JPH079330A - Ultraprecise surface polishing method and device - Google Patents

Abstract

PURPOSE:To make the relative polishing operation of a work with a polishing member uniform, and to polish evenly by loading the work on a lap on which separate abrasion grains or fixed abrasion grains are provided, and giving a preset looping movement or linear movement to the lap. CONSTITUTION:While a looping or a linear movement is given to a lap 1 on which a work 2 is loaded, a variation is given to the looping or the linear movement. As a result, the polishing surface of the work 2 is polished by the abrasive grains moving at random evenly. While the looping or the linear movement can be controlled automatically by program-moving the X table and the Y table in the square directions each other, the speed is converted by the movements of the tables, and a standardized operation can be prevented. As a result, the abrasive grains do not stay in one place, and an even polishing can be carried out. Furthermore, since all the polishing process can be carried out in one setting, a single worker can deal with plural devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-precision surface polishing method and apparatus intended to allow abrasive grains to act on the polishing surface of a workpiece under the same conditions.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional flat polishing apparatus normally mounts a work 2 on a radial portion of a rotary wrap 1 having an upper surface as a flat surface, and the wrap 1 is indicated by an arrow. The work 2 was rotated as indicated by the arrow. In this case, the work 2 was held by the roller 23 and rotated at a fixed position.

[0003]

According to the above-mentioned conventional polishing method, since the movement of the abrasive grains is different at all contact points of the lap and the work, it is difficult to uniformly polish the work. For example, in FIG. 5, the center part of the work is always polished by the constant speed lap (hence, abrasive grains), but the peripheral part of the work is subjected to the changed polishing action from low speed to high speed. In other words, the work is subjected to different polishing actions in the radial direction. It is possible to make the polishing conditions the same at any point of the work if the rotation of the work in the lap and the adjusting ring is set to a certain ratio, but in practice it is difficult to always grind under this condition.

Further, as shown in FIG. 5, since the work is placed on the radial portion of the lap, there is a problem that only one-third of the diameter of the wrap can actually be ground.

[0005]

SUMMARY OF THE INVENTION However, according to the present invention, since the loop or the linear motion is applied to the lap on which the work is placed and the loop or the linear motion is changed, the polishing surface of the work is randomly distributed. Since the particles are polished by moving abrasive grains, the above-mentioned conventional problems have been solved.

The loop or linear movement can be automatically controlled by program-moving the X table and the Y table at right angles to each other, and the movement of each table changes the speed to prevent unification. can do. Therefore, the abrasive grains do not stay in one place.

That is, in the invention of the method, the work is placed on the lap via the abrasive, and the loop or the linear motion preliminarily set on the lap is performed to equalize the relative polishing action between the work and the abrasive. This is an ultra-precision surface polishing method characterized in that the loop movement of the lap is performed by program-moving the lap in the directions of the X axis and the Y axis which are perpendicular to each other. Another invention is characterized in that the loop shape of the lap is changed with the passage of time, and the vector of the force applied to the work is changed by changing the acceleration applied to the lap. is there. Although the polishing surface of the work is a flat surface, it has a very large radius of curvature (for example, a radius of 50 m
Can be polished even with 100 m).

Next, the invention of the apparatus mounts a Y table movable on the machine base in the Y-axis direction, and mounts an X table movable on the Y table in a direction perpendicular to the moving direction of the Y table. Then, a lap frame having a cylindrical recess is fixed on the X table, a lap having a flat upper surface is fixed in the center of the cylindrical recess, and a work can be placed on the lap. In addition, the ultra-precision surface polishing apparatus is characterized in that the X-table and the Y-table are connected to the controlled driving means. In still another invention, the wrap frame has a tubular shape, and an elastic material is layered on the inner wall of the wrap frame.

As the driving means, a pulse motor or a servomotor, a ball screw rotated by the pulse motor, and a sliding or rolling guide screwed to the ball screw are used. For example, a sponge is used as the elastic material.

A program-controlled control circuit is provided in the electric circuit of the pulse motor or the servomotor, and the control circuit switches the motor circuit in the forward and reverse directions to X.
It is also possible to control the moving direction and moving speed of the table or the Y table.

[0011]

According to the present invention, the loop motion is imparted to the lapping to impart the loop motion to the abrasive grains for polishing the work, whereby the abrasive grains are not contacted with the polishing surface of the work to move uniformly. Can be made.

[0012]

Example 1: 200 mm diameter on a lap with a diameter of 300 mm,
A glass plate (work) weighing 1,500 g is placed.

Next, the elliptical loop motion is continued for 1 minute by giving the lap a reciprocating motion of 5 mm / sec in the X-axis direction and a reciprocating motion of 8 mm / sec in the Y-axis direction. Next, when the lap was changed and the same polishing was continued for 1 minute, an average roughness of 1 nanometer was obtained. On the other hand, the average roughness when polishing with a rotary lap was 10 nanometers.

When the lap is moved only in a certain circular motion, scratches may occur on the locus of the motion. In order to prevent this phenomenon, change the diameter of the circle with time,
The center of the circle is slightly shifted, and thereby the work is rotated (FIG. 4 (c)). In the case of elliptical motion, the size of the ellipse is changed with time, the center position of the ellipse is slightly shifted, and the ratio of the major axis to the minor axis and its direction are changed (see FIG. 4).
(A)) This gives rotation to the work.

There is also a case where an 8-shaped movement having different proportions is given (FIG. 4 (b)).

[0016]

[Embodiment 2] An embodiment of the present invention will be described with reference to FIGS.

A Y table 5 reciprocating in the Y-axis direction is mounted on a surface plate 4 fixed on the machine base 3. The Y table 5
Is fixed to a roller guide 7 of a ball screw 6 installed on a surface plate 4, and one end of the ball screw 6 is connected to a shaft of a pulse motor 9 by a coupling 8. The pulse motor 9 is fixed to the surface plate 4 via a bracket 10.

Next, an upper surface plate 11 is fixed on the Y table 5, and a ball screw 12 is installed on the upper surface plate 11 at a right angle to the ball screw 6. The ball screw 12 is screwed to an X table 14 via a roller guide 13,
One of the roller guides 13 is fixed to an X table 14 slidably mounted on the upper surface plate 11.

The shaft of a pulse motor 16 is connected to the other end of the ball screw 12 via a coupling 15, and the pulse motor 16 is fixed on a bracket 17 fixed to the upper surface plate 11.

A cylindrical wrap frame 18 is fixed on the X table 14. A sponge layer 19 is layered on the inner wall of the wrap frame 18, the wrap 1 is fixed in the wrap frame 18, and the work 2 is placed on the wrap 1.

In the above embodiment, when the movement of the lap 1 is set in the controller 20 and the switch is pressed, the output of the controller 20 is input to the pulse motors 9 and 16 via the cables 21 and 22. So the pulse motor 9,
When the ball screws 6 and 12 are rotated in a predetermined direction in accordance with an input instruction, the Y table 5 advances in the direction of an arrow 24 by a predetermined distance via the roller guides 7 and 13, and the X table 14 moves. Move forward a predetermined distance in the direction of arrow 25. Then, the inputs of the pulse motors 9 and 16 are reversed and the ball screws 6 and 12 are rotated in the reverse direction.
The table 14 moves in the direction opposite to the above as indicated by arrows 26 and 27. That is, by reciprocating the Y table 5 and the X table 14, the lap can be moved in a loop. The above-mentioned loop motion is repeated 1 to 30 times per second to continue polishing.

Next, it is possible to prevent uniform polishing by changing the sliding distance between the Y table and the X table, or by changing the sliding distance and the number of repeated movements per second.

In the above embodiment, a pulse motor is used,
Of course, a servo motor may be used.

Further, instead of the motor and the ball screw, a conventionally known driving means may be appropriately adopted as the driving means for the X and Y tables, such as a method of using a capstan by driving a motor and a cam or a roller, or a crank driving method. You can A sliding surface that is not a roller guide can also be used.
The tables do not necessarily need to be orthogonal, and can be used if they are crossed (for example, crossed at 60 degrees).

[0025]

That is, according to the present invention, fully automatic polishing can be performed by a single set, so that there is an effect that one operator can handle many machines.

Further, there is an effect that the moving state of the abrasive grains on the polishing surface of the work can be made uniform to perform uniform polishing.

Next, it is possible to replace the lap and set the work extremely easily and surely, and there are various effects such as a large degree of freedom in selecting the size of the wrap and the work.

Further, the working pressure can be kept constant and the working pressure can be easily adjusted.

In the control of the present invention, for example, computer graphics can be used to image-verify the best abrasive grain motion in planar polishing, which has the effect of clarifying the polishing mechanism.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a block diagram of a control system of the same.

FIG. 4 is an exemplary view of the same wrap. (A) Elliptical motion diagram.
(B) Figure 8 movement chart. (C) Circular motion diagram.

FIG. 5 is a partial plan view of a conventional polishing apparatus.

[Explanation of symbols]

 1 Lap 2 Work 3 Machine Stand 4 Plate 5 Y Table 6, 12 Ball Screw 7, 13 Roller Guide 8, 15 Coupling 9, 16 Pulse Motor 10, 17 Bracket 11 Upper Plate 14 X Table 18 Lap Frame 19 Sponge Layer 20 controller 21, 22 cable

Claims (7)

[Claims] 1. A relative polishing action between a work and an abrasive is obtained by placing a work on a lap provided with free abrasive grains or fixed abrasive grains and performing a loop or linear movement previously set on the lap. Ultra-precision surface polishing method characterized by equalization. 2. The ultra-precision surface polishing method according to claim 1, wherein the loop or linear movement of the lap is performed by program-moving the lap in the X-axis and Y-axis directions intersecting each other. 3. The ultra-precision surface polishing method according to claim 1, wherein the loop shape of the lap is changed with the passage of time. 4. The ultraprecision surface polishing method according to claim 1, wherein the vector of the force applied to the work is changed by changing the acceleration applied to the lapping. 5. The ultra-precision surface polishing method according to claim 1, wherein the polishing surface of the work is a flat surface or a spherical surface having an extremely large radius of curvature. 6. A Y table movable on the machine base in the Y axis direction is mounted, and an X table movable on the Y table so as to intersect with the moving direction of the Y table is mounted on the Y table. Fix the wrap frame that has the cylindrical recessed part upwards,
A lap having a flat upper surface is fixed in the central portion of the cylindrical recessed portion, a work can be placed on the lap, and controlled driving means are connected to the X table and the Y table. Characteristic ultra-precision surface polishing equipment. 7. The ultra-precision surface polishing apparatus according to claim 6, wherein the wrap frame has a cylindrical shape, and an elastic material is layered on the inner wall of the wrap frame.