Showing papers in "Journal of the Japan Society of Electrical-machining Engineers in 2001"
TL;DR: In this article, the authors discuss the effect of different types of transformations on the performance of a vehicle and show that the vehicle can adapt to the conditions of the environment and the environment.
Abstract: 1.は じめに エレクトロニクス化により, 情報通信分野の機器ば かりではなく, 家電品や 自動車等の高機能化も図ら れている, これを支えているのが, 半導体を構成す るICリードフレーム製造用の精密金型制作技術や 高集積電子部品の微細精密加工技術等の生産加 工技術である. これらの技術分野の一角を占める精 密加工技術として, ワイヤ放電加工技術がある。これ は、その原理から, 超硬金型, セラミックス等の硬質 材料の微細加工を可能にする技術であり, 今や工 業界では必要不可欠な存在となっている。長年に渡 って微細, 高精度, 高速加 上技術の追求が行われ るとともに合せて無人加工の推進などが進められて きた。最近では, 社会情勢に応じて, 自動車部品や 家電製品の部品に代表される部品加工にも本技術 が拡張利用されつつある, 本稿では, 現在汎川されている黄銅電極線から 最近の新しい被覆型電極線の開発状沙己まで, 金属 組織の制御の観点から述べてみたい。
8 citations
TL;DR: In this paper, the basic technological background of micro-EDM is discussed first, followed by some introduction of the types of equipment, present state of the technology and examples of machining are shown.
Abstract: In this paper, the contemporary technology of micro-EDM is overviewed. The basic technological background of micro-EDM is discussed first. Following some introduction of the types of equipment, present state of the technology and examples of machining are shown. Various possible combinations with other micromachining technologies are also discussed.
7 citations
TL;DR: In this article, a pulsed arc has been applied to deposit an electrode material on a metallic substrate, where die steels are sparked with electrodes of cermets containing both borides (TiB2, ZrB2) and metals (Co, Ni) in argon atmosphere.
Abstract: A pulsed arc has been applied to deposit an electrode material on a metallic substrate. Die steels are sparked with electrodes of cermets containing both borides (TiB2, ZrB2) and metals (Co, Ni) in argon atmosphere. A conventional NC EDM machine is used as a pulsed arc generator. A transistor-controlled capacitor circuit is adopted to obtain steep and high current electrical pulses promoting transfer of the electrode materials. Coatings of borides, which are difficult to build up, are deposited onto the substrates. Surfaces of the coatings are irregular and thickness varies in the range of 10 to 50um. No cracks are observed in interfaces between the coatings and the substrates. Vickers hardness value (0.098N load) changes between 1,000 to 3,200 Hv depending on both thickness of the coating and the electrode materials. Wear-out test is performed to investigate wear resistance of the coatings. Although the substrates without a coating are severely worn, the wear impression of the coated substrates is terminated in the coatings. An electrode mass transfer mechanism is observed. The electrode material is not transferred by a single discharge but by a highly concentrated discharge that occurs occasionally at arbitrary locations. key words: EDM, surface modification, electrode transfer, boride 1. はじめに 近年, 放電加工法を表面改質へ応用する様々な 試みがなされている1)4). なかでも, 放電加工油 中で電極材を放電により溶融 ・飛散させ改質層を 形成する手法においては, 硬質な皮膜が形成 され ている. 実用面でも, プレス金型, 冷間鍛造金型 および切削工具へ適用し, 優れた耐摩耗性を有す ることが確認されている5). しかしながら, 放電 加工油中で改質を行っているため, 加工油が放電 により分解 して生 じた炭化雰囲気中で改質を行 う ことになり, この手法では形成できる改質層は炭 化物に限定されている. 一方, 放電加工油を用いずアルゴンなどの不活 性な気中で放電を発生させ電極材を移行 し改質層 を形成するならば, 用いる電極材に応 じて, 炭化 物のみならず金属, 窒化物, およびホウ化物など 様々な組成の改質層を形成可能 と思われる. 気中放電を用いた表面改質法 としては, 古くか ら放電被覆法が知 られており, 超硬合金成分をは じめとする様々な組成からなる改質層が形成 され ている6). 奥宮らは酸窒化物を含む改質層が形成 可能なことを報告している7). さらに, 表面改質 ではないが, 早川 らにより電極の移行 ・付着現象 * 電 気加 工 学会 全 国大 会(1999)に て 発表 **神奈 川 県産 業 技術 総合 研 究所(海 老 名 市 下 今 泉705-1) E-mail: satsuta@kanagawa-iri.go.jp
4 citations
TL;DR: In this article, a surface modification method for titanium using a scanning electrode during the finishing process of EDM was presented, where the effects of several parameters, such as the electrode thickness, scanning speed and scanning pass, on the surface properties were investigated.
Abstract: In this paper we present a surface modification method for titanium using a scanning electrode during the finishing process of EDM. The effects of several parameters, such as the electrode thickness, scanning speed and scanning pass, on the surface properties were investigated. Using this method, the discharge process can be controlled without any difficulty. Therefore a smooth TiC layer with excellent tribological properties may result. The C/Ti ratio in the TiC layer, which influences the tribological properties of the machined surface, changed with the discharge number. The scanning electrode method proved to be effective for efficient surface modification of titanium.
3 citations
2 citations
2 citations
TL;DR: In this article, a new fine deep boring method is proposed in which EDM and laser beam machining are combined for obtaining a qualitatively machined shape and high surface integrity compared to conventional processes.
Abstract: This paper deals with fine deep boring of carbide alloys. Fine deep boring by EDM is superior for obtaining a qualitatively machined shape and high surface integrity compared to conventional processes. However, it is difficult to obtain a microhole smaller than 100μm in diameter with an aspect ratio larger than 5, because of remaining bubbles and debris in the small gap between the electrode and workpiece which cause unstable machining. A new fine boring method is proposed in which EDM and laser beam machining are combined. First, a penetrating prehole is machined with a YAG laser. In the next process, micro-EDM boring is carried out on the prehole. By removing the bubbles and debris through the prehole, it is possible to maintain stable EDM. With these two successive processes, a fine deep hole is obtained. The hole made by this method has a good roundness and a high aspect ratio that cannot be achieved using only the EDM process. We applied this method to a superfine grain carbide alloy which is widely used for precise metal molds and cutting tools. The main results of this study are as follows. (1) Using the combined process of EDM and LBM, ∅160μm holes were successfully machined through a 2-mm-thick superfine grain carbide. (2) It is possible to remove the bubbles and debris efficiently by suction flow through the prehole. (3) In the case of EDM boring with a prehole, electrode wear mainly occurs on the side of the electrode. (4) For a 1-mm-thick workpiece, it is possible to bore a microhole with a diameter of 100μm and an aspect ratio of 10.
2 citations
TL;DR: In this paper, a jump flushing system is proposed for drilling microholes with high aspect ratios, by inducing an intermittent jump of the workpiece, assisted by the horizontal main spindle and pure water dielectric.
Abstract: Machining microholes with high aspect ratios has become important in various industrial fields. Since the development of WEDG (wire electro discharge grinding), micro-EDM has been an excellent process for machining microholes in metals and alloys. However problems remain in machining the high-aspect-ratio holes. As the depth of microholes becomes deeper, drilling through the microholes becomes more difficult. In addition, the removal of debris and renewal of dielectric from the machining gap are difficult because unstable discharge and arcing usually result. In this study, the jump flushing system is proposed for drilling microholes with high aspect ratios, by inducing an intermittent jump of the workpiece. The system is assisted by the horizontal main spindle and pure water dielectric. As a result, a 1.5mm-deep hole with the diameter of 100μm was successfully machined in to stainless steel which is one of the more difficult materials in which to drill deep microholes.
2 citations
TL;DR: In this paper, the relationship between the reflectivity of the polished surface and the transverse rupture strength (IRS) was experimentally examined based on the assumption that polishing to a quasi-mirror-finish surface is not necessarily accompanied by recovery of the strength of the material.
Abstract: Heat-affected zones (HAZs), in which there are many cracks and microcraters, are generated by electrical discharge machining (EDM) of cemented carbides. These defects cause a substantial decrease in the strength of the materials. As one of the countermeasures, HAZs can be removed by polishing, which is dependent on hand finishing. However, it is difficult to remove HAZs completely through polishing. At present, a polishing operator subjectively evaluates whether defects such as cracks exist on a polished surface based on the degree of brilliance of the polished surface. In this study, the relationship between the reflectivity of the polished surface and the transverse rupture strength (IRS) was experimentally examined based on the assumption that polishing to a quasi-mirror-finish surface is not necessarily accompanied by recovery of the strength of the material. Our results showed that the reflectivity of the quasi-mirror-finish surface with surface roughness of 0.2μm Ry is 3-4 percent lower than that of a mirror-finish surface with surface roughness of less than 0.1μm Ry. The IRS ratio of a quasi-mirror-finish surface is 0.7, and that of an electrical discharge machined surface is 0.6 compared with 1.0 for a mirror-finish surface. Thus, we observed that the reflectivity of the quasi-mirror-finish surface is near that of the mirror-finish surface, and that the IRS of the quasi-mirror-finish surface is near that of the electrical discharge machined surface.
1 citations
1 citations
TL;DR: The Tandem micro-EDM system proposed in this article can machine a great number of microholes continuously after spindle setup, and it is not only suitable for machining micro tools but also suitable for micro-holes at the same time.
Abstract: Machining microholes has become important in various industrial fields. Since the development of WEDG (wire electro discharge) technology, micro-EDM has become an excellent method for machining microholes on metals and alloys. However, problems remain for achieving mass production of microholes by EDM. Conventional micro-EDM technology is needed to prepare a microtool before machining microholes. In this paper a new system is proposed for machining microholes, called the Tandem micro-EDM system. The new system is not only for machining microtools but also for machining microholes at the same time. As a result, the Tandem micro-EDM system can machine a great number of microholes continuously after spindle setup.