JP2001269850A - Surface polishing method and device for magnetic disk medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved surface polishing method and a device for a magnetic disk medium by pressing an abrasive tape to the surface of a disk invariably at a fixed load for high-precision surface polishing. SOLUTION: The abrasive tape 2 put on the surface of the rotating disk 1 fitted to a spindle 4 is pressed by a pressure pad 3 from behind for polishing in this surface polishing device for the magnetic disk medium. The pressure pad is fitted to the tip of a flexible support arm 6, and the support arm is fitted to a slide block 5a connected to a linear motor 9 to drive the pressure pad in the tape pressing direction. The support arm is fitted to a strain gauge 10 to detect the load of the pressure pad, the detected value is fed to a controller 11, and the output of the linear motor is feedback-controlled to keep the pressing load of the pressure pad at a predetermined pressure value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for polishing the surface of a magnetic disk medium for a magnetic recording medium of a hard disk drive.

[0002]

2. Description of the Related Art The above-mentioned magnetic disk medium has a base made of a disk made of aluminum alloy, glass, plastic, or the like, and a nickel-phosphorus (Ni-P) plating film formed on its surface to form a substrate. A chromium layer and a cobalt alloy magnetic layer are continuously formed as a base layer on the surface by sputtering, and further a carbon-based protective layer is coated on the surface, and a fluorocarbon-based liquid lubricating layer is applied on the outermost surface.

In the above-mentioned magnetic disk medium manufacturing process, a texture treatment for imparting fine roughness to the surface of the Ni-P plating layer, and protrusions and foreign matters remaining on the disk surface after the protective layer is coated, are removed. There are various surface polishing processes using a polishing tape, such as a burnishing process and a wiping process for a liquid lubricant applied to the outermost surface. In this surface polishing step, a polishing tape suitable for each processing step is applied to the surface of the rotating disk, and the processing is performed by pressing the polishing tape from behind to the disk surface with a pressure pad or the like. ing.

Here, the configuration and processing method of a conventional tape burnishing apparatus will be described with reference to FIGS. 5 (a) and 5 (b), taking the above burnishing process as an example. In the figure, 1
Is a disk of a magnetic disk medium, 2 is a polishing tape (burnish tape), 3 is a rubber pressure pad for pressing the polishing tape 2 from behind to the surface of the disk 1, and the disk 1 is a spindle of a drive motor 4. The chuck 4a is rotated and driven. On the other hand, the polishing tape 2, its driving mechanism, and the pressure pad 3 are mounted and mounted on a processing table 5, where the pressure pad 3 is a support arm that stands up from a slide block 5 guided and supported by rails on the table 5. 6, a weight 7 is connected to the slide block 5 via a wire 7a, and the pressing pad 3 which receives the load W of the weight 7 during processing is polished. The tape 2 is pressed against the disk 1. Although not shown, the working table 5 is moved in the radial direction of the disk 1 by an elevating mechanism, and the slide block 5 is connected to an air cylinder or the like to reciprocate between the load position and the unload position. I am trying to do it.

[0005] With this configuration, during burnishing of the disk 1, the processing table 5 is raised from the standby position to move the polishing tape 2 to the load start position ID (the inner peripheral end of the disk) of the disk 1, Slide block 5a
Is advanced to the load position, and the pressing pad 3 receiving the load W of the weight 7 presses the polishing tape 2 against the surface of the disk 1 (load: for example, 20 g), and starts varnishing while feeding the polishing tape 2. I do. In parallel with this operation, the working table 5 is lowered from the load start position ID, and the polishing tape 2 and the pressure pad 3 are moved along the radial direction of the disk 1 toward the load end position OD (the outer peripheral end of the disk). While moving, each surface area of the disk 1 is polished. When the disk reaches the loading end position OD, the pressure pad 3 is retracted by the cylinder operation and unloaded, and then the descent table 5 is further lowered to the standby position once. Finishes the varnishing process. In the illustrated example, the polishing tape 2 is drawn only on one side of the disk 1. However, in actuality, the polishing tape 2 and the pressure pad 3 are arranged on both sides of the disk 1, and both sides of the disk are simultaneously processed. Like that.

[0006]

The above-mentioned conventional surface polishing apparatus has the following problems in terms of processing accuracy and quality control. That is, in the conventional method in which the weight 7 is connected to the slide block 5a and the load of the weight 7 is applied to the pressure pad 3 to press the polishing tape 2 against the surface of the disk 1, the surface condition (undulation) of the disk 1 and the spindle Surface run-out of the disk 1 during rotation while being held at 4a, abrasion of the slide block 5 supported on the rails of the processing table 5, the pulley for stretching the wire 7a of the weight 7, deterioration of the lubricant, etc. If there is a change in resistance due to the change, it is extremely difficult to keep the pressure (on the order of tens of g) of the polishing tape 2 pressed against the surface of the disk 1 constant.

For this purpose, as shown by the actual measurement data of the actual machine shown in FIG. 4B, in the conventional method, the polishing tape 2 and the pressure pad 3 are moved from the load start position ID of the disk 1 to the load end position OD. A large variation in load occurs during the processing, which is one factor that lowers the surface processing accuracy and hinders the maintenance of the quality of the magnetic disk medium. The present invention has been made in view of the above points, and has as its object to solve the above-mentioned problems, and to improve the magnetic surface so that the polishing tape can always be pressed against the surface of the disk with a constant load to perform highly accurate surface polishing. An object of the present invention is to provide a method and an apparatus for polishing a surface of a disk medium.

[0008]

In order to achieve the above object, according to the processing method of the present invention, a polishing tape applied to the surface of a rotating disk is pressed against the disk from behind by a pressure pad to polish the disk. In the method for polishing the surface of a magnetic disk medium for processing, the pressure pad is attached to the tip of a flexible support arm, and the support arm is connected to a motor (preferably a linear motor) to tape the pressure pad to a tape. While driving in the pressing direction, a strain gauge is attached to the support arm to detect the pressing load of the pressure pad, and the output of the motor is feedback-controlled based on the detected value of the strain gauge to perform the pressing load of the pressure pad. Is held at a set value (claim 1).

Further, the surface polishing apparatus of the present invention used for carrying out the processing method comprises a processing unit equipped with a spindle for holding and rotating a disk of a magnetic disk medium, a polishing tape, and a pressure pad. The processing unit comprises a table moving in the radial direction of the disk, a slide block mounted on the table and connected to a motor (preferably a linear motor), A flexible support arm having a pad attached thereto, a strain gauge attached to the support arm to detect a pressing load of the pressure pad, and a pressure gauge based on a detection signal of the strain gauge and comparing with a set pressure value. And a control unit for feedback-controlling the output of the motor.

According to the processing method and apparatus described above, the surface condition of the disk, the surface deflection of the disk when rotating while being held on the spindle, and the movable portion of the slide block mounted and guided and supported on the table. Even if there is a change, etc., it is not directly affected by these, and the pressing load that presses the polishing tape to the disk surface via the pressure pad at each position from the start of loading to the loading to the end of loading is constant with good responsiveness As a result, high polishing accuracy and stable quality control of the magnetic disk medium can be secured. Further, the processing method and apparatus of the present invention can be suitably used for burnishing the disk surface after coating the protective layer.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on illustrated embodiments. It should be noted that FIG.
The same reference numerals are given to members corresponding to, and description thereof will be omitted. First, FIG. 1 shows an entire configuration of a surface polishing apparatus as a tape burnishing apparatus according to an embodiment of the present invention.
In the figure, a processing unit 5 equipped with a polishing tape 2, a pressure pad 3 and a drive mechanism thereof is provided with an elevating mechanism 8 on an elevating table 5b and a disk 1 coated with a carbon-based protective layer mounted on a spindle 4a. It moves up and down in the radial direction. 8a is a drive motor,
8b is a ball screw.

Here, a pair of left and right slide blocks 5a are slidably guided along rails on the elevating table 5b, and each slide block 5a is erected upward and pressurized at its tip. A support arm 6 to which the pad 3 is attached is provided.
a are individually connected to the linear motor 9. The support arm 6 is made of, for example, an aluminum plate having a thickness of about 1 mm so as to provide flexibility, and a strain gauge 10 is attached to the plate surface to reduce the pressing load of the pressure pad 3. I try to detect.

On the other hand, as shown in FIG. 2, the linear motor 9 includes a stator having a magnet 9b provided on the inner periphery of a cylindrical iron core 9a;
A voice coil motor including a mover coil 9c inserted into an iron core and a connection shaft 9d is employed, and a slide block 5a is connected to the connection shaft 9d. The operating principle of such a linear motor is well known. When a current (DC) is applied to the mover coil 9b, an axial driving force corresponding to the direction of the current is generated, and the driving output is supplied to the coil 9b. It is proportional to the current. In addition, since the motor body has no contact or wear parts, stable output characteristics can be obtained even when used for a long time.

In the illustrated embodiment, the detection signal of the strain gauge 10 is taken into the control unit 11 during polishing, and
The output of the linear motor 9 is feedback-controlled in comparison with a load set value set in advance according to the contents of the tape processing, and the load applied to the pressure pad 3 via the slide block 5a and the support arm 6, that is, the polishing tape 2 is removed. The pressure applied to the disk 1 is kept constant (set value).

Next, the polishing process and operation of the disk 1 by the processing apparatus having the above configuration will be described with reference to the flowchart shown in FIG. First, at the time of processing standby, the elevating table 5b of the processing unit 5 retreats to the lowered position, and the pair of slide blocks 5a is divided into right and left and stopped at the retracted standby position. Here, when the disk 1 is chucked to the spindle 4a and rotated, the lifting table 5
b moves from the standby position to move the polishing tape 2 and the pressure pad 3 to the inner peripheral end of the disk 1 corresponding to the load start position ID in FIG. 5a is moved from left and right to the center on the lifting table. Thereby, the disk 1
The pressing pad 3 presses the polishing tape 2 against the surface of the disc from behind with the polishing tape 2 facing on both sides of the disc (pat load).
At the same time, the surface polishing of the disk 1 with the polishing tape 2 is started. In parallel with this processing operation, the polishing tape 2 and the pressure pad 3 are moved to the loading end position O shown in FIG.
Then, when the lifting table 5b is moved downward toward the load position D, the current of the linear motor 9 is reversed to reach the load end position OD, the slide block 5a is moved backward to the standby position, and the pressure pad 3 is moved to the polishing tape 2. , And the processing unit 5 is returned to the standby position.

Also, during the above-mentioned polishing with the tape 2, the load of the pressure pad 3 detected by the strain gauge 10 is taken into the control unit 11 and compared with a set pressure value (for example, 20 g). Is equal to the set value (OK), the polishing is continued without correction, and if it is out of the set pressure value (NG), the linear motor is adjusted to correct the load applied to the press pad 3. 9 is feedback-controlled.

In addition, from the measurement results of the actual machine test actually performed by the inventors and others, as shown in FIG. 4C, the pressure pad is hardly varied at each position from the start to the end of the loading of the disk. It has been confirmed that the disk can be polished with high processing accuracy while maintaining a constant pressing load.
Further, the burnishing treatment may be performed after the liquid lubricating layer is formed on the protective layer by coating.

[0018]

As described above, the processing method of the present invention,
According to the present invention, the following effects can be obtained. (1) In the polishing step of moving the tape in the radial direction of the disk while pressing the polishing tape applied to the disk surface of the rotating magnetic disk medium from behind with a pressure pad,
The pressing force can be kept constant with good responsiveness without being directly affected by the disk surface condition, surface runout, and the resistance change of the slide block with the pressure pad attached. As a result, the quality of the magnetic disk medium can be stabilized.

(2) Even if the resistance of the movable part changes due to wear of the slide block or deterioration of the lubricant due to long-term use of the processing unit, the polishing tape is pressed against the disk as in the conventional weight load method. The force does not fluctuate, thereby improving the reliability of the processing apparatus and saving labor for maintenance.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a surface polishing apparatus for a magnetic disk medium according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a configuration of a linear motor used in the apparatus of FIG. 1;

FIG. 3 is a flowchart showing a surface polishing process of a magnetic disk medium by the apparatus of FIG. 1 and a control operation thereof;

4A and 4B are diagrams showing a change in load of a pressing pad in a grinding process of a magnetic disk medium, wherein FIG. 4A is a diagram schematically showing the start and end positions of loading on a disk, and FIGS. ) Is a diagram showing the transition of the load change from the start to the end of load by the conventional weight load method and the motor load method of the present invention, respectively.

5A and 5B are configuration diagrams of a conventional surface polishing apparatus illustrating a tape burnishing apparatus, wherein FIG. 5A is a schematic diagram of the configuration of the apparatus, and FIG. 5B is a perspective view illustrating a state of polishing processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic disk medium disk 2 Polishing tape 3 Pressure pad 4 Spindle motor 4a Spindle 5 Processing unit 5a Slide block 5b Elevating table 6 Support arm 9 Linear motor 10 Strain gauge

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuji Shirakawa 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Akihide Hara 1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 Inside Fuji Electric Co., Ltd. (72) Inventor Yasushi Zaitsu 1-1-1, Tanabe Shinden, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term inside Fuji Electric Co., Ltd. 3C058 AA05 AA11 AA12 AA14 AA16 AA18 AB04 AC02 BA05 BB01 BB09 CA01 CB01 5D112 AA24 GA13 GA16

Claims (2)

[Claims] In a method for polishing a surface of a magnetic disk medium in which a polishing tape applied to the surface of a rotating disk is pressed against the disk from behind by a pressing pad to perform processing, the pressing pad is flexible. The support arm is attached to the tip of the support arm, and the support arm is connected to a motor to drive the pressure pad in the tape pressing direction, and a strain gauge is attached to the support arm to detect the pressure load of the pressure pad, and A method for polishing the surface of a magnetic disk medium, wherein the output of the motor is feedback-controlled based on a detected value of a gauge to maintain a pressing load of a pressing pad at a set value. 2. A surface polishing apparatus used for carrying out the surface polishing method according to claim 1, comprising a spindle for holding and rotating a disk of a magnetic disk medium, a polishing tape, and a pressure pad. The processing unit comprises a table moving in the radial direction of the disc, a slide block mounted on the table and connected to a motor, and a pressure pad mounted on the slide block at the end by standing upright on the slide block. A support arm having flexibility attached thereto, a strain gauge attached to the support arm for detecting a pressing load of the pressure pad, and a motor for comparing the motor with a set pressure value based on a detection signal of the strain gauge. A surface polishing apparatus for a magnetic disk medium, comprising: a control unit for performing feedback control of an output.