JPH11221766A - Grinding device and glass plate end face grinding method using grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an in-process dressing type grinding device which is suitable to carry out a grinding process of plural sheets of glass plate end faces such as a semicylindrical form of processing, continuously and in a good formation stability, while dressing a grinding wheel. SOLUTION: This grinding device has a grinding wheel 2 having a grinding wheel groove on the outer periphery; a disk form rotary electrode 1 rotating on a shaft parallel to the grinding wheel spindle of the grinding wheel 2 opposing to the grinding wheel groove, a power supply 6 and a power feed body 7 to apply the voltage between the grinding wheel 2 and the disk form rotary electrode 1, and nozzles 5a and 5b to feed a conductive liquid or mist between the grinding wheel 2 and the electrode 1, and the disk form rotary electrode 1 is rotated in order to insert its outer periphery to the space in the gringing wheel groove. And, a truing is carried by a discharge process, and an in-process dressing is carried out by both a discharge and an electolysis processes the using this device, in the grinding method of the glass plate end face. Consequently, a semicylindrical form of processing of numerous sheets of glass plate end faces can be carried out in a good formation stability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding apparatus for grinding a plate-like workpiece while dressing (in-process dressing), and particularly to a grinding apparatus suitable for grinding an end face of a glass sheet and a glass sheet using the same. And an end surface grinding method.

[0002]

2. Description of the Related Art When industrially stably grinding end faces of a large number of glass plates to a certain dimensional accuracy with a constant dimensional accuracy, in order to stabilize the processing quality such as surface shape and dimensions of the grinding, it is necessary to use a grinding wheel. It is important to perform in-process dressing accurately.

Conventionally, on-machine electric discharge truing of a conductive grindstone is disclosed, for example, in Japanese Unexamined Patent Publication No. Hei 4-201073, in which an electrode for electric discharge machining is mounted on a machine, and a conductive thin blade mounted on a grinding machine and used. An on-machine discharge truing / dressing method and apparatus for shaping the outer peripheral portion of a conductive thin blade grindstone by causing the outer peripheral portion to approach the outer peripheral portion while rotating on the machine without removing the grindstone from the machine and shaping the outer peripheral portion of the conductive thin blade grindstone. It has been disclosed.

As a method of grinding a workpiece while dressing a grindstone, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Application Publication No. 254754, a state in which a conductive liquid flows between a conductive grindstone and an electrode facing the conductive grindstone during grinding, and a pulse voltage is applied between the two to bond the grindstone. There is an in-process dressing method (ELID method) in which a material is eluted and dressing is performed.

FIG. 3 shows a surface grinder using a conventional electrolytic in-process dressing technique. A wheel a made of a metal bond grindstone has a (+) pole and faces a circular ground surface b. The dressing electrode c provided as a negative electrode is a negative electrode, and a nozzle d for supplying a conductive electrolyte (coolant) faces these gaps. e indicates a table for holding a work, and f indicates a power supply.

During the grinding of the work W,
By supplying a coolant from the nozzle d, a DC pulse current is supplied in a state in which a gap between the wheel a and the dressing electrode c is filled with the coolant, so that a metal bond on the grinding surface b is eluted by an electrolytic action, and grinding is performed. The projected state of the abrasive grains on the surface b is maintained. However, in the above-mentioned prior art, truing and in-process dressing of the wheel need to be performed using separate devices.

[0007]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Laid-Open Publication No. 4-201
The method disclosed in Japanese Patent No. 073 is aimed at shaping the outer peripheral portion of the thin blade whetstone, and installs a truing jig on the machine, generates an electric discharge between the truing jig and the wheel, and generates a discharge between the truing jig and the wheel. The shape of the grindstone is shaped by the relative movement between the grindstone and the electrode by NC control. for that reason,
There is a problem that it takes time to set truing jigs, etc.
There is a problem that it is economically difficult to apply to a simple structure, for example, a glass plate chamfering device, which does not use the C device.

The electrolytic in-process dressing method disclosed in Japanese Patent Application Laid-Open No. 6-254754 uses a fixed dressing electrode, and its application to a straight grindstone, a cup grindstone, and a thin blade grindstone has been established. The rotating wheel grindstone has problems such as a problem in producing a dressing electrode and a problem of supplying an electrolytic solution to a gap between the wheel and the electrode.

In a grinding apparatus (shown in FIG. 3) using this fixed dressing electrode, a straight wheel grinding wheel a is used as a grinding wheel for performing surface grinding, and is relatively opposed to the grinding wheel a and is relatively easy to manufacture. An arc-shaped dressing electrode c is used. However, it is very difficult to manufacture and install a dressing electrode for a pencil-edge type rotary wheel grindstone having a complicated grindstone cross-sectional shape so that the gap between the two can be made uniform over a small distance. Further, when both of the above methods are applied to, for example, processing of an end face of a glass plate, it is necessary to perform discharge truing of the wheel and in-process dressing with separate devices, and there is a problem that the devices are complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a grinding machine capable of easily performing truing and in-process dressing of a pencil-edge type rotary wheel grindstone by the same apparatus. An object of the present invention is to provide an apparatus and a method for grinding an end face of a glass sheet using the apparatus.

[0011]

SUMMARY OF THE INVENTION The present invention provides a pencil-edge type conductive rotating wheel grindstone having a grindstone groove on its outer periphery,
A disk-shaped rotary electrode that faces the grindstone groove and rotates on an axis parallel to the grindstone axis of the rotary wheel grindstone to dress the rotary wheel grindstone, and between the rotary wheel grindstone and the disk-shaped rotary electrode. And a nozzle for supplying a conductive liquid or mist between the rotating wheel grindstone and the electrode, wherein the disk-shaped rotating electrode has an outer peripheral portion thereof. Is a grinding device that is positioned and rotated so as to be inserted into the space in the grindstone groove.

The disk-shaped rotary electrode of the present invention is provided with a fine movement device in order to accurately and easily adjust a gap between the electrode and a pencil-edge type conductive rotary wheel grindstone (hereinafter abbreviated as a rotary wheel grindstone). May be used.

In the present invention, the outer peripheral portion of the disk-shaped rotary electrode is positioned and rotated in the space of the grindstone groove of the rotary wheel grindstone, and is inserted into the space of the groove of the disk-shaped rotary electrode. The distance between the outer peripheral portion and the grindstone groove surface is preferably adjusted to have a substantially constant distance at the groove bottom and the groove side. The outer cross-sectional shape of the disk-shaped rotating electrode is
It is preferable that the shape is substantially similar to the cross-sectional shape of the grindstone groove and slightly smaller in order to perform dressing on the bottom and side portions of the grindstone groove to the same extent.

According to the present invention, there is also provided a method for rotating a conductive rotating wheel grindstone having a grindstone groove on an outer periphery thereof so as to face the grindstone groove,
And rotating a disk-shaped rotating electrode for dressing the rotating wheel grindstone around an axis parallel to the grinding wheel axis of the rotating wheel grindstone so that an outer peripheral portion thereof is located in the space in the grinding wheel groove. Applying a voltage between the and the disc-shaped rotating electrode, and supplying a conductive liquid or mist between the rotating wheel grindstone and the disc-shaped rotating electrode, while dressing the rotating wheel grindstone, This is a grinding method of a glass plate end surface which is ground by pressing the glass plate end surface against a grindstone groove.

In the present invention, the dressing performed while grinding the end face of the glass plate is performed by supplying a coolant (conductive liquid or mist) and a discharge process generated between the disk-shaped rotating electrode and the rotating wheel grindstone. It is preferable to determine the dressing operation parameters so as to use both of the electrolysis processes according to the above. The discharge of the discharge process may be an extremely weak discharge, and may be a discharge that is normally invisible.

In the dressing using only the electrolytic process, the dressing (sharpening) of the grindstone can be performed precisely. However, when a large number of glass plates are ground at high speed in a short time, the dressing ability (speed) is reduced. It is small and runs short. That is, it is difficult to balance with the high-speed grinding of the end face of the glass sheet. In order to solve such a problem, it is preferable that the dressing is performed by both actions of a discharge process and an electrolytic process.

In the present invention, it is preferable that the rotating wheel grindstone is trued by an electric discharge process prior to the grinding of the glass plate end face. This truing is
Normally until the spark discharge has disappeared. This truing is
It is preferable that the cross-sectional shape of the grindstone groove of the rotating wheel grindstone is similar to and slightly larger than the cross-sectional shape of the outer peripheral portion of the disc-shaped rotating electrode.

According to the present invention, it is possible to perform the semi-cylindrical grinding of the end surfaces of a large number of glass plates while maintaining a fixed semi-cylindrical shape. What is required to maintain a constant wavy shape is, for example, in the case of a glass plate for liquid crystal display cell display, in the exposure step for processing the transparent electrode,
Since the glass plates are positioned by the positioning mechanism based on the pin stopper control, the positioning of each glass plate is controlled based on the end surface of the glass plate. For this reason, it is required that the semi-cylindrical shape of the end face of the glass plate be constant in order to secure the positional accuracy.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments and drawings. Embodiment FIG. 1 shows a schematic front view of a grinding apparatus (in-process dressing apparatus) of the present invention. FIG. 2 is a view showing a state in which a disk-shaped rotary electrode used for performing the discharge truing / in-process dressing according to the present invention is arranged so as to face a rotary wheel grindstone.

As a grinding device, a rotary wheel grindstone 2 (diameter 250 mm, rotation speed 2400 rpm, metal bond 6
00 number diamond grindstone). A disk-shaped rotary electrode (diameter: 45 mm) 1 is provided to face the rotary wheel grindstone 2, and a nozzle 5b for supplying a coolant, which is a conductive liquid, in the form of a mist is provided between the two.

The rotating wheel grindstone 2 is a conductive so-called pencil edge type wheel made of metal bond, and is attached to the grinding wheel shaft 4. The disk-shaped rotating electrode 1 is made of a copper-tungsten alloy in a disk shape and is parallel to the grinding wheel shaft 4. The distance between the rotating wheel grindstone 2 and the disc-shaped electrode 1 is attached to the electrode shaft 3 so that the distance g shown in FIG.

The rotating wheel grindstone 2 is electrically connected to a (+) pole of a DC pulse power supply via a feeder 7 composed of a lead wire. The grinding wheel shaft 4 is connected to a drive source via a power transmission mechanism (not shown).

The disk-shaped rotary electrode 1 has a cross-sectional shape at the tip portion which is approximately 100 times larger than the cross-sectional shape of the grinding wheel groove of the rotary wheel grinding wheel 2.
It is molded into a similar shape smaller by μm and has a disk-shaped rotating electrode 1
Is electrically connected to the (-) pole of a DC pulse power supply via a brush (not shown). The electrode shaft 3 is connected to a drive source via a power transmission mechanism (not shown), and has a structure in which the electrode shaft 3 rotates in a direction opposite to the rotating wheel grindstone 2. In the present embodiment, a coolant is sprayed on a water wheel (not shown) attached to the electrode shaft 3 of the disc-shaped rotary electrode, and the disc-shaped rotary electrode 1 is turned in the opposite direction to the rotation direction of the rotary wheel grindstone 2 by the supply pressure. Rotated.

The discharge truing is performed by rotating the wheel 2
And the disk-shaped rotating electrode 1 are rotated, and a coolant (Aritake Company A
While supplying a small amount of mist of 50 times the FG-M city water diluent), a pulse voltage of 4 to 20 μsec was applied between the rotating wheel grindstone 2 and the disc-shaped rotating electrode 1,
A disk-shaped rotating electrode 1 is rotated by a fine moving device into a rotating wheel grindstone 2
The discharge was carried out by approaching. Peak voltage 140
V, a DC pulse voltage (ON / OFF ratio of 1: 1) having a period of 8 μsec was applied.

In the discharge truing, in order to make the grinding wheel groove sectional shape of the rotating wheel grindstone 2 a predetermined shape, the sectional shape of the disk-shaped rotating electrode 1 is changed to the disk-shaped rotating electrode 1 and the rotating wheel grinding stone 2 at the end of the discharge truing. A similar shape smaller than the predetermined grinding wheel groove cross-sectional shape by the gap of is used.

The state of generation of electric discharge between the disc-shaped rotary electrode 1 and the rotary wheel grindstone 2 is determined by the distance between the two, the set value of the DC pulse voltage, and the supply state of the coolant mist. Since the gap between the wheel grindstone 2 and the disc-shaped rotary electrode 1 was about 100 μm, the cross-sectional shape of the outer peripheral portion of the disc-shaped rotary electrode 1 was formed into a similar shape smaller by about 100 μm than the grindstone groove cross-sectional shape of the rotary wheel grindstone 2. Used.

Next, a description will be given of dressing (in-process dressing) of the grindstone performed simultaneously with the grinding of the glass plate end face. As shown in FIG. 4, the end face of a glass plate of 150 mm × 150 mm × 0.7 mm thick soda lime silica composition was used as a glass substrate for a liquid crystal display element.
The end face was processed into a kamaboko shape (R chamfer). A glass plate (indicated by W in FIG. 1) was fixed by a support (not shown) and pressed against the groove of the rotating wheel grindstone at a constant pressure, and 1200 glass plates were continuously ground.

The in-process dressing is performed by rotating the rotating wheel grindstone 2 and the disc-shaped electrode 1 while keeping the gap between the rotating wheel grindstone 2 and the disc-shaped rotating electrode 1 at the end of the discharge truing. Grinding wheel location to grind the end face (groove at the bottom of rotating wheel grinding wheel 2 in FIG. 1)
While supplying a coolant from the nozzle 5a to the nozzle 5a, a pulse voltage of a period of 4 to 20 μsec is applied between the rotating wheel grindstone 2 and the disc-shaped rotating electrode 1 so that no discharge is observed between them, and in-process dressing is performed. Was done.
In this example, the beak voltage of the DC pulse power supply was set to 100 V at which no discharge was observed, and a voltage of 8 μsec (ON / OFF ratio 1: 1) was applied.

In the in-process dressing, it has been confirmed from the observation of the grinding wheel grinding surface of the rotating wheel grindstone 2 that the dressing is performed by both the discharge process and the electrolytic process. By using these two processes in combination, it is possible to grind the grindstone surface efficiently in a short time and without causing chips or the like on the glass plate. When a spark discharge is observed between the rotating wheel grindstone 2 and the disc-shaped rotating electrode 1, the roughened grinding wheel surface of the rotating wheel grindstone 2 deteriorates the roughness of the processing surface of the glass plate. It is not preferable from the viewpoint of processing.

The coolant mist is supplied to the gap between the disc-shaped rotary electrode 1 and the rotary wheel grindstone 2 during the in-process dressing, as shown in FIG. 1, from the nozzle 5a to the grindstone for grinding the glass plate end face. The mist is produced by the scattered coolant being scattered and supplied between the two. When the dressing ability is insufficient, the disk-shaped rotary electrode 1
The coolant mist was also supplied from the nozzle 5b to the portion that was inserted into and meshed with the grindstone groove, thereby improving the dressing ability.

At the time of in-process dressing, coolant is supplied to the gap between the bottom of the grindstone groove and the disk-shaped rotary electrode 1. In the case of the rotating wheel grindstone 2 having the grindstone groove on the outer peripheral surface, the centrifugal force generated by the rotation of the rotating wheel grindstone is provided. Due to the fact that the coolant that has flown to the bottom of the grindstone groove is blown to the side of the grindstone groove, it is difficult to supply the coolant to the bottom of the grindstone groove. In some cases, the problem of insufficient dressing may occur.

In the present invention, since the disk-shaped rotary electrode 1 is rotated during the grinding process so as to be located in the space in the grindstone groove, the coolant is sufficiently supplied also to the bottom of the grindstone groove by the centrifugal force. . Therefore, according to the present invention, the disadvantage that the dressing state is different between the bottom of the grindstone groove and the side of the grindstone groove is solved.

At the start of the in-process dressing, the disk-shaped rotary electrode 1 and the rotary wheel grindstone 2
Are set at the end of the discharge truing, so that they are equally spaced over the entire groove. Therefore, uniform dressing can be performed on the entire grindstone groove.

By adjusting the gap between the disc-shaped rotary electrode 1 and the rotary wheel grindstone 2, the distance of the disc-shaped rotary electrode 1 from the surface of the entire grindstone groove (both bottom and side portions) can be relatively changed. Therefore, it is possible to change the dressing strength in each part of the grindstone groove.

For example, when the grinding load on the groove bottom of the rotary wheel grindstone 2 is large, the distance between the two is reduced so that the distance between the grinding wheel groove bottom is shorter than the distance on the grinding wheel groove side. Dressing can work harder. Also, when the distance between the two is increased, the dressing on the side of the grindstone groove can be made to work relatively stronger than its bottom.

In this embodiment, a copper-tungsten alloy is used as the material of the disk-shaped rotary electrode 1, but a conductive material such as another metal may be used. In this embodiment, a DC pulse power supply is used as a power supply for discharge truing and in-process dressing. However, a ripple waveform having a constant potential on a pulse waveform can be used. Is also possible.

The end surface grinding process of the glass plate obtained in the present embodiment was stable in the shape of a semicircle, and the variation in the roughness of the ground surface was sufficiently small.

In the present invention, one disk-shaped rotary electrode is provided for a rotary wheel grindstone. However, by providing a plurality of disk-shaped rotary electrodes 1, dressing efficiency can be increased.

[0039]

According to the present invention, as a dressing electrode to be combined with a pencil-edge-type conductive rotating wheel grindstone having a grindstone groove on the outer periphery, a disc-shaped rotating electrode which is positioned so that the outer peripheral portion is inserted into the grindstone groove and rotates. Since it is used, the effective length of the dressing electrode can be lengthened, thereby extending the life of the electrode. In addition, the coolant supplied between the disk-shaped rotary electrode and the rotary wheel grindstone reaches the bottom of the grindstone groove by the rotational centrifugal force of the rotating disk-shaped rotary electrode and the wind pressure due to the centrifugal force. It can be almost the same as the dressing of the section.

Further, by making the cross-sectional shape of the outer peripheral portion of the disc-shaped rotary electrode substantially similar to the cross-sectional shape of the grindstone groove and making it slightly smaller, the roughness of the grinding of the end surface of the glass plate can be reduced over the entire processed surface. At the same time, it is possible to keep the ground shape and the ground surface roughness of a large number of glass plates constant.

Since the in-process dressing of the present invention is carried out by using both the discharge process and the electrolytic process, the dressing can be performed at a high speed, whereby the grinding speed of the glass plate is increased, and hence the wear speed of the grindstone is increased. Even so, dressing of good quality can be achieved in a balanced manner. As a result, it is possible to secure the shape stability and the high efficiency in the end face grinding of the glass sheet.

[0042]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an embodiment of a grinding apparatus of the present invention.

FIG. 2 is a diagram illustrating a positional relationship between a disk-shaped rotating electrode and a rotating wheel grindstone according to the present invention.

FIG. 3 is a schematic sectional view of a grinding apparatus having a fixed dressing electrode according to the prior art.

FIG. 4 is a view for explaining a semi-cylindrical shape of an end face of a glass plate implemented in the present invention.

[Explanation of symbols]

1: disk-shaped rotating electrode 2: rotating wheel grinding wheel 3: electrode shaft 4: grinding wheel shaft 5a, 5b: nozzle for supplying conductive liquid or mist (coolant) 6: power supply 7: power supply

Claims (7)

[Claims] Claims: 1. A pencil-edge-type conductive rotating wheel grindstone having a grindstone groove on its outer periphery, facing the grindstone groove, and
A disk-shaped rotating electrode for rotating the rotating wheel grindstone to dress the rotating wheel grindstone by rotating about an axis parallel to the grinding wheel axis of the rotating wheel grindstone; a power supply and a power supply for applying a voltage between the rotating wheel grindstone and the disk-shaped rotating electrode And a nozzle for supplying a conductive liquid or mist between the rotating wheel grinding wheel and the electrode, wherein the disk-shaped rotating electrode has an outer peripheral portion inserted into a space in the grinding wheel groove. A grinding device that is positioned and rotated as it is. 2. A sectional shape of an outer peripheral portion of the disk-shaped rotating electrode is as follows:
The grinding device according to claim 1, wherein the grinding wheel groove has a shape substantially similar to a cross-sectional shape of the grinding wheel groove and is slightly smaller. 3. The grinding apparatus according to claim 1, wherein the rotating wheel grindstone is a metal-bonded diamond grindstone, and the disk-shaped rotating electrode is made of copper tungsten. 4. A method for rotating a conductive wheel grindstone having a grindstone groove on its outer periphery to dress the rotating wheel grindstone around an axis facing the grindstone groove and parallel to a grindstone axis of the rotating wheel grindstone. The disk-shaped rotating electrode is rotated so that the outer peripheral portion thereof is located in the space in the grinding wheel groove, a voltage is applied between the rotating wheel grinding wheel and the disk-shaped rotating electrode, and the rotating wheel grinding wheel and the disk-shaped rotating electrode are rotated. A grinding method for a glass plate end surface, in which a conductive liquid or mist is supplied between the electrodes to dress the rotating wheel grindstone and to grind the glass plate end surface by pressing the glass plate end surface against the grinding stone groove. 5. The method according to claim 4, wherein the dressing is performed by a discharge process and an electrolytic process. 6. The method according to claim 4, wherein prior to said grinding, the rotating wheel grindstone is trued by a discharge process using a disk-shaped rotary electrode as a discharge electrode. 7. A cross-sectional shape of an outer peripheral portion of a disk-shaped rotary electrode used for the truing is similar to a cross-sectional shape of the grindstone groove.
7. The method for grinding an end face of a glass sheet according to claim 6, wherein the size is slightly reduced.