JPH05208373A - Abrasive cutting wheel and cutting method - Google Patents

Abstract

PURPOSE:To obtain the properties of cutting face being obtained with an abrasive cutting wheel with small-diameter abrasive grains at the cutting speed equivalent to an abrasive cutting wheel with large-diameter abrasive grains, and prevent the abnormal abrasion of a corner. CONSTITUTION:An abrasive cutting wheel 11 is used, which has a large-diameter abrasive grains 23 at the center in thickness direction of a cutting wheel peripheral part 12 and has a small-diameter abrasive grains 13 at both side faces, and the sectional form of the large-diameter abrasive grain part of which has a taper 25 where the outer periphery side is large and the inner periphery side is small. Cutting is performed while reacting a small quantity of electrolytic dressing, as compared with the quantity of electrolytic dressing acting upon the outer periphery 12, upon both side faces of the abrasive cutting wheel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting grindstone and a cutting method for cutting and grooving glass, ceramics and the like with high precision and high speed.

[0002]

2. Description of the Related Art When a thin cutting grindstone is rotated at high speed to cut and groov materials such as glass and ceramics,
The cutting stone tends to bend due to factors such as low rigidity of the grinding stone itself, excessive grinding resistance, and uneven wear. Due to this bending, the side surface of the cutting grindstone comes into contact with the cutting surface, and the side surface slightly grinds or rubs the cutting surface. At that time, if the grinding performance of the abrasive grains on the side surface of the cutting grindstone is insufficient, peeling or chipping caused by a clogging phenomenon or the like occurs on the cut surface, and the cut surface properties such as surface roughness are deteriorated. To do.

The cut surface property can be improved by reducing the diameter of the abrasive grains distributed on the cutting grindstone and by appropriately maintaining the grinding performance of the abrasive grains by an appropriate dressing method. However, in general, the cut surface properties and the cutting speed are in a contradictory relationship, and a reduction in the diameter of the abrasive grains lowers the removal efficiency and leads to a reduction in the cutting processing speed. Therefore, conventionally, the abrasive grain size of the cutting grindstone has been determined in consideration of both the desired cutting surface property and the cutting speed.

As a method for solving the above-mentioned problems, a large-diameter abrasive grain is mainly provided in the central portion in the thickness direction of the outer peripheral portion of the cutting grindstone (hereinafter referred to as the outer peripheral portion), which is mainly used for removing the cutting allowance, and the cutting surface is mainly used. It has been reported that a grinding and cutting method using a cutting wheel having a small-diameter abrasive grain on the side surface portion of the wheel for performing only slight grinding. (Page 75 of the 1991 Autumn Meeting of the Precision Engineering Conference, Academic Lecture Meeting).

According to this method, the cutting speed is mainly determined by the large-diameter abrasive grains on the outer peripheral portion of the grindstone, and the cutting surface property is influenced by the grinding of the small-diameter abrasive grains on the side surface portion, so that the cutting surface property is not deteriorated. The cutting speed can be improved.

[0006]

However, in the grinding and cutting method using the conventional cutting grindstone having the large-diameter abrasive grains on the outer peripheral portion and the small-diameter abrasive grains on the side surface portion, abnormal abrasion occurs in the grindstone. It was easy. That is, due to the large difference in the grinding performance between the large-diameter abrasive grain and the small-diameter abrasive grain, a phenomenon in which either the large-diameter abrasive grain portion or the small-diameter abrasive grain portion is rapidly worn was likely to occur.

If abnormal wear occurs, the cutting grindstone is likely to be damaged at the outer peripheral portion thereof, and frequent truing work of the cutting grindstone is required. Therefore, the effect of this cutting grindstone cannot be obtained with good reproducibility.

The object of the present invention is to solve the above-mentioned conventional problems, to improve the cutting speed without deteriorating the properties of the cutting surface, and to obtain the effect with high reproducibility. To provide a method.

[0009]

The cutting grindstone of the present invention has a large-diameter abrasive grain in the central portion in the thickness direction of the outer peripheral portion of the grindstone, and has small-diameter abrasive grains on both side surfaces, The dimension in the thickness direction is
It is characterized by having a tapered cross-sectional shape with a large outer peripheral side and a small inner peripheral side.

The cutting method of the present invention uses the cutting grindstone of the present invention in which small-diameter abrasive grains are held by a method such as electrodeposition on both side surfaces of a large-diameter abrasive grain cutting grindstone made by metal bonding. It is characterized in that both side surfaces are cut while applying a small amount of electrolytic dressing as compared with the amount of electrolytic dressing applied to the outer peripheral portion.

[0011]

4 (a) and 4 (b) show the case where a conventional cutting wheel 11 having large-diameter abrasive grains 23 on the outer peripheral portion 12 and small-diameter abrasive grains 13 on both side surface portions 14 is used for cutting. It is the schematic which showed the cross-sectional shape of the typical abnormal wear which occurs in the.

The small-diameter abrasive grains 13 distributed on the side surface portion 14 of the cutting grindstone 11 mainly only slightly grind the cut surface, and it is considered that the amount of wear of the side surface portion 14 due to this light grinding is extremely small. There is. However, the conventional cutting wheel 11
In the above, the small-diameter abrasive grains 13 of the corner portion 26 are also subjected to removal processing of the cutting margin. At that time, if the machining is continued at a cutting speed suitable for the grinding ability of the large-diameter abrasive grains 23, the abrasive grains at the corners 26 have a small diameter, so that a sufficient protrusion amount of the abrasive grains cannot be obtained, and the small-diameter abrasive grains 1
When the grinding performance of No. 3 is exceeded, the cutting removal grinding removal process is performed. As a result, a clogging phenomenon or the like occurs in the small-diameter abrasive grains 13 and an excessive grinding resistance acts on the corner portions 26, so that only the small-diameter abrasive grains 13 at the corner portions 26 are rapidly worn, and FIG.
Abnormal wear occurs as shown in.

Therefore, in the cutting grindstone of the present invention, as shown in FIG. 1, the size of the large-diameter abrasive grain portion in the thickness direction has a tapered cross-sectional shape whose outer peripheral side is large and whose inner peripheral side is small. By using this cutting grindstone 11, only a large-diameter abrasive grain 23 grinds and removes a large amount of workpieces, and a small-diameter abrasive grain 13 only slightly grinds the cut surface. In this way, small-diameter abrasive grain 1
It becomes possible to obtain the cut surface properties obtained in No. 3 at the cutting speed when the large-diameter abrasive grains 23 are used.

Further, in consideration of the amount of wear of the side surface portion 14 (reduction of the thickness of the abrasive grain portion 17) along with the progress of cutting, the taper 25
When the angle of is determined, the outer peripheral portion 12 is worn and the cutting grindstone 1
Even if the outer diameter of 1 decreases, the cross-sectional shape is kept stable. That is, in the corner portion 26, the small-diameter abrasive grain 13 or the large-diameter abrasive grain 23
Even if any of the above is abraded first, the remaining abrasive grain portion will protrude. Excessive grinding resistance acts on these protrusions, causing rapid wear. As a result, as shown in FIG. 3, the corner portion 26 keeps an appropriate radius, abnormal wear does not occur, and a stable grindstone cross-sectional shape can be maintained.

On the other hand, in the case of cutting by the conventional method, an excessive load acts on the outer peripheral portion 12 which removes a large amount of grinding allowance, and the grinding performance cannot be maintained appropriately, as shown in FIG. 4 (b). Abnormal wear may occur. Such abnormal wear is caused by insufficient supply of grinding fluid to the central portion of the outer peripheral portion 12 in the thickness direction, and the outer peripheral portion 1 compared with the small-diameter abrasive grains 13.
It is also promoted by factors such as the weak holding force of the large-diameter abrasive grains 23 distributed in No. 2.

The above-mentioned abnormal wear occurs due to the difference in grinding performance between the large-diameter abrasive grain 23 and the small-diameter abrasive grain 13. Therefore, this abnormal wear can be suppressed by appropriately dressing the outer peripheral portion 12 in which the large-diameter abrasive grains 23 are distributed and the side surface portion 14 in which the small-diameter abrasive grains 13 are distributed. However, it is difficult to keep the outer peripheral portion 12 and the side surface portion 14 at appropriate grinding performances due to self-dressing as the cutting process progresses, and it is inefficient to perform mechanical dressing during the cutting pass. Is.

Therefore, in the cutting method of the present invention, the outer circumference of the cutting wheel 11 is used by using the cutting wheel of the present invention in which the small-diameter abrasive grains are held on both sides of the large-diameter abrasive grain portion produced by metal bonding by a method such as electrodeposition. A method of applying different amounts of electrolytic dressing to the portion 12 and the side surface portion 14 is adopted. FIG. 2 shows a plan view of a machined part used as an example.
Thus, by using the U-shaped negative electrode 16 and making the gap d ₁ between the grindstone side face portion 14 and the electrode 16 larger than the gap d ₂ between the outer peripheral portion 12 and the electrode 16, the side face portion 14 has an outer periphery. A small electrolytic current is applied as compared with the portion 12.

By this method, a large amount of electrolytic dressing can be applied to the outer peripheral portion 12 for removing a large amount of grinding allowance, and a small amount of electrolytic dressing can be applied to the side surface portion 14 that only slightly grinds the cut surface. it can. Outer part 1
The protrusion amounts of the large-diameter abrasive grains 23 of No. 2 and the small-diameter abrasive grains 13 of the side surface portion 14 are appropriately maintained even though the abrasive grain sizes are different, and it is possible to prevent abnormal wear of the cutting grindstone 11. Become.

[0019]

1 is a schematic sectional view of a cutting grindstone used in an embodiment of the present invention, and FIG. 2 is a plan view of a machined portion of the apparatus. The cutting grindstone 11 shown in FIG. 1 has an abrasive grain portion 17 having a thickness of 0.5 m.
m, the thickness of the base portion 18 is 0.3 mm, and a bronze-based or iron-based 1A1R type SD1200 metal bond cutting grindstone is provided with a taper 25 of about 1 degree by a truing operation.
Next, SD6000 abrasive grains were formed to a thickness of about 0.05 mm by electrodeposition or electroless plating, and thereafter, straight-shaped was prepared by double-side lapping.

First, as shown in FIG. 2, a U-shaped electrode 1
6 was installed adjacent to the cutting grindstone 11, and the water-soluble grinding fluid 15 having weak conductivity was supplied toward the side surface portion 14 of the cutting grindstone 11 from the supply hole provided in the cover 22. Here, the gap d ₂ between the grindstone outer peripheral portion 12 and the electrode 16 was 0.3 mm, the gap d ₁ between the side surface portion 14 and the electrode 16 was 0.8 mm, and the grinding fluid 15 was supplied at 3 liters per minute.

Then, the cutting grindstone 11 and the electrode 16 are connected to an electrolytic power source 19, the cutting grindstone 11 is rotated at 15000 RPM, and a glass substrate having a thickness of 5 mm is fed at a feed rate of 10 mm /
Grinding cut at min. In this embodiment, as a method of supplying the electrolytic power source 19 to the cutting grindstone 11, a method of bringing the carbon brush 24 into contact with the end surface of the main shaft 21 is adopted.

In the above embodiment, the mesh size 120
It is possible to grind and cut at a cutting speed comparable to that when a cutting whetstone of 0 is used, and the cutting speed is 6000 mesh size.
It was possible to improve it by more than 3 times as compared with the case of using the cutting whetstone. As for the surface roughness of the cut surface, R _{max of} 0.05 μm was obtained at the same time as when the cutting grindstone with a mesh size of 6000 was used.

Further, abnormal wear which occurred in the conventional method was prevented, and a stable wear shape of the cutting wheel 11 was obtained as shown in the schematic sectional view of FIG. As a result, the truing frequency was 1/4 or less of the conventional method, and the effect of the cutting wheel of the present description could be obtained with high reproducibility.

In this embodiment, the large-diameter abrasive grain 23 is S
The cutting grindstone 11 having SD6000 as the small abrasive 13 is used for the D1200, but a cutting grindstone using different abrasives such as CBN or the like may also be used. , A similar effect is obtained.

[0025]

As described above, according to the cutting grindstone and the cutting method of the present invention, the cutting speed can be improved without deteriorating the properties of the cutting surface, and the abnormal wear of the cutting grindstone can be suppressed, whereby the above-mentioned effects can be obtained. Can be achieved with high reproducibility.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a cutting grindstone used in an example of the present invention.

FIG. 2 is a plan view of a processing portion of the cutting device used in the embodiment of the present invention.

FIG. 3 is a diagram showing a change in cross-sectional shape of a cutting grindstone of the present invention as a cutting process progresses.

FIG. 4 is a diagram showing a cross-sectional shape of typical abnormal wear that occurs when a conventional cutting wheel having large-diameter abrasive grains on the outer peripheral portion and small-diameter abrasive grains on both side surfaces is used.

[Explanation of symbols]

 11 Cutting Whetstone 12 Outer Perimeter 13 Small Diameter Abrasive Grain 14 Side Surface 15 Grinding Fluid 16 Electrode 17 Abrasive Grain Part 18 Base 19 Electrolytic Power Supply 20 Glass Substrate 21 Spindle 22 Cover 23 Large Diameter Abrasive 24 Brush 25 Tapered Angle 26 Corner

Claims (2)

[Claims] 1. A large-diameter abrasive grain is provided at the center of the outer peripheral portion of the grindstone in the thickness direction, and small-diameter abrasive grains are provided on both side surfaces, and the large-diameter abrasive grain portion has a large inner diameter on the outer peripheral side. A cutting grindstone having a tapered cross-sectional shape on the peripheral side. 2. A cutting grindstone according to claim 1, wherein small-diameter abrasive grains are held on both side surfaces of a large-diameter abrasive grain cutting grindstone produced by metal bonding by a method such as electrodeposition. Is a cutting method characterized by cutting while applying a small amount of electrolytic dressing as compared with the amount of electrolytic dressing applied to the outer peripheral portion.