JPH0770186B2 - Method of polishing air bearing surface of slider of magnetic head - Google Patents

Description

The present invention relates to an air bearing surface polishing method suitable for processing the air bearing surface of a magnetic head used in a magnetic disk device into a highly accurate flat surface.

[Conventional technology]

In recent years, as the recording density of magnetic disk devices has increased, the flying height of the magnetic head with respect to the magnetic disk surface has tended to become narrower. In order to narrow the flying height of the magnetic head in this way, as shown in FIG. 9, the flatness of the floating surface of the magnetic head H, which floats above the surface of the magnetic disk with a minute gap, is processed with high precision. It is necessary.

Therefore, generally, as shown in FIG. 10, a disc-shaped lapping plate 1 having a polishing surface 1 ′ which is an upper surface formed flat is attached to a drive shaft 2, and the lapping plate 1 has a polishing surface. 1 '
, The slider 4 of the magnetic head and the correction wheel 5 attached to the work attaching jig 3 are placed, the lap surface plate 1 is rotated by the drive shaft 2, and the correction wheel 5 and the work attaching jig 3 are moved by the support shaft 6. The lap surface plate 1 processes the air bearing surface of the slider 4 into a highly precise flat surface by rotating the correction wheel 5, the slider 4 and the lap surface plate 1 to rub each other, and The flatness of the lap surface plate 1 worn by the processing of 1 is corrected. However, in such a polishing apparatus for a magnetic head, since the slider 4 and the correction wheel 5 are located at a fixed position on the lapping plate 1,
The use of the lap surface plate 1 causes wear and makes it difficult to maintain desired accuracy, and as a result, the accuracy of the air bearing surface of the slider 4 decreases.

There are a plurality of conventional techniques as measures against this. That is, in the first prior art, as shown in FIG. 11, the lapping surface 1'of the lapping plate 1 has a shape which linearly rises from the outer peripheral portion to the central portion, and the correction wheel 5 is moved to the center of gravity to polish the lapping surface. 1 ', or as shown in FIG. 12, the outer peripheral portion of the polishing surface 1'is linearly higher than the central portion, and the correction wheel 5 is similarly outer peripheral on the lapping plate 1. The lap surface plate 1 is thus worn out and corrected.

Further, in the second conventional technique, as shown in FIG. 13, a large correction wheel 5 extending over the central portion and the outer peripheral portion of the lap surface plate 1 is used, and the center portion of the lap surface plate 1 in the correction wheel 5 is used. And the weight 7 through the link mechanism 8 at a position corresponding to the outer peripheral portion,
The weights 7 and 7 are mounted on the lap surface 1 and the flatness of the lapping plate 1 is corrected by changing the center of gravity of the correction wheel 5. As a device related to this type, there is, for example, JP-A-59-81056.

[Problems to be solved by the invention]

By the way, when the flying height of the magnetic head is narrowed, for example, when a flying height of 0.2 to 0.3 μm is requested, in order to obtain the flying height, the flying height of the magnetic head shown in FIG. The flatness of the air bearing surface of the slider must be machined with an extremely high precision of 0.05 μm or less from the relationship with the degree.

However, the prior arts shown in FIGS. 11 and 12 and FIG. 13 are all for accurately correcting the flatness of the polishing surface 1 ′ of the lapping plate 1. No consideration is given to the relationship between the processing accuracy of the air bearing surface of the slider and the shape of the lapping plate 1.

Further, in any of the conventional techniques, the lap surface plate 1 has a substantially linear planar shape from the outer peripheral portion to the central portion. However, by using the lap surface plate 1 having such a shape, a slider of 0.05 μm or less can be formed. In order to obtain the flatness of the air bearing surface, it is necessary to repeat the mistake of trying to correct the polished surface of the lapping plate 1, which requires a very long correction time, which is impossible in some cases. Therefore, there is a problem that the operating rate of the polishing apparatus is significantly reduced, and even if the lapping platen 1 can be corrected to a linear plane, the machining accuracy of the air bearing surface of the magnetic head varies. However, there is a problem that the yield decreases.

In view of the above-mentioned problems of the prior art, an object of the present invention is to define the shape of the polished surface so that the required processing accuracy of the air bearing surface of the head slider can be easily obtained and the machine operating rate can be improved. Another object of the present invention is to provide a method of polishing an air bearing surface of a slider of a magnetic head.

[Means for solving problems]

In the present invention, the polishing surface of the lapping plate has an appropriate curvature based on the size of the lapping plate and the slider of the magnetic head and the plan view required for the air bearing surface of the slider, and the outer peripheral portion and the central portion of the polishing surface. The lap surface plate formed in an arc shape in which the wall thickness dimension of the effective polishing portion, which is the highest portion that can contact the slider with respect to the straight line connecting the With respect to the polishing surface of the lapping plate, while pressing the bottom surface of the slider and the correction wheel while locating the center of the air bearing surface of the slider at the effective polishing portion of the polishing surface, both the slider and the correction wheel are pressed. By rotating around the center of the slider air bearing surface, the air bearing surface of the slider is polished to a flat surface, while the polishing surface of the lapping plate is corrected by a correction wheel.

[Work]

In polishing a slider of a magnetic head, the slider rotates at a fixed position on the polishing surface of the lapping plate, so that the slider and the lapping plate must be in constant contact with each other. As shown in FIG. 8, various surfaces such as arcuate ones such as IX, true flat ones such as II-Y, and depressed arcuate ones such as III-Z can be considered. However, it is practically impossible to keep the shape of a flat surface such as II-Y, and a concave arc shape such as III-Z is worn from the outer peripheral portion of the polishing surface during polishing. , It is difficult to keep its shape.

In the present invention, as described above, the polishing surface of the lapping plate has an appropriate curvature based on the size of the lapping plate and the slider of the magnetic head and the flatness required for the air bearing surface of the slider, and the outer peripheral portion It is formed in an arc shape having the height of the highest portion (effective polishing portion r) at a midpoint on a straight line connecting to the central portion, and this lap surface plate is rotated around an axis to polish the rotating lap surface plate. With respect to the surface, the slider and the correction wheel are pressed while the center of the air bearing surface of the slider is positioned at the highest point of the polished surface, and the slider is rotated around the center of the air bearing surface of the slider. So when polishing,
The lapping platen and the slider are in constant contact, and the lapping platen can polish the slider's air bearing surface so that the lapping surface is transferred to the slider's air bearing surface. As a result, the slider's air bearing surface can be machined to the required accuracy. And stable processing accuracy can be obtained. Further, since the polishing surface is formed in an arc shape, it is possible to easily perform the work of correcting the polishing surface, and it is possible to prevent a decrease in the operating rate of the polishing device.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. 1 is a perspective view of a partial cross section showing an embodiment of the polishing method of the present invention, FIG. 2 is a perspective view of a partial cross section of a lapping plate used in the polishing method of the present invention, and FIG. 13 is a lap. FIG. 4 is an explanatory view showing the shape of the surface plate, and FIG. 4 is an explanatory view showing the relationship between the lap surface plate and the head slider in FIG.

In this embodiment of the polishing method, as shown in FIG. 1, the slider 14 of the magnetic head is pressed against the polishing surface 11 'of the rotated lapping plate 11 and rotated at a fixed position of the polishing surface 11'. Then, the air bearing surface of the slider 14 is polished by the polishing surface 11 '.

The central portion of the lap surface plate 11 is attached to the drive shaft 12 by a mounting bolt or the like, and the drive shaft 12 is driven to rotate about the axis. The slider 14 of the magnetic head is attached to the work attaching jig 13 arranged at the inner position of the correction wheel 15, and the air bearing surface of the slider 14 is attached to the lapping plate 11.
Is placed at a fixed position on the polishing surface 11 'of the lapping plate, and when the lapping plate 11 rotates, the air bearing surface is pressed against the polishing surface 11' of the lapping plate 11 and the lapping plate 11 'rotates at the fixed position. The air bearing surface is rubbed against the polishing surface 11 'for polishing. When the slider 14 is polished, a plurality of sliders are integrally polished into a block, and the slider 14 is simultaneously polished, and after the polishing, each slider is cut into a desired shape and assembled and wired. By doing so, a magnetic head is constructed.

The correction wheel 15 has an upper portion attached to the support shaft 16, and a work attaching jig having a slider 14 attached to a block is placed in a recess formed in the lower portion thereof. The slider 14 which is made into a block is rotated via the attachment jig 13. Further, at this time, the lower end surface of the correction wheel 15 rubs against the polishing surface 11 'of the lapping plate 11 so that the polishing surface 11'
To be modified into a desired shape.

Thus, in the embodiment, the polishing surface 11 'is formed in an arc shape having an appropriate curvature as shown in FIGS. That is, the polishing surface 11 'of the lapping plate 11
Has a desired curvature R based on the size of the lapping plate 11 and the size of the slider 14, and the flatness required for the air bearing surface of the slider 14, and is appropriately between the outer peripheral portion and the central portion. Of the effective polishing portion r which is formed in an arc shape having a height y of 1 and has the highest contact area with the slider 14 with respect to a straight line connecting the outer peripheral portion and the central portion of the arc surface.
The wall thickness dimension Δr up to is set appropriately. It is desirable that the central portion of the air bearing surface of the slider 14 which is a block is located in the effective polishing portion r.

Next, the size of the lap platen 11 and the slider 14,
The relationship of flatness required for the air bearing surface of the slider 14 will be described.

First, the radius inside the lapping plate 11 is l ₁ , the width of the polishing surface 11 ′ of the lapping plate 11 is l ₂ , the radius of the sphere is R, and the line connecting the center of the sphere and the outermost periphery of the lapping plate Let θ be the angle of, then the following equation holds.

(L ₁ + l ₂ ) ² + (Rsinθ) ² = R ² (1) l ₁ ² + (Rsin θ + y) ² = R ² (3) From the above formulas (1), (2) and (3), the wall thickness dimension Δr is as follows.

Further, the wall thickness dimension Δr of the lapping plate 11 and the flatness a of the length D of the slider 14 in the longitudinal direction and the flatness b of the length C of the lateral direction have the following relationship.

From the above formulas (4), (5), (6) and (7), according to the dimensions of the flatness a and b required for the air bearing surface of the slider 14,
The curvature R, the height y, and the wall thickness dimension Δr of the lapping plate 11 are obtained.

When the slider 14 is polished using the lapping plate 11 formed as described above, the polishing surface 11 'of the rotating lapping plate 11'
Is formed in an arc shape, and the center of the air bearing surface of the slider 14 is located at the highest portion of the polishing surface 11 '(effective polishing portion r) with respect to the polishing surface 11'.
Since 14 and the correction wheel 15 are pressed and rotated around the center of the slider air bearing surface, the air bearing surface of the slider 14 is always in contact with the polishing surface 11 'by forming a circular arc shape. Since the slider 14 can be processed so that the polishing surface 11 'is transferred to the air bearing surface, the air bearing surface of the slider 14 can be surely ground to the required accuracy, and stable processing accuracy can be obtained. Further, the lapping plate 11 is formed in an arc shape as described above, and the correction wheel 15 is provided so that the center of the air bearing surface of the slider 14 is located at the highest portion (effective polishing portion r) of the polishing surface 11 '. Since the lapping plate 11 is pressed and rotated, the correction surface 15 is used to correct the polishing surface 11 ', as compared with a flat plate such as II-Y and III-Z shown in FIG. Since it is simple and the correction work can be easily performed, it is possible to prevent the operating rate of the polishing apparatus from decreasing.

Incidentally, FIG. 5 shows the relationship between the wall thickness dimension Δr and the flatness in the longitudinal direction of the air bearing surface of the slider 14 when the height y of the lapping plate 11 is 10 μm. From the figure, it can be seen that the flatness of the slider 14 has the minimum value when the wall thickness dimension Δr is about −2 μm to 2 μm.

Further, FIG. 6 shows the relationship between the height y and the flatness in the longitudinal direction of the single slider 14 when the wall thickness dimension Δr of the lapping plate 11 is 1.5 μm. From the figure, the wall thickness dimension Δr is 1.
In the case of 5 μm, if the height y is set to about 10 μm, the slider 1
Since the flatness of the air bearing surface of 4 becomes the minimum and the flatness becomes large even if the height y is larger or smaller than that, the height y
Can be processed with extremely high precision by keeping the dimension of about 10 μm. The longitudinal direction of the slider 14 shown in FIG. 6 refers to a single slider 14, and corresponds to the lateral direction of the slider 14 which is blocked as shown in FIG.

Furthermore, the height y when the wall thickness dimension Δr is 1.5 μm
The relationship between the machining efficiency of the slider 14 and the machining efficiency of the slider 14 is shown in FIG. From the figure, it is understood that when the height y is approximately 10 μm, the machining efficiency with respect to the slider 14 is high, and if the height y is managed, the efficiency of the polishing work can be improved.

In the illustrated embodiment, when the diameter of the lapping plate 11 is a general 12 inches (about 305 mm), the height y is set to 15 μm and the wall thickness dimension Δr is set to 2 μm, whereby the flatness of the air bearing surface of the slider 14 is set. It was confirmed that it can be achieved below 0.05gμm,
It goes without saying that they are appropriately selected according to the sizes of the lapping plate 11 and the slider 14 and the flatness required for the air bearing surface of the slider 14.

〔The invention's effect〕

As described above, according to the present invention, the polishing surface has a desired curvature based on the size of the lapping plate and the slider and the flatness required for the air bearing surface of the slider, and is the outer peripheral portion of the polishing surface. The lap surface plate formed in an arc shape in which the wall thickness dimension of the effective polishing portion, which is the highest portion that can contact the slider with respect to the straight line connecting the central portion, is appropriately set is rotated around the axis, and the rotation is performed. For the polished surface of the lapping plate
The bottom of the slider and the correction wheel is pressed while the center of the air bearing surface of the slider is positioned on the effective polishing portion of the polishing surface, and both the slider and the correction wheel are rotated around the center of the slider air bearing surface. By doing so, the air bearing surface of the slider is polished to a flat surface, and the polishing surface of the lap surface plate is corrected by the correction wheel, so the air bearing surface of the slider always contacts the polishing surface of the lap surface plate during polishing. As a result, the slider can be machined so that the polished surface is transferred to the air bearing surface, so that the air bearing surface of the slider can be surely ground to the required accuracy, and stable processing accuracy can be obtained. The polishing surface can be easily and surely corrected, and the correction work can be easily performed. As a result, the operating rate of the polishing apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the polishing method of the present invention, FIG. 2 is a perspective view showing a lapping plate used in the polishing method of the present invention, and FIG. 3 is an explanatory view showing the shape of the lapping plate. FIG. 4 is an explanatory diagram showing the relationship between the lapping plate and the slider in FIG. 3, and FIG. 5 is an explanatory diagram showing the relationship between the wall thickness of the lapping plate and the flatness of the air bearing surface of the slider. 6 is an explanatory diagram showing the relationship between the height of the lapping plate and the flatness of the air bearing surface of the slider, FIG. 7 is an explanatory diagram showing the relationship between the height of the lapping plate and the machining efficiency of the slider, and FIG. Explanatory views showing various shapes of the lapping plate, FIGS. 9 (a) and 9 (b) are perspective views showing various magnetic heads, FIG. 10 is an explanatory perspective view showing a general polishing apparatus, and FIG. 13 to 13 are explanatory views showing various examples of the conventional polishing apparatus, and FIG. 14 shows the flying height of the magnetic head and the flying surface of the slider. Is an explanatory view showing the relationship between Mending. 1,11 …… lap surface plate, 1 ′, 11 ′ …… lap surface polishing surface, 4,14 …… magnetic head slider, R …… lap surface radius of curvature, y …… lap surface plate The height of the polished surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Takeshita 2880, Kozu, Odawara-shi, Kanagawa Inside the Odawara Plant, Hitachi Ltd. (56) References JP 62-166958 (JP, A) 61019 (JP, U)

Claims (1)

[Claims] 1. A lap surface of a rotating lapping plate is pressed against a polishing wheel and an air bearing surface of a slider of a magnetic head disposed inside the correction wheel to rotate the lap surface, and the air bearing surface of the slider is rotated by the polishing surface. In the polishing method for polishing a
It has the desired curvature based on the size of the lapping plate and slider and the flatness required for the air bearing surface of the slider, and is the most of the range that can contact the slider with respect to the straight line connecting the outer peripheral part and the central part of the polishing surface. The lap surface plate formed in an arc shape in which the wall thickness dimension of the effective polishing portion which is a high portion is appropriately set is rotated about an axis, and the effective surface of the polishing surface of the rotating lap surface plate is the effective surface of the polishing surface of the rotating lap surface plate. While arranging the center of the air bearing surface of the slider on the polishing portion, the bottom surface of the slider and the correction wheel is pressed, and both the slider and the correction wheel are rotated around the center of the slider air bearing surface, A method of polishing an air bearing surface of a slider of a magnetic head, characterized in that the air bearing surface is polished to a flat surface while a polishing wheel is used to correct the polishing surface of a lapping plate.