JP2000237956A - Machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machining device which machines as a desired machining curve and gives a high shaping accuracy. SOLUTION: A machining device having a rotary table 4 which holds and rotates a workpiece 3, a work stage 5 which holds and moves the rotary table 4 toward at least one direction, and a tool stage 9 which moves in a direction transverse to a movable direction of the rotary table 4 with a tool 8 rotating, is provided with change measuring means 13 (13s, 13i, 13m) which measure a positional change of the rotary table 4 in a direction of rotational axis of the rotary table 4 and a control means 14 which controls a position relationship between the rotary table 4 and the tool stage 9 in a direction of rotational axis of the tool stage 9 on the basis of information concerning a positional change in the rotary table 4 by the change measuring means 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus for manufacturing a workpiece, such as a lens or a mirror, which requires a highly accurate shape creation.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a lens, there are a rough grinding process, a fine grinding process, and the like, and a grinding device is used for performing the process. The grinding device includes a work held on a rotary table that can move in a direction parallel to a rotary surface of the rotary table, a tool stage that is provided with a spindle and moves in a direction perpendicular to the rotary surface of the rotary table. And a grindstone provided on the spindle. Then, the rotary table is moved to a desired position, and the tool is brought into contact with the workpiece while rotating the workpiece, thereby processing the workpiece into a desired shape.

[0003] In the grinding of the lens, the moving amount and the processing position of the work and the tool are determined by a processing curve given by a desired lens shape, and the moving amounts of the work and the tool are measured and feedback-controlled. It is possible to perform processing according to a desired processing curve.

[0004]

By the way, in a rotary table, a swing generally occurs in a thrust direction (a direction parallel to a rotation axis). There was a problem that an error was generated due to the runout, and machining could not be performed according to a desired machining curve. Accordingly, an object of the present invention is to provide a processing apparatus capable of obtaining high shape accuracy by performing processing according to a desired processing curve.

[0005]

According to the present invention, there is provided a rotary table for holding and rotating a work, a work stage for holding the rotary table and moving the rotary table in at least one direction. In a processing apparatus provided with a tool stage that moves in a direction perpendicular to a direction in which a rotary table can move while rotating a tool, a fluctuation amount for measuring a fluctuation amount of a position of the rotary table in a rotation axis direction of the rotary table. Measuring means, and control means for controlling the positional relationship between the rotary table and the tool stage in the direction of the rotation axis of the rotary table based on information on the amount of change in the position of the rotary table obtained from the fluctuation amount measuring means. It was characterized.

[0006] By measuring the amount of fluctuation of the rotary table holding the work in the direction of the rotation axis and controlling the position of the tool stage with respect to the rotary table in accordance with the amount of fluctuation of the rotary table, the rotary table moves in the thrust direction. Even when rotating while moving, the shape can be created so as to have a desired shape. In the present invention, a base, a rotary table that holds and rotates a workpiece, a work stage provided on the base and moves the rotary table in at least one direction, a spindle that holds and rotates a tool, and a spindle A processing apparatus having at least a tool stage that moves in a direction perpendicular to a direction in which the turntable can move, the processing apparatus including at least a reference mirror provided on a base and a measurement mirror arranged near a rotation center of the turntable. And a control means for controlling the moving amount of the tool stage from the moving amount of the rotary table obtained by the light wave interference measuring unit.

As described above, by providing the reference mirror on the base and the light wave interference measuring section having the measuring mirror near the center of rotation of the rotary table, the position of the rotary table can be measured with high accuracy. . Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to a grinding machine according to an embodiment. FIG. 1 is a schematic diagram of this grinding apparatus. FIG. 1 is a front view showing the configuration of the grinding apparatus according to the present embodiment. This grinding apparatus includes a base 1, a column 2, a rotary table 4 that holds and rotates a work 3, and a rotary table 4, and an X-axis in FIG. A work stage 5 movable in the direction, a movement amount measuring means 7 (hereinafter, referred to as a WS movement amount measuring device 7) for measuring a movement amount of the work stage 5, a spindle that holds and rotates a tool 8, and a spindle. A tool stage 9 movable in the Z-axis direction described in FIG. 1 which is a direction perpendicular to the rotation surface of the rotary table 4, and a movement amount measuring unit 12 (hereinafter, referred to as a movement amount measurement unit 12 for measuring the movement amount of the tool stage 9). TS movement amount measuring device 12) and fluctuation amount measuring means 13 for measuring the fluctuation amount of turntable 4 (hereinafter referred to as KT fluctuation amount measuring device 13).
And a control means 14 for controlling the work stage 5 and the tool stage 9.

[0009] All of these components are installed on a vibration isolation table 10. By the way, in the present grinding apparatus, a column 2 and a work stage 5 are provided on a base 1. The work stage 5 is provided with a spindle 6 for rotating the rotary table 4. The rotary table 4 is rotated by rotating the spindle 6. Note that the spindle 6 used in the present grinding apparatus is a spindle whose rotation axis is hollow.

In the present grinding apparatus, the column 2 is provided with a tool stage 9. The tool stage 9 is movable in a direction perpendicular to the rotation surface of the turntable 4. In the present grinding apparatus, the tool stage 9 is moved according to the position of the rotary table 4 to move the tool 8 to a desired position while moving the work stage 5 to change the position of the rotary table 4. In this way,
The work 3 can be ground into a desired shape.

By the way, each of the above-mentioned movement amount measuring devices 7 and 12
As the KT fluctuation amount measuring device 13, a laser interferometer is used. The laser interferometer has a laser light source, a measurement mirror, a reference mirror, and a beam splitter that splits light emitted from the laser light source into light emitted to the measurement mirror and light emitted to the reference mirror. , And a light receiving element that monitors an interference image between the reflected light of the measurement mirror and the reflected light of the reference mirror.

Meanwhile, the WS movement amount measuring device 7 includes a laser light source 7s, an interferometer unit 7i including a beam splitter, a reference mirror, and a light receiving element, and a measuring mirror 7m.
The laser light source 7s and the interferometer 7i are fixed to the column 2, respectively. The measuring mirror 7m is provided on the work stage 5, and monitors an interference image between the reflected light of the measuring mirror 7m and the reflected light of the reference mirror provided in the interferometer unit 7i.
Is detected.

The TS movement amount measuring device 12 includes a laser light source 7s, fixed mirrors 12a and 12b, an interferometer unit 12i including a beam splitter, a reference mirror, and a light receiving element.
And a measurement mirror 12m. The laser light source 7
For s, a light source common to the WS movement amount measuring device 7 is used. The measuring mirror 12m is fixed to the tool stage 9, and the other components are provided on the column 2. In addition,
The fixed mirrors 12a and 12b are arranged to guide light from the laser light source 7s to the interferometer unit 12i. Like this
In the disposed TS movement amount measuring device, the light receiving element in the interferometer unit 12i monitors the interference image between the reflected light of the measuring mirror 12m and the reflected light of the reference mirror, and detects the position of the tool stage 9 based on the change in the interference image. Has been detected.

In this manner, the positions of the work stage 5 and the tool stage 9 can be obtained. And
From this position information, it is possible to know where the tool 8 provided on the tool stage 9 is grinding the work 3 on the work stage 5, and based on the obtained position information,
By controlling the movement of the work stage 5 and the tool stage 9, processing into a desired shape can be performed.

Incidentally, the grinding apparatus according to the present embodiment further includes a KT fluctuation measuring device 13 for detecting a fluctuation amount of the rotary table 4 in the Z direction shown in the drawing. The KT fluctuation measuring device 13 includes a laser light source 13s, an interferometer 13i including a beam splitter, a reference mirror, and a light receiving element.
And a measuring mirror 13m provided on the surface opposite to the surface on which the work is placed. The measuring mirror 13m is fixed to the center of rotation of the turntable 4. Also, K
The laser light source 13 s and the interferometer 13 i constituting the T fluctuation measuring device 12 are fixed to the base 1. Inside the base 1, there is formed a space in which the laser light source 13s is installed, a space in which light emitted from the laser light source 13s passes, and a space in which the interferometer unit 13i moves with the work stage 5. .

The laser light source 13s emits laser light in parallel with the direction in which the work stage 5 can move, and makes the laser light incident on the interferometer 13i. Then, the interferometer unit 13i
The light emitted from the light source passes through the hollow portion of the hollow spindle 6 and reaches a measuring mirror 13 m provided near the center of the rotary table 4. In this way, by measuring the amount of change in the position of the measurement mirror 13m in the Z direction in the figure, the rotation of the rotary table 4 in the thrust direction that occurs when the spindle rotates, and the expansion and contraction of the components due to temperature changes, etc. The change due to the position of the work in the Z direction can be monitored.

The reason why the measuring mirror 13 is fixed to the center of rotation of the rotary table is that if the mirror is arranged at a position distant from the center of rotation, the position of the reflecting surface of the measuring mirror 13m will increase with the rotation of the rotary table 4. Will fluctuate. Therefore, there is a problem that the light from the interferometer unit 13i does not reach the measurement mirror 13m. If the size of the measurement mirror 13m is sufficiently large, it is possible to reflect the light from the interferometer 13i without placing the mirror at the center. However, most mirrors have irregularities on the reflective surface. As described above, when the rotary table 4 rotates, the optical path length between the interferometer unit 13i and the measurement mirror 13m changes due to the unevenness of the reflection surface. Therefore, it is preferable to arrange the measurement mirror 13m so as to reflect the light from the interferometer 13i at the rotation center position where the reflection surface does not change even when the turntable 4 rotates.

By the way, the fluctuation value of the rotary table obtained by the KT fluctuation detector 13 is input to the control means 14 next. The control unit 14 controls the movement of the work stage 5 and the tool stage 9, and based on signals obtained from the WS movement amount detector 7 and the TS movement amount detector 12,
Perform movement control. Further, in the present grinding apparatus, the T
The KT fluctuation amount detector 1
By using the variation obtained in step 3 as a correction value,
The position of the tool 8 with respect to the work 3 can be accurately positioned.

As described above, the grinding device according to the present embodiment is
Since the positioning of the tool 8 with respect to the workpiece 3 can be performed with extremely high accuracy, a highly accurate shape can be created. In particular, for processing in which the positioning error of the tool 3 is required to be less than 0.1 μm, the rotary table 4 is required.
The expansion and contraction of the components due to the deflection in the thrust direction and the temperature change cause a problem. A processing device suitable for such a problem can be provided.

Finally, the present grinding apparatus has been described as an embodiment of the present invention, but the present invention is not limited to this. For example, the measurement mirror 1 of the KT variation measuring device 13
3 m is arranged at the rotation center position of the rotary table 4, but is not limited to this. If the reflection surface of the measurement mirror 13 m has a surface suitable for measurement accuracy, it may be arranged at a position other than the rotation center position. Absent. Further, in the embodiment of the present invention, the relative position between the workpiece 3 and the tool 8 is corrected by moving the tool stage 9 with respect to the amount of fluctuation of the rotary table 4, but the present invention is not limited thereto. Not limited. In addition, it is also possible to provide a moving means for moving the work stage 6 so as to negate the direction in which the work stage 6 fluctuates with respect to the amount of fluctuation of the rotary table 4 so as to correct the position of the work 3 and the tool 8.

[0021]

As described above, according to the present invention, it is possible to perform processing according to a desired processing curve, and thus there is an effect that a workpiece having high shape accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view (partially, a sectional view) showing a configuration of a grinding device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Column 3 ... Work 4 ... Rotary table 5 ... Work stage 7i ... Interferometer part of WS movement amount measuring device 7s ... WS movement amount measuring device and TS Laser light source of travel distance measuring instrument 7m ・ ・ ・ Measurement mirror of WS travel distance measurement instrument 8 ・ ・ ・ Tool 9 ・ ・ ・ Tool stage 10 ・ ・ ・ Vibration isolator 12i ・ ・ ・ Interferometer part of TS travel distance measurement instrument 12m: Measurement mirror of TS movement measurement device 13i: Interferometer part of KT movement measurement device 13m: Measurement mirror of KT movement measurement device

Claims (1)

[Claims] 1. A rotary table for holding and rotating a work, a work stage for holding the rotary table and moving the rotary table in at least one direction, and moving the rotary table while rotating a tool In a processing apparatus having a tool stage that moves in a direction perpendicular to a possible direction, a fluctuation amount measuring unit that measures a fluctuation amount of a position of the rotary table in a rotation axis direction of the rotary table; Control means for controlling a positional relationship between the rotary table and the tool stage in the rotation axis direction of the rotary table, based on the obtained information on the amount of change in the position of the rotary table. Processing equipment.