1999 Fiscal Year Final Research Report Summary
Functional evaluation of surface waviness of contact recording magnetic disk and analytical estimation of head flying locus
| Project/Area Number |
09650162
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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 |
設計工学・機械要素・トライボロジー
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| Research Institution | NAGAOKA UNIVERSITY OF TECHNOLOGY |
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Principal Investigator |
YANAGI Kazuhisa Nagaoka University of Technology, School of Mechanical Engineering, Professor, 工学部, 教授 (80108216)
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| Co-Investigator(Kenkyū-buntansha) |
HARA Seiichiro Nagaoka University of Technology, School of Mechanical Engineering, Assistant, 工学部, 助手 (40293253)
AKETAGAWA Masato Nagaoka University of Technology, School of Mechanical Engineering, Associate Professor, 工学部, 助教授 (10231854)
YANABE Shigeo Nagaoka University of Technology, School of Mechanical Engineering, Professor, 工学部, 教授 (30016662)
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| Project Period (FY) |
1997 – 1999
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| Keywords | surface waviness / magnetic disk / tribology / head disk interface / head separation / filtration |
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| Research Abstract |
First of all in this study, a distinguished stylus instrument with extremely light load was developed to measure envelope curves along the circumferential tracks of disk surface. Pointed out were the higher measurement accuracy (±1nm/15mm) and the wider surface wavelength band than conventional optical interferometers on the market. An elaborate geometrical regression technique was developed to obtain the proper amplitude data with high S/N ratio.
Considering the head slider size and its follow-up motion to disk surface, the measuring conditions (sampling interval, evaluation length) for assessing the micro-waviness of disk surface were established and a conventional filtering method was adopted to divide the original envelope curve into several wavelength bands. A fairy good agreement was obtained between the processed profiles with the developed instrument and the commercial optical interferometer, OptiFlat. In this stage, some geo-statistical parameters such as mean wavelength, arithmetic mean amplitude and Motif parameters were introduced to evaluate the micro-waviness of disk surfaces.
Additionally, the head readout signal was measured and analyzed to know the relationship between the disk surface profile and the head flying height in operation. The micro-waviness component was closely related to the electro-magnetic conversion characteristics at the head/disk interface. It can be concluded that the disk micro-waviness has a great influence on the physical head-disk separation or the information storage density of HDD.
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