JPS6311283A - Diamond wheel and formation thereof - Google Patents

Abstract

PURPOSE:To make a grinding ratio larger and reduce the wear as well as to solve a problem on loading, by laminating each unit abrasive grain layer different in grinding performance each in the radial direction alternately in a state of positioning a fusion layer in between, and setting this laminated surface down to a grinding surface. CONSTITUTION:A ceramic material grinding diamond wheel 2 being bonded to a cup wheel type base metal is constituted in the following processes that plural unit abrasive grain layers 3 and 4 to be sintered and formed in a ring form by diamond abrasive grains 6 and a binder 7 are closely laminated and unitized in one in the radial direction, while a fusion layer 5 made up of fusing both these unit abrasive grain layers 3 and 4 with each other is formed and situated in a boundary part in space where these plural unit abrasive grain layers 3 and 4 are adjoined, and this laminated surface is set down to a grinding surface. Crushing power of the diamond abrasive grains 6 forming these adjoined unit abrasive grain layers 3 and 4 and holding power of the binder 7 are set to the different value. In addition, at the fusion layer 5, each composition of these abrasive grains 6 and the binder 7 of both these unit abrasive grain layers 3 and 4 adjoined to each other is mixed up, holding intermediate physical properties of these unit abrasive grain layers 3 and 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diamond grindstone for grinding ceramic materials and a method for forming the same.

"Prior Art" Wheels made of diamond, which has excellent hardness, are the mainstream tools for cutting, grinding, etc. ceramic materials.

However, there are a wide variety of ceramic materials, such as alumina, silicon nitride, and zircon, and each material has different physical properties, so they cannot be processed under the same conditions.

Furthermore, since ceramic materials are brittle, unlike general metal materials, the shavings become powder, so a special diamond grindstone is required for processing.

FIG. 8 is a cross-sectional view of the microstructure showing the composition of this type of diamond grinding wheel, in which diamond abrasive grains 6, binder 7,
It is composed of three components: the filler 8, and in particular, the friability of the abrasive grains 6, the concentration, which is the blending ratio of the abrasive grains 6, and the properties of each abrasive grain 6 due to the properties of the binder 7. The three factors of degree of bonding are important issues, and as a result of integrating these factors, it can be said that a grindstone with a high grinding ratio is an excellent grindstone.

Here, the grinding ratio refers to the volume of the workpiece actually ground divided by the volume of grinding waste consumed by the grinding wheel. This results in a grindstone with good performance, that is, a high grinding ratio.

First, if we consider the fragility of the diamond abrasive grains 6, we can say that brittle abrasive grains have high fragility because they are easily shattered when an impact is applied, whereas strong abrasive grains are It does not shatter immediately even when an impact is applied, so it has low fragility.

When grinding ceramic materials, each abrasive grain impacts the ceramic material and continuously generates minute fractures. The exposed surface of the abrasive grain is crushed by the impact, and new edges are constantly formed, so it is less likely to become rounded, so it has excellent so-called self-growth ability and can maintain the desired sharpness, but it also suffers from a large amount of wear. Therefore, the grinding ratio is low and it is uneconomical.

On the other hand, abrasive grains with low friability tend to have a rounded or flattened surface as they are used, making it impossible to maintain a certain level of sharpness and resulting in poor self-sharpening ability. The result will be a large one.

In other words, the degree of friability of abrasive grains has both advantages and disadvantages.

Next, if we consider the degree of concentration of abrasive grains, if the degree of concentration is high, the number of abrasive grains is large, so the sharpness itself will be excellent, but the degree of bonding through the binding material will be weak. Therefore, it is easy to fall off due to impact, and in that respect, although it has excellent self-synthesis ability, the grinding ratio is inferior and the unit cost of diamond abrasive grains is high, making it uneconomical.

Considering the degree of bonding, which is the degree of bonding of abrasive grains, if the degree of bonding of each abrasive grain is strengthened according to the properties of the binder, the initial grinding can be achieved well because the holding force for the abrasive grains is strong. However, since the abrasive grains do not fall off even when they are worn away by grinding, a self-regeneration effect cannot be expected, and new abrasive grains are not exposed, resulting in dull cutting.Furthermore, friction with the ceramic material overheats and burns the abrasive grains. A phenomenon occurs.

In addition, if the degree of bonding is strong, it is difficult to form chip pockets in which chips accumulate, resulting in clogging and poor grinding performance.

On the other hand, if the degree of bonding is weak, the self-growth effect is good, but the abrasive grains fall off and are severely consumed during grinding, resulting in a lower grinding ratio and poor grinding performance.

If we pursue the ideal grinding wheel by comprehensively considering the above factors, we will find that: ■ It has a high grinding ratio and has little wear and tear on the grindstone, ■ It is free from clogging, and it is easy to remove chips. ■ The cutting edge is sharp, there is little grinding resistance and less heat is generated, ■ It does not lose its shape and has a long life, ■ It is inexpensive, and furthermore, ■ The roughness of the ground surface is small. , (2) Good characteristics of the ground surface are required.

However, in the conventional grindstones of this type, no product has been developed that can satisfy all of the above conditions and demands at the same time.

Therefore, it was necessary to use a grindstone that has crushability, degree of concentration, and degree of bonding that correspond to the material of the workpiece, the grinding machine, the grinding method, etc. 6 [Problems to be Solved by the Invention] ] Once the composition of the abrasive grains, such as friability, concentration, and bonding, is determined for the resulting whetstone, the grinding ability of the whetstone is determined accordingly.

For example, if abrasive grains with low fragility are used, they are likely to be crushed, and if abrasive grains with high fragility are used, the abrasive grains themselves can be expected to have a self-synthesizing effect, but they will wear out a lot, and the degree of bonding may not be strong enough. On the other hand, if the degree of bonding is weakened, there will be more wear.

In other words, the above three elements required of a grindstone work against each other, and when carrying out specific grinding operations, it is important to take advantage of the most important elements in consideration of the physical properties of the ceramic material to be ground. , and had to accept other drawbacks that resulted from this.

The present invention solves the above-mentioned conventional problems, and proposes a diamond grindstone and a method for forming the same, which were invented in view of the demand, and which has three important elements required of a grindstone. The purpose is to provide the most effective means for molding it.

[Means and effects for solving the problems] The present invention will be explained below with reference to the drawings showing one embodiment of the present invention.

First, the diamond grinding wheel 2 for grinding ceramic materials of the present invention is bonded to a cup wheel type base metal 1 (see FIG. 1), and is made of diamond abrasive grains 6 and a bonding agent 7.
A plurality of unit abrasive grain layers are sintered and formed into a ring shape by stacking them densely in the radial direction and integrating them, and a boundary portion between adjacent unit abrasive grain layers is placed at the position of both wheels. The structure is such that a fusion layer 5 in which grain layers are fused with each other is formed and the laminated surface is used as the grinding surface (see FIGS. 2 and 3).

The compositions are made such that the crushing performance of the diamond abrasive grains 6 forming adjacent unit abrasive grain layers and the holding power of the binder 7 are set to different values.

In the fusion layer 5, the abrasive grains 6 and binder 7 of both adjacent unit abrasive grain layers
The composition of the two unit abrasive grain layers is mixed, and the physical properties are intermediate between the two unit abrasive grain layers.

Grindability, self-synthesis ability, grinding ratio, degree of abrasion, economic efficiency, etc. vary depending on the friability of the abrasive grains 6, and the shedding and self-synthesis of the abrasive grains 6 vary depending on the strength of the holding force of the binder 7. However, in the grinding wheel 2 here, unit abrasive grain layers each having different grinding performance are alternately laminated in the radial direction with a fusion layer 5 positioned between them, and the laminated surface serves as the grinding surface. Because there are
The grinding surface will have all the advantages of each layer.

Therefore, according to the grinding wheel 2 of the present invention, the grinding ratio is large, the wear and tear of the grinding wheel 2 is small, and no clogging occurs, making it easy to remove chips. It generates less, does not lose its shape, has a long life, can be molded at low cost, is economical, has a small roughness of the ground surface, and has good characteristics of the ground surface.

Even in this case, if the structure is such that unit abrasive grain layers with different physical properties are stacked directly and alternately, there will be significant differences in physical properties, which may damage the ceramic material itself or the unit abrasive grain layers during processing. However, since the fusion layer 5 exists here, the physical properties change slowly, and there is no room for such a problem to occur.

Next, the most effective means for forming the diamond grindstone 2 of the present invention having the above-described structure is as described below.

First, a plurality of primary unit abrasive grain layers are solidified into a ring shape to the extent that they can be self-retained to form a temporarily formed state (see FIG. 4).

In this case, the crushing performance of the diamond abrasive grains 6 and the retention force of the bonding agent 7 in the plurality of primary unit abrasive grain layers to be temporarily formed are set to different values, and these primary unit abrasive grains with different compositions are set to different values. The grain layers are densely laminated in the radial direction to form a primary molded product 9 (see FIG. 5), and each layer is sintered while the boundary portions of each layer are fused to form a fused layer 5. In this way, a unit abrasive grain layer is formed.

As a result, the unit abrasive grain layers are alternately laminated in the radial direction with the fusion layer 5 formed therebetween, and it is possible to form a grindstone 2 in which the laminated surface serves as the grinding surface.

Since each layer is sintered while fusing the mutual boundary portions, the mutual integration is extremely reliable and strong, and the formation of the fused layer 5 can be easily achieved.

``Example'' The drawing shows an example of the present invention, in which a first layer 3 and a twentieth layer 4 are formed as unit abrasive grain layers in a radial direction with their mutual boundary portions fused. The structure is such that they are laminated and integrated, and the laminated surface serves as the grinding surface (see Fig. 2).

For example, the first layer 3 includes diamond abrasive grains 6 with low fragility.
The abrasive grains 6 are mixed with a binder 7 that has a strong holding power to the abrasive grains 6, and the abrasive grains 6 are sintered and molded into a ring shape.

The second layer 4 is composed of highly friable abrasive grains 6 mixed with a binder 7 that has a low retention force for the abrasive grains 6, and is sintered and molded into a ring shape. .

As mentioned above, since the first layer 3 and the second layer 4 are fused at their mutual boundary, a fused layer 5 is formed in this area (see Figure 3), and this fused layer In No. 5, abrasive grains 6 with low friability and abrasive grains 6 with high friability are mixed, and a binder 7 with a large holding force for the abrasive grains 6 and a binder 7 with a small holding power are mixed. , maintains intermediate physical properties between the first layer 3 and the second layer 4.

Since the abrasive grains 6 in the first layer 3 have low friability, the grinding ratio is high and the layer ratio is small, making it economical. Since the bonding agent 7 with a large holding force for the abrasive grains 6 is used, the abrasive The grains 6 are not scattered and do not fall off.

Furthermore, since the abrasive grains 6 in the second layer 4 are highly friable, they are sharp and have a self-synthesizing ability, and since the binder 7 having a small holding force for the abrasive grains 6 is used, the self-synthesizing ability is high. is even more certain.

The fusion layer 5 performs an intermediate function between the two layers 3 and 4.

The illustrated embodiment in FIG. 6 shows a case where the first layer 3 and the second layer 4 are laminated concentrically as unit abrasive grain layers, and the illustrated embodiment in FIG. 3 and the 20th layer 4 are stacked and arranged in a spiral shape.

Next, as a means for forming the diamond abrasive wheel 2 of the embodiment having the above-described structure, the diamond abrasive grains 6 with low friability are mixed with a bonding agent 7 with a large holding force for the abrasive grains 6.
A ring-shaped first plate layer 3' as a primary unit abrasive grain layer, which is mixed together with highly friable abrasive grains 6, is mixed with a binder 7 which has a small holding force against the abrasive grains 6. The ring-shaped second plate layer 4' as a primary unit abrasive grain layer composed of The fifth step is to form a primary molded product 9 by alternately stacking and assembling in the radial direction.
(see figure), each layer may be sintered while fusing the boundary between each layer.

As a result, the first layer 3 and the 20th layer 4 as unit abrasive grain layers
The above-described fusion layer 5 is formed between the first layer 3, the fusion layer 5, and the second layer 4, which are alternately laminated in the radial direction.
This means that it is possible to form a grindstone 2 in which the laminated surface serves as the grinding surface.

As for the forming means in the illustrated embodiment of FIG. 6, the method shown above may be carried out as is. In the case of the illustrated embodiment of FIG. 7, the first plate layer 3' and the second plate layer 4'' It would be best to temporarily form the two into a band shape, overlap each other, and further wind the material to form a ring-shaped primary molded product 9.

In order to solidify the first plate layer 3'' and the second plate layer 4' into a pre-molded state that allows self-retention, it is possible to achieve this by reducing the heating and pressure applied during the forming process.

Further, the next molded product 9 can be sintered by placing it in a full-scale mold, applying predetermined heating and pressure, and pressing.

Note that a filler 8 is mixed as a component of the grindstone 2.

This is used for purposes such as weakening the bonding force of the binder 7, serving as an auxiliary abrasive grain, improving heat conduction, and facilitating the formation of chip pockets.

〔effect〕

As is clear from the above description, the diamond grinding wheel for grinding ceramic materials of the present invention has a large grinding ratio (which causes less wear and tear, and does not cause clogging, making it easy to remove chips). , the cutting edge is sharp, the grinding resistance is low, the generation of heat is small, the life is long without losing the shape, it can be formed at low cost, the roughness of the ground surface is small, the properties of the ground surface are good, and According to the method for forming a diamond grinding wheel of the present invention, each layer is sintered while fusing its boundary parts with each other, so the mutual integration is extremely reliable and strong, and the formation of the fused layer is also easy. It has many excellent effects, such as making it easier to form the grindstone itself.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a state in which a diamond grindstone according to the present invention is adhered to a base metal. FIG. 2 is a cross-sectional view of the grinding wheel. FIG. 3 is an enlarged sectional view of the grinding wheel. FIG. 4 is a perspective view of each layer in a temporarily molded state. FIG. 5 is a perspective view of the second molded product. FIG. 6 is a plan view of the case where each layer is laminated concentrically. FIG. 7 is a plan view when the layers are stacked in a spiral shape. FIG. 8 is an enlarged sectional view showing the composition of the grindstone. Explanation of symbols I; Alloy, 2; Grindstone, 3; First layer, 4; Second layer, 5
fused layer, 6: abrasive grains, 7: binder, 9: - next molded product. Applicant Daido Sangyo Zuto 4 Tsuba Co., Ltd.

Claims (2)

[Claims] (1) A cup wheel type diamond whetstone,
A plurality of unit abrasive grain layers sintered into a ring shape by diamond abrasive grains (6) and a binder (7) are densely stacked in the radial direction, and a boundary portion between adjacent unit abrasive grain layers is arranged. , a fusion layer (5
), and the crushing performance of the diamond abrasive grains (6) forming the adjacent unit abrasive grain layers and the holding power of the binder (7) are set to different values. (2) A method for forming a cup wheel type diamond grinding wheel, in which a plurality of primary unit abrasive grain layers hardened into a ring shape to the extent that they can be self-retained are temporarily formed, and the adjacent primary unit abrasive grain layers are diamond abrasive. The crushing performance of the grains (6) and the holding power of the binder (7) are set to different values, and the primary unit abrasive grain layers with different compositions are densely stacked in the radial direction to form a primary molded product. (9) and sintering each of the layers while fusing the boundaries between the layers to form a fused layer (5).