2006 Fiscal Year Final Research Report Summary
Improvement of wear resistance of natural mono-crystalline diamond tool by plasma irradiation
| Project/Area Number |
17560109
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Production engineering/Processing studies
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| Research Institution | Kansai University |
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Principal Investigator |
HIGUCHI Masahiro Kansai University, Faculty of Engineering, Professor, 工学部, 教授 (50067732)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Tomomi , 助教授 (10268310)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Accelerator / Ultra-precision machining / Single Point Diamond Tool / Tool Life / Plasma Etching |
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| Research Abstract |
In order to extend the tool life of natural mono-crystalline diamond tools, methods for screening raw diamonds and polishing them were investigated, and besides, the machining atmosphere to suppress the tool wear was explored. A summary of the results is shown below.
(1) The correlations between the defects due to nitrogen impurities in raw diamond and the resistances to crater wear and chipping were obtained as follows : The larger the amount of B2-center, the higher the chipping resistance. Thus the diamond tool including the larger amount of B2-center is more suitable for diamond tool with high durability. The results suggest that the inspection by IRA can be a useful method for screening of raw diamond for highly durable cutting tools.
(2) A new polishing method for diamond cutting tools was discussed using thermo-chemical reaction with copper. It is a very simple and practical way of bringing a diamond tool into contact with a copper plate heated in air. Hertzian fracture tests show
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ed that the microstrength of thermo-chemically polished diamond surface becomes higher because of the elimination of microcracks. In addition, the cutting experiments abundantly demonstrated that the thermo-chemically polished tool is superior in terms of the wear resistance and the tool life to the mechanically polished one. Accordingly, thermo-chemical polishing is recommended as a finishing technique for the diamond tool because of its efficiency.
(3) To understand the mechanism of cutting edge chipping in diamond turning of copper over an extended time, changes in Hertzian strength of diamonds subjected to high temperatures in air and in contact with copper powder were investigated. The results suggest that the strength of diamond in contact with copper at elevated temperatures decreases due to a thermo-chemical erosion at the atomic scale at the crack tip, together with a catalytic reaction of copper and ambient oxygen. Consequently, cutting under a reduced oxygen atmosphere, which suppresses the decrease in strength of the diamond, is proposed as a useful technique to suppress cutting edge chipping in diamond turning of copper. Less
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Research Products
(12 results)
