精密工学会誌
Online ISSN : 1882-675X
Print ISSN : 0912-0289
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選択された号の論文の19件中1~19を表示しています
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特集:極限精度のミラー加工技術
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グラビアとインタビュー 精密工学の最前線
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論文
  • 西田 勇, 奥村 龍馬, 佐藤 隆太, 白瀬 敬一
    84 巻 (2018) 6 号 p. 572-577
    公開日: 2018/06/05
    ジャーナル フリー

    In order to improve machining efficiency, it is required to recognize machining status and optimize cutting conditions. This study develops a newly cutting simulator for end-milling operation, which considers the elastic deflection of tool system. This simulator is based on an instantaneous rigid force model. The uncut chip thickness, which is required to estimate cutting force, is calculated under the consideration of the elastic deflection of the tool system, which corresponds to tool and tool holder deflections caused by cutting force. The newly developed end-milling simulator represents work material by voxel model and calculates the uncut chip thickness from the removed voxels, which are penetrated by tool cutting edges. In our previous study, the uncut chip thickness is calculated from voxels removed by each minute tool rotational angle, and the instantaneous cutting force in a minute time interval can be estimated. Therefore, this study proposes a method to consider the elastic deflection of the tool system caused by the estimated instantaneous cutting force. This study considers the elastic deflection of the tool system, which consists of the tool deflection, the displacement between the tool and the tool holder parallel to the tool axis, the displacement between the tool holder and the spindle parallel to the spindle axis, and the rotational displacement at the tool holding part. The actual uncut chip thickness affected by the elastic deflection of the tool system has to be calculated to estimate the actual cutting force for each minute time. In order to validate the effectiveness of the proposed algorithm, the experimental 3-axis milling operations were conducted. It was confirmed that the predicted cross-sectional shape of the machined surface had good agreement with the measured one.

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  • 鈴木 隆太, 川村 拓史, 松坂 壮太, 比田井 洋史, 千葉 明, 森田 昇
    84 巻 (2018) 6 号 p. 578-583
    公開日: 2018/06/05
    ジャーナル フリー

    Using electric field-assisted solid-state ion-exchange technique, metal ions were doped into a borosilicate glass and a buried metal precipitation thin layer was formed in the glass substrate. In this study, silver ions were doped into glass surface by voltage application using the silver foil as an anode (referred to as forward voltage). After ions doping by forward voltage application, a buried silver layer was formed in a glass substrate by additional voltage application with opposite direction to the case of doping (referred to as reverse voltage). Because the silver layer is electrically conductive and surrounded by glass matrix with high electric resistivity, the formed layer can be used as a buried electrical circuit in glass substrate. In order to form multi silver layers in glass, we alternatively doped silver and sodium ions into glass surface. In the case of sodium doping, a soda-lime glass sheet was used as a sodium ion source. Doped sodium ions exchanged the sites occupied by silver ions which doped in advance. As a result, we successfully formed the multi layered structure consisted of silver-rich and sodium-rich layers. In addition, two silver layers separated by sodium-lich layer were formed by reverse voltage application.

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  • 津野田 亘, 進士 忠彦, 藤原 浩幸, 松下 修己
    84 巻 (2018) 6 号 p. 584-588
    公開日: 2018/06/05
    ジャーナル フリー

    Oil film bearings have higher load capacity and larger damping than ball bearings. Therefore, the rotors of large turbomachines are usually supported by oil film bearings. However, at high rotational speeds, the swirling flow of the lubricant destabilizes the rotor system and induces self-excited vibrations such as oil whip and oil whirl. Since these vibrations limit the operational speed and reliability, a method for eliminating them and increasing the operational range is necessary. We propose a method for stabilizing these self-excited vibrations by using an electro-magnetic actuator to cancel the force due to the cross-coupled stiffness. This study demonstrated the experimental evaluation of the effectiveness in suppressing the self-excited vibration using the electro-magnetic actuator.

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