JPH04195923A - Surface smoothing device for magnetic disk substrate - Google Patents

Abstract

PURPOSE:To prevent a deterioration of smoothing operation for the surface of magnetic disk substrate by always supplying an abrassive liquid containing many minute abrassive grains to the space between the surface of magnetic disk substrate and spheroidal grinding tools during the machining operation. CONSTITUTION:The abrassive liquid 13 containing many minute abrassive grains is always supplied to the space between the machining surface of magnetic disk substrate 1 and the spheroidal grinding tools 12 by the surface tension of abrassive liquid 13, during the machining operation. So, the smoothing operation for the magnetic disk substrate 11 can be maintained for a long time. Also, the magnetic disk substrate 11 can be smoothed in a short time since many spheroidal grinding tools 12 which are held with an grinding plate 21 through an elastic body 14, exert on the magnetic disk substrate 11 in a single action. By this procedure, the surface smoothing of magnetic disk substrate and the improvement of productibity are attained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention can be used stably in a small gap between a magnetic head and a magnetic head. ,
The present invention relates to a surface smoothing device for a magnetic disk substrate for obtaining a high-precision magnetic disk '5:yJ that can be lifted.

[Conventional technology]

In general, magnetic disk substrates have an aluminum alloy surface, a non-magnetic nickel-phosphorus plated surface formed on an aluminum alloy surface, or an anodized surface formed on an aluminum alloy surface, corresponding to the seed head of a recording medium. A highly polished surface is used.

In a magnetic disk device, the smaller the flying height of the magnetic head above the surface of a magnetic disk rotating at high speed, the higher the recording density and the greater the output. For this reason, the flying height of the magnetic head in a typical coated magnetic disk is 0.3 to 0.4 μm, whereas in a high-density magnetic disk, such as a thin film media disk made by plating or sputtering, The levitation amount of the magnetic head is 0.1 μm, and the magnetic head is levitated through an extremely small gap.

However, in general, a large number of microprotrusions with a height of 0.1 μm or more remain on the surface of a magnetic disk, which collide with the magnetic head. For this reason, especially for thin-film media disks with a recording medium thickness of 0.1 μm or less, the micro protrusions that collide with the magnetic head are removed from the magnetic disk substrate surface at the stage of the magnetic disk substrate before the media processing, and the surface is smoothed. It is necessary to

Conventionally, as a method for smoothing the surface of a magnetic disk substrate, a method of smoothing the surface by bringing a burnishing head, which has an abrasive layer containing hard fine particles formed on the surface of a magnetic hent slider, into contact with the surface of the magnetic disk substrate (for example, Kosho 58-467
No. 67) has been proposed.

[Problem to be solved by the invention]

In the conventional method, as shown in FIG. 4, abrasive grains 20 formed in a portion with a small flying height relative to the magnetic disk substrate 11 at the rear of the burnishing head 19 are attached to minute protrusions 15 of the magnetic disk substrate 11. It contacts to smooth the surface of the magnetic disk substrate 11.

However, if the abrasive grains 20 are worn out or if machining debris from microprotrusions removed by the abrasive grains 20 adheres to the abrasive grains 20, the smoothing effect decreases rapidly, resulting in a problem of low productivity.

SUMMARY OF THE INVENTION An object of the present invention is to solve such conventional problems and provide a surface smoothing device that is highly productive in smoothing the surface of a magnetic disk substrate.

[Means to solve the problem]

In order to achieve the above object, a surface smoothing device for a magnetic disk substrate according to a first aspect of the invention includes a mechanism for rotating a magnetic disk substrate and an elastic body provided with a plurality of holes to adjust the protrusion amount of a spherical polishing tool. The present invention has a mechanism for holding the spherical polishing tool in a constant state facing the polishing plate, and a mechanism for moving the spherical polishing tool relative to the surface of the magnetic disk substrate while supplying polishing liquid.

In addition, the surface smoothing device for a magnetic disk substrate according to the second invention includes a polishing liquid container filled with a polishing liquid and a plurality of spherical polishing tools having a specific gravity smaller than the polishing liquid, and a polishing liquid container directly below the surface to be processed of the magnetic disk substrate. and a mechanism for immersing the magnetic disk substrate in the polishing liquid container and rotating the magnetic disk substrate.

[Effect]

The operation of the first invention will be explained using FIG. 1 and FIG. 2.

In the first invention, as shown in FIG. 1, a polishing liquid 13 containing a large number of fine abrasive particles is applied to the surface of the magnetic disk substrate 11 to be processed and the spherical polishing tool 12 due to the surface tension of the polishing liquid 13. is constantly supplied to the gap during machining. Therefore, the smoothing effect of the magnetic disk substrate 11 can be maintained for a long time.

Further, since a large number of spherical polishing tools 12 held on the polishing plate 21 via the elastic bodies 14 act on the magnetic disk substrate 11 at once, the magnetic disk substrate 11 can be smoothed in a short time.

Here, as shown in FIG. 2, the polishing liquid 13 forms a liquid film in the gap between the surface of the magnetic disk substrate 11 and the spherical polishing tool 12, so that only the minute protrusions 15 are selectively removed and the minute The surface of the magnetic disk substrate 11 other than the projections 15 will not be damaged.

The elastic body 14 has the effect of allowing a large number of spherical polishing tools 12 to act on the magnetic disk substrate 11 at once with uniform processing pressure. Furthermore, as shown in FIG.
This reduces the rigidity when the spherical polishing tool 12 is pressed against the magnetic disk substrate 11. By doing this, even if the magnetic disk substrate 11 has undulations, a large number of spherical polishing tools 12 can be applied with uniform processing pressure to follow the undulations of the magnetic disk substrate 11 at a -degree angle.

Next, the operation of the second invention will be explained using FIG. 3.

In the second invention, the spherical polishing tool is made hollow, etc.
The specific gravity of the polishing liquid 13 is lower than that of the polishing liquid 13, and the polishing liquid is suspended in the upper part of the polishing liquid container 16. As shown in FIG. 3, when the magnetic disk substrate 11 is immersed in the polishing liquid container 16 with the surface of the substrate to be processed directly below, the hollow spherical polishing tool 22 will be able to process the magnetic disk substrate with uniform processing pressure due to its buoyancy. In this way, in the same way as the effect of the first invention, only the minute protrusions existing on the surface of the magnetic disk substrate 11 are selectively removed, and the magnetic disk substrate 11 is smoothed in a short time. I can do it.

In addition, in the present invention, the hollow spherical polishing tool 22 is suspended in the polishing liquid 13, so that it undergoes a shifting movement during processing. Therefore, no local wear occurs on the spherical polishing tool 22. Further, even if the spherical polishing tool 22 wears out, it is easy to replace the spherical polishing tool 22 in the polishing liquid container 16, so that the smoothing process can be continued for a long period of time.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) FIG. 1 is a sectional view showing Example 1 of the present invention, and FIG. 2 is a sectional view showing Example 1 of the present invention.
FIG. 3 is an enlarged cross-sectional view showing a polished state.

In the figure, a nylon spherical polishing tool 12 is supported on a polishing plate 21 via an elastic body 14, and a magnetic disk substrate 11 is supported on a polishing plate 21 via an elastic body 14.
The polishing liquid 13 is supplied to the gap between the magnetic disk substrate 11 and the spherical polishing tool 12 to remove the minute protrusions 15 on the magnetic disk substrate 11. Further, the elastic body 14 forms a gap 23 and reduces the rigidity when the spherical polishing tool 12 is pressed against the magnetic disk plate 11.

In this embodiment, as an example, a nylon sphere with a radius of 3 cm was used as the spherical polishing tool 12, and abrasive W a 13 (alumina abrasive grain diameter 1 μm) was supplied from the center of the rotating shaft 17 of the polishing plate 21. The magnetic disk substrate 11, which is an aluminum disc plated and polished with N1-P, is rotated at 100 rpm, and the polishing plate 21 is rotated at 5 rpm, and the spherical polishing tool 12 is rotated by the pressurizing device 18. The micro protrusions 15 of the magnetic disk substrate 11 were removed by pressing it against the surface of the magnetic disk substrate 11 to be processed at a pressure of about 4 gf.

According to this embodiment, as a result of smoothing the magnetic disk substrate 11 using the above-mentioned processing conditions, the roughness was 0.12 μm due to the large number of micro protrusions 15 before processing, or the roughness was reduced after 15 seconds of processing. We were able to complete a high-precision magnetic disk with a significantly smaller size of 0.002 μm or less, and in which the magnetic head can stably float in a minute gap (0.05 μm).

(Example 2) Next, Example 2 of the present invention will be described with reference to FIG. 3.

In FIG. 3, a magnetic disk substrate 11 is supported on a rotating shaft 17 and rotated with the surface of the substrate to be processed directly below. Below the magnetic disk substrate 11 is a hollow spherical polishing tool 22.
A polishing liquid container 16 filled with a polishing liquid 13 in which . The micro protrusions 15 of the magnetic disk substrate 11 were removed by pressing the magnetic disk substrate 11 against the magnetic disk substrate 11 .

In this example, a nylon hollow sphere with a diameter of 3 mm and an inner diameter of 2.6 mm was used as the hollow spherical polishing tool 22, and alumina abrasive grains with an abrasive grain size of 1 μm were used as the polishing liquid. While stirring the polishing liquid 13 with a propeller 24, a magnetic disk substrate (an aluminum disk plated with N1-P and polished) was rotated at 100 rpm.

As a result of smoothing a magnetic disk substrate according to the present invention using the processing conditions described above, the result is that the state before processing is 0.
．． The roughness, which was 12 μm, was significantly reduced to 0.02 μm or less after processing time of about 20 seconds. As a result, we were able to complete a high-precision magnetic disk in which the magnetic head can stably float in a minute gap (O, OS μm).

〔Effect of the invention〕

As described above, in the present invention, polishing liquid containing a large number of fine abrasive grains is constantly supplied to the gap between the magnetic disk substrate surface and the spherical polishing tool during processing, so that it has a smoothing effect on the magnetic disk substrate surface. In addition, in the present invention, a large number of spherical tools are created at the same time with uniform processing pressure, so a large number of magnetic disk substrates can be smoothed in a short time, and productivity is high.

As a result of the above, the magnetic head can stably levitate in minute gaps.
There is an advantage that high-precision magnetic disks can be obtained efficiently.

In the embodiment, the magnetic disk substrate to be smoothed is a substrate before the magnetic medium is formed, but the present invention is not limited to this, and it is also possible to smooth the substrate after the magnetic medium is formed.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a surface smoothing device for a magnetic disk substrate according to Example 1 of the present invention, FIG. 2 is an enlarged sectional view showing the processing state of Example 1 @ Example 1, and FIG. Implementation of the invention g
FIG. 4 is a side view showing a surface smoothing device for a magnetic disk substrate according to AJ2. FIG. 4 is a partial side view showing a conventional method for smoothing the surface of a magnetic disk substrate. 11... Magnetic disk substrate 12... Spherical polishing tool 13... Polishing liquid 14... Elastic body 15.
...Minute protrusions 16...Polishing liquid container 17...
・Rotating shaft 18... Pressure device 19... Burnishing head 20... Abrasive grain 21... Polishing plate 22.
...Hollow spherical polishing tool 23...Groove 24...Propeller Patent Applicant: NEC Corporation - 1' Representative Patent Attorney: Naka Kanno PA) Tanney/One-Dove Tooth Figure 1 15, ゛Whoops! ri[・), J.

Claims (2)

[Claims] (1) A mechanism for rotating a magnetic disk substrate, a mechanism for holding a spherical polishing tool opposite a polishing plate with a constant protrusion amount through an elastic body provided with a plurality of grooves, and the spherical polishing tool An apparatus for smoothing the surface of a magnetic disk substrate, comprising a mechanism for causing relative movement while supplying a polishing liquid facing the surface of the magnetic disk substrate. (2) a polishing liquid container filled with a polishing liquid and a plurality of spherical polishing tools having a specific gravity lower than that of the polishing liquid, and immersing the magnetic disk substrate in the polishing liquid container with the surface to be processed directly below;
and a mechanism for rotating the magnetic disk substrate.