1993 Fiscal Year Final Research Report Summary
Development of Quick-mirror Finishing Method for Ceramic Balls using Magnetic Fluid
| Project/Area Number |
04555031
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作
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| Research Institution | Tohoku University |
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Principal Investigator |
KATO Koji Tohoku University, Faculty of Engineering, Professor, 工学部, 教授 (50005443)
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| Co-Investigator(Kenkyū-buntansha) |
ADACHI Shigeru Japan Fine Ceramics Co.Ltd, researcher, 研究開発部, 研究員
HARADA Yoshitsugu Japan Fine Ceramics Co.Ltd, manager, 研究開発部, 部長
UMEHARA Noritsugu Tohoku University, Faculty of Engineering, research associate, 工学部, 講師 (70203586)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Magnetic Fluid / Polishing / Mirror sufrace / Ceramics / Ball |
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| Research Abstract |
In order to develop quick-mirror finishing method for ceramic balls using magnetic fluid, and construct the optimum design method for this new technique, many polishing characteristics have been investigated, Obtained results are shown as follows.
(1) Special permanent magnetic circuits were designed in order to get different supporting stiffness of a float under the same grinding load, It was found that larger stiffness provided higher removal rate and quick decreasing rate of sphericity, and the smaller stiffness provided smaller minimum sphericity. It was obvious from these results that larger stiffness of a float is better for initial polishing and smaller stiffness is better for final polishing.
(2) In order to design buoyant force Fb of a float and the supporting stiffness *F_b/*h of a float, simple calculation method was suggerstd and verified by comparing between calculated and measured values. Magnetic buoyantforce Fb and the supporting stiffness *F_b/*h of a float were given by the following equation :
where Ms is saturated magnetization of the magnetic fluid, 'A'area of a float, and 't'thickness of the float, Br residual flux density of the magnet, 'a'width of magnets and thickness of a float 't', It was found that calculated results almost consist with measured values.
(3) New type of magnetic fluid grinding for polishing ceramic balls, which consisted of tapered float, flat end driving shaff and guide ring was introduced. It was found that large eccentricity between driving shaft and guide ring provided smaller sphericity of ceramic balls.
(4) It was found that exact classification of the size of abrasive grains in their preparation could avoid the generation of scratch on polishing surface.
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