JP2000033566A - Control method for polishing machine and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a pressing force of a polishing tool against a workpiece. SOLUTION: A machining head 21 can move vertically and freely on a base 11 on which a table 12 supporting a workpiece W is provided. A polishing spindle 23 on which a polishing tool 22 polishing a surface of the workpiece W is mounted can rotate freely on the machining head 21, and a motor for pressurization 31 which brings the table 12 and the polishing spindle 23 near relatively and gives a pressing force to the polishing tool 22 is provided in a condition in which the workpiece W is in contact with a polishing face 22a of the polishing tool 22. A rotary angle of the motor for pressurization 31 is detected by a rotary encoder 35, and a displacement amount in the axial direction of the polishing face 22a when a pressing force is given between the workpiece W and the polishing tool 22 by the motor for pressurization 31 is detected by a linear encoder 36. A pressing force applied on the polishing tool 22 in the axial direction is compound based on both detected values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for controlling a polishing machine on which a polishing tool such as a grindstone is mounted.

[0002]

2. Description of the Related Art A process of shaving a workpiece, that is, a work, using a grinding wheel is called a grinding process, and the grinding process and the polishing process are collectively called a polishing process. Polishing includes lapping for adjusting the dimensional error of the work and improving the surface finish, and polishing for forming a high-level mirror surface on the work surface.Buffing tools such as buffs are used for each. In addition, at the time of lapping, alumina powder, silicon carbide powder, glass powder, diamond powder, or the like is used as lapping abrasive grains. Polishing uses abrasive grains having finer particles than lapping abrasive grains.

[0003] Surface grinding for grinding a flat surface of a work includes grinding the work on the end face of a disk-shaped or ring-shaped grindstone, or grinding the work on the outer peripheral surface of the grindstone. Usually, the grindstone is fed at a constant speed toward the workpiece.

[0004]

When the polishing tool is fed in a fixed size, if the polishing performance of the polishing tool changes, the pressing force of the polishing tool against the work changes, and the desired polishing precision cannot be obtained. Sometimes.

[0005] If the pressing force can be detected, the polishing performance of the polishing tool can be detected and the workpiece can be polished with high accuracy. Also, when the polishing tool is dressed, if the pressing force can be detected, the polishing tool can be dressed in an optimal state.

An object of the present invention is to enable detection of a pressing force of a polishing tool against a contacted member such as a work or a dressing tool.

[0007]

According to the present invention, there is provided a method for controlling a polishing machine, comprising the steps of: rotating the polishing tool while the surface of the polishing tool is in contact with the surface of a member to be contacted supported on a table; A step of detecting a rotation angle of a pressing motor that applies a pressing force to the contact member to the polishing tool,
A step of detecting a displacement amount of the polishing surface in a pressing direction when the polishing tool is pressed against the contacted member by the pressing motor; and the polishing tool based on the rotation angle and the displacement amount in the pressing direction. And calculating a pressing force applied to the stiffener. Further, the method of controlling a polishing machine according to the present invention compares the input value of the pressing force set in advance with the calculated pressing force, and controls the pressing motor so that the pressing force becomes the input value. Characterized by a step of performing

The control apparatus for a polishing machine according to the present invention comprises: a table for supporting a member to be contacted; a polishing shaft on which a polishing tool for contacting the surface of the member to be mounted is mounted; A pressurizing motor for applying a pressing force between the contacted member and the polishing tool by relatively bringing the table and the polishing shaft close to each other in a state where the polishing surface is in contact with the polishing surface; Rotation angle detection means for detecting a rotation angle of a pressure motor; and detecting a displacement amount of the polishing surface in a pressing direction when a pressing force is applied between the contacted member and the polishing tool by the pressing motor. It has a displacement amount detecting means, and a calculating means for calculating a pressing force applied to the polishing tool based on signals from the rotation angle detecting means and the displacement amount detecting means. Further, the method of controlling a polishing machine according to the present invention compares the input value of the pressing force set in advance with the calculated pressing force, and controls the pressing motor so that the pressing force becomes the input value. Characterized by a step of performing The rotation angle detecting means may be a rotary encoder, and the displacement amount detecting means may be a linear encoder.

The contacted member is a dressing tool for dressing a workpiece or a polishing tool.

In the present invention, the pressing force can be detected by detecting the rotation angle of the pressing motor for applying the pressing force in the axial direction to the polishing tool,
Polishing of a workpiece and dressing of a polishing tool can be performed with high accuracy.

[0011]

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

FIG. 1 is a sectional view showing a schematic structure of a polishing apparatus according to an embodiment of the present invention. A table 11 for supporting a workpiece, that is, a work W, is rotatably mounted on a base 11. . A pulley 14 attached to a table rotation shaft 13 fixed to the table 12 and a work rotation motor 15
A timing belt 18 is stretched between a pulley 17 attached to the shaft 16 of the motor.

A processing head 21 is arranged above the base 11 so as to be movable up and down.
A polishing shaft 23 to which is mounted is rotatably provided. In order to rotationally drive the polishing shaft 23, a spline portion 24 is formed on the polishing shaft 23, and a pulley 25 fitted along the spline portion 24 so as to be adjustable and movable in the axial direction, and a shaft of a motor 26 for rotating a grinding wheel. 27 and a pulley 28 attached to the timing belt 2.
Nine have been bridged. Therefore, the machining head 21 is moved down to the base 11 so that the grindstone 2
The surface of the work W is polished by rotating the table 12 by the work rotation motor 15 and rotating the grindstone 22 by the grindstone rotation motor 26 while the two flat polishing surfaces 22a are in contact with each other. In addition,
Instead of providing the spline portion 24, the polishing shaft 23 and the pulley 25 may be connected via a sliding key, and the pulley 25 and the polishing shaft 23 may be fitted so as to be adjustable in the axial direction.

In order to apply a pressing force between the workpiece W and the grindstone 22 during polishing, a pressurizing motor 31 composed of a servomotor is attached to the processing head 21, and the pressurizing motor 31 is driven to rotate by a shaft. A pressing block 33 is screwed to the feed screw 32 to be screwed. A ball screw may be used as the feed screw 32. The pressing block 33 is a thrust bearing 3
4 is connected to the polishing shaft 23.

By rotating the pressurizing motor 31, the pressing stroke of the grindstone 22 in contact with the workpiece W can be detected. In order to detect the rotation angle of the pressurizing motor 31, the motor 31 is rotated. Is provided with a rotary encoder 35 as rotation angle detecting means. As the rotary encoder 35, any of a known absolute type and an increment type may be used.

When the pressing motor 31 is driven in a state where the grinding wheel 22 is not in contact with the work W, the vertical movement amount of the pressing block 33 corresponding to the rotation angle of the feed screw 32, that is, The grindstone 22 moves up and down by the same distance as the feed amount of the screw 32. The entire apparatus including the pressing block 33, the polishing shaft 23, and the table 12 constitutes an apparatus elastic body that elastically deforms in the axial direction when subjected to an axial load. Therefore, whetstone 2
When the pressing motor 31 is rotationally driven in a state in which the grinding wheel 22 is in contact with the workpiece W, the grindstone 22 receives a resistance force from the workpiece W, so that the device elastic body is elastically deformed in the axial direction.

Therefore, by comparing the value detected by the rotary encoder 35 with the amount of displacement in the pressing direction between the table 12 and the polishing surface of the grindstone 22, the amount of elastic deformation of the elastic body of the device can be obtained. The pressing force of the grindstone 22 against the work W can be determined from the elastic deformation amount.

When the amount of elastic deformation of the member such as the polishing shaft 23 due to the pressing force applied to the whetstone 22 is not sufficient and the amount of deformation is small, an elastic body such as rubber or a spring member is placed in the pressing block 33. By incorporating it, the device elastic body may be configured at that portion. Also,
The housing of the pressurizing motor 31 may be attached to the processing head 12, and a portion that is torsionally deformed by the load of the motor shaft may be provided in the motor housing, and that portion may be used as a device elastic body.

The work W and the grindstone 2 are driven by the pressing motor 31.
In order to detect the amount of displacement in the pressing direction between the table 12 and the polishing surface 22a of the grindstone 22 when a pressing force is applied between the polishing shaft 23 and the processing head 21.
A linear encoder 36 is provided as a displacement detector between the two. The linear encoder 36 has a main scale 36a fixed to a support ring 38 fitted to the polishing shaft 23 via a bearing 37, and an index scale 36b attached to the processing head 21. The index scale 36b is provided with a fixed-side slit, a light source that irradiates light to the moving slit and the fixed-side slit on the main scale 36a side, and a light receiving element. As the linear encoder, in addition to such an optical encoder, a capacitance encoder or an electromagnetic encoder may be used.

When a pressing force against the work W is applied to the grindstone 22 by driving the pressing motor 31, a normal resistance Fn is generated in the grindstone 22 in the axial direction, and a tangential resistance Ft is generated in the rotation direction of the grindstone. Will be. The ratio ε between Ft and Fn is determined by the grinding resistance ratio ε = (Ft / F
When defined as n), the tangential resistance Ft increases as the normal resistance Fn increases. As the value of ε increases, the wear of the workpiece increases, the grinding performance increases, and the value of ε decreases. It has been found that the polishing performance becomes lower as much as possible. Therefore, it is important to monitor or monitor the normal resistance Fn in order to perform the polishing with high accuracy.

The normal resistance Fn is obtained by comparing the feed amount of the feed screw 32 obtained by detecting the rotation angle of the pressurizing motor 31 with the rotary encoder 35 and the displacement amount of the polishing surface obtained by the linear encoder 36. It is required by doing. In FIG. 2, the feed amount obtained by the rotary encoder 35 is indicated by a symbol R, and the displacement amount of the polished surface is indicated by a symbol L. The difference between the two values will correspond to the normal resistance Fn.

FIG. 3 is a block diagram showing a control circuit of the grinding machine shown in FIG.
6 is sent to a CPU (arithmetic processing unit) 41, which has a ROM 42,
A memory such as a RAM 43 and an operation board 44 are connected. When the operator operates the keys and the like of the operation board 44, the motor and the like constituting the polishing apparatus are operated.

The ROM 42 has a rotary encoder 35
A data table and an arithmetic expression for calculating the normal resistance Fn applied to the grindstone 22 from the amount of deformation of the elastic body in the pressing direction based on the detected value from the linear encoder 36 and the detected value from the linear encoder 36 are stored. And the calculation result is displayed on the display unit 4.
5 is displayed.

From the CPU 41, the work rotating motor 1
5, an operation signal is sent to each of the grinding wheel rotation motor 26 and the pressurization motor 31, and an operation signal is also sent to a vertical movement motor 46 for vertically moving the processing head 21. I have.

Therefore, when the value of the normal resistance Fn, that is, the pressing force of the grindstone 22 is set by operating a key or the like provided on the operation board 44, the rotation angle of the pressing motor 31 is set to the set value. Is feedback controlled, and the pressing force of the grindstone is adjusted so as to have a predetermined normal resistance. When the normal resistance value exceeds a predetermined value due to a malfunction of the polishing apparatus, an abnormal state is lit on a display unit 45 for displaying the detected normal resistance value, or a lamp or a buzzer is operated. You may make it do. In this way, the pressing force of the grindstone is controlled such that a predetermined normal resistance is always obtained.

FIG. 4 is a view showing a grinding apparatus according to another embodiment of the present invention, wherein members common to those shown in FIG. 1 are denoted by the same reference numerals. In this case, the table 12 supporting the work W is mounted on the base 11 so as to be vertically movable without rotating. Accordingly, the work W is polished by the grindstone 22 that is rotationally driven while being fixed to the table 12 and stationary.
The table 12 is screwed to a feed screw 32 of a pressurizing motor 31 incorporated in the base 11, and the pressing force between the grindstone 22 and the work W is adjusted by the pressurizing motor 31. I have.

The table 12 has a large capacity.
When the table 12 acts as a rigid body with respect to the pressing force to the grinding wheel 2, the amount of elastic deformation of the table itself due to the pressing force applied to the grindstone 22 becomes small. The elastic body 39 made of is incorporated. As a result, the elastic body 39 mainly deforms elastically, so that the value of the normal resistance is determined. Also in this case, similarly to the above-described embodiment, the value of the obtained normal resistance may be lit and displayed on the display unit 45 for monitoring, and may be input in advance by a key operation of the operation board or the like. A feedback signal may be sent to the pressurizing motor 31 so as to have a normal resistance value.

In each of the embodiments, the polishing operation is performed by using the workpiece W as a contacted member and bringing a polishing tool into contact with the workpiece W. However, a dressing tool is mounted as the contacted member and the dressing tool is used. Even when the polishing tool is dressed with a tool, it is possible to detect the value of the normal resistance and perform an optimal dressing process.

The present invention is not limited to the above embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

For example, in the polishing apparatus of the embodiment, the polishing surface of the grinding stone is formed by the end surface of the grinding stone, but when a grinding stone having a peripheral surface as the polishing surface is used, or a conical surface is used as the polishing surface. The present invention can also be applied to a case where chamfering is performed using a grindstone. Further, although the case where the work W is polished using the grindstone 22 is described in the embodiment, the present invention can be applied to a case where lapping or polishing is performed using a polishing tool such as a buff. it can.

[0031]

According to the present invention, the pressing force can be detected by detecting the rotation angle of the pressing motor that applies the pressing force to the contacting member such as the work to the polishing tool. Since the pressing force can be detected, a constant pressing force can be applied to the polishing tool by controlling the operation of the pressing motor so as to achieve the set pressing force. Polishing accuracy can be improved by applying a constant pressing force to the polishing tool to polish the workpiece, that is, the workpiece, and dressing the polishing tool to dress the polishing tool in an optimal state. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic structure of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a normal resistance of a grindstone based on detection values of a rotary encoder and a linear encoder.

FIG. 3 is a block diagram showing a control circuit of the polishing apparatus.

FIG. 4 is a cross-sectional view illustrating a schematic structure of a polishing apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Base 12 Table 13 Table rotation shaft 14 Pulley 15 Work rotation motor 16 Motor shaft 17 Pulley 18 Timing belt 21 Processing head 22 Grinding stone (polishing tool) 23 Polishing shaft 24 Spline part 25 Pulley 26 Grinding stone rotation motor 27 Motor shaft 28 Pulley 29 timing belt 31 pressurizing motor 32 feed screw 33 pressing block 34 thrust bearing 35 rotary encoder 36 linear encoder

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Shimamoto 2-2-2 Nakajima, Nagaoka City, Niigata Prefecture Inside Nanotem Corporation (72) Inventor Atsushi Takada 2-2-2 Nakajima, Nagaoka City, Niigata Stock Association F term (reference) in Nanotem Corporation 3C034 AA08 CA11 CA26 CA30 CB13 DD20 3C047 BB01

Claims (7)

[Claims] A step of rotating and driving the polishing tool while the surface of the polishing tool is in contact with the surface of the contacted member supported on the table; and applying a pressing force to the polishing tool to the polishing tool. Detecting the rotation angle of the pressing motor; detecting the displacement of the polishing surface in the pressing direction when the polishing tool is pressed against the contacted member by the pressing motor; and Calculating the pressing force applied to the polishing tool based on the displacement amount in the pressing direction. 2. The method for controlling a polishing machine according to claim 1, wherein an input value of a preset pressing force is compared with a calculated pressing force so that the pressing force becomes the input value. A method for controlling a polishing machine, comprising a step of controlling a pressurizing motor. 3. The control method for a polishing machine according to claim 1, wherein said contacted member is a dressing tool for dressing a workpiece or a polishing tool. Method. 4. A table for supporting a member to be contacted, a polishing shaft on which a polishing tool that comes into contact with the surface of the member to be mounted is mounted, and a state in which the member to be contacted and the polishing surface of the polishing tool are in contact A pressurizing motor for applying a pressing force between the contacted member and the polishing tool by relatively bringing the table and the polishing shaft close to each other, and detecting a rotation angle of the pressurizing motor. Rotation angle detection means, displacement amount detection means for detecting a displacement amount of the polishing surface in a pressing direction when a pressing force is applied between the contacted member and the polishing tool by the pressing motor, and the rotation A control device for a polishing machine, comprising: a calculating means for calculating a pressing force applied to the polishing tool based on signals from an angle detecting means and the displacement detecting means. 5. The control apparatus for a polishing machine according to claim 4, wherein an input value of a preset pressing force is compared with a calculated pressing force so that the pressing force becomes the input value. A control device for a polishing machine, comprising a control means for controlling a pressurizing motor. 6. A control apparatus for a polishing machine according to claim 4, wherein said rotation angle detecting means is a rotary encoder, and said displacement amount detecting means is a linear encoder. . 7. The polishing machine control device according to claim 4, wherein the contacted member is a dressing tool for dressing a workpiece or a polishing tool. Characteristic polishing machine control device.