Metal working – Burnishing
Reexamination Certificate
1999-07-23
2002-03-19
Hughes, S. Thomas (Department: 3726)
Metal working
Burnishing
C451S290000, C451S317000
Reexamination Certificate
active
06357095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to burnishing devices for hard disks, and more particularly to a burnish head having a plurality of burnishing pads.
2. Description of the Prior Art
A hard disk is cleaned and burnished following the deposition of thin film layers to remove debris and asperities from the surface. Such debris and asperities must be removed, or at least reduced in height, to enable a slider to fly smoothly over the disk surface. As slider flying heights become lower for improved higher density disks, the disks must be burnished to a greater extent than was heretofore necessary to lower the projection height of such asperities and to more efficiently remove disk surface debris.
Several different burnishing pad designs are currently utilized. Some heads have a burnishing ridge providing a burnishing edge that extends across the entire front surface of the head. Other current head designs have burnishing members on the left side and right side of the burnishing head, but have a lengthwise channel between the left and right burnishing members. In such heads, a significant portion of the burnishing head does not burnish the disk, resulting in significant inefficiency in the burnishing process.
A further prior art burnishing head is described in U.S. Pat. No. 4,845,816. It has a waffle type pattern of burnishing pads; that is, a plurality of diamond shaped burnishing pads that are disposed on the burnishing head surface. The diamond shaped pads are oriented such that the point of each diamond shaped pad is directed towards the media to be burnished. In distinction to this pad configuration, burnishing pads of the present invention each have a straight burnishing edge that is directed towards the media to be burnished. In a prior art variation of this waffle patterned head the leading burnishing pads may be triangularly shaped, as are the leading pads of the present invention.
The present invention includes a different burnishing pad configuration from that described in copending U.S. patent application Ser. No. 09/190,946, to which cross-reference has been made above. Specifically, the present invention includes two burnishing pads at the rearward surface and one at the leading surface, whereas the invention described in the cross-referenced application has two leading surface burnishing pads and one rearward surface burnishing pad.
A need therefore exists for improvements in burnishing heads that remove debris and asperities to a greater degree than has been previously necessary. The present invention provides a burnishing head with a plurality of burnishing pads in a unique configuration that accomplishes these results.
SUMMARY OF THE INVENTION
The burnishing head for hard disk processing includes a solid body having generally rectangular surfaces, including an upper surface, a burnishing pad surface, a front surface, a rear surface and two side surfaces. A plurality of burnishing pads are disposed upon the burnishing pad surface. The pads are shaped such that each pad has a burnishing edge that is generally parallel to said front surface and therefore orthogonal to the direction of media travel. The burnishing pads are preferably configured such that one frontward leading pad is centrally disposed proximate the front surface of the head, followed by two middle pads that are disposed in a spaced apart relationship. A single centrally disposed rear middle pad is formed behind the two middle pads, and two rear pads are disposed in a spaced apart relationship at the rear surface of the head. In the preferred embodiment the pads are generally triangular in shape and the outer surface of the leading and rearward pads is tapered. The method for manufacturing the burnishing head, includes the steps of making a series of parallel cuts in a surface of a solid body of material. The burnishing pads result from material that remains following the cuts.
It is an advantage of the present invention that a more efficient burnishing head is provided.
It is another advantage of the present invention that a burnishing head is provided having a plurality of burnishing pads, each of which includes a straight burnishing edge that is generally orthogonal to the direction of hard disk media travel.
It is a further advantage of the present invention that a burnishing head is provided that is easy to manufacture in quantity and maintain high accuracy.
It is yet another advantage of the present invention that a burnishing head is provided which includes two effective burnishing edges which extend across the width of the burnishing head.
It is yet a further advantage of the present invention that a burnishing head is provided which includes two burnishing pads formed proximate the rear surface, such that they are in close proximity to the surface being burnished, whereby efficient, effective burnishing is achieved.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description which makes reference to the several figures of the drawings.
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Duan Shanlin
Lee Wei-Ming
Leung Wai C.
Guillot Robert O.
Hughes S. Thomas
Omgba Essama
Oppenheimer Wolff & Donnelly LLP
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