Browse Prior Art Database

Not-Quite-Flat Disk for Durability and Stiction

IP.com Disclosure Number: IPCOM000122272D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 94K

Publishing Venue

IBM

Related People

Buettner, DC: AUTHOR [+2]

Abstract

Experiments have shown that positive (convex) head crown has better durability and stiction performance on a head/disk interface than negative (concave) head crown. However, head manufacturers have had difficulty in controlling the head crown parameter in manufacturing. For a head/disk interface, curvature on a head is equivalent to curvature on a disk. Therefore, instead of using a head with positive crown on a flat disk, it is possible to achieve the same performance by using a curved disk. A number of different shapes are possible for the disk surface all of which would enhance the durability and stiction performance of the interface.

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Not-Quite-Flat Disk for Durability and Stiction

      Experiments have shown that positive (convex) head crown
has better durability and stiction performance on a head/disk
interface than negative (concave) head crown.  However, head
manufacturers have had difficulty in controlling the head crown
parameter in manufacturing.  For a head/disk interface, curvature on
a head is equivalent to curvature on a disk.  Therefore, instead of
using a head with positive crown on a flat disk, it is possible to
achieve the same performance by using a curved disk.  A number of
different shapes are possible for the disk surface all of which would
enhance the durability and stiction performance of the interface.

      Experiments have shown that an increase in head crown has a
beneficial effect on durability and stiction.  An increase of head
crown in the positive (convex) direction of as small as 20 nanometers
can cause the durability of the disk to change from being
unacceptable to being perfectly acceptable.  In addition, positive
crown appears to reduce stiction.  The camber of the head appears to
be a secondary effect.

      Although controlling the head crown would appear to be a
solution to durability and stiction problems, in general, the crown
and camber of the head have been difficult parameters for head
manufacturers to control.  Furthermore, head manufacturers have tried
to make heads with positive crown to tight tolerances, but have had
more problems controlling the process for larger values of crown.

      By manufacturing a disk with surfaces that are not perfectly
flat, it is possible to have an interface that has...