Abrading – Abrading process
Reexamination Certificate
1999-11-12
2001-08-21
Banks, Derris H. (Department: 3723)
Abrading
Abrading process
C451S259000
Reexamination Certificate
active
06276991
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a crown forming method of forming a crown on the floating surface of a floating type magnetic head.
2. Description of the Related Art
Floating type magnetic heads record and reproduce information to and from magnetic recording mediums while floating therefrom.
The floating type magnetic head is operated by a so-called CSS system in such a manner that it is floated from the magnetic recording medium by the movement thereof and placed on the magnetic recording medium again when it stops.
Since the surfaces of the floating type magnetic head and the magnetic recording medium, which confront each other, have high flatness, they are liable to be adsorbed by each other. Thus, it is possible that a drawback is caused to the floating type magnetic head and the magnetic recording medium.
To cope with this problem, the absorption between the floating type magnetic head and the magnetic recording medium is prevented by forming the floating surface of the floating type magnetic head to a convex surface so as to reduce the area where the floating surface is in contact with the magnetic recording medium.
The convex surface formed on the floating surface is referred to as a crown. Various methods are conventionally employed to form the crown.
Conventional methods of forming a crown on a floating type magnetic head will be described with reference to drawings.
FIGS. 15A-15E
show a first example of the conventional methods of forming a crown on a floating type magnetic head.
In
FIGS. 15A-15E
, an approximately rectangular-prism-shaped bar
61
having floating type magnetic head elements disposed thereto in a row and a groove jig
62
are prepared.
The bar
61
has the plurality of magnetic head elements formed on a surface (left side surface)
61
a
thereof. The bar
61
is made in such a manner that a wafer having a multiplicity of magnetic head elements formed thereto is cut to have an approximately rectangular-prism-shape and other surface (bottom surface)
61
c
is polished and the gaps between the magnetic head elements and coils are adjusted. Further, the groove jig
62
has a groove
62
a
formed on a surface (upper surface) thereof.
Next, a melted wax
63
is coated to the groove
62
a
and the bar
61
is placed on the groove jig
62
with the other surface
61
c
facing downward so that the other surface
61
c
comes into contact with the wax
63
.
Then, the wax
63
is cooled and solidified so that it is contracted, whereby the bar
61
is deformed to an arc-shape. The bar
61
is fixed to the groove jig
62
by the wax
63
. At the time, the other surface
61
c
of the curved bar is made to a convex surface.
Subsequently, the surface
61
b
of the bar
61
, which is curved in confrontation with the other surface
61
c
is polished and flatly cut, thereby obtaining the floating type magnetic head.
A floating type magnetic head is obtained by removing the bar
61
from the groove jig
62
and cutting it in the longitudinal direction thereof at equal intervals.
The floating type magnetic head has a crown which is made to the convex surface by the deformation of the bar
61
.
FIGS. 16A-16C
show a second example of the conventional methods of forming a crown on a floating type magnetic head.
In
FIGS. 16A-16C
, first, an approximately rectangular-prism-shaped magnetic head slider
71
is prepared. The magnetic head slider
71
has magnetic head elements (not shown) previously disposed thereon. Further, the magnetic head slider
71
has a pair of rails
72
a
and
72
a
formed on the floating surface
72
thereof.
Next, a laser beam
74
is irradiated between the rails
72
a
and
72
a
of the magnetic head slider
71
so as to form a plurality of cracks
73
. . . along the short direction of the magnetic head slider
71
.
Subsequently, the magnetic head slider
71
is deformed to an arc shape along the longitudinal direction thereof, thereby making the floating surface
72
of the magnetic head slider
71
to a convex surface. Since the cracks
73
. . . are formed on the floating surface
72
, the magnetic head slider
71
can be easily deformed. With this process, a crown is formed on the floating surface
72
of the magnetic head slider
71
.
FIGS. 17A-17E
show a third example of the conventional methods of forming a crown on a floating type magnetic head.
In
FIGS. 17A-17E
, first, an approximately rectangular-prism-shaped magnetic head slider
81
is prepared. Further, a lapping surface plate
85
having a concave processing surface
85
a
is prepared.
Magnetic head elements (not shown) are previously formed on the magnetic head slider
81
. Further, a pair of rails
82
a
and
82
a
are formed on the floating surface
82
of the magnetic head slider
81
.
Next, the magnetic head slider
81
is fixed on the flat surface
84
a
of a jig
84
through an elastic sheet
83
with the floating surface
82
facing upward.
Then, the jig
84
, on which the magnetic head slider
81
is fixed, is placed on the fixing plate
85
in such a manner that the floating surface
82
of the magnetic head slider
81
is abutted against the processing surface
85
a
of the fixing plate
85
.
Subsequently, a polishing agent is sprayed on the processing surface
85
a
and the processing surface
85
a
is pressed against the floating surface
82
by imposing a load on the magnetic head slider
81
by the jig
84
. Further, the jig
84
is rotated while rotating the lap fixing plate
85
so that lapping is carried out by causing the floating surface
82
of the magnetic head slider
81
and the processing surface
85
a
to slide each other.
At the time, since the shape of the processing surface
85
a
is transferred onto the floating surface
82
, the floating surface
82
is formed to a convex surface having a radius of curvature similar to that of the processing surface
85
a.
The thus obtained magnetic head slider
81
has a crown
87
formed thereon which has a convex surface along the longitudinal direction and the short direction of the magnetic head slider
81
.
FIGS. 19A-19F
show a fourth example of the conventional methods of forming a crown on a floating type magnetic head.
In
FIGS. 19A-19F
, first, an approximately rectangular-prism-shaped bar
127
is prepared. The bar
127
is made in such a manner that after a multiplicity of head elements are formed on a surface of a wafer composed of a material of the slider of a floating type magnetic head using a thin film forming technology or the like, a portion of the wafer is cut to a rectangular-prism-shape. A plurality of magnetic head elements
128
. . . are disposed on a side wall of the bar
127
in a row.
Next, a spring type concave/convex jig
129
is mounted on the bar
127
.
The spring type concave/convex jig
129
is composed of a spring sheet
130
and a concave/convex sheet
131
jointed to both the ends of the spring sheet, and grooves
132
are formed to the concave/convex sheet
131
at predetermined intervals. The spring type concave/convex jig
129
can be elastically deformed along the longitudinal direction thereof.
The bar
127
is mounted on the spring type concave/convex jig
129
such that the grooves
132
of the spring type concave/convex jig
129
are located between the respective magnetic head elements
128
.
Next, the bar
127
is cut at equal intervals along the short direction thereof and made to chips
138
. . . The
127
is cut at the positions of the grooves
132
of the spring type concave/convex jig
129
.
Next, the spring type concave/convex jig
129
is mounted on a columnar jig
133
. An elastic member
134
is interposed between the spring type concave/convex jig
129
and the columnar jig
133
.
Further, one surfaces
136
. . . of the respective chips
138
. . . are pressed against a concave processing surface
135
and the one surfaces
136
. . . are subjected to lapping by moving the columnar jig
133
relative to the processing surface
135
.
Since the processing surface
135
is formed to the concave surface,
Kobayashi Hideaki
Nakabayashi Isao
Nakagawa Koichi
Sugai Katsuya
Alps Electric Co. ,Ltd.
Banks Derris H.
Brinks Hofer Gilson & Lione
Shakeri Hadi
LandOfFree
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