
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• 1999

Wire electrical discharge machining (WEDM) is one of the unconventional machining processes, which is utilizing electrical energy to remove work-piece. In recent years WEDM used widely in die-sinking industry because WEDM can machine any hard materials if only it has conductivity and can machine accurately to the complex geometry, for fine wire is used in WEDM for the tool electrode. However WEDM is non-contact machining process, which is utilizing discharge phenomena occurring between two electrodes, the size of the machined part is larger than that of the tool electrode size. It is called discharge gap or clearance the difference size between the tool electrode and the machined part in WEDM. By the experiment clearances according to the machining condition was investigated.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.101-106
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• 2008

In the wire cut electrical discharge machining, the optimal machining parameters setting satisfying the requirements of both high efficiency and good quality is very difficult because its process involves a series of complex physical phenomena and the machining parameters are numerous over diverse range. In this paper, the experimental investigation has been performed to find out the influence of the machining parameters on the machining performance such as cutting speed and surface roughness. The selected experimental parameters are no load voltage, discharge peak current and pulse-off time. The experimental results give the guideline for selecting suitable machining parameters.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1865-1868
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• 2003

This paper provides a new method for hybrid machining, particularly suited to micro fabrication applications such as micro point, micro line, micro structure, micro partition and so on. Developed micro fabrication process by electrical discharge machining (EDM) and electrical discharge deposition (EDD) with metal powder (Ti, Fe) has been studied to build TiC or FeC structure. Titanium powder or iron powder is supplied from working fluid (kerosene or de-ionized water with powder) and adheres on a workpiece by the heat and electric power caused by the electrical discharge. The use of a tool electrode is expected to keep powder concentration high in the gap between a workpiece and a tool electrode and to accrete powder material on the workpiece. The deposition is tried under various electrical conditions (workpiece. tool electrode, working fluid, discharge current, voltage and powder etc.). On the other hand. using electrical discharge machining (EDM) with the same tool electrode, it can be used as a removal process (cutting) by electro erosion at the same time. Therefore. this new method can do a hybrid machining to build up and down a structure with the workpiece.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.604-607
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• 2005

In the electro-discharge machining the machining performance is closely related to the characteristics of discharge which can be identified from electrical behavior in gap between workpiece and electrode. Therefore, the accurate prediction of electrical behavior in electro-discharge machining (EDM) is useful to process control and optimization. However, any simulation model fur prediction of electrical behavior in EDM process has never been reported until now. In this study, a simulation model is developed to analyze the electrical behavior of electro-discharge plasma which significantly influences electrical behavior in EDM process. For the purpose of this the fundamentals of electro-discharge mechanism such as inception, propagation, formation of plasma channel and termination are investigated to accurately predict the cycle of discharge plasma in EDM. As a result, a mathematical model of electro-discharge plasma is constructed with considering the fundamentals of electro-discharge plasma. Consequently, it is demonstrated that the developed model can predict the electrical behavior of plasma such as electron density in various conditions.

• 한국정밀공학회지
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• 제15권2호
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• pp.7-13
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• 1998

This paper presents a methodology for determining machining conditions in Electric Discharge Wire-Cut. Unification of two phase neural network approach with an automatic generation of machining parameters is designed. The first phase neural network, which is 1 to M backward-mapping neural net, produces approximate machining conditions. Using approximate conditions, all possible conditions are newly created by the proposed automatic generation procedure. The second phase neural net, which is a M to 1 forward-mapping neural net, determines the best one among the generated candidates. Simulation results with ANN are given to verify that the presenting methodology could apply for determining machining parameters in Electric Discharge Wire-Cut.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.315-316
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• 2002

Electrochemical discharge machining is a very recent technique for non-conducting materials such as ceramics and glasses. ECDM is conducted in the NaOH solution and the cathode electrode is separated from the solution by $H_2$ gas bubble. Then the discharge is appeared and the non-conductive material is removed by spark and some chemical reactions. In the ECDM technology, the $H_2$ bubble control is the most important factor to stabilize the discharging condition. In this paper, we proposed the discharge peak monitoring/ discharging duty feedback algorithms for the discharge stabilization and the feasibility of this algorithm is verified by various pattern machining in the constant preload conditions for the cathode electrode.

• KSTLE International Journal
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• 제3권2호
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• pp.95-100
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• 2002

Electrochemical discharge machining is a very recent technique for non-conducting materials such as ceramics and glasses. ECDM is conducted in the NaOH solution and the cathode electrode is separated from the solution by H$_2$ gas bubble. Then the discharge is appeared and the non-conductive material is removed by spark and some chemical reactions. In the ECDM technology, the H$_2$ bubble control is the most important factor to stabilize the discharging condition. In this paper we proposed the discharge peak monitoring/discharging duty feedback algorithms fur the discharge stabilization and the feasibility of this algorithm is verified by various pattern machining in the constant preload conditions for the cathode electrode.

• 한국정밀공학회지
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• 제15권7호
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• pp.44-51
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• 1998

Two-step neural network is designed for determining electrical discharge machining parameters in low erosion. The first neural network, which is used as a classification network, checks whether the current conditions are appropriate to electrical discharge machining in low tool erosion. If the conditions are appropriate to EDM in low erosion, suitable EDM parameters are generated by the second neural network. Theoretically known EDM conditions are produced and also utilized for training the second neural network. The trained neural network is tested how well suitable EDM machining conditions are generated under unknown machining situations Experimental result shows that the proposed two-step neural network approach could be effectively used for determining EDM parameters in low tool erosion. The results also have a practical contribution to EDM area in that it could be applied for maintaining low tool wear as well as obtaining maximum machining rates simultaneously.

• 한국안전학회지
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• 제16권4호
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• pp.7-13
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• 2001

Wire electrical discharge machining experiments in conducted to investigate characteristics of acoustic emission (AE) and electrical discharge energy due to current peak (I$_{p}$), pulse on time($\tau$/on/). The AE signals are obtained with a sensor attached to workpiece side. Machining states are identified with scanning electron microscopy and residual stress analyzer. It is demonstrated that the residual stress provide reliable informations about the machining states. Moreover, machining states can be detected successfully using both the residual stress and AE count rate.e.

• 한국정밀공학회지
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• 제21권6호
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• pp.35-42
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• 2004

At the large-sized mold fer injection molding, the remaining gas in the mold causes some problems with final products. In order to solve these problems, air-bent was drilled on the surface of mold. However, this method leaves the scar on the surface of a product. Therefore, porous material was developed to the removal of remaining gas in this study. Porcerax II, which is a commercialized porous material, were developed in USA. It requires the electric discharge machining(EDM) process to make pores on the surface of the materials. The electric discharge machining (EDM) process, however, cause the increase of the time and cost for the fabrication of the mold. In this study, high speed machining(HSM) process was applied to the fabrication of porous mold without electric discharge machining(EDM) process. Some characteristics of the developed materials machined by high speed machining(HSM) and electric discharge machining(EDM) including air-permeability and porosity were compared with those of Porcerax II. Besides, in order to be applied to the molding process, hardness and tensile ＆ yield strength were compared between Porcerax II and developed materials.