Browse Prior Art Database

Texturing of Surfaces, Especially Magnetic Disk Substrates

IP.com Disclosure Number: IPCOM000110988D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 4 page(s) / 124K

Publishing Venue

IBM

Related People

Hofmann, U: AUTHOR

Abstract

The surface of the substrate of a thin film magnetic disk is prepared by providing a texture prior to the sputtering process such that later-on no stiction occurs in the start/stop operation of the disk. By special configuration of a conically shaped grinding pad and control of the surface grinding velocity or the circumferential velocity, respectively, an optimal homogenous texture is provided over the entire radii. The texture image can be changed by oscillating the grinding pad and by changing the velocity. The special construction of the grinding pad allows an easy removal of the abrasion. Also, cleaning of the surface is considerably enhanced and improved.

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Texturing of Surfaces, Especially Magnetic Disk Substrates

      The surface of the substrate of a thin film magnetic disk is
prepared by providing a texture prior to the sputtering process such
that later-on no stiction occurs in the start/stop operation of the
disk.  By special configuration of a conically shaped grinding pad
and control of the surface grinding velocity or the circumferential
velocity, respectively, an optimal homogenous texture is provided
over the entire radii.  The texture image can be changed by
oscillating the grinding pad and by changing the velocity.  The
special construction of the grinding pad allows an easy removal of
the abrasion.  Also, cleaning of the surface is considerably enhanced
and improved.

      Fig. 1 shows schematically the grinding arrangement.  Disk 1
with its surfaces 2 and 3 is clamped and turned around an axis 4 in
the direction of arrow 5.  The clamping device is not shown.  Disk 1
has an inner diameter d[1]  with an associated angle velocity
&omega.[1], and it has an outer diameter d[2]  with an associated
angle velocity &omega.[2].  The grinding pad is realized by
cone-shaped wheels 6 and 7.  Grinding wheel 6 turns around axis 8 in
the direction of arrow 9.  Through spindle 10 and pipe 11 water can
be applied to the inside of wheel 6.  The same is true concerning
grinding wheel 7 which turns around axis 12 in the direction of arrow
13.  Also, here through spindle 14 a pipe 15 guides water into the
interior of grinding wheel 7.  Both grinding wheels 6 and 7 can
oscillate in the direction indicated by double arrow 16 and can be
moved onto and away from the surfaces 2 and 3 of disk 1 in the
direction of double arrow 17.  Through pipes 18 and 19 water is
applied to the two surfaces 2 and 3.  This can be done for wetting
purposes and for cleaning purposes with higher pressure.
Furthermore, pipes 20 and 21 are provided in the vicinity of the
grinding wheels 6 and 7 to supply abrasive compound in a liquid
fluid.  By the relative movement between disk 1 with its surfaces 2
and 3 and grinding wheels 6 and 7 with their conical outer surfaces
and the free abrasive inbetween, the grinding action on the surfaces
2 and 3 is performed.

      In operation, disk 1 is clamped and brought up to operational
speed.  Then, the disk surfaces are wetted with distilled water by
applying water through the pipes 18 and 19.  Also, the rotating
grinding wheels 6 and 7 are now moved toward the surfaces 2 and 3 of
disk 1.  The slurry supply adds free abrasive in a fluid to the
grinding surfaces through pipes 20 and 21.

      After enough grinding time, the grinding wheels 6 and 7 are
moved away from disk 1, for example, about 1 to 2 mm.  Then, grinding
wheels 6 and 7 are accelerated onto high velocity of about 6000 RPM.

At the same time distilled water is supplied with high pressure
through pipes 11 and 15 for cleaning the brush.  Fi...