JPH10244451A - Polishing tool and polishing method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To polish works of various shapes by a small number of tools without requiring to slidingly adjusting to each other by covering a polishing surface of the tools with an extensible/contractible polisher, and sealing liquid inside of it. SOLUTION: A tool main body 4 is arranged between upper and lower electromagnets 7 and 7', and a work 5 is arranged between a tool main body 4 and the upper electromagnet 7. The tool main body 4 is constituted by using a cup 4a whose upper surface is covered with a polisher 2 as a base body, and is driven in rotation. A peripheral edge part of the polisher 2 is liquidtightly sealed by a holder 9. An opening 4c is formed at the bottom of the cup 4a, and an extensible/contractible bottom plate 4b is stuck, and a magnetic fluid 3 is sealed in the cup 4a. An extensible/ contractible sheet having a thickness of about 0.1 to about 1.0mm is used as the polisher 2. A similar extensible/contactible material is also used as the bottom plate 4b. When a work quantity is little, a magnetic field is not impressed, and the magnetic fluid 3 is freely moved according to a projecting surface of the work 5. When the work quantity is much, the magnetic field is impressed, and the magnetic fluid 3 is moved in the direction of an iron core 6, and is deformed, and pressure is imparted to the work 5. Therefore, a polishing quantity can be optimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing lenses, optical elements, and the like, and a polishing tool used therefor. In particular, the present invention relates to a polishing tool capable of coping with works of various shapes with a small number of polishing tools and a polishing method using the same.

[0002]

2. Description of the Related Art For final polishing of lenses, optical elements, etc., which require a high degree of shape precision, as shown in FIG.
A polishing tool using a polisher 10 made of an elastic material is used. The polisher 10 is formed of a pitch mainly composed of tar or the like, a polishing pad mainly composed of urethane foam or the like, and is attached on the holding plate 13.
The polisher 10 rotates around its axis together with the holding plate 13. Then, a work (not shown) is pressed and polished while supplying a polishing liquid to the polishing surface 11 (work surface) on the upper surface of the polisher 10. Usually, grooves and pits 12 and the like are formed on the polishing surface 11 of such a polisher 10, and free abrasive grains supplied during polishing are appropriately held between the polishing surface 11 and the surface of the workpiece. I have.

[0003]

By the way, the polishing surface 11 of the polisher 10 of this kind of polishing tool is precisely shaped into a curvature and a diameter suitable for processing a workpiece having a specific shape. In other words, one polishing tool is used only for polishing a surface to be polished having a specific shape. Therefore, there arises a disadvantage that a polishing tool suitable for each curvature and each diameter of various kinds of lenses must be prepared.

[0004] As the polishing process proceeds, the polisher 1
Since the shape of the polished surface 11 of the polisher 10 is gradually deformed and deteriorated, the polishing surface 11 of the polisher 10 is appropriately rubbed during the polishing process to recover the polishing performance represented by the transferability. It is said to be the standard to be adopted to maintain accuracy. However, there is a problem that a great amount of time spent in the complicated rubbing process is directly linked to a reduction in manufacturing efficiency and an increase in manufacturing cost. In other words, the polisher cannot be used for production during the rubbing process.
The production facilities are waiting to be assembled.

SUMMARY OF THE INVENTION An object of the present invention is to provide an innovative polishing tool which can cope with works of various shapes with a small number of polishing tools and does not require rubbing, and a polishing method using the polishing tool.

[0006]

In order to solve the above problems, a polishing tool according to the present invention has a polishing surface covered with an elastic polisher, and a liquid is sealed inside the polisher. And

[0007] The polishing method of the present invention uses a polishing tool having a polishing surface covered with an elastic polisher and a liquid sealed inside the polisher, and pressing the polishing tool against a workpiece. The polished surface of the polisher is fitted to the polished surface of the work, and in this state, the polished surface is polished by relatively moving the elastic polisher and the work.

[0008]

In the present invention, the liquid is a magnetic fluid, and the elastic polisher is polished to the surface to be polished by using magnetic urging means for urging the magnetic fluid in a selected direction. Preferably.

In this embodiment, the polisher can be freely deformed by the movement of the magnetic fluid in the magnetic field. The deformed shape of the polisher can also be controlled by changing the shape of the iron core. That is, since the curvature and the polishing pressure of the polished surface of the polisher can be freely changed, it is possible to perform polishing of various lenses having different curvatures without changing the polishing tool. Further, it is possible to perform a polishing process with a good finish on a workpiece such as an aspherical lens whose surface shape changes in curvature. At this time, it is not necessary to perform the rubbing process.

Hereinafter, embodiments will be described in detail with reference to the drawings. The magnetic fluid used in this embodiment is a colloid solution in which ferromagnetic fine powder such as ferrite is dispersed in a liquid phase (water). Since the ferromagnetic fine powder (dispersant) has an extremely fine particle size of about several tens to several hundreds of millimeters, it has magnetic properties that always exhibit sexual behavior. That is, by applying a magnetic field, the magnetic fluid is attracted to the magnetic flux path,
In particular, the magnetic flux density is attracted to the larger one.

FIG. 1 is a side sectional view schematically showing the entire configuration of a polishing tool according to one embodiment of the present invention. FIG.
FIG. 2 is a side sectional view showing details of a cup portion of the polishing tool of FIG. 1. This polishing tool 1 is composed of upper and lower electromagnets 7, 7 'and a tool body 4 interposed therebetween. A work 5 (lens) is arranged between the upper surface of the tool body 4 and under the upper electromagnet 7 for processing. The work 5 is basically positioned and fixed at a certain reference position with respect to the tool body 4. However, depending on the type of the work, a structure that rotates, swings, and moves left and right, back and forth may be used.

The tool body 4 includes a cup 4a which is driven to rotate.
(Material: brass, etc.). The upper surface of the cup 4a is open, and this upper surface is
(Details described later). The polisher 2 is polished by pressing the upper surface (polishing surface) against the work 5 by a mechanism described later. The peripheral portion 2a of the polisher 2 is a cup 4a
Overhangs the outer peripheral surface of. The outer periphery of the peripheral edge portion 2a is firmly and uniformly fastened by the holder 9. The holder 9 has a metal band such as a fastener for a water hose and a tightening mechanism (not shown), seals the polisher peripheral portion 2a in a liquid-tight manner, and keeps the upper surface free of wrinkles.

An opening 4c is opened at the bottom of the cup 4a except for a small peripheral portion. A cup 4a is placed on the opening 4c.
An elastic bottom plate 4b for keeping the inside volume constant is attached. The bottom plate 4b is made of a material having the same elasticity as the polisher 2. The bottom plate 4b is liquid-tightly fixed to the cup 4a with an adhesive and a mechanical fastener (not shown). The above-described magnetic fluid 3 is sealed in the cup 4a.

The electromagnet 8 has an iron core 6 at the center and a coil 8 around the core. When the coil 8 is energized, a magnetic flux φ (phi, two-dot chain line) is formed between the upper and lower iron cores 6, 6 '. Under the influence of this magnetic flux, the enclosed magnetic fluid 3 is attracted to the magnetic flux forming portion and the liquid surface rises, the polisher 2 rises as shown by the dotted line, and the polished surface of the polisher 2 Surface). Here, the intensity of the magnetic field applied to the magnetic fluid 3 can be adjusted by changing the amount of current flowing through the coil 8. On the other hand, since the magnetic field distribution can be changed by changing the shape of the tip of the iron core 6, the hardness and shape of the polisher can be adjusted.
For example, if the central part of the iron core 6 is formed so as to protrude in the direction of the work 5, the central part of the polisher 2 also rises sharply.
Further, if the iron core 6 is formed in a ring shape, the polisher 2 also rises in a ring shape.

The electromagnet 7 comprises a polishing tool 4 and a work 5
It is not necessary to be on both sides, and a similar effect can be obtained with only one of them. So that the effect of the electromagnet is
It is preferable that the center of the iron core 6 and the center of the polishing tool 4 coincide with each other, and the polisher surface and the iron core 6 be located at right angles. Needless to say, the same effect can be obtained even if a permanent magnet is used instead of the electromagnet 7. In this case, the strength of the magnetic field can be changed by changing the position of the permanent magnet.

Here, the polisher uses a stretchable sheet having a thickness of about 0.1 to 1.0 mm. The material is preferably chloroprene rubber or nitrile rubber. However, the present invention is not limited to this, and any material having elasticity can be used.

FIG. 3 is a partial cross-sectional side view showing a state in which a convex surface of a work (lens) is polished using the polishing tool of FIG. In the state where no magnetic field is applied, the magnetic fluid 3 can move freely. Therefore, when polishing the work 5 having a polished surface as shown in FIG. 3, the polisher 2 is deformed into a concave shape along the convex surface. Fluid 3 moves. In this case, the polisher 2 does not positively act on the surface to be polished of the work 5 and is suitable for obtaining a small processing amount.

When a large amount of machining is required, the magnetic fluid 3 moves in the direction of the iron core 6 by applying a magnetic field, and applies an appropriate pressure to the work 5. Shape can be obtained.

FIG. 4 is a partial cross-sectional side view showing a state in which a flat polished surface is polished using the polishing tool of FIG. In such a case, the magnetic fluid 3 is applied by applying a magnetic field.
Is moved in the direction of the iron core 6, and the current flowing through the coil of the electromagnet is adjusted so that the pressure distribution on the surface of the polisher 2 becomes uniform. Since the polisher 2 applies an appropriate pressure to the work 5, it is possible to obtain a good polishing amount and a processed surface shape.

FIG. 5 is a partial cross-sectional side view showing a manner of polishing a concave surface to be polished using the polishing tool of FIG. In such a case, the magnetic fluid 3 is applied by applying a magnetic field.
Is moved in the upward direction of the iron core 6, and the current flowing through the coil of the electromagnet is adjusted so that the pressure at the center of the surface of the polisher 2 is increased. Since the polisher 2 is deformed to a convex surface and applies an appropriate pressure to the work 5, a good polishing amount and a processed surface shape can be obtained.

FIG. 6 is a partial cross-sectional side view showing a state in which a convex surface of a work is polished using a polishing tool corresponding to a convex surface having a large curvature. The polisher 2 is attached to the cup 4 so as not to wrinkle, and the magnetic fluid 3 is sealed between the cup 4 and the polisher 2. At this time, the holding tool 9 chucks the magnetic fluid 3 so as not to leak. When processing such a convex workpiece 5 having a large curvature, it is easier to follow the deformation caused by the movement of the magnetic fluid by using a polisher that has been formed into a convex shape in advance, so that more effective processing can be performed. Become.

When no magnetic field is applied, the magnetic fluid 3 can move freely. Therefore, when polishing a convex work 5 having a large curvature as shown in FIG. 6, the polisher 2 is deformed concavely along the convex surface of the work 5. Accordingly, the magnetic fluid 3 moves. In this case, the polisher 2 does not positively act on the convex surface of the work 5 and is suitable for obtaining a small processing amount.

When a large amount of machining is required, the magnetic fluid 3 moves in the direction of the iron core 6 by applying a magnetic field, and applies an appropriate pressure to the work 5. Shape can be obtained.

FIG. 7 is a partial cross-sectional side view showing a state in which a concave surface of a work is polished using a polishing tool corresponding to a concave surface having a large curvature. As in the case of FIG. 6, the polishing of the concave surface with a large curvature can be performed.

The processing pressure at the time of polishing can be controlled by changing the intensity of the applied magnetic field. If this is applied, aspherical surface processing is also possible. By controlling the magnetic field so that the processing pressure increases in a portion having a large curvature, and controlling the magnetic field so that the processing pressure decreases in a portion having a small curvature, an aspherical shape can be obtained by continuous processing. Since the intensity of the processing pressure can be smoothly changed, the bending and distortion due to the processing are reduced as compared with the conventional processing method.

[0026]

As is apparent from the above description, according to the present invention, by using the polishing tool of the present invention, it is possible to cope with various workpiece shapes even with a small number of polishing tools. In the embodiment in which the magnetic field is adjusted, the surface shape and processing pressure of the fine polisher can also be controlled by changing the iron core shape and the magnetic field strength. That is, since the curvature of the working surface of the polisher and the polishing pressure can be freely changed, it is possible to perform polishing of various lenses having different curvatures without changing the polishing tool. Further, it is possible to perform a polishing process with a good finish on a workpiece such as an aspherical lens whose surface shape changes in curvature. Therefore, it is not necessary to apply a grinding process to the polishing tool, and a great amount of time and cost spent for preparing the polishing tool can be reduced.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view schematically showing an overall configuration of a polishing tool according to one embodiment of the present invention.

FIG. 2 is a side sectional view showing details of a cup portion of the polishing tool of FIG. 1;

FIG. 3 is a partial cross-sectional side view showing a state where a convex surface of a work is polished using the polishing tool of FIG. 1;

FIG. 4 is a partial cross-sectional side view showing a state in which a flat polished surface is polished using the polishing tool of FIG. 1;

FIG. 5 is a partial cross-sectional side view showing a manner of polishing a concave surface to be polished using the polishing tool of FIG. 1;

FIG. 6 is a partial cross-sectional side view showing a state in which a convex surface of a work is polished using a polishing tool corresponding to a convex surface having a large curvature.

FIG. 7 is a partial cross-sectional side view showing a state in which a concave surface of a workpiece is polished using a polishing tool corresponding to a concave surface having a large curvature.

FIG. 8 is a side view showing a configuration of a conventional polishing tool.

[Explanation of symbols]

Reference Signs List 1 polishing tool 2 polisher 2a peripheral part 3 magnetic fluid 4 tool body 4a cup 4b elastic bottom plate 4c bottom opening 5 work (lens) 6 iron core 7 electromagnet 8 coil 9 holder 10 polisher (pitch, urethane) 11 polished surface 12 pit 13 Holding board

Claims (4)

[Claims] 1. A polishing tool having a polishing surface covered with an elastic polisher, wherein a liquid is sealed inside the polisher. 2. The method according to claim 1, wherein the liquid is a magnetic fluid, and magnetic biasing means for biasing the magnetic fluid in a selected direction is provided.
Polishing tool as described. 3. A polishing tool having a polishing surface covered with an elastic polisher and having a liquid sealed inside the polisher, pressing the polishing tool against the work, and polishing the polishing surface of the polisher to the work A polishing method, wherein the elastic polisher and the work are relatively moved to polish the surface to be polished in this state. 4. The polishing method according to claim 3, wherein the liquid is a magnetic fluid, and the elastic fluid is urged in a selected direction to press the elastic polisher against the surface to be polished. Method.