JPH05228827A - Disc grinding device and plate thickness control method for disc grinding device - Google Patents

Abstract

PURPOSE:To control the plate thickness accurately and stably, and improve the yield of products by measuring the initial plate thickness of a disc to be ground, and computing the target grinding quantity on the basis of the initial plate thickness, and stopping a grinding device when the grinding quantity achieves the target grinding quantity. CONSTITUTION:A grinding device pinches a disc with a carry between a pair of grinding surface plates, which rotate in the directions opposite to each other, to pressurize them, and the carry is epicycle-rotated to grind the disc. In this case, the displacement quantity, which is detected by a displacement quantity detecting unit 7 of the grinding surface plates positioned in the upper, and the existence of the rotation, which is detected by a rotation sensor 90 of the fixed grinder positioned in the lower, are input to a control means 8. The target grinding quantity of the disc to be ground is computed by a computing means 80 on the basis of the initial plate thickness of the disc to be ground. The required standard data is inputted by an input means 9. Furthermore, a result of the computing is displayed by a display means 81, and on the other hand, the upper and the lower grinding surface plates, a driving motor 4 and an elevation driving device 35 are controlled in response to the target grinding quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk polishing apparatus for polishing a hard disk substrate such as a magnetic disk, and a plate thickness control method for the disk polishing apparatus.

[0002]

2. Description of the Related Art A polishing apparatus of this type has a disk, which is thinner than the disk to be polished and is held in a planetary gear-shaped carrier, and is held together with the carrier between a pair of polishing surface plates that rotate in opposite directions. It is a structure in which the disc is polished while being sandwiched and pressurized, and the carrier is planetarily rotated around the sun gear. And, since the polishing amount per fixed time is determined by the type of polishing stones installed on the polishing side of both polishing surface plates, the number of rotations of both surface plates and the sun gear, and the material of the disk to be polished, conventional disk polishing The plate thickness control in the device is based on time control, the plate thickness is measured by polishing for a certain period of time, and the product whose plate thickness is within the allowable range as a result of the measurement is considered as a product. As well as being treated, those exceeding the permissible range were polished again.

[0003]

However, in the disk group, there are variations in the plate thickness of each other in the manufacturing process, and when the discs having such plate thickness variations are polished by the time control as described above, the initial plate Since the variation in thickness is easily reflected as it is on the disk after polishing, stable plate thickness control cannot be performed, and the product yield often becomes extremely poor. Further, since the plate thickness control becomes more unstable due to the state of the polishing liquid, the clogging of the polishing grindstone, the parallelism between the polishing platens, and the like, the product yield is further reduced in such a case. The purpose of the present invention is to
An object of the present invention is to provide a disk polishing apparatus and a plate thickness control method for the disk polishing device, which can solve such problems and enable extremely stable plate thickness control and improve the product yield.

[0004]

In order to achieve the above-mentioned object, a disk polishing apparatus according to the present invention rotates a disk, which is thinner than a disk to be polished and is held by a planetary gear-like carrier, in the opposite direction. In a polishing device that presses by sandwiching it with a carrier between a pair of polishing surface plates, and polishing the disk while planetarily rotating the carrier around a sun gear, the displacement when the polishing surface plates approach each other. A displacement amount detector for measuring the plate thickness of the disk to be polished by detecting the amount, a calculating means for calculating a target polishing amount of the disk to be polished based on the initial plate thickness of the disk to be polished, and this calculating means Control means for controlling the drive of the both polishing platens and the sun gear based on the target polishing amount,
And an input means for inputting a standard plate thickness and a standard polishing amount of the disk to be polished. The displacement amount detector in the apparatus is preferably installed at the center of the rotary shaft of the polishing platen.

In order to achieve the above-mentioned object, the plate thickness controlling method of the disk polishing apparatus according to the present invention rotates the disk, which is thinner than the disk to be polished and is held through the planetary gear-shaped carrier, in the opposite direction. In a polishing apparatus for sandwiching and pressing the carrier between a pair of polishing platens and polishing the disk while planetarily rotating the carrier around a sun gear, the disk to be polished is held in a state of being penetrated and held by the carrier. Is set on one surface plate, the initial plate thickness of the disk to be polished is measured by detecting the amount of displacement when the both polishing surface plates are close to each other, and the target of the disk to be polished is based on this measured plate thickness. The polishing amount is calculated, and the polishing operation of the apparatus is performed at a predetermined time interval while measuring the proximity amount of both polishing surface plates, and the proximity amount of both polishing surface plates reaches the target polishing amount a predetermined number of times. Characterized when controlled to stop when the plate thickness control method for a disk polishing apparatus. How many times the proximity amount of both polishing surface plates reaches the target polishing amount determines how the surface plate and the sun gear are stopped, the material of the disc, the degree of variation in the plate thickness, the type of polishing wheel, the parallelism of both polishing surface plates. It is empirically set appropriately depending on the degree and other conditions. When measuring the initial plate thickness of the disk to be polished, the proximity amount of both polishing surface plates is detected at a predetermined time interval, and the disk to be polished is detected based on the same proximity amount being detected at least twice. It is desirable to configure so as to determine the initial plate thickness.

[0006]

According to the disk polishing apparatus of the present invention described above, the target polishing amount is calculated based on the measured initial plate thickness (plate thickness before polishing) of the disk to be polished and the standard polishing amount, and this target polishing amount is calculated. Based on this, the operation of the polishing apparatus is controlled. That is, the disk is given a target polishing amount by the measured initial plate thickness, and the polishing apparatus is operated until the target polishing amount is reached. When the displacement detector is installed at the center of the rotary shaft of the polishing platen, a plurality of carriers holding the discs penetrating them are arranged side by side in the circumferential direction between the polishing platens, and these discs are polished simultaneously. Suitable for construction equipment.

According to the plate thickness control method of the present invention, when the disk is polished, the proximity amount of both polishing surface plates detected by the displacement amount detector at a predetermined time interval, that is, the amount of disk polishing is previously determined. The polishing apparatus is operated until the target polishing amount is reached the set number of times. Therefore, the plate thickness control when polishing a disk having plate thickness variations becomes more accurate and stable, and the product plate thickness variations due to the parallel and coarse parallelism of both polishing surface plates are also absorbed. Set the discs on one polishing surface plate and bring both polishing surface plates closer to each other, and when the surface plate is stopped, the disks are sandwiched between both polishing surface plates, and the distance between both surface plates at this point is the plate thickness of the disk. Equivalent to. However, if the surface plate that is approaching has stopped,
Since it is difficult to detect accurately in m units, the displacement detector is controlled to detect the proximity amount between the both polishing surface plates at predetermined time intervals, and the same proximity amount is detected at least twice. If the initial plate thickness of the disk-to-be-polished is determined based on the detection, it is possible to reliably detect the stop of the surface plate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 is a sectional view showing an example of a polishing apparatus according to the present invention, FIG. 2 is a partial sectional view taken along the arrow AA in FIG. 1, FIG. 3 is a block diagram showing a control system of the polishing apparatus according to the present invention, and FIG. FIG. 5 is a cross-sectional view showing another embodiment of the polishing apparatus, which is a flow chart for explaining the outline of plate thickness control according to an example of the method of the present invention.

In FIGS. 1 and 2, reference numeral 1 is an installation base 1.
0 is a mounting shaft provided upright on the shaft 0. A pipe-shaped rotating shaft 30 for rotating the upper polishing platen 3 is mounted on the mounting shaft 1 via a bearing metal 11. Is attached so that the pipe-shaped rotary shaft 20 of the lower polishing platen 2 is movable. Wheels 21 and 31 are attached to the lower portions of the rotating shafts 20 and 30, respectively, and are configured to rotate in opposite directions by the same motor 4 via the transmission mechanisms 22 and 32, respectively.

The lower polishing platen 2 of this embodiment is a frame plate.
It is rotatably supported on the inner bottom portion of the counterbore portion 51 of the cam 5 through the bearing 23, and rotates integrally with the rotary shaft 20.
On the other hand, the upper polishing platen 3 engages with a clutch (or gear) 33 formed on the upper portion of the rotating shaft 30 to allow the rotating shaft 3 to rotate.
It is designed to rotate with 0.

Polishing grindstones 24 and 34 are fixed to the opposite sides of the two polishing platens 2 and 3, respectively, and the grinding grindstones 24 and 34 are covered with the carrier 60 while being held there. The polishing disk 6 is configured to be sandwiched. The carrier 60 is slightly thinner than the disk 6 to be polished and is formed in a planetary gear shape as shown in FIG. 2, one of which meshes with a sun gear 25 formed on the upper end portion of the rotary shaft 20, and the other of which has an outer periphery. Is engaged with the internal gear 5 attached to the frame 50, and is configured so that the rotation of the rotary shaft 20 causes planetary rotation around the gear. In this embodiment, a plurality of carriers 60 are arranged on the grindstone 24 of the lower polishing platen 2 at equal angular intervals.

A mounting piece 36 is provided on the upper surface of the upper polishing platen 3.
A lifting drive device 35 composed of an air cylinder is attached via a bearing 37 and the lifting drive device 35.
It is configured to move up and down. In the polishing apparatus of this embodiment, a displacement amount detector 7 including a differential transformer is attached to the lower surface of the attachment piece 36, and the movable contact 70 of the displacement amount detector 7 is connected to the upper end of the attachment shaft 1 described above. The movable contact 70 is retracted in the main body by a spring (not shown) and is displaced (lowered) when the polishing platen 3 comes into contact with the lower polishing platen 2 and approaches the lower polishing platen 2. Amount) is detected, and the detected value is displayed on the display 71 composed of a display amplifier. The rotation of the rotating shaft 20 is detected by the rotation sensor 90.

The apparatus of this embodiment is equipped with a control means 8 as shown in FIG. 3, and the displacement amount of the upper polishing platen 3 detected by the displacement amount detector 7 and the rotation sensor 90 are detected. The detected presence / absence of rotation of the rotary shaft 20 is input to the control means 8. The control means 8 further calculates the target polishing amount of the disk 6 to be polished based on the initial measured plate thickness of the disk 6 to be polished measured by the displacement detected by the displacement detector 7, and the polishing means 80. An input means 9 for inputting the standard plate thickness of the disk 6, the standard polishing amount at the standard plate thickness and other necessary standard data, and a display means for displaying the calculation result of the calculating means 80 and the control state of each part. Based on the target polishing amount calculated by the calculating means 80, the motor 4 for driving both the polishing platens 2, 3, the sun gear 25 and the like, and the lifting drive device 35 are controlled. Mode
Specifically, the stopping of the cutter 4 is controlled by how many times the polishing amount of the disk 6 to be polished reaches the target polishing amount.

The plate thickness control of the disk using the polishing apparatus of the above-mentioned embodiment is performed in the following manner, for example. Before the operation, the upper polishing platen 3 is controlled by the control means 8 as shown in FIG.
The disk to be polished 6 is not set because the disk 6 has risen above the position. Before starting operation, the standard plate thickness (eg, 1900 μm) and standard polishing amount (eg, 30 μm) of the disk group to be polished in advance and the polishing amount of the disk reaches the target polishing amount (eg, 65 times). Necessary data such as whether or not to stop the motor 4 are input from the input means 9 and these input data are displayed on the display means 81.

When the disk to be polished 6 held by the carrier 60 is set on the lower polishing platen 2 as shown in FIGS. 1 and 2, it is controlled as in the flow chart of FIG. Means 8
The upper polishing surface plate 3 is controlled by the lifting drive device 35 from
Starts to descend, and the displacement amount detector 7 detects the displacement amount (lowering amount) of the polishing platen 3 every one second, for example, and the control means 8
Is input to. When the detection by the detector 7 is continuously performed, the detected value is input to the control means 8 every one second, for example. Further, the fact that the polishing platen 3 is descending is displayed by the lamp of the display means 81. At the position where the polishing surface plate 3 starts to descend, the contact 70 of the displacement detector 7 is in contact with the upper end of the mounting shaft 1,
The change in the displacement amount is detected after the contact 70 of the displacement amount detector 7 contacts the upper end of the mounting shaft 1.

Polishing surface plate 3 input from displacement amount detector 7
When the amount of displacement of 2 is the same numerical value twice, the control means 8 determines that the polishing surface plate 3 has stopped, and the amount of displacement at that time and the standard plate thickness are calculated by the computing means 80 at the initial stage of the disk 6 to be polished. The plate thickness is calculated, and the calculated value is displayed on the display 71 as an excess / deficiency amount with respect to the standard plate thickness. For example, if the standard plate thickness is 13 μm shorter than 1900 μm, it is displayed as “−0013”. In this embodiment, since four disks 6 to be polished are set, the initial plate thickness is almost an average value of the four disks 6.

When the initial plate thickness of the disk 6 is determined as described above, the target polishing amount of the disk 6 is calculated by the calculating means 80 (difference between initial plate thickness and standard plate thickness + standard polishing amount, the above-mentioned setting example). Then, −13 + 30 = 17 μm.) Then, the control means 8 drives the upper and lower polishing surface plates 2 and 3 and the sun gear 25 through the motor 4 to start polishing. In this embodiment, at the same time as the polishing is started, the pitch of the displacement value of the polishing surface plate 3 detected by the displacement detector 7 (or the pitch at which the detection value is input to the control means 8) is changed to 0.2 seconds. The target polishing amount is continuous.
When it is achieved 65 times, the control means 8 stops the upper and lower surface plates 2, 3 and the sun gear 25 through the motor 4. When the rotation sensor 90 confirms that the rotation shaft 20 of the polishing platen 2 has stopped rotating, the elevation drive device 35 is actuated by the control of the control means 8 to raise the polishing platen 3 on the upper side, and each disk. 6 is recovered.

According to the disk polishing apparatus and the plate thickness control method of the above-mentioned embodiment, the target polishing amount is calculated by the measured initial plate thickness (plate thickness before polishing) of the disk to be polished and the standard polishing amount, Depending on the conditions such as disc material, degree of variation in plate thickness, type of grinding stone, parallelism of both polishing plates, and other conditions, the target polishing amount is polished until the number of times reaches a preset number which is empirically set in advance. The device is operated. Therefore, the plate thickness control when polishing the disk 6 having the uneven plate thickness is more accurate and stable, and the variation of the product plate thickness due to the unevenness of the parallelism between the two polishing platens 2 and 3 is within the allowable error range. Will be stored inside. In addition, whether or not the polishing surface plate 3 approaching is stopped
Although it is difficult to detect the displacement accurately in units, the displacement detector 7 is controlled to detect the displacement between the polishing platens 2 and 3 at a predetermined time interval, and at least twice the same. Since the initial plate thickness of the disk-to-be-polished is determined based on the detected amount of displacement, it is possible to reliably detect the stop of the surface plate. Further, the displacement detector 7
Is installed at the center of the rotation axis, the initial plate thickness of the plurality of disks 6 can be measured more evenly.

In the above-described embodiment, the displacement detector 7 is fixed to the upper polishing platen 3, but the displacement detector 7 can also be implemented by the structure shown in FIG. 5, for example. In the example of FIG. 5, the rotating shaft 30 is erected rotatably upright on the installation base 10. A cup-shaped portion 38 is provided at the upper end of the rotating shaft 30, and the cup-shaped portion 38 is surrounded. A clutch 33 is formed on the upper surface of the cup-shaped portion 38, and a displacement amount detector 7 is attached to the inner bottom portion of the cup-shaped portion 38. It is configured to come into contact with the attachment piece 36 fixed to the polishing platen 3. Therefore, when the upper polishing platen 3 moves downward, the movable contactor 70 is retracted into the main body by a spring (not shown), and the displacement amount of the polishing platen 3 is detected.

In the embodiment shown in FIG. 5, a dish-shaped rotary table 52 is rotatably mounted on the countersunk portion 51 of the frame 50 by a bearing 53, and an interface is provided at the upper edge of the rotary table 52.
To fix the null gear 5 and to attach the wheel 54 to the shaft portion 56 of the rotary table 52 externally mounted on the rotary shaft 20, and to rotate the rotary table 50 by another motor 40 via the transmission mechanism 55. Thus, the internal gear 5 is configured to rotate in the opposite direction with respect to the sun gear 25. In the apparatus of this embodiment, in the control system as shown in FIG. 3, the control means 8 controls the motor 40 together with the motor 4. Other configurations and operations of the apparatus of the embodiment shown in FIG. 5 are almost the same as those of the embodiment described with reference to FIGS. 1 to 3, and therefore their description will be omitted.

In each of the above-mentioned embodiments, when the polishing platens 2 and 3 are brought close to each other, only the upper polishing platen 3 is lowered, but the upper polishing platen 3 is fixed and the lower platen is fixed. The polishing platen 2 may be raised, or the upper and lower polishing platens 2 and 3 may be raised and lowered with respect to each other. Further, the control means 8 can be implemented even if it also serves as the calculation means 80.

The disk polishing apparatus and the disk plate thickness control method according to the present invention are not limited to the above-mentioned embodiments, but in the claims, change or replace a non-main part, or other parts. It also includes the case where elements are added for implementation.

[0023]

According to the disk polishing apparatus and the disk plate thickness control method of the present invention, there is a problem of the plate thickness variation by measuring the initial plate thickness of the disk by the displacement amount detector before the start of polishing. Can be solved, by calculating the target polishing amount based on the initial plate thickness for each disk set on the polishing platen, by controlling to stop the device when the target polishing amount is achieved several times, The plate thickness control becomes more accurate and stable, and the variation of the product plate thickness due to the degree of parallelism of both polishing surface plates can be kept within the allowable range of the product. Therefore, the product yield is significantly improved as compared with the conventional time-based plate thickness control.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a polishing apparatus according to the present invention.

FIG. 2 is a partial cross-sectional view taken along the arrow AA of FIG.

FIG. 3 is a block diagram showing an example of a control system of the polishing apparatus of FIG.

FIG. 4 is a flowchart for explaining the procedure of plate thickness control according to an example of the method of the present invention.

FIG. 5 is a sectional view showing another embodiment of the polishing apparatus according to the present invention.

[Explanation of symbols]

 1 Mounting Shaft 10 Installation Base 11 Bearing Metal 2,3 Polishing Surface Plate 20,30 Rotating Shaft 21,31,54 Wheel 22,32,55 Transmission Mechanism 23,37,53 Bearing 33 Clutch 24,34 Polishing Wheel 25 sun gear 35 lifting drive device 36 mounting piece 38 cup-shaped portion 4,40 motor 5 internal gear 50 frame 51 counterbore portion 52 rotary table 6 polished disk 60 carry 7 displacement detector 7 70 movable contact Child 71 Display 8 Control means 80 Computing means 81 Display means 9 Input means 90 Rotation sensor

Claims (4)

[Claims] 1. A disk, which is thinner than the disk to be polished and is held by a carrier in the form of a planetary gear, is sandwiched between a pair of polishing surface plates that rotate in opposite directions together with the carrier to apply pressure to the carrier. In a polishing device for polishing the disk while planetary rotation is performed around a sun gear, a displacement amount detector for measuring the plate thickness of the disk to be polished by detecting the displacement amount when the both polishing surface plates approach each other. ,
A calculating means for calculating a target polishing amount of the disk to be polished based on the initial measured plate thickness of the disk to be polished, and a drive of both the polishing platen and the sun gear based on the target polishing amount calculated by this calculating means. A disk polishing apparatus comprising: a control means and an input means for inputting a standard plate thickness and a standard polishing amount of a disk to be polished. 2. The disk polishing apparatus according to claim 1, wherein the displacement amount detector is installed at a rotation axis of the polishing platen. 3. A disk, which is thinner than the disk to be ground and is held through a carrier in the form of a planetary gear, is sandwiched between a pair of polishing surface plates that rotate in opposite directions together with the carrier to apply pressure to the carrier. In a polishing device that polishes the disc while planet-rotating the sun gear around the sun gear, the disc to be polished is set on one surface plate while being held by a carrier, and when both the polishing surface plates are close to each other. The initial plate thickness of the disk to be polished is measured by detecting the displacement amount, the target polishing amount of the disk to be polished is calculated based on the measured plate thickness, and the polishing operation of the device is performed at predetermined time intervals. A method for controlling the plate thickness of a disk polishing apparatus, which is performed while measuring a proximity amount of a polishing platen and is controlled to stop when the proximity amount of both polishing platens reaches the target polishing amount a predetermined number of times. . 4. When the initial plate thickness of the disk to be polished is measured by detecting the displacement amount when the two polishing platens come close to each other, the proximity amount of the both polishing platens is detected at a predetermined time interval. The plate thickness control method for a disk polishing apparatus according to claim 2, wherein the initial plate thickness of the disk to be polished is determined based on the same proximity amount being detected at least twice.