JPS58160053A - Polishing device - Google Patents

Abstract

PURPOSE:To enable to obtain an excellent finished surface with fine surface roughness and scarce directional property for grinding by a method wherein the contact pressure of an abrasive tape applied to a magnetic disc is supported by an air bearing in the magnetic disc surface polishing device. CONSTITUTION:A magnetic disc 1 to be polished is fixed on the upper surface of a rotary shaft part 2 by means of a fixing jig 3 and shifted between a feed and a take-up reels 5 and 6 and polished its surface in such a way that the abrasive tape 4 running along a pad roller 8 covered by an elastic body such as felt or the like is brought into lightly contact with the surface of the rotating magnetic disc 1. The air bearing compressing a moving part 9 and a fixed part 10 with a large number of small hole groups 11 is arranged just beneath said contact part in order to support the magnetic disc 1 by the moving part 9, which is kept under favorably lubricated state due to the air jetted out of the small hole groups 11. In such a manner as mentioned above, the surface to be polished is prevented from being applied by excess force, resulting in enabling to obtain the excellent finished surface with fine surface roughness and scarce directional property due to grinding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polishing device for polishing the surface of a magnetic disk.

As a magnetic disk, for example, a polyester film with a thickness of about 75 μm is coated with magnetic paint on the front and back sides, and a thickness of 1~
There is one in which a magnetic layer of about 3 μm is formed. In order to stabilize the electromagnetic characteristics of such flexible magnetic disks, it is necessary to remove minute protrusions from the surface of the disk to make it smooth.This is done by pressing an abrasive tape against the surface of the disk while it is rotating. The method was common.

One method is to fix the magnetic disk to a disk-shaped turntable and polish it, and another method is to sandwich the rotating magnetic disk from the front and back between abrasive tape, felt, or other suitable sliding contact materials. There are methods of polishing.

However, with these methods, it is very difficult to adjust the pressure with which the polishing tape is pressed against the magnetic disk surface, and if the pressure is insufficient, the polishing will be insufficient, and if the pressure is too high, deep polishing scratches will occur. there were. In addition, the finish of surface polishing is not only affected by the material and condition of the turntable and sliding contact, but also if the selection is inappropriate, there is the problem of damaging the magnetic layer formed on the back surface. In addition, the present invention provides a magnetic disk polishing device that solves these problems, and uses an air bearing to support the pressure of the polishing tape applied to the rotating magnetic disk by its cylindrical movable part. It is characterized by the fact that

Since the friction between the movable part and the fixed part is extremely small, air bearings rotate with a minute force, can follow high-speed rotation, and are free from seizure. In addition, since there is room for slight deviation depending on the applied pressure, it has the feature of absorbing excessive pressure. Flexible magnetic disks are easily deformed by external forces even when rotating, but when the cylindrical movable part of the air bearing comes into contact with the magnetic disk, it follows the rotation well due to the slight frictional force, so it is necessary to install it on the surface of the magnetic disk. It can support the pressure of the polishing tape without damaging the thin magnetic film. Furthermore, in the case of flexible magnetic disks, it is difficult to maintain a completely flat state during rotation, and for this reason, if the object supporting the magnetic disk cannot follow the fluctuations of the magnetic disk surface, the contact pressure of the abrasive tape will temporarily decrease. This caused the polishing to become excessively large, causing deep polishing scratches.

In this case, if an air bearing is used, there is room for the movable part to follow pressure fluctuations and deviate, so there is no such problem and a good polishing state can be maintained. Note that the characteristics of air bearings can be changed significantly depending on the gap length between the fixed part and the movable part, the position and number of air jet holes, the air pressure, etc.

It is possible to select optimal conditions depending on the case.

Next, one embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 1(a) and 1(b) are a front view and a side view showing a schematic configuration of a polishing apparatus of the present invention. In the figures, 1 is a magnetic disk to be polished, and a rotatable shaft portion 2 is It is fixed to the upper surface by a fixing jig 3 and is configured to rotate. 4 is a polishing tape, unwinding 9 winding reel 6
, 6 gradually moves, and Ryo is a guide roll. 8 is a pad roller whose surface is covered with an elastic material such as felt, and can be moved in the vertical direction.
The surface of the magnetic disk 1 is polished by bringing the polishing tape 4 along the surface of the rad roller into light contact with the surface of the magnetic disk 1. Reference numeral 9 denotes a cylindrical movable part of an air bearing provided in a receptacle that supports this contact part from the back side of the magnetic disk 1, and can rotate around the fixed part 10. The air bearing is located directly below the contact area between the magnetic disk 1 and the polishing tape 4, with its axial direction parallel to the diameter direction of the magnetic disk, and the cylindrical movable portion is placed in contact with the back surface of the magnetic disk 1. It is located in

FIG. 2 is a cross-sectional view showing the structure of the movable part 9 and the fixed part 10 of the air bearing. Extremely good lubrication is maintained.

The movable parts of air bearings are suitably made of a light material such as plastic, but if charging due to frictional electricity is insufficient or if fine powder generated by polishing adheres to the surface, conductive carbon black may be added to prevent charging. It is recommended to use plastics that have been removed.

Next, the effects obtained by the polishing apparatus of the present invention having such a configuration are shown in the following table in comparison with a conventional method of polishing a magnetic disk by fixing it to a turntable.

In both cases, a 3-inch floppy disk was polished at 1o while feeding a -11:4ooo abrasive tape made of white alundum abrasive grains with an average particle size of 3μ at a speed of 1 mm and 7 seconds.
The surface was polished while rotating at oo rotations/second, and the surface roughness was calculated by the centerline average roughness.

(J-1, Lower 9) As is clear from the table above, in the present invention, good polishing conditions were obtained in both the circumferential and diametrical directions, but in the conventional example, there were obvious polishing scratches along the polishing direction. It can be seen that the surface roughness is particularly large in the diametrical direction.

The present invention can also be applied to polishing both the front and back sides of a magnetic disk at the same time, by using two sets of polishing mechanisms shown in FIG. 1 and operating them simultaneously at different positions on the front and back sides.

Note that if the radius of the magnetic disk to be polished is larger than the width of the polishing tape, a mechanism for moving the polishing tape and pad roll in the radial direction of the magnetic disk may be provided. Furthermore, in the present invention, the polishing tape is moved gradually in order to avoid the adverse effects of tape clogging, but if polishing is to be completed in a short period of time without clogging, intermittent tape feeding may be used. There is no problem even if there is. Further, the method of pressing the abrasive tape against the magnetic disk is not limited to the method using a pad roller as shown in FIG. 1, and the present invention can be similarly applied to other methods.

As is clear from the above description, the polishing device according to the present invention uses an air bearing to support the contact pressure of the polishing tape applied to the magnetic disk, and prevents excessive force from being applied to the surface to be polished. It is of great industrial value because it makes it possible to manufacture magnetic disks with a good finish, with less surface roughness, and less directional polishing.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a front view and a side view showing a schematic configuration of a polishing apparatus according to the present invention, and FIG. 2 is a sectional view of an example of an air bearing part used in the present invention. 1...Magnetic disk, 2...Shaft part, 3
・River: Fixing jig, 4: Polishing tape, 6:
... Unwinding reel, 6... Winding reel,
7...Guide roll, 8...Pad roller, 9...Cylindrical movable part, 10...
·Fixed part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (2)

[Claims] (1) A rotatable shaft portion capable of holding a magnetic disk, and a nokurado roller whose surface is coated with an elastic material, which is disposed on one main surface side of the magnetic disk held on the shaft portion;
An air bearing having an abrasive tape movably disposed in contact with the pad roller, and a cylindrical movable portion disposed on the other main surface side of the magnetic disk at a position facing the pad roller. , the cylindrical movable part of the air bearing is arranged so that its rotation axis is parallel to the diametrical direction of the magnetic disk, and the magnetic disk is sandwiched between the pad roller and the air bearing, so that the abrasive tape is removed. A polishing device characterized in that the polishing device is configured to polish the surface of the magnetic disk by bringing it into contact with the magnetic disk rotated by the shaft portion. (2) The polishing device according to claim (1), wherein the cylindrical movable part of the air bearing is made of antistatic plastic.