JPS624562A - Magnetic polishing device - Google Patents

Abstract

PURPOSE:To enable the front and back surfaces of a work to be simultaneously polished in a formed polishing brush irrespective of the presence of magnetism by forming the magnetic pole S in one of opposed disks rotated in the same direction and the magnetic pole N in the other and interposing magnetic abrasives between both disks. CONSTITUTION:Two opposed magnetic disks 41 are fixedly secured to the outer periphery of a centering sleeve 42 secured fixedly to a rotary shaft 21. A permanent magnet 43 is secured fixedly between said disks and provided on the surface with a non-magnetic cover body 44. Also, on the opposed surfaces of the disks 41 are radially disposed fins 45 and magnetic lines of force generated from the permanent magnet 43 pass through the disks 41 and fins 45 to constitute a closed loop magnetic field and NS poles in the disks 41. Thus, when magnetic abrasives 40 are filled between the disks 41, they are oriented by the magnetic field to form a brush of abrasives 40. As a result, a disk D held and rotated by a shaft 28 has both surfaces polished uniformly by the brush in the same time.

Description

Detailed Description of the Invention [Claim 2] [Technical Field] The present invention provides a magnetic polishing method in which a magnetic abrasive is oriented in a magnetic field to form an abrasive brush, and the brush polishes an object to be polished. The present invention relates to a polishing apparatus, and particularly to a magnetic polishing apparatus capable of polishing a non-magnetic object to be polished, and also capable of polishing both sides of a disc-shaped object to be polished.

[Technical background and conventional problems]

The work of polishing an object to be polished involves contacting the object with an abrasive that is higher in quality than the object being polished, and polishing at a speed and pressure depending on the conditions such as the material of the object to be polished and the required polishing accuracy. The agent is made to slide onto the polishing surface.

In this polishing work, in order to precisely polish the polishing surface, it is important to have an even T of the polishing agent and an appropriate pressure. To achieve this, it is necessary to consider technical innovations such as the material of the plate that holds the abrasive. Conventionally, cloth, rubber, synthetic resin, etc. have been used as this material. Also, recently,
Polishing devices using magnetism are being considered. An example of this type of magnetic polishing apparatus is one in which a magnetic polishing agent is oriented in a magnetic field to form an abrasive brush, and an object to be polished is polished by this abrasive brush. This type of conventional magnetic polishing device is most suitable for polishing objects in the shape of a rotary body processed by a lathe, such as molds and parts for sewing machines.

On the other hand, recently, there have been an increasing number of objects to be polished that require precision polishing. Examples of this type of object to be polished include:
magnetic disks, magnetic tapes, aluminum disks,
There are synthetic resin discs, synthetic resin films, etc. These objects to be polished have a relatively wide polishing surface, and must be polished with high precision.

This will be explained with reference to FIG. 5, which is a conventional example of a polishing apparatus for polishing a disk among objects to be polished, and FIG. 6, which is a side view thereof. In this polishing step, the disk D is rotated clockwise or counterclockwise in FIG. 5 by a predetermined rotational drive device. Also, disk D has a polishing disk 1.
is facing from both sides. Each polishing disk l is composed of a polishing pad 3 and a rigid plate 4 that supports the polishing pad 3, and is rotatably driven by a rotating shaft 2. The polishing pad 3 is made of polyurethane, ohm mixed with abrasive, or the like. In this type of polishing apparatus, each polishing disk 1 is pressed against both surfaces of the disk D and rotated to perform polishing. Since the polishing pad 3 is made of a mixture of urethane foam and abrasive, its elastic properties allow the abrasive to contact the surface of the disk D evenly with uniform pressure to perform polishing. It has become. By using a polishing pad 3 mixed with this type of resin, a device has been devised to realize an appropriate contact pressure of the polishing agent. An example of this type of polishing apparatus is one disclosed in Japanese Patent Laid-Open No. 183834/1983. However, even if such improvements are made to the polishing pad 3, there is a limit to the ability to accurately set the contact pressure of the polishing agent against the disk D, and the polishing pad 3 may wear out as the polishing work progresses. There are also problems.

Furthermore, it is necessary to clean the polishing layer after the polishing operation has progressed, but this requires equipment such as a nozzle, which also has the drawback of complicating the apparatus.

Therefore, it is conceivable to polish this type of disk D using a magnetic polishing device. In a magnetic polishing device, the strength of the magnetic field orients the abrasive to form a uniform abrasive surface, making it easier to perform high-precision polishing work with appropriate pressure.

As an example of polishing a relatively large polishing surface such as a disk D using this magnetic polishing device, a rotating disk having magnetic poles is provided on a work table that supports the object to be polished, and the object to be polished is There is a method in which a magnetic field is formed as a circuit that passes through the rotating disk and the object to be polished, and a magnetic abrasive is oriented and interposed in the magnetic field between the rotary disk and the object to be polished, thereby forming a brush made of the abrasive. However, this type of magnetic polishing device has a structure in which the lines of magnetic force pass through the inside of the object to be polished, so it can only process objects to be polished that are magnetic, and has the disadvantage that it is difficult to polish disks made of aluminum or resin. .

FIG. 7 shows another conventional example of a magnetic polishing device capable of polishing disks and the like. In this magnetic polishing device, a coil 7 is wound around an iron core 6 provided in a yoke 5 to constitute an electromagnet. Magnetic poles 8a and 8b are provided on the lower surfaces of the yoke 5 and the iron core 6, and both the magnetic poles 8a and 8b are joined via a nonmagnetic material 9. The portion where the non-magnetic material 9 is interposed faces the disk D, which is the object to be polished, on the work table 10. In this polishing apparatus, when the disk D is made of a magnetic material, lines of magnetic force emerging from one magnetic pole 8a pass through the disk D and return into the other magnetic pole 8b. If a magnetic abrasive is interposed between the magnetic poles 8a, 8b and the disk D, this abrasive is oriented by a magnetic field and formed into a brush shape. Magnetic poles 8a, 8b and work table 1
If 0 is moved relatively, the surface of the disk D will be polished by the abrasive brush. If the disk D, which is the object to be polished, is made of a non-magnetic material, a plate 11 made of a magnetic material is placed on the work table 10k, and the disk D is placed on it. With this configuration, a magnetic circuit is formed from the magnetic pole 8a through the magnetic plate 11 to the magnetic pole 8b, and by interposing the abrasive in this magnetic field, an abrasive brush can be formed. Therefore, it becomes possible to polish a non-magnetic object to be polished. This kind of magnetic polishing device is known as
It is disclosed in Publication No. 0.

However, in such a magnetic polishing device.

There is a drawback that only one side of the disc-shaped object to be polished can be polished. Therefore, polishing work has to be done twice, on the front and back sides, and each time the magnetic field must be destroyed to recover the abrasive, and the abrasive must be supplied again to form the brush, making the setup complicated. There is a drawback.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and is capable of uniformly polishing the back surface of a disc-shaped object to be polished at the same time and with uniform pressure. It is an object of the present invention to provide a magnetic polishing apparatus that can perform polishing and also polish non-magnetic objects.

[Structure of the invention]

The magnetic polishing device according to the present invention includes a pair of discs that face each other and rotate in the same direction, one of which has an S magnetic pole and the other a N pole, and a magnetic abrasive is placed between the two discs. A polishing brush made of abrasives oriented by a magnetic field is interposed therebetween, and a holding member for holding the object to be polished is provided on the side of the polishing brush.

Hereinafter, a detailed explanation will be given with reference to the drawings of FIGS. 1 to 3.

FIG. 1 is a front view showing a magnetic polishing apparatus according to the present invention, and FIG. 2 is a left side view thereof.

Reference numeral 21 in the figure is a rotating shaft. This rotary shaft 21 is supported by bearings 22a and 22b, and a pair of discs 23 are fixedly mounted opposite to each other on the 0-rotary shaft 21, which is rotatably driven by a drive source such as a motor. . This disk 23 includes a permanent magnet 24 such as a ferrite magnet,
It is composed of a soft iron disc 25 fixed to the opposing surface, and a fin 26 fixed to the opposing surface. One of the opposing surfaces of the two discs 23 is a north pole and the other is a south pole.
A magnetic pole is configured to serve as a pole.

The fins 26 are made of a magnetic material, and as shown in FIG. 2, four fins 26 are fixedly arranged radially around the rotating shaft 21. The fins 26 are provided to partially increase the magnetic flux density.

Reference numeral 27 is a liquid injection pipe. This liquid injection pipe 27 is inserted into the center hole 21a of the rotating shaft. The tip of the liquid injection tube 27 extends to the center of the opposing portions of the two discs 23. And it communicates with a liquid injection port 21b bored in the radial direction of the rotating shaft 21.

Reference numeral 28 is a holding shaft. This holding shaft 28 is rotatably supported by a bearing 29. Further, the holding shaft 28 is rotationally driven by a motor. A holder 28a using a nut or the like is provided at the tip of the holding shaft 28.
The object to be polished, such as the disk D, is held by this holder 28a.

As shown in FIG. 2, struts 32 and 33 are fixedly mounted on the pedestal 31. As shown in FIG. The bearings 22a and 2 are attached to one of the pillars 32.
2b is held, thereby supporting the rotating shaft 21. A bearing 29 is held on the other support 33, and the holding shaft 28 is supported by this. Further, a cover support post 34 is fixed to the edge of the frame 31, and a cover 35 is fixed to the top of this support post 34, and a cover 36 is fixed to the bottom thereof.

The magnetic abrasive 40 is filled between the two disks 23 . The magnetic abrasive 4 is created by the magnetic field between the two permanent magnets 24.
0 is oriented, and an abrasive brush made of magnetic abrasive is formed between the two circles @23. On the other hand, the disk D, which is the object to be polished, is inserted into the brush formed by the abrasive 40 while being held by the holding shaft 28 . The rotating shaft 21 and the holding shaft 28 are rotationally driven by the motor clockwise in FIG. 2, that is, in the same direction. Then, both sides of the disk D are simultaneously polished by the brush of the polishing agent 40. As shown in FIG. 2, the disk 23 and the disk D
Because they rotate in the same direction.

This means that the relative speed between the disk D and the brush of the abrasive 40 can be increased. Also, in Figure 2 (^)
The angular velocity of the disk D is small in the section, but the abrasive 4
The angular velocity of the 0 brush is increasing. In part (B), conversely, the angular velocity of the disk D is large and the angular velocity of the brush is small. In this way, the speed differences between the radii of the rotating bodies are compensated for each other, so that each part can be polished under uniform conditions.

Also, if liquid is injected into the liquid injection pipe 27 during the polishing operation,
The liquid flows from the liquid inlet 21b into the abrasive 40 by rotating centrifugal force.
Flows inside toward the outer circumference. This flow makes it possible to continuously discharge polishing debris from the disk D.

When the disk D is made of a non-magnetic material, by discharging the polishing debris as a liquid, it is possible to prevent the polishing debris from interfering with the orientation of the polishing agent 40.

FIG. 3 is a front view showing a magnetic polishing apparatus according to the present invention configured using a single magnet.

FIG. 4 is its left side view.

This magnetic polishing device has a centering sleeve 42 fixed at the center of the one-rotation shaft 21, and this sleeve 42
Two disks 41 facing each other are fixedly installed on the outer periphery of the disk. This disc 41 is made of a magnetic material such as soft iron, and a permanent magnet 43 such as a ferrite magnet is fixed in the middle of the disc 41 . Further, a non-magnetic cover 44 is provided on the surface of the permanent magnet 43. Also, inner disk 4
A fin 45 is fixedly provided on the opposing surface of 1. As shown in FIG. 4, the lines of magnetic force emitted from the permanent magnets 43 that are arranged radially around the rotating shaft 21 pass through the disk 41 and the fins 45 to form a closed loop magnetic field, and the inner disk At 41, magnetic poles of an N pole and an S pole are configured. A magnetic abrasive 40 is filled in the middle of the inner disk 41 and oriented by a magnetic field to form a brush of the abrasive 40. The disk D held by the holding shaft 2B is inserted into the brush. Polishing is then performed by the rotation of the brush and the rotation of the disk D.

Since the magnetic polishing apparatus shown in FIG. 3 uses only one permanent magnet 43 to form a closed loop magnetic field, it is possible to construct a simple and efficient apparatus.

In both the embodiments shown in FIGS. 1 and 3, the disk D is shown as the object to be polished, but it is also possible to polish a long object or the like. In this case, a long object to be polished is fed in a direction across the brush of the abrasive 40 and polished by the rotating abrasive brush. 3rd to #
In the case of the configuration shown in the figure, the area of the brush of the abrasive 40 becomes smaller as the permanent magnet 43 is closer to the rotating shaft 21, so when polishing a long object to be polished, the first
It is more suitable than the one shown.

Further, in each figure, the magnetic circuit is constituted by permanent magnets 24, 43, but it is also possible to use an electromagnet made of a coil. In this case, since the electromagnet rotates, the coil is energized using a single-rotation type electrical contact. Although it is better to use an electromagnet to obtain a larger magnetic force, the use of a permanent magnet has advantages such as being lighter and not having to worry about preventing the coil from generating heat. In addition, when a permanent magnet is used, the magnetic force that orients the abrasive 40 becomes slightly weaker, but when polishing a soft object such as an aluminum disk or a plastic disk, its abrasive action is can be fully demonstrated.

Magnetic polishing agent 40 used in the magnetic polishing device according to the present invention
may be the same as those conventionally used; however, in the present invention, a magnetic field is formed between the opposing disks,
Since the brush is formed by filling the abrasive 40 between them, the magnetic abrasive suitable for this structure should be one with a uniform and fine particle size, and one with a small specific gravity that is easy to handle for practical purposes. Examples of the abrasive 40 include alumina-iron, ferrite, and chromium dioxide. Among these magnetic abrasives, ferrite-based abrasives (barium ferrite, etc.) have plate-like particles and therefore have a low polishing rate, but are suitable for high-precision finishing. Furthermore, since chromium dioxide is acicular, it has good orientation in a magnetic field.

In practice, polishing oil and additives are added to the polishing agent to prevent seizure, prevent oxidation of the polishing surface, and prevent the polishing agent from scattering. Examples of these include higher fatty acids, metal soaps of higher fatty acids, higher fatty acid esters, mineral oils, silicone oils, or combinations thereof, or dispersions thereof in water. In addition,
These liquids may be supplied from the liquid injection pipe 27 shown in FIG.

[Embodiments of the invention]

Next, specific embodiments of the present invention will be described.

(Example 1) In the magnetic polishing apparatus shown in FIG. 1, a soft iron disk 25 with a diameter of 130 mm was fixed to a ferrite magnet 24 with a diameter of 12 mm, and the spacing between the disks 23 was set to 10 mm. The abrasive 40 used was an alumina-iron based material (85% iron, average particle size 5°, addition of about 3% stearin).

The object to be polished was a 5-inch aluminum magnetic disk substrate, and polishing was performed for 2 minutes at a rotational speed of 100 rpm (linear velocity at the outer periphery of the disk: 88 cm/5 ea).

The surface roughness of the polished surface before polishing was Rsax = 104m, but the surface roughness after polishing was Rmax at the outer periphery of the disk.
x m O, 3pm, Rmax +Ill G at inner circumference
, 4ILm.

(Example 2) The same disk as shown in Example 1 was used as the object to be polished,
Polishing work was carried out under the same equipment conditions as in Example 1, using chromium dioxide (stearic acid!2 added) as the polishing agent.

Polishing was performed for 4 minutes at a disk rotation speed of 120 rpm. As a result, the surface roughness after polishing is Rax = 0.01 m at the outer circumference of the disk, and Rd! at the inner circumference. =
It was 0.01 pot m.

(Example 3) The apparatus conditions were the same as in Example 1, and barium ferrite was used as the polishing agent 40. While supplying pure water containing 0.03 g of sodium laurate and 0.1 g of carboxymethyl cellulose from the liquid injection pipe 27 shown in Fig. 1 at a rate of 1 oocc/min, the object to be polished was polished with a diameter of 12 cm and a thickness of 2 cm.
The polycarbonate disc of ■■ was polished for 6 minutes.

The surface roughness after polishing is Rwax at the outer periphery of the disk.
= Q, Q44m, Rmax = Q, Q4Bm at the inner circumference.

〔Effect of the invention〕

As described above, according to the present invention, the following effects can be achieved.

(1) In the case of a disk-shaped object to be polished, its front and back surfaces can be polished simultaneously. Therefore, polishing work can be done efficiently.

(2) Since a magnetic field is created between the opposing discs to form a polishing agent brush, even objects to be polished made of non-magnetic materials can be polished.

(3) It is possible to polish not only a disk-shaped object but also a long object.

(Since the abrasive comes into contact with the object to be polished with uniform pressure, proper polishing work can be performed even on a wide polishing surface.

[Brief explanation of drawings]

FIG. 1 is a front view showing a magnetic polishing apparatus according to the present invention, and FIG.
The figure is a left side view, FIG. 3 is a front view of a magnetic polishing device having a structure different from that in FIG. 1, FIG. 4 is a left side view, and FIG.
6 is a front view of a conventional disk polishing device, FIG. 6 is a side view thereof, and FIG. 7 is a sectional view showing a conventional magnetic polishing device for disks. 21... Rotating shaft, 23... Disc, 24... Permanent magnet, 25... Soft iron disc, 28... Holding shaft, 28a
...Holder, 40...Abrasive, 41...Disc, 4
3...Permanent magnet, D...Disc. Figure 2 1I ・ Procedural amendments stamped) l Indication of the case 1985 Patent Application No. 145067 2 Name of the invention Magnetic polishing device 3 Representative of the person making the amendment Hiroshi Takahashi 4 Agent address 〒160 Name Patent attorney ( 8545) Teruo Nozaki8
Contents of amendment (1) Changed “2 claims” in line 3 of page 2 of the specification to “3
"Detailed Description of the Invention". (2) "Altitude" on page 2, lines 12-13' of the specification will be corrected to "hardness."

Claims (4)

[Claims] (1) S on one side of a pair of disks that face each other and rotate in the same direction.
One magnetic pole is formed on the other side, and a magnetic abrasive is interposed between the two disks to form a polishing brush made of the abrasive that is oriented in a magnetic field. A magnetic polishing device comprising a polishing brush and a polishing object holding member provided on the side of the polishing brush. (2) The magnetic polishing apparatus according to claim 1, wherein the object to be polished is disk-shaped, and both surfaces of the object to be polished are polished within a magnetic brush while being rotated by a holding member. (3) The magnetic polishing device according to claim 1, wherein the opposing disks are formed by a permanent magnet and a soft iron disk provided on the opposing surface thereof. (4) The magnetic polishing device according to claim 1, wherein the opposing disks are formed of soft iron disks, and a permanent magnet is interposed between the two disks at a portion near the rotation axis.