JP2002079444A - Outer peripheral face grinding method and device for quarts glass material, and control method for outer peripheral face grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding method capable of efficiently and precisely machining an outer peripheral face of a quartz glass material, and to provide a grinding device applying the method. SOLUTION: A flat type grinding wheel 21 of high grinding efficiency is reciprocated, the rough grinding is executed while applying cuts to both terminal ends of a going way and a returning way, and then the finish grinding is executed by means of a straight cup grinding wheel 30 of high grinding accuracy. The straight cup grinding wheel 30 executes the grinding while being fed in the constant direction, and the grinding is not executed when the grinding wheel is returned in the reverse direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for grinding an outer peripheral surface of a quartz glass material for precisely processing the outer peripheral surface of a quartz glass material such as a reaction furnace used in the semiconductor industry and an outer peripheral surface grinding of the quartz glass material. The present invention relates to an apparatus and a control method for an apparatus for grinding an outer peripheral surface of a quartz glass material.

[0002]

2. Description of the Related Art A conventional method of grinding the outer peripheral surface of a quartz glass material will be described with reference to FIGS. FIG.
2 is a front view schematically showing a conventional grinding apparatus, and FIG. 13 is a side view of the apparatus shown in FIG. FIG. 14 is a view showing the cup wheel type grinding wheel 3,
(A) is a front view as viewed from the front end face, and (b) is a side view (the upper half is a longitudinal sectional view). FIG. 15 is a schematic view showing a grinding process.

For grinding the outer peripheral surface of a quartz glass material, FIG.
The wheel 3 shown in FIG. The cup wheel-type grindstone 3 includes a base metal part 4 as a main body, and a diamond layer part 5 provided at a tip end of the base metal part 4, and a taper provided on an inner surface of the base metal part 4. The part 4a is made rotatable by being fitted on a spindle of a polishing unit (not shown).

In order to perform grinding using this cup wheel type grinding wheel 3, as shown in FIGS. 12 and 13, a cylindrical quartz glass material 1 is rotated about an axis as a rotation center, and Is rotated, and the front surface is brought into contact with the outer peripheral surface of the quartz glass material 1. Thereby, the outer peripheral surface of the columnar quartz glass material is ground. At this time, the grinding liquid is supplied from the coolant nozzle 2 to the contact surface between the quartz glass material 1 and the cup wheel type grindstone 3. Further, as shown in FIG. 15, the cup-wheel type grindstone 3 rotationally driven by the spindle is reciprocated in parallel with the rotation axis of the rotating quartz glass material 1, and a predetermined cut amount is set at the end of the forward path and the return path. , Predetermined grinding is performed.

[0005]

Generally, smooth irregularities are formed on the outer peripheral surface of a quartz glass material before grinding. This is because the quartz glass material is manufactured by solidifying the fused quartz glass, which is inevitably caused by a so-called melting technique. Specifically, in a quartz glass material having a diameter of about 180 mm, the height difference is about 20
mm irregularities occur.

Therefore, at the start of grinding, it is necessary to grind with a cup wheel-type grindstone starting from the maximum diameter portion (convex portion) of the quartz glass material, and thereafter, a predetermined cutting amount is given at the end portions of the outward path and the return path. Then, gradually, the entire outer peripheral surface of the quartz glass material must be ground. Therefore, in the first feed, the cup wheel-type grindstone grinds only the maximum diameter portion, and in other regions, the wheel is idled and grinding is not performed. Therefore, there is a technical problem that a useless grinding time increases.

[0007] Further, since a predetermined surface roughness is required on the outer peripheral surface of the quartz glass material after grinding, at the end of the grinding, the cutting amount is almost zero and the feed speed is reduced at present. Surface roughness is improved. On the other hand, in the early and middle stages of grinding, in order to shorten the grinding time, grinding is performed with an increased cutting depth and feed rate compared to the end stage described above.However, the cutting depth of the conventional cup wheel type grinding wheel has an upper limit, which is wasteful. It has been difficult to reduce the ratio of time required for efficient grinding.

Further, in the conventional grinding method, the rotation direction of the quartz glass material and the cup wheel type grindstone is always constant, and the feed direction of the cup wheel type grindstone is reversed between the outward path and the return path. Therefore, when feeding in a certain direction, there is a technical problem that countless scratches are made on the outer peripheral surface of the quartz glass material due to the relationship between the rotation direction and the feeding direction of the cup wheel type grindstone.

SUMMARY OF THE INVENTION The present invention has been made to solve such a technical problem, and a grinding method, a grinding apparatus, and a quartz glass using the method capable of highly precisely processing the outer peripheral surface of a quartz glass material. It is an object of the present invention to provide a method for controlling an apparatus for grinding an outer peripheral surface of a material.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, a method for grinding the outer peripheral surface of a quartz glass material according to the present invention is a method for grinding the outer peripheral surface of a quartz glass material, the method comprising: By rotating the quartz glass material about its axis as a center of rotation and rotating the flat wheel-type grindstone, a predetermined amount of grinding cut is given to reciprocate in parallel with the axis of the quartz glass material, thereby obtaining quartz glass. The method is characterized in that rough grinding of the outer peripheral surface of the material is performed, and then, a predetermined grinding cut amount is given to the rotating cup wheel-type grindstone to finish-grind the rough ground surface.

As described above, in the method for grinding the outer peripheral surface of a quartz glass material according to the present invention, in the rough grinding of the initial stage and the middle stage, a flat wheel type grindstone is used instead of a cup wheel type grindstone. And the grinding time can be shortened. Further, in the final grinding in the final stage, since the grinding is performed with a cup wheel-type grindstone, the same dimensional accuracy and surface roughness as in the related art can be secured.

Here, the flat wheel-type grindstone is composed of a plurality of flat wheel-type grindstones whose diameters gradually decrease in the direction of grinding feed, and each of the plurality of flat wheel-type grindstones has an outer peripheral surface of a quartz glass material. In order to perform rough grinding, the plurality of flat wheel-type grindstones are moved in the grinding feed direction while rotating, and then a predetermined amount of grinding cut is given to the rotating cup wheel-type grindstone to finish the rough ground surface. It is desirable to grind.

As described above, in the rough grinding of the early stage and the middle stage, since the grinding is performed simultaneously by a plurality of flat wheel grindstones, the rough grinding time is reduced according to the number of the flat wheel grindstones. Further, in the final grinding, since the grinding is performed with a cup wheel-type grindstone, the same dimensional accuracy and surface roughness as those of the related art can be secured.

Further, the cup wheel type grindstone reciprocates in parallel with the axis of the quartz glass material and performs grinding in the outward path, and separates from the quartz glass material in the return path and does not perform grinding. desirable. With this configuration, it is possible to prevent the outer peripheral surface of the quartz glass material from being damaged due to the relationship between the rotation direction and the feed direction of the cup wheel type grindstone.

According to another aspect of the present invention, there is provided a grinding apparatus for grinding an outer peripheral surface of a quartz glass material, comprising: a headstock for chucking the quartz glass material; A carriage that can move in a direction parallel to the axis of the chucked quartz glass material,
A coarse grinding unit that is provided so as to be able to advance and retreat on the carriage toward the quartz glass material, and that rotationally drives a flat wheel-type grindstone mounted on a spindle to roughly grind the outer peripheral surface of the quartz glass material; A finish grinding unit is provided so as to be able to advance and retreat on the table toward the quartz glass material, and rotationally drives a cup wheel-type grindstone to finish grind the outer peripheral surface of the quartz glass material.

In the grinding apparatus configured as described above, the rough grinding unit and the finish grinding unit reciprocate in parallel with the axis of the chucked quartz glass material together with the carriage. In rough grinding, the finish grinding unit is retracted,
Only the rough grinding unit advances at the end of the forward and backward passes of the carriage, and the flat wheel-type grindstone is given a cutting amount to perform rough grinding. On the other hand, in the finish grinding, the rough grinding unit is retracted, and the finish grinding is performed by the cup wheel type grindstone of the finish grinding unit.

Here, the spindle of the rough grinding unit has a length such that a plurality of flat wheel-type grindstones can be coaxially arranged and mounted, and a plurality of flat wheel-type grindstones having different diameters are oriented in the grinding feed direction. Therefore, it is desirable to arrange them so that the diameters are sequentially reduced. As described above, the rough grinding can be simultaneously performed by the plurality of flat wheel-type grindstones, so that the rough grinding time is greatly reduced.

[0018] The apparatus may further comprise detecting means for detecting a load of a motor for driving the flat wheel type grindstone to rotate, and control means for controlling a feed speed of the carriage in accordance with the load detected by the detecting means. desirable. in this way,
Since the control means for controlling the feed speed of the carriage in accordance with the load of the motor for rotating and driving the flat wheel grindstone is provided, the rough grinding time is greatly reduced.

Further, the control method of the apparatus for grinding an outer peripheral surface of a quartz glass material according to the present invention, which has been made to achieve the above object, reduces the load on a motor for rotating and driving a flat wheel type grindstone, or eliminates the load. In this case, the feed speed of the carriage is increased, and when the load increases, the feed speed of the carriage is controlled to decrease. As described above, when the load of the motor that rotationally drives the flat wheel-type grindstone decreases or becomes no load, the feed speed of the carriage increases, and when the load increases, the carriage moves. Since the feed speed is controlled so as to decrease, the rough grinding time can be greatly reduced, the breakage of the flat wheel-type grindstone can be prevented, and the rough grinding can be performed accurately.

In order to achieve the above object, the control method of the apparatus for grinding an outer peripheral surface of a quartz glass material according to the present invention is characterized in that the carriage is moved from one end to the other end along a cylindrical quartz glass material. When the load detecting means of the motor detects that the load of the motor for rotating the flat wheel-type grindstone is in a no-load state when it is moved, the carriage is again made of a cylindrical quartz glass material. Moving from one end to the other end along with grinding the outer peripheral surface of the quartz glass material with a flat wheel, and that the load of the motor that rotationally drives the flat wheel type grinding wheel is in a no-load state, If the load detecting means of the motor does not detect the load, the grinding of the outer peripheral surface of the quartz glass material is terminated at the other end.

As described above, when it is detected that the load of the motor that rotationally drives the flat wheel-type grindstone is in a no-load state (in a case where the load state and the no-load state are mixed), the cylindrical quartz glass is used. There are irregularities on the outer peripheral surface of the material. Therefore, the carriage is moved again from one end to the other end along the quartz glass material, and the outer peripheral surface of the quartz glass material is ground by the flat wheel. On the other hand, when it is not detected that the load of the motor that rotationally drives the flat wheel-type grindstone is in a no-load state, there is no unevenness to be ground by the flat wheel on the outer peripheral surface of the quartz glass material. Therefore, the grinding of the outer peripheral surface of the quartz glass material is completed at the other end.
Therefore, since unnecessary grinding is not performed, the rough grinding time is greatly reduced.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to FIGS. FIG.
FIG. 2 is a front view of a main part of a grinding apparatus for performing the grinding method according to the present invention, FIG. 2 is a right side view of FIG. 1, FIG. 3 is a right side view of FIG.
4A and 4B are a front view of a flat wheel-type grindstone and a cross-sectional view taken along line AA of FIG. 4A, FIG. 5 is a plan view for explaining grinding, FIG. 6 is a side view of FIG. FIG. 7 is a conceptual diagram for explaining rough grinding, FIG. 8 is a right side view of a grinding device equipped with a plurality of flat wheel-type grinding wheels, and FIG. 9 is a concept for explaining rough grinding with a plurality of flat wheel-type grinding wheels. FIG.

As shown in FIG. 1, the bed 1 of the grinding device A
The upper surface of the bed 0 is provided with a mountain-shaped guide portion 10a extending in the longitudinal direction of the bed 10 and a planar sliding surface 10b. In addition, the carriage 1 placed on the bed 10
1 has a concave portion 11 which slides on the guide portion 10a.
a, and a flat sliding surface 1 sliding on the sliding surface 10b.
1b is provided. Further, legs 11c extending downward are provided at both ends in the width direction of the carriage 11, and a lower sliding surface 10c protruding from both ends in the width direction of the bed 10 is provided on a lower end surface of the legs 11c. Is attached. Thus, the carriage 11 is the bed 1
It is configured to be slidable on the upper side and to be capable of reciprocating by a drive mechanism (not shown).

At the end of the bed 10, there is provided a headstock (not shown) which chucks the columnar (or cylindrical) quartz glass material 1 and drives it to rotate. The quartz glass material 1 has its axis centered on the carriage 11.
Are chucked so as to be parallel to the sliding direction, and receive a rotational driving force from the chucking, and are attached to the headstock so as to be rotatable about its axis as a center of rotation.

The carriage 11 has a rough grinding unit 13
And guide portions 15a and 16a for slidingly guiding the finish grinding unit 14 toward the outer peripheral surface of the quartz glass material 1.
Are provided, and the rough grinding unit 13 and the finish grinding unit 14 are provided with sliding portions 15b and 16b (see FIG. 2). Then, the rough grinding unit 13 and the finish grinding unit 14 advance and retreat toward the outer peripheral surface of the quartz glass material 1 by respective drive mechanisms (not shown).

The rough grinding unit 13 is provided with a saddle 17 sliding on the carriage 11, a housing 18 provided on the saddle, and a spindle 19 supported on bearings inside the housing 18 (see FIG. 2). , Housing 18
The motor 20 is attached to the rear of the vehicle (see FIG. 3). A flat wheel-type grindstone 21 is attached to a tip end of the spindle 19 by a clamp 22, and a pulley 23 is attached to a rear end of the spindle 19 (see FIG. 2). A belt 25 is wound around the pulley 23 and a pulley 24 mounted on the output shaft of the motor 20, and the flat wheel type grinding wheel 21 is rotated by the driving force of the motor 20.

The finish grinding unit 14 is provided with a saddle 26 that slides on the carriage 11, a housing 27 fixed on the saddle 26, and a spindle 28 that is supported by a bearing inside the housing 27. 1),
A motor 29 is mounted on the upper surface of the housing 27 (see FIGS. 1 and 3). Further, a cup wheel-type grindstone 30 is attached to the tip of the spindle 28, and a pulley 31 is attached to the rear end of the spindle 28 (see FIG. 1). Also, the pulley 31 and the motor 2
A belt 33 is wound around a pulley 32 attached to an output shaft 9 and a cup wheel-type grindstone 30 is rotated by a driving force of a motor 29.

As shown in FIGS. 4 (a) and 4 (b), the flat wheel type grindstone 21 of the rough grinding unit 13 has a diamond layer portion 35 on the periphery of a disk-shaped base metal portion 34 as a main body.
A spindle 1 is provided at the center of the base 34.
There is a hole 36 into which 9 is inserted. Since the flat wheel-type grindstone 21 can increase the cutting depth, the flat wheel-type grindstone 21 has an advantage that the grinding ability is larger than that of the cup wheel-type grindstone 30, but has a disadvantage that the surface roughness of the finished surface is rough.

A method of polishing the outer periphery of the quartz glass material 1 by the grinding apparatus A configured as described above will be described with reference to FIGS. First, the rough grinding unit 13 and the finish grinding unit 14 are retracted to a position where the cylindrical quartz glass material 1 does not hinder the setting. The axis of the quartz glass material 1 is the center of rotation, and the carriage 1
The quartz glass material 1 is chucked to the headstock so as to be parallel to the direction of movement of the quartz glass material 1.

Before starting the grinding, the carriage 11 is placed on the end of the quartz glass material, and the flat wheel-type grindstone 21 is
As shown in FIG. 7, the quartz glass material 1 is placed at a position separated from the end of the quartz glass material 1. At this time, when the flat wheel type grinding wheel 21 moves in parallel with the axis of the quartz glass material 1, the quartz glass material 1
Flat wheel type grinding wheel 21
To move forward. On the other hand, the cup wheel-type grindstone 30 is retracted so as not to contact the maximum diameter portion of the quartz glass material 1. In this state, the outer peripheral surface of the quartz glass material 1 is rotated while rotating the flat wheel grindstone 21 and discharging the grinding fluid from the coolant nozzle 2 to the grinding area, and moving the carriage 11 in the axial direction of the quartz glass material 1. Grinding.

Then, as shown in FIG. 7, the flat wheel type grindstone 21 is sent to a position passing through the right end of the quartz glass material 1 to complete the first rough grinding, and the rough grinding unit 13
The (flat wheel-type grindstone 21) is advanced to give a predetermined cutting amount. Thereafter, the flat wheel-type grindstone 21 is sent to a position passing through the left end portion of the quartz glass material 1 to perform the second rough grinding, and the cut amount is given again and sent to the right to perform the third rough grinding. .

After the above operation is repeated to complete the rough grinding, the flat wheel type grindstone 21 is retracted and moved away from the outer peripheral surface of the quartz glass material 1. Next, the cup wheel type grindstone 30 is brought close to the outer peripheral surface of the quartz glass material 1 to give a predetermined cutting amount. Then, the finish grinding is performed while rotating the cup wheel-type grindstone 30 and discharging the grinding fluid from the coolant nozzle 2 to the grinding area. The cut amount of the cup wheel type grindstone 30 is smaller than the cut amount of the flat wheel type grindstone 21 described above. In this finish grinding, the finish grinding is performed by feeding the cup wheel type grindstone 30 only in a certain direction. When the cup wheel type grindstone 30 is fed in the opposite direction, the cup wheel type grindstone 30 is separated from the quartz glass material 1 and finish grinding is not performed. As a result, scratches generated on the outer peripheral surface of the quartz glass material 1 can be prevented.

As described above, rough grinding is performed by the flat wheel-type grindstone 21 having high grinding efficiency, and then finish grinding is performed by the cup wheel-type grindstone 30 capable of increasing the surface roughness of the finished surface. Therefore, highly accurate and efficient grinding can be performed.

In order to further reduce the processing time of the rough grinding, as shown in FIG. 8, a grinding apparatus A 'equipped with a rough grinding unit 13' having a spindle 19 'longer than the spindle 19 is provided. It is desirable to use The spindle 19 'has a front end portion protruding forward from the housing 18 longer than the spindle 19, and a plurality of (five in this embodiment) flat wheel grindstones 21a and 21b having different diameters are provided at this portion. , 21c, 21d, 21e
Are mounted so as to be sequentially reduced in diameter in the grinding feed direction. Other configurations of the grinding device A ′ are the same as those of the above-described grinding device A.

A rough grinding method using the grinding apparatus A 'having the above structure will be described with reference to FIG. A spindle 19 'located at a distance D from the axis of the quartz glass material 1
The flat wheel grindstones 21a to 21e are attached to the flat wheel grindstones 21a to 21e, and the flat wheel grindstones 21a having the minimum diameter are attached at the forefront in the grinding feed direction indicated by the arrow F.
The flat wheel-type grindstones 21b to 21e are arranged so that the diameter increases sequentially from the grinding feed direction side.

When the spindle glass 19 is rotated about the axis thereof and moved in the grinding feed direction while rotating the spindle 19 ', the flat wheel type grinding wheel having the smallest diameter farthest from the quartz glass material 1 is obtained. Next, a small diameter flat wheel grindstone 21b grinds the outer peripheral surface of the quartz glass material 1 with a slight time lag. Similarly, the flat wheel type grindstones 21c, 21d, and 21e perform the grinding process one after another. As a result, the grinding process is performed about five times (the number of flat wheel-type grindstones) by a single grinding feed of the spindle 19 ', and the rough grinding time is greatly reduced. In the return step of the grinding feed, the spindle 19 'is moved backward to perform no grinding. Also, as described above, in the finish grinding using the cup wheel-type grindstone 30, the finish grinding unit 14 is retracted in the return step of the grinding feed so that the grinding is not performed, so that the surface of the quartz glass material 1 is not damaged.

Next, a plurality of flat wheel type grinding wheels 21a to 21a-2
After performing rough grinding in 1e, the cup wheel-type grindstone 30
Example 1 in which finish grinding was performed in Example 1 and a conventional grinding method (Comparative Example 1) in which grinding was performed only with the cup wheel type grinding wheel 3 were performed under the following conditions, and the results were compared and studied.

(1) Grinding Process When Five Flat Wheel Type Grinding Stones are Used in Rough Grinding (Example 1) Conditions Length of quartz glass material 1 …………………………………………………………………………………… 2000 mm quartz Maximum outer diameter of glass material 1 (before grinding) 181 mm Minimum outer diameter of quartz glass material 1 (before grinding) 161 mm Number of flat wheel type grindstones used ............ …………………………………………………………………………………………………………………………………………………………………………………………………………………………… 5mm in diameter 50 mm / min Cutting depth per feed of cup wheel-type grindstone ... 0.1 mm in diameter Feeding speed of cup wheel-type grindstone ... 25 mm / min

(2) Grinding Conditions of Conventional Grinding Method (Comparative Example 1) Length of Quartz Glass Material 1 2,000 mm Maximum outer diameter of quartz glass material 1 (before grinding) 181 mm Minimum outer diameter of quartz glass material 1 (before grinding) 161 mm Cut amount per feed of cup wheel-type grindstone During rough grinding 1 mm diameter finish Grinding: 0.1 mm in diameter Feeding speed of cup wheel type grindstone Rough grinding: 40 mm / min Finish grinding: 25 mm / min

(3) Comparison between Example 1 and Comparative Example 1 The outer diameter machining accuracy with respect to Example 1 is 160 ± 0.05 mm Surface roughness... ……… 90μm Required processing time …………………………………… 2.0 hours OD accuracy in Comparative Example 1 is 160 ± 0.05mm Surface roughness …… …………… 90 μm Processing time …………… 18.8 hours As is clear from the comparison results, in Example 1, the conventional grinding method (comparison) It was found that grinding with the same accuracy can be performed in a much shorter time than in Example 1).

Next, a second embodiment of the outer peripheral surface grinding apparatus for a quartz glass material according to the present invention and a control method of the apparatus will be described with reference to FIGS. FIG.
In the figure corresponding to FIG. 2, the same or corresponding members as those of the quartz glass outer peripheral surface grinding apparatus shown in FIGS. 1 to 6 are denoted by the same reference numerals, and description thereof will be omitted. This second
The apparatus for grinding an outer peripheral surface of a quartz glass material according to the embodiment is characterized in that a flat wheel type grindstone 21 is attached to a distal end portion of a spindle S of a motor M by a clamp 22. That is, the belt 25 is wound around the pulley 23 and the pulley 24 attached to the output shaft of the motor 20 as in the grinding device shown in FIG. Instead of rotating the wheel, the flat wheel type grinding wheel 21 is directly rotated by the motor M.

The apparatus for grinding the outer peripheral surface of a quartz glass material detects the current value of the motor M,
Detection means 40 for detecting a load acting on the motor M is provided. The load acting on the motor M is generated when the flat wheel grindstone 21 grinds the outer peripheral surface of the quartz glass material. The load detected by the detection unit 40 is configured to be input to an arithmetic processing unit (CPU) 42.

Also, the arithmetic processing unit (CPU) 42
In the connected memory 41, five-stage load values are set in advance.
(Set load value R₁ , R_Two , R_Three , R_Four , R_Five : R
₁ <R_Two <R_Three <R_Four <R_Five ), Its set load value R₁ ,
R_Two , R_Three , R_Four , R_Five Feed speed of carriage 11 corresponding to
Degree (set feed speed V₁ , V_Two , V_Three , V_Four , V_Five : V ₁ 
> V_Two > V_Three > V_Four > V_Five ) Is stored. That is,
When there is no load (set load value R₁ ), The carriage 1
Set speed feed speed V where feed speed of 1 is the fastest₁ Read
Similarly, the set load value R_TwoIn Case of,
The feed speed of the carriage 11 is the set feed speed V_Two Read out
The following is the same configuration.

Further, the carriage processing speed control means 43 is connected to the arithmetic processing unit (CPU) 42, and the processing unit (CPU) 42 comprises the carriage movement speed control means 4.
In order to move the carriage 11 at a set feed speed read from the memory 41, a control signal for the carriage 3 is transmitted.

Further, while the carriage 11 is being moved from one end to the other end along the columnar quartz glass material, the load of the motor M for rotating and driving the flat wheel-type grindstone 21 becomes no load even once. When the detecting means 40 detects that the carriage 11 is moved again from one end to the other end along the cylindrical quartz glass material, the outer peripheral surface of the quartz glass material is ground by the flat wheel 21. Thus, the feed control means 4 of the carriage 11 from the arithmetic processing unit (CPU) 42
3 is transmitted.

On the other hand, when the detecting means 40 does not detect that the load of the motor for rotating and driving the flat wheel type grindstone has become no load at all, the other end portion of the outer peripheral surface of the quartz glass material An arithmetic processing unit (C
The control signal is sent from the PU (PU) 42 to the feed control means 43 of the carriage 11.

Next, the operation of the apparatus according to the above control method will be described. For example, the speed of the V _x (V _x is V ₁ ~
If the detected value of the load of the motor M exceeds the set load value _Rx during grinding (rapid feed) at V ₄ ), the feed speed of the grinding wheel (the carriage 11)
Feed rate) is switched to V _{x + 1} to continue grinding. Incidentally, maintained during grinding (fast forward) at a rate of V _5, when the detected value of the load of the motor M exceeds the set load value R ₅ also, a is V ₅ (feed speed of the carriage 11) feed speed of the grinding And continue grinding.

The feed speed V _Y (V _Y is V _{2 to} V ₅ )
During grinding with the motor, the detected value of the load of the motor M is determined by the feed speed V _Y
When the load falls below the load value R _Y corresponding to the following, the feed rate V _Y is maintained during one rotation of the columnar transparent quartz glass (1 to 60 seconds).
After that, the feed speed of the grindstone (the feed speed of the carriage 11) is the feed speed V _Y-1 , that is, the fast feed is performed at a speed one step lower. Incidentally, the speed of V ₁ was set load value (R ₁₎
But zero, namely the case of a no-load condition, the feed rate is not reduced speed of the V _1.

When the carriage 11 is moved from one end to the other along the cylindrical quartz glass material,
When the detecting means 40 detects that the load of the motor M for rotating and driving the flat wheel-type grindstone 21 has at least once been in a no-load state, the carriage 11 is once again moved along the cylindrical quartz glass material at one end. The flat wheel 21 is used to grind the outer peripheral surface of the quartz glass material. As described above, when it is detected that the load of the motor M that rotationally drives the flat wheel-type grindstone 21 is in the no-load state (when the load state and the no-load state are mixed), the columnar quartz glass is used. There are irregularities on the outer peripheral surface of the material. Therefore, the carriage 11 is moved again from one end to the other end along the cylindrical quartz glass material, and the flat wheel-type grindstone 21 is moved again.
Is to be ground.

On the other hand, when the carriage 11 is moved from one end to the other end along the columnar quartz glass material, the load of the motor M for rotating and driving the flat wheel type grindstone 21 becomes no load. If this is never detected by the detecting means 40, the grinding is terminated at the other end of the quartz glass material. As described above, when the no-load state is not detected (in the case of all the load states), there is no large unevenness on the outer peripheral surface of the cylindrical quartz glass material, and the purpose of the coarse grinding is achieved. To end.

As described above, as the load on the motor decreases, the feed speed of the grinding wheel (the feed speed of the carriage 11) can be increased, so that the grinding time can be greatly reduced. Also, as the load on the motor increases, the feed speed of the grinding wheel (the feeding speed of the carriage 11) can be reduced, so that abnormal wear of the grinding wheel,
Damage can be prevented.

When the carriage 11 is moved from one end to the other end along the cylindrical quartz glass material, the load of the motor M for rotating and driving the flat wheel type grindstone 21 is in a no-load state. If this is not detected by the detecting means 40, the grinding is terminated at the other end of the quartz glass material, so that unnecessary grinding is not performed and the grinding time can be greatly reduced.

[0053]

According to the method for grinding the outer peripheral surface of a quartz glass material, the apparatus for grinding the outer peripheral surface of a quartz glass material, and the method for controlling the apparatus according to the present invention, the outer peripheral surface of the quartz glass material can be precisely processed with high efficiency. Can.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a grinding apparatus for performing a grinding method of the present invention.

FIG. 2 is a right side view of FIG.

FIG. 3 is a right side view of FIG. 2;

FIGS. 4 (a) and 4 (b) are a front view and a cross-sectional view taken along line AA of a flat wheel-type grindstone.

FIG. 5 is a plan view illustrating a grinding process according to the present invention.

FIG. 6 is a side view of FIG. 5;

FIG. 7 is an explanatory diagram of rough grinding in the grinding method of the present invention.

FIG. 8 is a right side view of a grinding device equipped with a plurality of flat wheel-type grindstones.

FIG. 9 is an explanatory diagram of rough grinding using a plurality of flat wheel-type grindstones.

FIG. 10 is a side view showing a second embodiment of the grinding apparatus according to the present invention.

FIG. 11 is a block diagram showing control means used in the grinding device according to the present invention.

FIG. 12 is a front view illustrating a conventional grinding method.

FIG. 13 is a side view of FIG. 12;

14 (a) and (b) are a front view and a side view (the upper half is a cross-sectional view) of a cup wheel type grinding wheel.

FIG. 15 is a schematic diagram for explaining a conventional grinding method.

[Explanation of symbols]

 A, A 'Grinding device 1 Quartz glass material 10 Bed 11 Carriage 13 Coarse grinding unit 14 Finish grinding unit 19 Spindle 20 Motor 21, 21a to 21e Flat wheel grindstone 28 Spindle 29 Motor 30 Cup wheel grindstone 40 Motor load detecting means 41 memory 42 CPU 43 carriage speed control means M motor S spindle

Continued on the front page. (72) Inventor: Mamoru Yamamon, 8321, Eguchi Kaisaku, Tokuyama, Tokuyama-shi, Yamaguchi 5 Inside Tokuyama Toshiba Ceramics Co., Ltd. (72) Inventor: Isamu Takahashi, 8231, Kaisaku Eguchi, Tokuyama, Tokuyama, Yamaguchi Tokuyama Toshiba Ceramics Corporation F term (reference) 3C043 AA03 CC03 CC12 4G059 AA20 AB03 AC03

Claims (8)

[Claims] 1. A method for grinding an outer peripheral surface of a quartz glass material, which grinds an outer peripheral surface of the quartz glass material, wherein the quartz glass material is rotated about an axis as a rotation center, and a predetermined grinding is performed while rotating a flat wheel type grindstone. By giving a cutting amount and reciprocating in parallel to the axis of the quartz glass material, rough grinding of the outer peripheral surface of the quartz glass material is performed. Subsequently, a predetermined grinding cutting amount is given to the rotating cup wheel type grindstone. And a finish grinding of the rough ground surface. 2. The flat wheel-type grindstone is composed of a plurality of flat wheel-type grindstones whose diameters gradually decrease in a grinding feed direction, and each of the plurality of flat wheel-type grindstones has a rough surface of a quartz glass material outer peripheral surface. In order to perform the grinding, the plurality of flat wheel-type grindstones are moved in the grinding feed direction while rotating, and then, the rotating cup wheel-type grindstone is given a predetermined grinding cut amount to finish-grind the rough ground surface. The method for grinding an outer peripheral surface of a quartz glass material according to claim 1, wherein: 3. The cup wheel-type grindstone reciprocates in parallel to the axis of the quartz glass material, performs grinding in the outward path, and separates from the quartz glass material in the return path, and does not perform grinding. 3. The method for grinding an outer peripheral surface of a quartz glass material according to claim 1, wherein the outer peripheral surface is ground. 4. A grinding apparatus for grinding an outer peripheral surface of a quartz glass material, wherein the quartz glass material is chucked, and a headstock that is driven to rotate is moved in a direction parallel to an axis of the chucked quartz glass material. A possible carriage, which is provided so as to be able to advance and retreat on the carriage toward the quartz glass material, rotates a flat wheel-type grindstone mounted on a spindle, and coarsely grinds the outer peripheral surface of the quartz glass material. A grinding unit, and a finish grinding unit that is provided so as to be able to advance and retreat on the carriage toward the quartz glass material, that rotationally drives a cup wheel-type grindstone, and that finish grinds the outer peripheral surface of the quartz glass material. An apparatus for grinding an outer peripheral surface of a quartz glass material. 5. The spindle of the rough grinding unit has a length such that a plurality of flat wheel-type grindstones can be coaxially arranged and mounted, and a plurality of flat wheel-type grindstones having different diameters are arranged in the grinding feed direction. 5. The apparatus for grinding an outer peripheral surface of a quartz glass material according to claim 4, wherein the apparatus is arranged so that the diameters thereof are sequentially reduced. 6. A detecting means for detecting a load of a motor for rotating and driving the flat wheel type grinding wheel, and a control means for controlling a feed amount of the carriage in accordance with the load detected by the detecting means. The apparatus for grinding an outer peripheral surface of a quartz glass material according to claim 4, characterized in that: 7. The method for controlling an apparatus for grinding an outer peripheral surface of a quartz glass material according to claim 6, wherein a load of a motor for rotating and driving the flat wheel type grindstone decreases or becomes no load. A feed rate of the carriage increases, and when the load increases, control is performed so that the feed rate of the carriage decreases. 8. The control method for an apparatus for grinding an outer peripheral surface of a quartz glass material according to claim 6, wherein the carriage is moved from one end to the other end along the cylindrical quartz glass material. When the load detecting means of the motor detects that the load of the motor for rotating and driving the flat wheel type grindstone is in a no-load state, the carriage is again moved at one end along the cylindrical quartz glass material. To the other end, the flat wheel grinds the outer peripheral surface of the quartz glass material, and the load detection means of the motor that the load of the motor for rotating and driving the flat wheel grindstone is in a no-load state is determined. The method of controlling an outer peripheral surface grinding apparatus for a quartz glass material, wherein the grinding of the outer peripheral surface of the quartz glass material is terminated at the other end when no detection is made.