JP2001047350A - Polishing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To polish a long stretching work uniformly in a short time. SOLUTION: A polishing tool 10 is pressed by a bellow-phragm cylinder 11 to the surface processed of a work W1, which is polished by scanning in longitudinal direction a placing table 20 for the work W1 while the tool 10 is swung in the shorter side direction by a motor 12. If the work W1 is scanned only in the longitudinal direction, surface unevenness, waviness, etc., in the longitudinal direction can not be removed satisfactorily, so that the scan is performed with the table 20 swung in the longitudinal direction by controlling the rotation in regular and reverse direction of a stepping motor 21. At this time, the table 20 is allowed to follow up after a template 23 so that the attitude of the work W1 (inclination) is controlled on the basis of the change in the shape in longitudinal direction, and the polished point on the work W1 is kept vertically with respect to the tool 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and a polishing apparatus for polishing a long workpiece having a curved surface to be processed, for example, a toric shape.

[0002]

2. Description of the Related Art For example, when manufacturing a mold for forming a toric lens (a toric mold) or the like, a process of polishing a long curved surface to be mirror-finished by polishing is required.
As a polishing apparatus used in such a case, a polishing tool is pressed against a work surface of a long work such as a toric mold, and the work surface of the work is scanned while scanning in the longitudinal direction of the work surface. The process of oscillating the polishing tool in the lateral direction and rubbing the workpiece and the polishing tool is repeated.

[0003] The swinging of the polishing tool in the short direction is performed by swinging a kansashi, whose tip is a pin joint, for pressing the polishing tool against the work surface of the workpiece by a swing mechanism. In addition, the movement in the longitudinal direction, that is, scanning, is performed by moving the mounting table on which the work is placed in the longitudinal direction by a linear drive mechanism.

[0004] In this way, the process of polishing the work surface of the work in a belt shape by feeding the work in the longitudinal direction while swinging the polishing tool in the short direction is repeated.

[0005]

However, according to the above-mentioned prior art, since the relative movement of the polishing tool in the longitudinal direction of the work is only a movement for scanning or feeding by linear drive, the work is long and long. If the moving distance in the direction is long, high-speed scanning cannot be performed, and it is difficult to achieve a polishing speed for obtaining a required polishing amount. As a result, the processing time becomes longer, and it is not possible to completely remove longitudinal irregularities and undulations remaining on the surface to be processed of the work, or processing marks in the lateral direction.

If the shape of the workpiece changes greatly in the longitudinal direction, the polishing tool cannot follow the change in the inclination of the work surface of the work and the polishing tool separates from the work surface, so that polishing cannot be performed.

Further, when the workpiece has a shape change in the longitudinal direction and the radius of curvature in the short direction is constant, the center position of the swing in the short direction is always constant. Accordingly, there is an unsolved problem that the swing radius in the short direction changes and uniform polishing cannot be performed.

The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and in particular, it can completely remove irregularities and undulations existing in the longitudinal direction and can shorten the processing time. It is another object of the present invention to provide a polishing method and a polishing apparatus capable of performing uniform polishing in response to a change in the shape of any work.

[0009]

In order to achieve the above object, a polishing method according to the present invention comprises pressing a polishing tool against a workpiece and swinging the polishing tool in a short direction of the workpiece. A polishing method having a step of relatively scanning in the longitudinal direction of the workpiece while scanning the polishing tool while relatively swinging the polishing tool in the longitudinal direction of the workpiece. .

When moving the workpiece in the longitudinal direction,
The posture or height of the workpiece may be controlled based on a change in the shape of the workpiece.

A polishing apparatus according to the present invention comprises: a polishing tool; pressing means for pressing the polishing tool against a workpiece; and short-side swing means for swinging the polishing tool in a short direction of the workpiece. A scanning means for scanning the work in the longitudinal direction thereof, and a longitudinal swing means for swinging the work in the longitudinal direction.

It is preferable that the scanning means and the longitudinal swing means are constituted by a stepping motor and a ball screw which can be rotated forward and backward, and a controller which controls forward and reverse rotation of the stepping motor.

It is preferable that a pair of templates is provided for controlling the posture or height of the workpiece based on a change in the shape of the workpiece in the longitudinal direction.

It is preferable that the mounting table on which the workpiece is mounted has a cam follower abutting on the guide surface of each template and a cam follower abutting on the inner surface of each template.

[0015]

The workpiece is scanned while the workpiece is relatively swung in the longitudinal direction with respect to the polishing tool, and the workpiece is formed into a curved surface by sliding with the polishing tool which is pivoted in the transverse direction. Polish the surface. By swinging in the longitudinal direction, a sufficient polishing rate is secured also in the longitudinal direction, and undulations and irregularities in the longitudinal direction are reliably removed in a short time. As a result, the processing time of a toric mold or the like can be shortened, and the productivity of long components such as a toric lens can be greatly improved.

The uniformity of longitudinal polishing can be improved by changing the posture of the workpiece based on the change in the shape of the workpiece in the longitudinal direction and keeping the polishing point perpendicular to the polishing tool.

Alternatively, the height of the workpiece is changed based on a change in the shape of the workpiece in the longitudinal direction, and the polishing point is maintained at a constant height with respect to the polishing tool, so that polishing in the short direction is performed. Uniformity can be improved.

[0018]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a polishing method according to an embodiment, and a long work (workpiece) such as a toric mold.
The treated surface of the W _1, is pressed against the polishing tool (not shown)
While relatively scanning as shown in the longitudinal direction of the work W ₁ by the arrow A, in the lateral direction to oscillate the polishing tool as indicated by arrow B, and length of the workpiece W ₁ as shown by an arrow C also is relatively swinging direction, performs lapping between the workpiece W ₁ and the polishing tool.

For example, the movement of the work W _{1 in} the longitudinal direction is as follows.
Scanning indicated by arrow A is performed by advancing a little by one swing while swinging back and forth as indicated by arrow C. As a result, a sufficient polishing rate can be obtained in the longitudinal direction as well as in the lateral direction. By sufficiently increasing the polishing rate in the longitudinal direction, irregularities and undulations in the longitudinal direction, processing marks in the lateral direction, and the like can be completely removed in a short time.

The longitudinal direction of the swing and the scanning of the workpiece W ₁ is in conformity with the shape change of the processed surface of the workpiece W _1, carried out while adjusting the inclination of the workpiece W _1. Alternatively, by changing the height of the workpiece W ₁ to keep the height of the polishing point or working point of the workpiece W ₁ in contact with the polishing tool constant,
Perform uniform polishing.

FIG. 2 shows a polishing apparatus provided with a mechanism for swinging in the short direction and swinging and scanning in the long direction as described above.

The polishing tool 10 is moved downward in the figure by a bellow frame cylinder 11 which is a pressing means, and the workpiece W ₁ is moved.
Is pressed in the treated surface, swings in the lateral direction of the work W ₁ by driving the motor 12 is a lateral direction rocking means.

The scanning and swinging in the longitudinal direction of the mounting table 20 on which the work W ₁ is mounted is performed by forward and reverse rotation of a ball screw 22 driven by a stepping motor 21. The scanning means and the longitudinal swing means are constituted by a controller (not shown) for controlling the rotation. Further, by following the table 20 mounting a pair of templates 23 having a curvature close to the shape change of the processed surface of the workpiece W _1,
During the longitudinal direction of the scanning or oscillating, the inclination of the work W ₁ (orientation)
Or the height is adjusted, and the polishing tool 10
Are constantly in contact with each other to perform uniform polishing.

The short-side swing mechanism of the polishing tool 10 will be described in detail. As shown in FIG. 5, the ring 13 connected to the motor 12 rotates in the direction of arrow d, and the bearing 14
By connecting the ring 13 and the polishing tool support 16 with lot rods 15 having both ends a and 14b, the polishing tool 1
The polishing tool support 16 and the polishing tool support 16 are integrally formed so as to perform a swinging motion about a fulcrum e. By vertically moving the entire swing mechanism of the lateral direction, it is possible to match the fulcrum e in the lateral direction of the workpiece W ₁ spherical center. Further, the swinging width can be changed by shifting the connecting portion between the ring 13 and the bearing 14a.

The polishing tool 10 includes a bellofram cylinder 1
1, floating joint 17, linear slider 1
8, connected to the tip of the ball base 19,
As shown in FIG. 5B, when the pneumatic pressure in the direction of arrow f is introduced into the belofram cylinder 11 at an arbitrary pressure, the polishing tool 10 is moved in a substantially vertical direction along the movement of the linear slider 18 with a constant load. in contact with the workpiece W _1. The ball seat 19, linked polishing tool 10 is configured so as to be inclined in all directions, which makes it possible to polishing tool 10 to follow the shape of the processed surface of the workpiece W _1.

[0027] On the other hand, scanning the longitudinal direction of the swing of the workpiece W ₁ is carried out by placing table 20 carrying the workpiece W ₁ is moved on the guide surface 23a of the template pair 23 by normal and reverse rotation of the ball screw 22 It is. That is,
The support 25 connected to the mounting table 20 reciprocates in the longitudinal direction by forward and reverse rotation of the ball screw 22 connected to the stepping motor 21, and the controller moves the work W _1.
Is controlled so that it moves forward little by little by one swing. In this way, relatively polishing tool 10 is swung-scanned over the workpiece W ₁ in the longitudinal direction.

The shape of the guide surface 23a of the template 23 is, as shown in FIGS.
A curved shape having a curvature close to the curvature of the _first longitudinal surface, eliminating the inclination of the work surface at the polishing point of the workpiece W ₁ in contact with the polishing tool 10, to keep perpendicular to the polishing tool 10 Be composed. Alternatively, as shown in FIG. 6C, cam followers 20 a, 2 connected to the mounting table 20 are obtained by inverting the shape of the work longitudinal surface with respect to the horizontal axis.
0b (see FIG. 3 and FIG. 4), the height of the polishing point (working point) is kept constant, and the position of the center of oscillation of the spherical center of the polishing tool 10 is not changed. The configuration is as follows.

Template Guy for Eliminating Work Inclination
The radius of curvature R of the curved surface is obtained as follows. FIG. 7 and FIG.
Work W having a convex shape as shown in FIG._TwoAnd concave shaped work
W _ThreeIn the case of, the work length represented by the following equation (1)
Least-squares method expressing the aspherical shape in the hand direction by equation (2)
Approximation. Where R_aIs the basic curvature, k, B_iIs aspheric
Indicates a coefficient.

[0030]

(Equation 1)

[0031]

(Equation 2)

As shown in FIG. 9 and FIG.
₂ , the radius of curvature of the longitudinal approximation of W ₃ is R _m , the height of the work center from the center of the cam followers 20a, 20b of the mounting table 20 is h, and 1/2 of the distance between the cam followers 20a, 20b of the mounting table 20 is B, Assuming that the radius of the cam follower 20a is Rr, the R of the template 20 to be obtained is as shown in the following equations (3) and (4).

[0033]

(Equation 3)

[0034]

(Equation 4)

Further, the guide surface of the template for keeping the height of the polishing point constant and not changing the position of the center of swing of the spherical center has the aspherical shape shown by the equation (1) and the following equation (5). ), The sign is reversed, and this is shown in FIG.
(C), the shapes are arranged at the distance between the cam followers 20a and 20b.

[0036]

(Equation 5)

Next, the driving mechanism of the mounting table 20 in the longitudinal direction will be described in detail. As shown in FIG. 3, the mounting table 20 is driven in the longitudinal direction by sandwiching a support 25 that moves in the longitudinal direction by rotation of the ball screw 22 with a joint 24 provided below the mounting table.

The joint 24 and the support 25 are connected with a degree of freedom in the vertical direction, so that the mounting table 20 can move up and down along the shape of the template 23.

As shown in FIG. 4, the cam followers 20a and 20b provided on both sides of the mounting table 20 roll on the guide surfaces 23a of the pair of templates 23, so that the mounting table 20 moves. . On the lower surface of the mounting table 20,
Another four cam followers 20c and 20d are provided so as to be in contact with the inner surface of the template 23. The two cam followers 20c and 20d on one side incorporate a spring 26, and
It is urged so that it is always pushed outward and pressed against the inner surface of the template 23. With such a guide mechanism, the mounting table 20 can move smoothly between the pair of templates 23 without tilting.

According to the present embodiment, in the polishing of a long workpiece having different curvatures in the directions of two orthogonal axes, irregularities and undulations in the longitudinal direction, processing marks in the lateral direction, and the like can be completely eliminated in a short time. And very uniform polishing can be performed following changes in the shape of the work surface of the workpiece.

[0041]

Since the present invention is configured as described above, the following effects can be obtained.

The work of any shape can be uniformly polished and the processing time can be greatly reduced. by this,
This can greatly contribute to lower prices for toric lenses and the like.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a polishing method according to an embodiment.

FIG. 2 is a perspective view showing a polishing apparatus according to the embodiment.

FIG. 3 is a schematic elevation view showing a driving mechanism in a longitudinal direction.

FIG. 4 is a side view showing the apparatus of FIG. 3;

FIG. 5 is a diagram illustrating a lateral swing mechanism.

FIG. 6 is a diagram illustrating the relationship between the shape of a work and the shape of a template.

FIG. 7 is a diagram illustrating an approximation method of a shape change of a convex workpiece.

FIG. 8 is a diagram illustrating an approximate method of shape change of a concave workpiece.

FIG. 9 is a diagram illustrating a method for calculating a template shape for a convex workpiece.

FIG. 10 is a diagram illustrating a method of calculating a template shape for a concave workpiece.

[Explanation of symbols]

 Reference Signs List 10 polishing tool 11 bellofram cylinder 12 motor 16 tool support 17 floating joint 20 mounting table 20a to 20d cam follower 21 stepping motor 22 ball screw 23 template 24 joint 25 support 26 spring

Claims (7)

[Claims] 1. A polishing method comprising the steps of: pressing a polishing tool against a workpiece, and relatively scanning in the longitudinal direction of the workpiece while swinging the polishing tool in the short direction of the workpiece. A polishing method, wherein scanning is performed while the polishing tool is relatively oscillated in the longitudinal direction of the workpiece. 2. The polishing method according to claim 1, wherein when the workpiece is moved in the longitudinal direction, the posture or the height of the workpiece is controlled based on a change in the shape of the workpiece. Method. 3. A polishing tool, pressing means for pressing the polishing tool against a workpiece, short-side swing means for swinging the polishing tool in a short direction of the workpiece, and the workpiece And a longitudinal direction swinging means for swinging the workpiece in the longitudinal direction. 4. The scanning means and the longitudinal swinging means are constituted by a stepping motor and a ball screw which can freely rotate forward and backward, and a controller which controls forward and reverse rotation of the stepping motor.
The polishing apparatus according to the above. 5. A polishing machine according to claim 3, wherein a pair of templates for controlling the posture or height of the workpiece based on a change in the shape of the workpiece in the longitudinal direction is provided. apparatus. 6. A mounting table on which a workpiece is placed has a cam follower abutting on a guide surface of each template and a cam follower abutting on an inner surface of each template. Item 6. The polishing apparatus according to Item 5. 7. The polishing apparatus according to claim 6, further comprising a spring for pressing the cam follower against the inner surface of the template.