JPS6119386B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of polishing a side edge of a glass plate.

Generally, cut glass sheets have relatively large irregularities on their side edges, and the side edges are sharp and dangerous. The entire side edge is polished.

Such side edge polishing involves first grinding the side edges of the glass plate using a coarse-grained whetstone to create a uniform surface with no unevenness, then chamfering the edges, and then polishing the side edges using a fine-grained whetstone. The process sequence is usually followed by final polishing the surface.

Generally, the above-mentioned polishing method provides a sufficiently satisfactory end surface quality, but in recent years, with the trend towards luxury goods for consumer goods, there has been a strong desire for a higher quality glass plate end surface.

In other words, when grinding the side edge surface of a glass plate with a grindstone, it is essentially inevitable that a minute notch (commonly known as a crack) will occur on the side edge. This can be removed by increasing the chamfer width to a certain extent. However, depending on the application, it is desired to make the edge chamfer width as small as possible for reasons such as making the thickness of the glass plate appear smaller.For such applications, conventional polishing methods However, there was a problem in that the size of the "burr clams" generated was much larger than the allowable chamfer width, making it impossible to provide products of satisfactory quality.

The main purpose of the present invention is to solve the above-mentioned conventional problems,
To provide a method for polishing a side edge of a glass plate, which can reduce the size of "chatter" that inevitably occurs during side edge grinding, compared to the conventional method.

Another object of the present invention is to provide a simple and economical method for polishing the side edge of a glass plate, which can improve the quality of the finish without reducing polishing efficiency.

That is, the gist of the present invention is that, before grinding the side edge surface of a glass plate with a rotary whetstone, at least the flank edge of the side edge of the rotary whetstone is polished in advance.

The present invention will be explained in more detail below with reference to the drawings.

A to C in FIG. 1 are a plan view, a side view, and a front view, respectively, showing a conventional glass plate side edge surface grinding method, and as shown, the side edge of the glass plate 1 is transferred in the direction of arrow 2. 1A, a rotary grindstone 3 such as a diamond wheel is usually provided with its center axis 3A inclined in a horizontal plane, so that one side of the grindstone 3 contacts the side edge 1A of the glass plate to perform surface grinding with a predetermined depth of cut. ing.

Here, in this specification, the side where specific abrasive grains of the whetstone start to come into contact with the glass is called the incidence side of the whetstone, and the side where the abrasive grains leave the glass after finishing grinding is called the escape side of the whetstone, and the edge of the glass plate side. Of both edges, the edge located on the incident side of the grindstone will be called the entrance side edge, and the edge located on the escape side of the grindstone will be called the escape side edge.

For example, as shown in FIG. 1, if the right side of the grinding wheel 3 is in contact with the glass plate and the rotation direction 4 is clockwise, the upper edge of the glass plate side edge becomes the entrance edge E1, and the lower side becomes the escape edge. It is E2.
If the rotating direction of the grindstone 3 or the contact end with respect to the glass is opposite to the above, the positional relationship between the entrance edge and the escape edge will be reversed in terms of name.

In addition, when both sides of the circular grindstone are in contact with the glass plate, both the upper and lower edges of the side edge of the glass plate are escape edges as used herein.

When the side edge surface of the glass plate is ground as described above, a large number of chips 5 called "burr clams" as shown in FIG. 2 occur particularly along the escape edge E2 of the glass plate 1.

Although this "burry clam" is minute, it becomes a quality problem if there is a restriction on the edge chamfer width as mentioned at the beginning.

The inventors of the present invention have repeatedly conducted extensive experimental studies regarding the above-mentioned problems, and have found that when grinding the side edge surface with a rotary grindstone,
The present invention was completed by discovering that by pre-obliquely polishing the side edge, at least the escape edge of the rotary grindstone, the size of the "burr" that occurs can be made smaller than before.

The present invention will be described below based on the embodiment shown in FIG. When grinding is performed as a side, prior to this grinding, the escape edge E2 of the side edge of the glass plate (lower side in this example) is first obliquely polished, and then a predetermined side edge surface is ground.

It goes without saying that during this edge bevel polishing, the amount of polishing and the bevel angle Θ should be selected so that the edge E4 of the side edge surface after the subsequent side edge surface grinding is located within the oblique section 7.

When the side edge surface is ground beyond the edge E3 of the oblique section 7 to the inside, the result is much the same as in the conventional case.

Figures 4A and 4B show other embodiments of the present invention. In this example method, a predetermined position 6 is set with the escape side of the grindstone facing upward.
Before grinding the side edge surface up to a predetermined position 6, the glass portion including both the entrance edge E1 and the relief edge E2 is removed and polished to form an oblique cross section 7 diagonally upward, and then the side edge surface up to a predetermined position 6 is polished. Perform grinding.

According to the above-mentioned method of the present invention, the size of the "filter clam" that occurs on the flank edge of the grinding wheel is very small. It is possible to completely remove the ``billy clam'' by simply applying a thread chamfering process.

Note that oblique polishing applies not only to the escape edge E2, where large "burr clams" are likely to occur, but also to the entrance edge E2.
1 may also be applied.

The reason why the size of the generated "filter clam" is smaller than that of the conventional method using the method according to the present invention is presumed as follows.

To explain the cross-sectional model shown in FIGS. 5 and 6, in side edge grinding, the abrasive grains 8 of the grindstone advance perpendicularly to the surface of the glass plate 1, and at this time, the abrasive grains 8 and the remaining portion of the glass Stress concentration occurs at the contact corner of the glass plate 1, and a minute clutch 9 is formed in the glass plate 1 obliquely in the direction of movement of the abrasive grains 8. This crack 9 does not pose a problem at the stage where there are many unground parts of the glass, but when the abrasive grains 8 reach near the surface of the glass plate 1, as shown in FIG. 5, the tip of the crack 9 and the surface of the glass plate are connected. When the distance Δd becomes less than the breakage limit of the glass, the remaining glass portion 10 is peeled off along the crack 9, and a "burry clam" of a size indicated by ΔW1 is generated.

On the other hand, when the escape edge of the abrasive grain 8 is beveled as shown in FIG. 6, the distance between the tip of the crack 9 and the surface of the glass plate is △d Abrasive grain 8 at the stage when it should become
The tip of is in an open state, so the load applied to the remaining glass portion is small, and the crack does not progress to the extent shown by the broken line in Figure 6, but instead becomes a crack with a short distance as shown by 11, which is smaller than △W1 above. Na△
It is thought that only "filter clams" of the size of W2 will occur.

In a preferred embodiment of the present invention, oblique polishing is performed on the side that will become the relief edge of a rotary grindstone that grinds the side edge surface of the glass. Polish it with a rotating whetstone.

In other words, the "burr" that occurs on the relief side of the grinding wheel during edge bevel polishing is smaller than that that occurs during side edge grinding, but if the rotation direction is selected as described above, it will occur during edge bevel polishing. The "burry clam" will be removed by later side edge surface grinding.

7 and 8 illustrate a preferred embodiment of the invention.

In FIGS. 7 and 8, arrow 12 is the escape direction of the grindstone during edge oblique polishing, and arrow 1
3 is the escape direction of the grindstone during side edge surface grinding. The methods shown in FIGS. 7 and 8 can be implemented with the apparatuses illustrated in FIGS. 9 and 10, respectively.

That is, in the device of FIG. 9 corresponding to FIG. 7,
At the side edge position of the glass plate 1, which is transferred to the right side in the figure by a rotary belt or the like pressed from the upper and lower surfaces, a rotating grindstone 14 such as a diamond wheel for oblique polishing is installed on the upper side in the direction of movement of the glass plate. In addition, on the lower side, there is a rotating whetstone 15 sen for side edge surface grinding, and both whetstones 14,
15 have their central axes inclined so that their left sides contact the side edges of the glass plate.

The edge bevel grinding wheel 14 may be rotated counterclockwise, and the side edge surface grinding wheel 15 may be rotated clockwise.

Further, as shown in FIG. 10, by rotating the edge beveled grinding wheel 14 whose grinding surface is tilted diagonally upward clockwise and the side edge surface grinding wheel 15 counterclockwise, the polishing direction relationship shown in FIG. can be obtained.

If we mention the edge oblique angle Θ here,
If this angle Θ is too large, the amount of side edge grinding will become large and the polishing efficiency will decrease when the edge chamfer width is kept as small as possible. On the other hand, if Θ is too small, the Since it becomes difficult to adjust the amount, it is generally desirable to select Θ within the range of 5 degrees to 45 degrees, and particularly preferably within the range of 10 degrees to 20 degrees.

Next, examples of the present invention will be described.

Example A glass plate with a thickness of 5 m/m was transported at a speed of 3 m/min, and a rotary grindstone was brought into contact with one side edge of the glass plate to perform a predetermined edge bevel polishing, followed by side edge surface grinding. The size of the "burr clam" that occurred on the flank edge of the grinding wheel during surface grinding was measured.

In the experiment, the bevel angle was set to 45 degrees in relation to the polishing direction shown in Figure 7, and a white arundum grindstone was used for bevel polishing, and a 270-320 mesh diamond wheel was used for side edge grinding.

The bevel angle is set to 5 degrees in relation to the polishing direction shown in Fig. 7, and the same diamond wheel is used for oblique polishing and side edge surface grinding.

The bevel angle is 10 degrees in relation to the polishing direction shown in Figure 8, and the same diamond wheel is used for both bevel polishing and side edge surface grinding.

Testing was carried out using 20 pieces of each glass plate under the above three conditions.

In addition, as a comparative example, 20 pieces of glass plates were subjected to direct side edge surface grinding without bevel edge grinding, and the size of "burr clams" generated on the flank edge of the grindstone was measured.

In the above experiment, the depth of cut during side edge surface grinding was set to 0.5 m/m in both the example and comparative example.
In the example, the width of the oblique section left after side edge surface grinding is approximately 0.1 m/m.

Further, the glass feeding speed and the grindstone used in the comparative example were the same as in the example.

The size of the "Biri clam" is defined as the width dimension from the side edge of the glass plate to the top of the "Biri clam", and as a result of the experiment, under the above conditions, the maximum is 0.20 mm, the average value is 0.20 mm, and under the conditions, the maximum is 0.5 mm, the average value Under the condition of 0.24 mm, the maximum value was 0.5 mm, and the average value was 0.27 mm. On the other hand, in the comparative example, the maximum size of "Biri clam" is 0.8 mm,
The average value was 0.53 mm, and it was confirmed that according to the method of the present invention, the size of the "filter clam" could be made smaller than before.

[Brief explanation of the drawing]

Figure 1 A, B, and C are a plan view, a side view, a front view, and a front view, respectively, showing the conventional method of grinding the side edge surface of a glass plate.
Fig. 2 is a plan view showing the occurrence of "filter clams", Fig. 3 A and B are cross-sectional views showing one embodiment of the present invention in the order of steps, and Fig. 4 A and B are other embodiments of the present invention. FIG. 5 and FIG. 6 are cross-sectional views that model the difference in phenomenon between the conventional method and the method of the present invention, and FIG. 8 is a sectional view showing another example of the same relationship as above, and FIG. 9 is a plan view showing the main parts of a device that realizes the relationship shown in FIG. 7. , FIG. 10 is a plan view showing the main parts of an apparatus that realizes the relationship shown in FIG. 8. 1...Glass plate, 1A...Side edge, 3...Rotary grindstone, E2...Escape side edge, 5...Biri clam, 7...
...Beveled section, Θ...Beveled angle.

Claims (1)

[Scope of Claims] 1. After diagonally polishing at least one edge of the side edge of the glass plate, the surface of the side edge is polished so that the one diagonally polished edge becomes the escape edge of the grindstone. A method of polishing the side edge of a glass plate, which is characterized by grinding with a rotating grindstone. 2. In the method for polishing a side edge of a glass plate as set forth in claim 1, the side that becomes the escape edge of the rotary grindstone that grinds the surface of the side edge becomes the relief edge of the rotary grindstone that performs oblique polishing. A method of polishing the side edge of a glass plate in which the diagonal polishing of one edge is performed using a rotating whetstone.