JPH0615572A - Grinding wheel - Google Patents

Abstract

PURPOSE:To provide a grinding wheel that is hard to cause any clogging even if an air curtain occurs on a wheel working surface, and that prevents any scratch from being left behind even if a workpiece is a blank of glass or ceramics and the like. CONSTITUTION:This grinding wheel 1 is composed of bonding a lot of granule grains 6, made up of bonding a lot of abrasive grains 4 with a first bonding agent (metal bond 5), through a second bonding agent (vitrified bond 7), and in this case, at least one side of both first and second bonding agents is the vitrified bond 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding wheel that is rotated and used to grind materials such as glass and ceramics.

[0002]

2. Description of the Related Art As shown in FIG. 4, a grinding wheel has a large number of abrasive grains 4 which are held together by a binder (also referred to as a bond) 15. Abrasive grains held by a binder are exposed on the surface of the grindstone to serve as a cutting blade.

The grinding wheel is rotated, and the surface to be used is brought into contact with an object to be processed (also called a work material) to grind the object to be processed. The chips and fallen abrasive grains generated at this time are received in the chip pocket 8 provided on the use surface and removed by the rotation of the grindstone.

When the binder has a large number of pores, the tip pocket is one of those pores that is open to the use surface. When the binder does not have pores, after shaping the surface to be used, the binder is scooped out with a dresser (device for setting up), or the binder is removed by an electrochemical method. As a result, a chip pocket is formed.

If chips and fallen abrasive grains are accumulated in the chip pocket and the chip pocket is filled (clogging occurs), the performance of the grindstone deteriorates. For this reason, a grinding liquid is sprayed on the surface where the grindstone is used, and the chips and falling abrasive grains accumulated in the chip pocket are blown away to perform the grinding work.

In order to grind steel such as hardened steel,
Vitrified whetstones are commonly used. this is,
This is because the vitrified grindstone has many chip pockets and is unlikely to be clogged.

On the other hand, when grinding glass for lens processing, a vitrified grindstone is not used,
Metal bond grindstones and resinoid grindstones are used.
Grinding hard and brittle materials such as glass using a vitrified grindstone causes a lot of grindstone wear and leaves scratches on the abrasive grains, resulting in a poor finish.However, a metal bond grindstone or resinoid grindstone causes less grindstone wear and provides a good finished surface. can get.

[0008]

When grinding is performed by increasing the number of revolutions of the grinding wheel, the rotation of the grinding wheel causes an air curtain to cover the surface to be used, which makes it difficult for the grinding fluid to reach the surface to be used. For this reason, the heat of processing causes burning or clogging, which reduces the performance of the grindstone.
This phenomenon becomes remarkable as the number of rotations of the grindstone is increased.

In order to prevent the occurrence of the air curtain, it is necessary to change the overall design of the device, which requires cost and time.

The inventors therefore considered that if a grindstone having more chip pockets than the conventional grindstone is used, clogging is less likely to occur even if an air curtain occurs.

However, when a vitrified grindstone having a large number of chip pockets is used for grinding a hard and brittle material such as glass or ceramic, there is a problem that the grindstone wear is large as described above and a good finished surface cannot be obtained. This is because when a vitrified grindstone is used for hard and brittle material processing, the binder itself breaks brittlely and the abrasive grains fall off, and wear progresses. It is considered that this is because the finished surface cannot be obtained.

It is an object of the present invention to provide a grinding wheel which does not leave scratches on the ground surface of the object to be treated when it is ground and which is less likely to be clogged even if an air curtain is generated on the surface where the wheel is used. To do.

[0013]

In order to solve the above-mentioned problems, the present invention provides a large number of granulated particles (sometimes referred to as clusters) in which a large number of abrasive grains are bonded and held by a first binder. Is bonded and held with a second binder, and one of the first binder and the second binder is a vitrified bond.

According to the present invention, the grinding stone portion formed by holding a large number of granulated particles, which are held by bonding a large number of abrasive grains with a first binder, is disc-shaped. Provided is a grinding wheel which is integrally bonded to the outer periphery of a base and in which one of a first binder and a second binder is a vitrified bond.

Thus, the grinding wheel in which the grindstone portion is integrally connected to the outer periphery of the disk-shaped base has the advantages of lowering the cost and increasing the mounting accuracy as compared with those without such a base. Have.

Abrasive grains include superabrasive grains such as diamond and CBN (Cubic Boron Nitride); general abrasive grains such as aluminum oxide (eg, WA) and silicon carbide (eg, GC). One of them may be used alone, or two or more may be used in combination, depending on the object to be treated, the finished state of grinding, and the like. Abrasive particles having an average particle diameter of 1 to 50 μm are usually used, but the abrasive particles are not limited to this range. Generally, abrasive grains having a large grain size are used for rough grinding, and grains having a small grain size are used for fine grinding such as finishing.

In the present invention, granulated particles in which a large number of abrasive particles are bonded and held by a first binder are used. Granulated particles are crushed and / or crushed after mixing a large number of abrasive grains with a binder raw material and firing in the same manner as in the ordinary method of manufacturing a whetstone (however, molding and shaping can be omitted). It is made through the process of. After crushing or crushing, if necessary, the crushed or crushed product may be classified by sieving. The average particle size of the granulated particles is not particularly limited, but 10 to
The range of 500 μm is preferable. With the number of abrasive grains, for example,
The number of granulated particles is about 3 to 4 to 20 to 30. When the abrasive grain size is large, the granulated grains are also large. If the average particle size of the granulated particles exceeds the above range, the life of the grindstone may be shortened, and if the average particle size of the granulated particles is less than the above range, a good finished surface may not be obtained.

The grinding wheel of the present invention is made by binding and holding a large number of granulated particles obtained as described above with a second binder. A large number of granulated particles are mixed with a binder raw material and, if necessary, a large number of abrasive grains, and the same steps as those of a manufacturing method of a normal grindstone are performed, whereby the large number of granulated particles are mixed with a second binder. A grinding wheel obtained by bonding and holding is obtained.

In the present invention, a vitrified bond is used as a material for one of the first binder and the second binder.

The vitrified bond is a binder whose composition can be appropriately set so as to obtain a desired degree of bonding and structure depending on the material of the object to be treated and the grinding conditions.
A vitrified bond is a mixture of ceramic raw materials such as clay and feldspar and organic substances that are scattered as a gas by burning wood powder and the like, which are molded, dried, and shaped by a pressing method, a pouring method, or the like, and then 700 to It is made by firing at a temperature of 1350 ° C.

In the present invention, when one of the first binder and the second binder is a vitrified bond and the other is another binder, as the other binder,
For example, any of the conventionally known binders can be used, but it is preferable to use a metal bond. That is,
In the present invention, the first binder is a vitrified bond,
It is preferable that the second binder is a metal bond, the first binder is a metal bond, and the second binder is a vitrified bond.

When the first binder is a vitrified bond and the second binder is a metal bond, there is an advantage that a good workability can be obtained because a chip pocket exists beside the abrasive grains serving as a cutting edge. .

When the first binder is a metal bond and the second binder is a vitrified bond, there is an advantage that the falling of the abrasive grains is less, resulting in a longer life and better shaping of the grindstone. .

In the present invention, a conventionally known metal bond can be used. For example, a metal powder such as bronze, Ni or cast iron can be used as an abrasive grain (when the metal bond is used as the first binder) or the above. It is mixed with granulated particles (when metal bond is used as the second binder), and the mixture is hot-formed, or abrasive particles (metal bond is used as the first binder on a metal surface of a predetermined shape). Or) and the above-mentioned granulated particles (when metal bond is used as the second binder).

The grinding wheel of the present invention is, for example, JIS
It may have any shape defined by the standard or any other shape as long as it can be ground by rotating.

The grinding wheel of the present invention is used to grind an object to be processed while rotating. The peripheral speed due to rotation ranges from low speed to ultra high speed, for example, 300 to 20000 m /
set to min. The object to be treated is not particularly limited, and examples thereof include materials such as glass and ceramics, which have conventionally been difficult to grind at an ultra-high speed. Therefore,
If the grindstone of the present invention is used, precision grinding such as lens processing can be performed, and a good surface finish with high efficiency and no scratches can be obtained.

[0027]

The grinding wheel of the present invention has a large number of small depressions formed by opening pores on the surface of the vitrified bond which is one of the first binder and the second binder. These recesses become chip pockets. Moreover, when grinding is performed with the grinding wheel of the present invention, the pores contained in the vitrified bond are opened by the abrasion of the bond, and a new chip pocket is formed.

For this reason, the chip pocket can receive a larger amount of polishing debris and fallen abrasive grains than ever before.
Less likely to clog.

Although the vitrified bond has a weak holding force for the abrasive grains, in the present invention, the abrasive grains are made into granulated particles to be coarsened,
By adopting a form in which the granulated particles are bound and held by a binder, the holding area becomes large, and a strong holding force can be obtained even if a vitrified bond is used. For this reason,
Even if a material with high hardness such as glass or ceramic is ground by rotating the grinding wheel of the present invention at a high rotational speed, a good finish without scratches can be obtained.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially enlarged schematic view of an embodiment of a grinding wheel of the present invention. As shown in FIG. 3, the grinding wheel 1 as a whole is a grinding wheel in which a grinding wheel portion 2 is joined and integrated with an outer periphery of a disk-shaped base 3. As shown in FIG. 1, the grindstone portion 2 holds a large number of clusters 6 ... Which are held by being bonded by a metal bond 5 and a large number of clusters 6 ... With a vitrified bond 7. In this example, the contact area between the cluster 6 holding the abrasive grains 4 and the vitrified bond 7 is much larger than the contact area between the abrasive grain 4 and the vitrified bond 7 as shown in FIG. 4 is strongly held by the binder and is hard to fall off.

FIG. 2 is a partially enlarged schematic view of another embodiment of the grinding wheel of the present invention. This grinding wheel 10
As a whole, as shown in FIG. 3, the grindstone portion 20 is combined and integrated with the outer periphery of the disk-shaped base 3 to form a grindstone wheel. As shown in FIG. 2, the grindstone portion 20 holds a large number of clusters 60 ... Which are held together by a large number of abrasive grains 4 ... In this embodiment, the abrasive grains 4 and the vitrified bond 7 are used.
Although the contact area with is exactly the same as that of the conventional vitrified grindstone as shown in FIG. 4, since the clusters 60 are independent, the abrasive grains 4 do not drop off in a chain.

As shown in FIGS. 1 and 2, abrasive grains 4 are exposed and chip pockets 8 are provided on the use surface of the grindstone 1. The vitrified bond 7 is provided with pores 9 ... Which serve as chip pockets.

The abrasive grains 4 have an average particle diameter of 1 to 50 μm such as diamond and CBN (cubic boron nitride) when a grinding stone is used for grinding a material such as glass or ceramic for lens processing. Not limited to.

The disk-shaped base 3 has a shaft hole 31 for receiving a rotary shaft (not shown), and is made of steel, aluminum alloy, or other material. The grinding wheel of the present invention shown in FIGS. 1 to 3 includes the case where the disk-shaped base 3 is not provided.

Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples.

Example 1 This is an example of a grinding wheel of the type shown in FIG.

The disk-shaped base used was made of steel having a diameter of 60 mm. The abrasive grains used were diamond with an average grain size of 10 μm. The metal bond used was a bronze-based metal bond.

Similar to the conventional method for producing a metal bond grindstone, the above metal bond powder and abrasive grains were mixed and fired. After that, what was baked and hardened with a metal bond was crushed and classified to form clusters. This cluster has an average grain size of about 40 μm and has an abrasive grain number of 10 to 20.
It was an individual. The obtained cluster and vitrified powder were mixed and fired. At this time, it is desirable that the firing temperature be lower than the temperature during cluster production. this is,
This is to prevent damage to the cluster. In this way, a grindstone portion was produced on the outer circumference of the disk-shaped base,
The grinding wheel of the present invention as shown in 3 and 4 was obtained. The above-mentioned bond and abrasive grains were in a ratio of 1: 9 to 3: 7.

Example 2 This is an example of a grinding wheel of the type shown in FIG.

The disk-shaped base used was made of steel having a diameter of 60 mm. The abrasive grains used were diamond with an average grain size of 10 μm. The metal bond used was a bronze-based metal bond.

As in the conventional method for producing a vitrified grindstone, vitrified powder and the above-mentioned abrasive grains were mixed and fired. Then, what was baked and hardened with vitrified bond was crushed and classified to form clusters. This cluster had an average particle size of about 40 μm and had 10 to 20 abrasive grains. The obtained cluster and the above-mentioned metal bond powder were mixed and fired. At this time, it is desirable that the firing temperature be lower than the temperature during cluster production. This is to prevent damage to the cluster. In this way, a grindstone portion was produced on the outer periphery of the disk-shaped base to obtain the grinding grindstone of the present invention as seen in FIGS. The above-mentioned bond and abrasive grains were in a ratio of 1: 9 to 3: 7.

Comparative Example 1 A vitrified grinding wheel was obtained in the same manner as in Example 1 except that the vitrified bond and the abrasive grains were used at a concentration degree of 75 in Example 1 and the grindstone portion was formed without forming clusters.

Comparative Example 2 A metal bond grinding wheel was obtained in the same manner as in Example 2 except that the metal bond and the abrasive grains were used at a concentration of 75 in Example 2 and the grindstone portion was formed without forming clusters. .

The grinding wheels obtained in the above Examples and Comparative Examples were rotated at a peripheral speed of 2500 m / min., And the glass was ground while spraying a chemical solution as a grinding liquid onto the outer peripheral surface of the grinding wheels. As a result, Example 1
The grindstones of No. 2 and No. 2 have a grindstone life extended about twice as long as that of Comparative Example 1, and can be continuously used for 1 hour or more without being clogged with that of Comparative Example 2.

[0045]

The grinding wheel of the present invention has a large number of abrasive grains first.
A large number of granulated particles bound and held by the second binder and held by the second binder, the first binder and the second binder
Since either one of the binders is a vitrified bond, when the grindstone of the present invention is used for grinding, clogging is less likely to occur even if an air curtain is generated on the surface where the grindstone is used, and the object to be treated is glass or No scratches are left on the ground surface even with materials such as ceramics.

[Brief description of drawings]

FIG. 1 is a schematic view in which a grinding wheel according to an embodiment of the present invention is partially enlarged.

FIG. 2 is a partially enlarged schematic view of a grinding wheel according to another embodiment of the present invention.

FIG. 3 is a perspective view showing an entire grinding wheel according to another embodiment of the present invention.

FIG. 4 is a partially enlarged schematic view of an example of a conventional grinding wheel.

[Explanation of symbols] 1 grinding wheel 2 grinding wheel section 4 abrasive grains 5 metal bond 6 cluster 7 vitrified bond 8 chip pocket 9 pores 10 grinding wheel 20 grinding wheel section 60 cluster

Claims (4)

[Claims] 1. A large number of granulated particles obtained by binding and holding a large number of abrasive grains with a first binder, and a large number of agglomerated particles held by being bound with a second binder. A grinding wheel in which one of the binders is a vitrified bond. 2. The outer periphery of the disk-shaped base is a grindstone part formed by binding and holding a large number of granulated particles, which are held by binding a large number of abrasive grains with a first binder. A grinding wheel in which one of the first binder and the second binder is a vitrified bond. 3. The grinding wheel according to claim 1, wherein the first binder is a vitrified bond and the second binder is a metal bond. 4. The grinding wheel according to claim 1, wherein the first binder is a metal bond and the second binder is a vitrified bond.