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Development of efficient and precious finishing method of ceramic balls with magnetic fluids

磁流体高效精密陶瓷球精加工方法的开发

基本信息

批准号：
11694116
负责人：
KATO Koji
金额：
$ 2.56万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11694116/
关键词：
Ceramics Ball Polishing Magnetic fluid Efficiency Precision

项目摘要

Advanced ceramic balls are expected as ball element for high speed bearing or ultra precision bearing used in jet turbine engine or ultra precision grinding machine. However, the applications of ceramic bearings are limited because of their high prices. One of main causes of high price is high manufacturing cost since ceramic balls take significant grinding and finishing time even by using expensive diamond abrasives in order to avoid introducing surface defects as cracks. In these ceramic balls, mirror-surface are required for low rolling friction and small noise in operating.To overcome these problems, new polishing method with magnetic fluids was proposed, and a special element named 'float' was introduced by investigators to increase the grinding force and improve the shape accuracy. As a result, the combination of magnetic fluid, a float, abrasive grains, and magnetic field showed to form a new practical grinding method named "Magnetic Fluid Grinding."In the present research project, more high efficient and precious finishing methods for ceramic balls with magnetic fluids were tried to proposed.For those purposes, investigator Umehara visited at the laboratory of Prof. Komanduri who is an expert in the field of manufacturing of brittle materials in US and discuss about how to improve this method with magnetic fluid in the first year. On the basis of the discussion, polishing test of Si3N4 balls were done and showed design concept for optimum abrasives for this method. In the second year, single crystal silicon balls were tried to polished with this method. As a result, it was shown that magnetic fluid polishing is adequate for the polishing of single crystal Silicon balls because of thin damage layer of Silicon balls during polishing.

高级陶瓷球可望作为高速轴承或喷气涡轮机发动机、超精密磨床等超精密轴承的球元件。然而，陶瓷轴承的应用受到限制，因为它们的高价格。高价格的主要原因之一是高制造成本，因为即使使用昂贵的金刚石磨料，陶瓷球也需要大量的研磨和精加工时间，以避免引入表面缺陷如裂纹。为了克服这些问题，提出了一种新的磁流体抛光方法，并引入了一种特殊的“浮子”元件，以提高磨削力和形状精度。结果表明，磁流体、浮子、磨粒和磁场的组合形成了一种新的实用磨削方法--“磁流体磨削”。“在本研究项目中，尝试提出更高效、更精密的磁性流体陶瓷球表面处理方法。为此，梅原研究员访问了美国脆性材料制造领域的专家Komanduri教授的实验室，并在第一年讨论了如何使用磁性流体改进该方法。在此基础上，对氮化硅球进行了抛光试验，给出了该方法最佳磨料的设计思路。第二年，用这种方法对单晶硅球进行了抛光试验。结果表明，由于硅球在抛光过程中损伤层较薄，磁流体抛光适用于单晶硅球的抛光。