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Durability Test Method by Decreasing Air Pressure

IP.com Disclosure Number: IPCOM000109759D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Katsura, Y: AUTHOR [+4]

Abstract

Disclosed is an efficient test method to study durability performance of a rigid magnetic disk quickly. Disk wear test is conducted under reduced air pressure so that a head can contact the disk surface constantly at higher motor speed.

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Durability Test Method by Decreasing Air Pressure

       Disclosed is an efficient test method to study durability
performance of a rigid magnetic disk quickly.  Disk wear test is
conducted under reduced air pressure so that a head can contact the
disk surface constantly at higher motor speed.

      This tester is schematically shown in Fig. 1.  To attain lower
pressure, a vacuum pump is connected to a disk wear apparatus system.
When the spindle motor is driven at lower speed, a head contacts the
disk surface due to insufficient hydrodynamic buoyancy.  A strain
gauge or acoustic emission sensor is mounted on an actuator arm to
detect the failure of disk wear.  This test method had the
disadvantage that it took a long period to get disk failure, since
the motor cannot be driven at high speed.

      The disclosed test method reduces air pressure and assumes the
environmental condition in which the head cannot fly at higher disk
speed.  The merit of this test is to take the disk failure quickly
for high relative speed between a head and a disk.

      The relationship between head flying height and air pressure is
shown in Fig. 2 due to air bearing simulation for some designed
heads.  Head flying height is decreased as air pressure is lower.
Higher disk speed is selected from this relationship.