JP2001079738A - Grinder for work outer peripheral surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten working time of an outer peripheral surface of a glass substrate. SOLUTION: This device supports a work W on a work table 14 by negative pressure supplied from a negative load generating mechanism 15 of a work supporting mechanism 10. Outer peripheral surface grinding mechanisms 20 and 30 are arranged on both sides of the work supporting mechanism 10. Finishing grooves of grinding wheels 27, 37 are made to approach the work W by driving X axis motors 22, 32 of the outer peripheral surface grinding mechanisms 20, 30 and are positioned at specified positions against the outer peripheral surface of the work W by driving a Z axis motor. The outer peripheral surface of the work W is worked by making the grinding wheels 27, 37 rotating at high speed approach a center of the work W continuously while rotating the work W at low speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for grinding an outer peripheral surface of a hard and brittle material such as a glass substrate of a hard disk.

[0002]

2. Description of the Related Art Conventionally, the outer peripheral surface of a silicon wafer or a hard disk glass substrate serving as a substrate of an VLSI has been ground with a diamond grindstone. Chamfering is performed to prevent crystal defects from entering.

[0003] As an apparatus for grinding the outer peripheral surface of such a work, a single grindstone is rotatably supported by a support member, and the grindstone is moved relative to the support member of the work from one direction toward or away from the work. Something to move. The movement of the grindstone is driven by a motor. That is, a grindstone driven by the motor and rotated about the axis is brought into sliding contact with the outer peripheral surface of the work driven by the motor and rotated about the axis. In such a grinding device, the position of the grindstone is controlled such that the outer peripheral surface of the work and the grindstone are in contact with each other on a straight line connecting the rotation center of the grindstone and the axis of the work.

[0004]

In the above-described grinding apparatus,
The outer peripheral surface of a work already formed in a predetermined shape must be ground while maintaining the predetermined shape. Therefore, grinding has been performed with one grindstone from the viewpoint of simplicity of movement control of the grindstone. On the other hand, there is a problem that grinding takes time.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a grinding apparatus capable of shortening a processing time of an outer peripheral surface of a work.

[0006]

According to the present invention, there is provided an apparatus for grinding a peripheral surface of a work according to the present invention, comprising: a work rotating means for rotating the work around an axis; and a movable means for moving toward or away from the work. A plurality of whetstones to be slid on the surface and movement of the whetstones so that each of the whetstones at the outer peripheral surface of the workpiece is already ground by another whetstone among the plurality of whetstones and newly exposed as an outer peripheral surface. And control means for controlling

When the trajectories of the displacements of the respective sliding contact positions between the plurality of grindstones and the outer peripheral surface of the work are viewed from a direction orthogonal to the surface of the work, for example, follow a spiral shape and the outer peripheral surfaces of the other grindstones and the work. The trajectory of the displacement of the sliding contact position with the workpiece and the workpiece are alternately traced in the radial direction of the workpiece.

Preferably, when processing the outer peripheral surface of the work, the plurality of grindstones are respectively continuously moved toward the center of the work.

When the trajectories of the displacements of the respective sliding positions of the plurality of grinding wheels and the outer peripheral surface of the work are viewed from a direction orthogonal to the surface of the work, for example, the trajectory follows a circular arc of a concentric circle at the center of the work, and The trajectory of the displacement of the sliding contact position between the workpiece and the outer peripheral surface of the workpiece and the workpiece are alternately traced in the radial direction of the workpiece.

Preferably, when processing the outer peripheral surface of the work, the plurality of grindstones are moved stepwise toward the center of the work.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view schematically showing an apparatus for grinding a glass substrate of a hard disk to which the first embodiment according to the present invention is applied. In FIG. 1, some components of the respective mechanisms are omitted in order to clarify the relative positional relationship between the mechanisms constituting the grinding apparatus.

In the work support mechanism 10, a work spindle 11 is provided with a pulley 12 rotatably.
The pulley 12 and the output shaft (not shown) of the servomotor are connected by a belt 13. That is, the rotation of the servomotor is transmitted to the pulley 12 via the belt 13, and the worktable 14 provided on the work spindle 11 rotates according to the rotation of the pulley 12.

A negative pressure introducing passage (not shown) is formed in the work spindle 11 and communicates with an opening (not shown) formed in an end face of the work table 14. The negative pressure introducing passage is connected to a vacuum pump (not shown) by a rotary joint 15. That is, the work W is attracted to the work table 14 by the negative pressure supplied from the vacuum pump to the opening of the work table 14 via the rotary joint 15 and the negative pressure introducing passage. The workpiece W is a thin glass substrate formed in a circular shape, and an inner hole which is a circle concentric with the circle on the outer peripheral surface is formed at the center thereof.
The work W is mounted on the work table 14 such that the center of the work W is positioned on the axis of the work spindle 11. Therefore, the work W rotates coaxially according to the rotation of the rotation shaft of the work spindle 11.

On both sides of the work support mechanism 10, outer peripheral surface grinding mechanisms 20 and 30 are provided. Outer surface grinding mechanism 20,
At 30, the table 21 includes an X-axis motor 22 and a grinding wheel spindle 23, and the table 31 includes an X-axis motor 32,
A grindstone spindle 33 is provided. The X-axis motors 22 and 32 are servomotors, and are provided on both sides of the work support mechanism 10 so that their axes are orthogonal to the axis of the work spindle 11. The tables 21 and 31 move in the X direction orthogonal to the axis of the work spindle 11 according to the rotation of the X-axis motors 22 and 32, respectively.

The grinding wheel spindles 23 and 33 are provided so that their axes are parallel to the axis of the work spindle 11. Pulleys 24 and 34 are rotatably provided on the grindstone spindles 23 and 33, respectively. Pulley 24
A belt 25 is wound around an output shaft (not shown) of the motor and a motor. Similarly, a belt 35 is wound around a pulley 34 and an output shaft (not shown) of the motor. That is, the rotation of each motor is controlled by pulleys 24, 34 via belts 25, 35.
And the rotating shafts of the grindstone spindles 23 and 33 rotate.

The grindstone flanges 26 and 36 are cylindrical members fixed to the rotating shafts of the grindstone spindles 23 and 33, respectively, and grindstones 27 and 37 are provided on the outer peripheral surfaces of the grindstone flanges 26 and 36, respectively.
Is attached. As shown in FIG. 2, a finishing groove G1 corresponding to the processing shape of the outer peripheral surface of the work W is formed on the outer peripheral surfaces of the grindstones 27 and 37. Each finishing groove G1 has the same grinding ability. In the step of grinding the outer peripheral surface of the work W, the grindstones 27 and 37 are rotated at high speed by the corresponding servomotors.

Further, the tables 21 and 31 each include a Z-axis motor (not shown) as a servomotor.
The tables 21 and 31 move in the Z direction by driving the Z-axis motor. The mechanism for attaching the Z-axis motor to the tables 21 and 31 is the same as the mechanism for attaching the X-axis motors 22 and 32 described above.

The finishing grooves G1 of the grinding wheels 27 and 37 are Z
It is positioned at a predetermined position with respect to the outer peripheral surface of the work W by driving the axis motor, and is driven by the X-axis motors 22 and 32 to approach the work W. Thereby, the outer peripheral surface of the work W is ground.

An inner peripheral surface grinding mechanism 40 is disposed on the surface of the work W opposite to the surface in contact with the work table 14. In the inner peripheral surface grinding mechanism 40, the table 41
Has an X-axis motor 42 and a grinding wheel spindle 43. The X-axis motor 42 is a servomotor similarly to the X-axis motors 22 and 32 described above, and its axis is provided in parallel with the axis of the X-axis motors 22 and 32. That is, the table 41 moves in the X direction orthogonal to the axis of the work spindle 11 according to the rotation of the X-axis motor 42.

A pulley 44 is rotatably provided on the grindstone spindle 43. A belt 45 is wound around the pulley 44 and an output shaft (not shown) of the servomotor. The rotation of the servomotor is transmitted to the pulley 44 via the belt 45, and the grinding wheel spindle 43 is rotated in accordance with the rotation of the pulley 44.
Rotation shaft rotates. The grindstone 46 is coaxially fixed with respect to the rotation axis of the grindstone spindle 43, and its outer peripheral surface has a finishing groove G2 corresponding to the processing shape of the inner peripheral surface of the inner hole of the work W as shown in FIG. Is formed over the entire circumference.

Further, the table 41 has a Z-axis motor (not shown) which is a servomotor. The table 41 moves in the Z direction by driving the Z-axis motor. The mechanism for attaching the Z-axis motor to the table 41 is the same as the mechanism for attaching the X-axis motor 42.

The grindstone spindle 43 is positioned at a predetermined position with respect to the inner peripheral surface of the inner hole of the work W by driving the Z-axis motor, and is moved to the inner peripheral surface of the inner hole of the work W by driving the X-axis motor 42. approach. Thereby, the inner peripheral surface of the inner hole of the work W is ground.

The process of grinding the outer peripheral surface of the work W in the first embodiment will be described with reference to FIGS. Grinding wheel 2
The work W is performed while rotating the workpieces 7 and 37 at a high speed while contacting the workpiece W, and the workpiece W rotates at a low speed in the grinding process.
3 to 7, the inner hole of the work W is omitted. Further, in order to clearly show the grinding process, the width to be ground with respect to the diameter of the workpiece W is exaggerated from the actual size, and the grinding process is simplified.

FIG. 3 shows a state in which whetstones 27 and 37 are brought into contact with the outer peripheral surface of a work W in an initial state which has not been subjected to a grinding process.
It is a figure which shows the state which carried out half rotation counterclockwise as seen from the side. In the first embodiment, the grindstones 27 and 37
Are successively moved toward the center of each. Therefore, as shown in FIG. 3, the trajectories of the displacement of the sliding contact positions between the grindstones 27 and 37 and the outer peripheral surface of the workpiece W trace as shown by a solid line L11 and a broken line L12, respectively. The portions hatched by thick lines are portions ground by the grindstone 27, and the portions provided by minute dots are portions ground by the grindstone 37.

After the state shown in FIG. 3, when the work W rotates in the direction of the arrow while the grindstones 27 and 37 are continuously moved toward the center of the work W, the grindstone 27 is rotated in the first half rotation of the work W. The grinding wheel 37 comes into sliding contact with the newly exposed outer peripheral surface by the grinding of the grindstone 37, and the grinding stone 37 comes into sliding contact with the newly exposed outer peripheral surface by the grinding of the grinding wheel 27 in the first half rotation of the work W. That is, FIG. 4 is a diagram illustrating a state in which the work W has been further rotated half a turn in the direction of the arrow from the state of FIG. The trajectory of the displacement of the sliding contact position between the grindstone 27 and the outer peripheral surface of the work W follows a spiral shape as shown by the solid line L11. Similarly, the trajectory of the displacement of the sliding contact position of the grindstone 37 with the outer peripheral surface of the work W is The spiral follows a dashed line L12.

FIG. 5 shows a state in which the work W has been further rotated half a turn in the direction of the arrow from the state of FIG. 4, that is, a state in which it has been rotated 1.5 times from the initial state. This is a rotated state, that is, a state of two rotations from the initial state. As described above, the grindstones 27 and 37 are continuously moved toward the center of the work W. Therefore, the whetstone 27
Always comes into sliding contact with the outer peripheral surface that has already been exposed by grinding the grindstone 37, and the grinding stone 37 always comes into sliding contact with the outer peripheral surface that has already been exposed by grinding the grindstone 27. As a result, the locus of displacement of the sliding contact position between the grindstone 27 and the outer peripheral surface of the work W is represented by a solid line L1.
The spiral wheel 37 and the workpiece W
The trajectory of the displacement of the sliding contact position with the outer peripheral surface of the workpiece W continues to follow a spiral shape as shown by a broken line L12, and the trajectory of the displacement of the sliding contact position of each grindstone with the outer peripheral surface of the workpiece W is represented by the other grinding stone and the workpiece. The trajectory of the displacement of the sliding contact position with the outer peripheral surface of W and the workpiece W alternately follow in the radial direction.

As shown in FIG. 6, when the work W is rotated twice from the initial state, the grindstone 37 is moved in a direction away from the work W, and the work W is further rotated in the direction of the arrow. That is, the outer peripheral surface of the work W is ground only with the grindstone 27, and as a result, a glass substrate having a shape of a perfect circle R1 as shown in FIG. 7 is formed.

FIG. 8 is a graph showing the grinding amount and the processing time of the work W. The upper part shows the case of a conventional grinding device for grinding with one grindstone, and the lower part shows the case of applying the first embodiment. In FIG. 8, T1 is the time required for the work W to make one rotation. In order to obtain the glass substrate shown in FIG. 7 by a conventional apparatus, the work W is rotated four times while continuously bringing a single grindstone close to the center of the work W, and further rotated one turn to form the work W into a perfect circle. Let it. That is, the work W
Must be rotated 5 times, and the processing time is T1 × 5. On the other hand, according to the first embodiment, if the work W is rotated three times as described above, the glass substrate of FIG.
The processing time is T1 × 3. Therefore, a significant reduction in processing time can be achieved in grinding the outer peripheral surface of the work W.

In the description with reference to FIGS. 3 to 7, the grinding amount at each time T1 is exaggerated as described above, and the grinding process is also simplified. Time T in actual grinding process
The grinding amount for each is very small, and the work W is rotated several tens of times. Therefore, the last one rotation for forming the work W into the perfect circle R1 is negligible compared to the actual total number of rotations of the work W. That is, as compared with the processing time of the conventional grinding process using one grindstone, 2 times in the first embodiment.
The processing time of the grinding process by the two grindstones 27 and 37 is substantially halved.

FIGS. 9 to 13 are views showing a process of grinding the outer peripheral surface of a work in a glass substrate grinding apparatus to which the second embodiment of the present invention is applied. In the second embodiment,
The configuration of the grinding device is the same as that of the first embodiment. 9 to 13, similarly to FIGS. 3 to 7, the trajectories of the displacements of the sliding contact positions between the grindstones 27 and 37 and the outer peripheral surface of the workpiece W are represented by solid lines L21 and broken lines L22, respectively. The ground part is hatched by a thick line, and the part ground by the grindstone 37 is provided with minute dots.

FIG. 9 is a diagram showing a state in which only the grindstone 27 is brought into contact with the outer peripheral surface of the work W in the initial state, and the work W is rotated half a counterclockwise as viewed from the rotary joint 15 in FIG. is there. Whetstone 2 in the second embodiment
7 and 37 are respectively moved stepwise toward the center of the work W. In the first half rotation of the work W, the grindstone 27 is fixed so as to be in sliding contact with the center C of the work W by S1 from the outer edge of the work W in the initial state. Accordingly, as shown in FIG. 3, the trajectory of the displacement of the sliding contact position between the grindstone 27 and the outer peripheral surface of the workpiece W follows as shown by the solid line L21.

After the state shown in FIG. 9, the grindstone 27 is maintained at the above-mentioned position, while the grindstone 37 is in contact with the outer peripheral surface newly ground by the grindstone 27 so that the outer edge of the work W in the initial state is brought into sliding contact. It is positioned at a position close to the center C of the workpiece W by S1 × 2 from the part. FIG. 10 shows a state in which the work W is rotated half a turn in the direction of the arrow in this state, that is, a state in which the work W is rotated once from the initial state. The outermost surface of the workpiece W is ground by a predetermined amount by the grindstone 27, and the outer peripheral surface exposed by the first half rotation is ground by the grindstone 37.
The trajectory of the displacement of the sliding contact position between the grindstone 37 and the outer peripheral surface of the work W follows as shown by a broken line L22.

Then, the grindstone 37 is maintained at the above-mentioned position, and the grindstone 27 is moved from the outer edge of the work W in the initial state by S1 × 3 so that the grindstone 37 is brought into sliding contact with the newly exposed outer peripheral surface. It is positioned at a position close to the center C of W. FIG. 11 shows a state in which the work W is rotated half a turn in the direction of the arrow in this state, that is, a state in which the work W is rotated 1.5 times from the initial state.

Further, the grindstone 27 is maintained at a position close to the center C of the work W by S1 × 3 from the outer edge of the work W in the initial state, and after the work W has rotated 1.0 times, it rotates 1.5 times. The grinding wheel 37 is positioned at a position close to the center C of the work W by S1 × 4 from the outer edge of the work W in the initial state in order to grind the outer peripheral surface newly exposed by the grinding of the grind stone 27 during the period. . In this state, when the work W is rotated half a turn in the direction of the arrow, the state shown in FIG. 12 is obtained. That is, FIG.
Is a state when the work W is rotated twice from the initial state.

In the state shown in FIG. 12, the grindstone 27 is separated from the outer peripheral surface of the work W, and the grindstone 37 is maintained at a position close to the center C of the work W by S1 × 4 from the outer edge of the work W in the initial state. The work W is further rotated half a turn in the direction of the arrow. As a result, a glass substrate having a shape of a perfect circle R2 as shown in FIG. 13 is formed. That is, the glass substrate shown in FIG. 13 is formed by rotating the work W 2.5 times from the initial state.

As is apparent from FIG.
The trajectory of the displacement of the sliding contact position between the workpiece 7 and the outer peripheral surface of the workpiece W follows a concentric arc at the center of the workpiece W as shown by a solid line L21 and a broken line L22, respectively.

FIG. 14 is a graph showing the grinding amount and the processing time of the work W. The upper part shows the case of a conventional grinding device for grinding with one grindstone, and the lower part shows the case of applying the second embodiment. In FIG. 14, T2 is the time required for the work W to make one rotation. Further, in the graph in the case where the second embodiment is applied, the solid line indicates the grinding by the grindstone 27, and the broken line indicates the grinding by the grindstone 37. FIG.
In order to obtain the glass substrate shown in (1), a single grindstone must be moved stepwise for each rotation of the work W to rotate the work W four times. On the other hand, according to the second embodiment,
If the work W is rotated 2.5 times as described above, the glass substrate shown in FIG. 13 is obtained. Therefore, a significant reduction in processing time can be achieved in grinding the outer peripheral surface of the work W.

In the description of the second embodiment, the first
As in the embodiment, the grinding amount for each time T2 is exaggerated,
The grinding process has also been simplified. In other words, the amount of grinding for each time T2 in the actual grinding process is extremely small, and the work W is rotated several tens of times.

As described above, according to the first and second embodiments, the processing time in grinding the outer peripheral surface of the work W is reduced. According to the second embodiment, since the tables 21 and 41 need only be drive-controlled so that the grindstones 27 and 37 are alternately brought closer to the center of the work W, the NC control is easy. According to the first embodiment as described above, the grinding time is further reduced by continuously bringing the grindstones 27 and 37 closer to the center of the work W.

It should be noted that the grinding devices of the first and second embodiments have two
Although three outer peripheral surface grinding mechanisms are provided, the present invention is not limited to this. By providing three or more outer peripheral surface grinding mechanisms, it is possible to further reduce the processing time.

[0041]

As described above, according to the present invention, a grinding apparatus capable of shortening the processing time of the outer peripheral surface of a glass substrate or the like can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a glass substrate grinding apparatus of the present invention.

FIG. 2 is a view showing an example of a finishing groove of a grindstone.

FIG. 3 is a diagram when the work W is rotated by 0.5 in the first embodiment.

FIG. 4 is a diagram when the work W is rotated once in the first embodiment.

FIG. 5 is a diagram when the work W is rotated 1.5 times in the first embodiment.

FIG. 6 is a diagram when the work W is rotated twice in the first embodiment.

FIG. 7 is a diagram when the work W is rotated three times in the first embodiment.

FIG. 8 is a graph comparing the processing time of a work W according to the first embodiment with that of a conventional example.

FIG. 9 is a diagram when the work W is rotated by 0.5 in the second embodiment.

FIG. 10 is a diagram when a work W is rotated once in the second embodiment.

FIG. 11 is a diagram when the work W is rotated 1.5 times in the second embodiment.

FIG. 12 is a diagram when the work W is rotated twice in the second embodiment.

FIG. 13 is a diagram when the work W is rotated 2.5 times in the second embodiment.

FIG. 14 is a graph comparing the processing time of a workpiece W according to a second embodiment with that of a conventional example.

[Explanation of symbols]

 Reference Signs List 10 Work support mechanism 11 Work spindle 14 Work table 15 Rotary joint 20, 30 Outer surface grinding mechanism 21, 31 Table 22, 32 X-axis motor 23, 33 Grinding wheel spindle 26, 36 Grinding wheel flange 27, 37 Grinding stone 40 Inner circumferential surface grinding mechanism

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C049 AA03 AA11 AA13 AA16 AA18 AB04 AB06 BB02 BB06 BC02 CA04 CA06 CB03

Claims (5)

[Claims] 1. A work rotating means for rotating a work around an axis, a plurality of grindstones movable in a direction approaching or moving away from the work and slidably contacting an outer peripheral surface of the work, and Control means for controlling the movement of the grindstones, so that each grindstone grinds a portion of the plurality of grindstones already ground by the other grindstones and newly exposed as an outer peripheral surface. Grinding device for the outer peripheral surface of the work. 2. The trajectory of displacement of each of the plurality of grindstones and the outer peripheral surface of the work in a sliding contact position, when viewed from a direction orthogonal to the surface of the work, follows a spiral shape and communicates with other grindstones. 2. The apparatus according to claim 1, wherein a locus of displacement of a sliding contact position with the outer peripheral surface of the work and the locus of the displacement are alternately traced in a radial direction of the work. 3. 3. The apparatus according to claim 1, wherein the plurality of whetstones are continuously moved toward the center of the work when processing the outer circumferential surface of the work. . 4. A trajectory of displacement of a sliding contact position between each of the plurality of whetstones and an outer peripheral surface of the work follows an arc of a concentric circle at the center of the work when viewed from a direction orthogonal to the surface of the work. 2. The apparatus according to claim 1, wherein a locus of displacement of a sliding contact position between another grindstone and an outer peripheral surface of the work alternately follows in a radial direction of the work. 3. 5. The apparatus according to claim 1, wherein the plurality of grindstones are moved stepwise toward the center of the work when processing the outer circumferential surface of the work. .