• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.27-36
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• 2005

Some studies have shown that unstable factors are inherent in WEDM process, causing the instability of the discharging pulse to reach about 40∼60％ in normal machining. Transient stability is an important subject in WEDM process since there is a close relationship between stability and machining performance, such as the characteristics of a machined surface, machining speed and problem of instability like wire rupture phenomenon. Among the many machining parameters affecting WEDM machining state, three specific parameters (Vr, Ip, off time ) are major controllable variables that can be applied in transient stability control. And, this research investigates the implementation and analysis of real-time micro control of the discharging stability of WEDM (Wire Electric Discharge Machining) process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.143-144
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• 2012

• Transactions of Materials Processing
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• v.15 no.9 s.90
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• pp.648-653
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• 2006

In this study, the characteristics of Wire Electrical Discharge Machining(WEDM) of the high-hardened mold steel were investigated. WEDM experiments have been carried out based on parameter of wire diameter, pulse on time, pulse off time, feed rate and cycle etc. From the results, the optimized WEDM cycle of RIGOR steel has been revealed as $5{\sim}7$ times. Also, geometrical accuracy of the Core Pin is dependent on WEDM wire radius machining condition and wire chattering.

• Tribology and Lubricants
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• v.32 no.6
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• pp.201-206
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• 2016

In this study, we attempt to produce a semi-elliptical riblet with a shark skin-like surface using wire electrical discharge machining (WEDM) and micro molding techniques. Our design for the production of the semi-elliptical mold includes an electrode, a winding roller, and a guide on the WEDM system. A replication mold with negative riblets is machined using WEDM, and a shark skin inspired surface with positive riblets is fabricated using a micro molding technique. For a comparison with the original shark skin, a shark skin replica is also produced using the micro molding technique directly from a shark skin template. Droplet contact angles on a flat surface, the shark skin replica, and the epoxy resin-based micro riblet shark skin-like surface are evaluated. The effect of a Teflon coating on the contact angles for the three different surfaces is also investigated. The results show the micro riblet with a shark skin-like surface has a similar contact angle as the shark skin replica, which means that the simplified riblet shark skin surface strongly influences the performance of wettability. This study confirms the effectiveness of using the WEDM method to prepare hydrophobic surfaces with diverse surface patterns.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.215-222
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• 2014

This paper presents an experimental study of a vibration-assisted dry micro-wire electrical discharge machining (${\mu}$-WEDM) utilized in high precision and micro-manufacturing area. The assisted vibration was applied to the workpiece using a piezoelectric actuator, and high pressure air was injected directly into the machining gap through a nozzle. Investigation experiments were performed to estimate the importance of input parameters and it was observed from experiment results that the width (kerf) of the cutting slot and the machining time were significantly affected by the air injection pressure and input energy. Moreover, it was also observed that there exists an optimal relationship between the machining time and input parameters including the air pressure and vibration frequency and amplitude. Central composite design based experiments were also carried out, and empirical models of the machining time and cutting slot kerf have been developed using the response surface methodology to analyze and optimize the process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.193-194
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• 2012

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.117-122
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• 2002

Electrical discharge machining uses thermal energy from electrical discharge, while wire electrical discharge machining (WEDM) technology is widely used in conductive material machining. This paper proposes a method for evaluating the characteristics of wires in WEDM. In order to evaluate the wire processing performance, processing speed and roughness, straightness, corner processing have been assessed with precision experiment equipment and image processing including Laplacian filtering with various threshold levels.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.629-635
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• 2000

Vibrational characteristics and tension fluctuation of a translating wire in WEDM are the main problems to deteriorate the cutting accuracy and processing performance. In this paper, we analyze natural frequencies of the wire used in WEDM, both theoretically and experimentally. To reduce the tension variation of the wire. which directly affects cutting performance. we have designed a simply tension reduction device using springs and rollers. It is shown that tension fluctuation is reduced about 25% using the passive tension controller.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.86-92
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• 2001

Vibrational characteristics and tension fluctuation of a translating wire in WEDM are the main problems to deteriorate the cutting accuracy and processing performance. In this paper, we analyze natural frequencies of the wire used in WEDM, both theoretically and experimentally. To reduce the tension variation of the wire, which directly affects cutting performance, we have designed a simply tension reduction device using springs and rollers. It is shown that tension fluctuation is reduced about 35% using the passive tension controller.