Papers by Keyword: Micro Electro Discharge Machining

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Authors: M. Mahardika, Kimiyuki Mitsui, Zahari Taha
Abstract: The mechanism of fracture in micro-electrical discharge machining (-EDM) processes is related to the discharge pulses energy. This paper investigates the correlation of fractures and discharge pulses energy in the -EDM of polycrystalline diamond (PCD) to the acoustic emission (AE) signals. The evaluation of fracture mechanism was done by measuring the generation and propagation of elastic wave in single discharge pulse by using AE sensor. The results show a strong correlation between fractures and discharge pulses energy to the AE signals and mechanism of material removal in the -EDM processes.
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Authors: Ping Mei Ming, Di Zhu, Yang Yang Hu, Yong Bin Zeng
Abstract: This paper investigated the impact of area effect in the batch mode micro-EDM on shape accuracy and surface morphology of the machined microstructures, as well as electrode wear, using both the positive-type and the negative-type electrode arrays fabricated by the UV-LIGA process. Experimental results showed that ,with the increase of electrode-pair scale from Φ1mm, Φ2mm, Φ4mm to Φ8mm, the shape accuracy of the machined stainless steel microstructures increased, but the eroded microcavities of the machined area reduced in both the positive-type and the negative-type micro-EDM using the same electrical pulse parameters. It was also found that, with the same pulse energy and electrode-pair area, the electrode wear reduced as the electrode-couple area increased, and the wear ratio in the positive-type micro-EDM was larger than that in the negative-type micro-EDM.
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Authors: Bülent Ekmekci, Atakan Sayar, Tahsin Tecelli Öpöz, Abdulkadir Erden
Abstract: Micro Electric Discharge Machining is mostly used micromachining technique for manufacturing of micro holes and mini cavities. It is a thermal material removal process achieved by application of recursive electrical sparks between two conductive materials immersed in dielectric liquid. There are many electrical and technological parameters, which are effective in the machining characteristics and machined material surface integrity. In this study, effects of pulse energy on characteristics of surface damage in micro electric discharge machining of micro holes are investigated. To observe the influences of investigated pulse forms, a series of micro-holes were machined and cut from cross sections for metallurgical examinations. Unconventional etching agents were applied to examine the metallurgical transformations using optical and scanning electron microscopy. It was observed that heat-damaged segment is composed of three distinctive layers, have relatively high thicknesses (0.2 to 10 μm) when compared with the size of the micro holes and varies noticeably with respect to drilling dept. Different morphological structures and deformations in the subsurface of micro-hole walls at several sections were illustrated. Finally, analyzed machining parameters and variation of hat damaged layer thicknesses were discussed in terms of drilling depth.
688
Authors: Yuan Gang Wang, Meng Hua Wu, Fu Ling Zhao, Jin Wang
Abstract: Lateral and edge wear of electrodes in micro-EDM affects workpiece shape accuracy. A method that change materials property of lateral side of electrode was put forward, based on discharge performance difference of different materials, and it was demonstrated with experiments. Results show that the method proposed is more effective and improves the precision of deep holes, compared with traditional sampling methods. The technology can provide reference to practicality of micro-EDM for 3D structure cavity and deep holes.
421
Authors: Wan Sheng Zhao, Y. Zhang, Zhen Long Wang, B.X. Jia, Fu Qiang Hu, Z.Y. Li
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Authors: Guo Zhe Yang, Hai Bo Lin
Abstract: In the paper, a micro-EDM prototype was designed, and a preliminary machining experiment was done. The micro-EDM prototype was makeup by three dimensions stage, transistor type isopulse generator with pulse duration of 80ns, and environment maintain system. The machining experiment approved that the prototype in good working order, the stage can reach very high precision, and simple micro-EDM machining was done.
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Authors: Meng Hua Wu, Yuan Gang Wang, Fu Ling Zhao
Abstract: Wear course was experimental analyzed and mechanism of electrode wear was discussed based on finite element analysis and electromagnetic theory. Cu–TiN nano composite electrode was prepared on Cu electrode by electro deposition and effects of the electrode on discharging were studied. It is shown that electric field distortion and skin effect are two of the basic reasons on electrode wear. Cu–TiN nano composite electrode is one of the the effective ways for uniform wear of electrode in EDM.
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