JPH0716870B2 - Polishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention provides a rotating elastic body in the vicinity of a surface to be polished of a work piece immersed in a suspension in which fine powder abrasive grains are uniformly dispersed. The polishing apparatus is configured to process the surface to be polished of the workpiece by causing the suspension to flow between the two.

<Prior Art> In recent years, EEM (Elastic Emi
ssion Machining) has been proposed as a polishing device that realizes a processing technique that utilizes the extremely small amount of elastic fracture phenomenon.

This polishing apparatus is shown in FIGS. 3 and 4 and will be described with reference to these figures.

In the figure, reference numeral 1 is an NC spindle head that is vertically movable in a vertical direction. A motor 2 is attached to the NC spindle head 1 and a cross spring 3 is provided.
It is suspended diagonally.

A rotary elastic body 5 such as a polyurethane ball is attached to the shaft end of the output shaft 4 of the motor 2.

Reference numeral 6 is a container in which a suspension 7 in which fine powder abrasive grains are uniformly dispersed is housed. A workpiece 8 is fixed to the bottom of the container 6 and the rotary elastic body 5 is dipped therein. ing.

The container 6 is fixed to an X table 10 driven by an air slide 9 for the X direction.
It is fixed to a Y table 12 driven by a directional air slide 11.

The X table 10 and the Y table 12 allow the workpiece 8 to be fed in the horizontal direction together with the container 6.

Reference numeral 13 is a load supporting rod for adjusting the degree of proximity between the surface 8a to be polished of the workpiece 8 and the rotary elastic body 5.

Next, the operation will be described.

While rotating the rotary elastic body 5 by the motor 2, the workpiece 8 is arbitrarily sent in the XY directions by the X table 10 and the Y table 12 to bring the workpiece 8 close to the rotary elastic body 5.

Due to the rotation of the rotary elastic body 5, as shown in FIG.
The suspension 7 flows like a hydrodynamic bearing in a minute gap between the rotary elastic body 5 and the surface 8a to be polished of the workpiece 8, and the fine powder abrasive grains in the suspension 7 are mixed with the surface 8a to be polished. The surface 8a to be polished is polished by colliding with and sliding on.

That is, according to the present polishing apparatus, it is possible to perform processing in atomic units by utilizing the extremely small amount of elastic fracture phenomenon, and to polish the polished surface 8a of the workpiece 8 with high precision without multiplying lattice defects. can do. The polishing amount can be controlled, for example, by the passing speed of the workpiece 8 with respect to the rotary elastic body 5.

Specifically, in this type of polishing apparatus, the polishing amount tends to increase as the passing speed, that is, the feed speed of the X table 10 and the Y table 12 is decreased.

In the polishing apparatus having such a configuration, for example, as shown in FIG. 5 (a), when forming an aspherical lens having a curved surface 8b shown by a broken line, the feed pattern of the workpiece 8 to the rotary elastic body 5 is formed. As shown in FIG. 5 (b).

That is, while linearly moving in the X direction with the X table 10 so as to traverse the workpiece 8 with respect to the rotary elastic body 5,
Each time it is sent once in the X direction, the Y table 12 sends it by Δy in the Y direction.

Then, according to the difference between the pre-processed shape and the desired processed shape, X
In order to partially increase or decrease the polishing amount in the direction, the feed speed or the stop time of the X table 10 is controlled so as to change the processing time of the workpiece 8 from the start point to the end point of the X-direction feed range.

<Problems to be Solved by the Invention> However, the conventional example having such a configuration has the following problems.

As described above, in the conventional polishing apparatus configured to advance the polishing of the surface 8a to be polished by the X table 10 and the Y table 12, for example, when the aspherical lens is formed, the preprocessed surface is completely Even if it is a spherical surface, the amount of polishing in the X direction increases or decreases, so the processing time must be changed, and the feed pitch in the X direction must be extremely small in order to obtain a curved surface with a predetermined accuracy. Since high positioning accuracy is also required, the feed control of the X table 10 becomes very complicated and high mechanical accuracy is required. The present invention was devised in view of such circumstances, and an object of the present invention is to provide a polishing apparatus capable of performing processing with a predetermined accuracy by simple control particularly when forming a lens or the like.

<Means for Solving Problems> The present invention has the following configuration in order to achieve such an object.

That is, the polishing apparatus according to the present invention is arranged such that the rotary elastic body is brought close to the surface to be polished of the work piece immersed in the suspension in which the fine powder abrasive grains are uniformly dispersed, and between the both. A structure for processing a surface to be polished of the workpiece by causing the suspension to flow, and a rotary drive mechanism for rotating the workpiece, and a drive shaft orthogonal to a rotation center axis of the rotary drive mechanism. And a feed mechanism for displacing the relative position between the rotary drive mechanism and the rotary elastic body in the direction.

<Operation> The operation of the configuration of the present invention is as follows.

For example, when forming an aspherical lens having a predetermined curved surface from a work piece having a completely spherical surface to be polished, for example, in a concentric or spiral shape from the outermost peripheral edge of the surface to be polished toward the center point, The rotation drive mechanism sends the work piece in the circumferential direction, and the feed mechanism sends the work piece in the radial direction by a predetermined pitch, but the polishing amount is constant on the circumference of a constant radius distance, so the same circumference In the above, the processing time may be constant. That is,
The feed speed of the workpiece by the rotary drive mechanism or the stop time may be controlled to change each time the workpiece is fed in the radial direction by a predetermined pitch.

On the actual surface, the shape accuracy of the pre-machined surface is not absolute, so control is required even on the same circumference, but since the error in the pre-machined accuracy only needs to be corrected, the change in the machining amount is small. Time control is also easier than in the conventional method.

In order to improve the machining accuracy in this machining, it is necessary to coordinate each position on the surface to be machined and input the machining amount at that position in advance as machining information. Even if it is obtained, the number of coordinates to be input can be reduced, so that not only the storage device can be downsized, but also mechanical work can be easily followed.

<Example> Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

1 and 2 show an embodiment of the present invention,
FIG. 1 is a partially longitudinal side view showing the outline of a polishing apparatus, and FIG.
(A) And (b) is explanatory drawing which shows the feed pattern of a to-be-processed object.

In these figures, the same reference numerals as those shown in FIGS. 3 to 5 indicate the same parts or corresponding parts.

In this embodiment, only the structure different from that of the conventional example will be described.

A motor 14 as a rotation drive mechanism is attached to one side surface of the container 6. The rotation center axis 15 of the motor 14 is oriented parallel to the horizontal direction.

A support base 16 is rotatably provided at one end of the motor 14, and the workpiece 8 is fixed to the support base 16.

Further, the container 6 is installed on an X table 17 serving as a feeding mechanism, and the X table 17 is reciprocally fed by an air slide 18 in the X direction, for example, a direction perpendicular to the paper surface of FIG.

Next, the operation will be described.

First, when attaching the workpiece 8 to the motor 14, the center point of the workpiece 8 is positioned on the rotation center shaft 15 of the motor 14.

Then, for example, when the workpiece 8 is sent in the circumferential direction by the motor 14 at a control speed input in advance, the surface 8a to be polished can be circularly scanned with the rotary elastic body 5.

On the other hand, when the workpiece 8 is sent in the circumferential direction by the motor 14 and the X table 17 is driven at a constant rotation angle or time, the rotary elastic body 5 can be spirally scanned.

Thus, in the polishing apparatus of this embodiment, the motor 14 sends the work 8 in the circumferential direction, and the X table 17 sends the work 8 in the direction perpendicular to the rotation axis of the work 8. In this configuration, various processing can be performed by controlling the feed rate of the motor 14 in the circumferential direction.

Therefore, a procedure for forming an aspherical lens with the present polishing apparatus will be described.

During processing, the surface shape of the surface to be polished 8a of the workpiece 8 before the processed surface is accurately measured, and the amount of polishing required to obtain the desired surface shape is calculated from this measurement value. The feed rate of the workpiece 8 in the circumferential direction by the 14 is controlled. Here, the aspherical lens having a predetermined curved surface is formed from the circular plate-shaped workpiece 8 having the spherical surface 8a to be polished. I shall.

When attaching the workpiece 8 to the motor 14, the motor 14
The center point of the workpiece 8 is located on the rotation center axis 15 of.

In this way, the feed pattern of the workpiece 8 is set as shown in FIG.

This will be specifically described.

With the X-table 17 and the spindle head 1 that moves in the vertical Z-direction, any one of the outermost peripheral edges of the workpiece 8 with respect to the rotating elastic body 5
Position point A.

From this position, the work piece 8 is sent by the motor 14 in the circumferential direction at a speed determined by the machining allowance to make one turn.

The X table 17 and the spindle head 1 feed the workpiece 8 by Δx to the center side in the radial direction.

From this position, the workpiece 8 is rotated once at a speed determined by the machining allowance in the same manner as described above.

Subsequently, the X table 17 and the spindle head 1 sequentially feed the workpiece 8 to the center side in the radial direction by Δx, and the feed speed of the workpiece 8 by the motor 14 is changed.

As described above, according to the polishing apparatus of the present embodiment, when the aspherical lens is formed, the workpiece 14 is circularly moved by the motor 14 so that the polishing is advanced along each contour line of the curved surface to be obtained by the aspherical mens. Since it can be fed in the circumferential direction, the degree to which the polishing amount in the circumferential direction is increased or decreased is small, and the motor 14
The feed rate control and the positioning control of the work piece 8 by means of are facilitated.

The feed pattern of the workpiece 8 when forming the lens with the polishing apparatus of the present embodiment is assumed to be concentric as shown in FIG. 2 (a), but in addition to this, FIG. 2 (b). It is also possible to make a spiral as shown in FIG.

In this case, the motor 14 moves the workpiece 8 in the circumferential direction by a predetermined angle Δ.
The motor 14, the X table 17, and the spindle head 1 may be controlled so that the workpiece 8 is fed to the center side in the radial direction by Δx each time it is fed by c, and is fed once.

Further, although the X table 17 is adopted as the feeding mechanism in the above-mentioned embodiment, the present invention is not limited to this, and for example, the motor 14 or the spindle head 1 in which the rotation center shaft 15 is oriented in the horizontal direction is set in the vertical direction. It is also possible to employ a feeding mechanism that feeds to.

Further, in the above embodiment, the rotation center shaft 15 of the motor 14 is oriented in the horizontal direction, but the present invention is not limited to this.For example, the rotation center shaft 15 of the motor 14 is oriented in the vertical direction, and It is also possible to make the surface 8a to be polished of the workpiece 8 horizontal.

<Effects of the Invention> In the present invention, polishing can be made to proceed in the circumferential direction along each contour line of the curved surface to be obtained by the lens, so that the amount of polishing can be made constant for one contour line in the proceeding direction.

Of course, each contour line must be controlled so as to increase or decrease the polishing amount in order to correct the pre-processing accuracy during one round of each contour line, but it is not necessary to perform it frequently as in the conventional case.

Therefore, according to the polishing apparatus of the present invention, the control for feeding the workpiece can be made much simpler than in the conventional case, and the lens with a predetermined accuracy can be easily processed.

[Brief description of drawings]

1 and 2 relate to an embodiment of the present invention.
The figure is a side view of a partial cross section showing the outline of the polishing apparatus, and FIGS. 3 to 5 relate to a conventional example, FIG. 3 is a side view of a partial cross section showing an outline of a polishing apparatus, and FIG. 4 is an enlarged view showing a rotating body and a workpiece during processing, FIG. 5 (a) is a side view of the workpiece, and FIG. 5 (b) is an explanatory view showing the feed pattern of the workpiece. 5 …… Rotary elastic body 6 …… Container 7 …… Suspension 8 …… Workpiece 8a …… Surface to be polished 14 …… Motor (rotary drive mechanism) 15 …… Rotation center axis 16 …… X table (feed mechanism).

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP 62-88565 (JP, A) JP 62-199353 (JP, A) JP 63-232949 (JP, A)

Claims (2)

[Claims] 1. A rotary elastic body is brought close to the surface to be polished of a work piece immersed in a suspension in which fine powder abrasive grains are uniformly dispersed, and the suspension is placed between the two. A polishing apparatus configured to process a surface to be polished of a workpiece by flowing the rotary drive mechanism for rotating the workpiece, and the rotation drive mechanism in a direction orthogonal to a rotation center axis of the rotary drive mechanism. A polishing apparatus comprising: a drive mechanism and a feed mechanism for displacing the relative position of the rotary elastic body. 2. A rotation center axis of the rotation drive mechanism is oriented parallel to a horizontal direction, and the rotation drive mechanism rotates the workpiece around the rotation center axis. The polishing apparatus according to claim (1).