成果報告書詳細
管理番号20160000000761
タイトル*平成27年度中間年報 SIP(戦略的イノベーション創造プログラム)/革新的設計生産技術 次世代型高性能電解加工機の研究開発(3)  
公開日2016/9/15
報告書年度2015 - 2015
委託先名国立大学法人東京大学
プロジェクト番号P14030
部署名IoT推進部
和文要約
英文要約Development of High-performance Electrochemical Machining System of Next Generation

(1) ECM gap phenomena were observed directly using a transparent electrode made of SiC single crystal, which is electrically conductive and optically transparent. First, gap phenomena with flushing flow were observed. Most of the bubbles were flushed out smoothly due to the radial flow. However, some large bubbles, elongated in the radial direction, stayed continuously on the surface due to the effect of cavitation. Since the bubbles block the electrolytic current, electrolyte flushing with excessively high velocity can deteriorate machining accuracy.
(2) To develop a simulation method which can consider the effect of bubbles in the inter-electrode gap, the bubbly flow model was used. Based on the calculation of the volume fraction of the gas in the electrolyte, the conductivity of the electrolyte was corrected by using the Bruggmann equation. A simulation of machining accuracy using a cylindrical pipe electrode was conducted with a flushing flow of electrolyte supplied from the hollow space of the pipe electrode.
(3) A flat electrolyte jet was translated over the workpiece surface to finish a large area efficiently. Using short pulse durations in the order of several tens of microseconds with alternating polarity, mirror-like surfaces were obtained successfully.
(4) The electrostatic induction feeding method was used to machine micro rods by ECM with ultra-short pulse duration of several nanoseconds order. Since a pulse voltage is coupled to the working gap by a capacitance, electrolytic current flows only at the moment of rise and fall of the pulse voltage. Straight stainless micro-rods 50 micrometers in diameter and 200 micrometers in length were machined with surface roughness smoother than that obtained by EDM using NaNO3 aqueous solution.
(5) An equipment for electrolyte treatment is being developed. To reduce hexavalent chromium to trivalent chromium, and to adsorb the chromium ions, activated carbon (AC) was utilized. By adjusting the pH of the electrolyte solution to make it acid, hexavalent Cr could be reduced to trivalent Cr. Cast iron chips produced in common machining processes could also remove chromium ions to a certain extent.
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