JPH03186360A - How to crush diamond or cubic boron nitride - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing diamond powder or cubic boron nitride powder for use in grinding wheels or lapping, particularly a crushing method.

<Conventional technology> Conventionally, diamond or cubic boron nitride (hereinafter referred to as CB
An example of creating abrasive powder by crushing a sintered body (referred to as N) is a method of crushing and classifying a CBN sintered body, as described in Japanese Patent Application Laid-Open No. 1986-
It is disclosed in Japanese Patent No. 30641.

These sintered bodies are pulverized by a mill method using a beater mill as shown in FIG. 2 or by an air gun method using an air hammer as shown in FIG.

That is, in the beater mill shown in FIG.
1, the material to be crushed is put between the outer frame 12 and the bead roller 11, and the material to be crushed is crushed by rotating the bead roller 11 in the direction of the arrow 14. The crushing part of the air hammer is shown in Figure 2, and the object to be crushed is placed in the bottom of the U-shaped outer frame 21, and the object to be crushed is crushed by vibrating the vibrating rod 22 up and down in the direction of the arrow 24. be.

<Problems to be Solved by the Invention> However, since the conventional pulverization method described above uses a milling device or an impact crushing device as shown in FIGS. or C
It is scraped off by BN and impurities are mixed in. ■Crushing capacity is low and it takes time to grind. ■The particle size distribution of the pulverized product is wide, making it difficult to obtain powder with the desired particle size.

There were other problems.

(Means for Solving the Problems) The present inventors have studied methods for crushing diamond or CBN in order to solve the problems of the conventional crushing methods described above, and as a result they have arrived at the present invention.

That is, in this invention, a metal hard ball having a radius almost the same as that of the hemisphere is fitted into a metal cylindrical outer frame whose center part is cylindrical and both ends are hemispherical, and the metal rigid ball is inserted into the cylindrical outer frame in advance. After putting the same fine powder as the material to be crushed and vibrating the outer frame and the hard ball to form a hard layer of fine powder on the inner wall surface of the cylindrical outer frame and the outer peripheral surface of the hard ball, the inside of the cylindrical outer frame is To provide a method for crushing diamond or CBN, which is characterized in that a diamond or CBN object to be crushed is placed in a cylindrical outer frame and a rigid ball, and the object to be crushed is crushed between them by applying vibrations to the cylindrical outer frame and a rigid ball. be.

<Operation> This invention will be explained in more detail with reference to the crushing device shown in FIG. 3.

In this invention, in order to overcome the problems of the conventional method described above, (a) a metal hard ball 2 and an object to be crushed 4 are placed in a metal cylindrical outer frame 1 and violently vibrated. 2
The object to be crushed 4 was sandwiched and crushed between the cylindrical outer frame 1 and crushed.

(O) A small amount of the same material to be crushed is placed in advance with a metal hard ball 2.
The crushed material is placed in a metal cylindrical outer frame 1 fitted with the material, and by violently vibrating the outer frame 1 and the hard ball 2, the crushed material is embedded in the inner wall surface of the outer frame 1 and the outer peripheral surface of the hard ball 2, thereby making it hard. Layer 3 was formed.

(C) Both ends of the metal cylindrical outer frame were hemispherical with approximately the same radius as the hard sphere fitted into the outer frame.

In particular, (0, (C)) is a major feature of the present invention.

That is, (a) improves the problem (2) of the conventional method described above.

In order to increase the crushing effect of the object to be crushed, the object to be crushed is placed in a sealed container made of a metal cylindrical outer frame, and a rigid ball placed in the container is violently vibrated, and the impact causes a sintered body of diamond or CBN, Grinds objects to be crushed such as abrasive grains and single crystals.

Although only one hard ball may be placed in the closed container, it is preferable to have two hard balls as shown in the figure to further improve the crushing ability.

Further, by making the diameter of the rigid sphere substantially the same as the inner diameter of the cylindrical outer frame, wasteful scattering of the material to be crushed can be prevented and the crushing ability can be improved.

Next, forming a hard layer made of the same material as the object to be crushed on the inner wall surface of the outer frame (ω) and the outer peripheral surface of the hard sphere contributes to improving problems (1) and (2) of the conventional method described above. .

That is, since a hard layer is formed in advance on the inner wall surface of the outer frame and the outer peripheral surface of the rigid sphere, there is no fear that the material of the outer frame will be scraped off even by vibration, and a highly pure pulverized product can be obtained. In addition, the hard layer makes it extremely easy for the object to be crushed to be crushed.

Furthermore, the fact that both ends of the outer frame in (C) above are made into a hemispherical shape having approximately the same radius as the hard sphere improves the aforementioned problem (2).

That is, in order to crush the material to be crushed into a uniform size, it is necessary to keep the distance between the opposing crushing surfaces constant. Therefore,
In this invention, by making both ends of the outer frame semispherical with the same radius as the radius of the rigid sphere, the interval between the crushing surfaces is constant, and thereby the particle size of the crushed particles can be made uniform. be.

<Example> Hereinafter, this invention will be explained in detail with reference to Examples.

The CBN polycrystal was pulverized using the pulverizer shown in FIG. 1 and the beater mill and air gun shown in FIGS. 2 and 3.

The grinding conditions were selected so as to obtain a ground material with a particle size of 88 to 105 gm. The results are shown in Table 1.

Incidentally, in the pulverization according to the method of this invention, a small amount of CBN abrasive grains were added in advance to form a hard layer of CBN on the inner surface and the surface of the hard sphere, and after the formation, the inner surface and the hard sphere were washed to remove CBN residue.

From the above table, it was confirmed that the method of the present invention was the fastest, contained less impurities, and could be ground to a uniform particle size.

<Effects of the Invention> As explained above, the method of this invention makes it possible to grind diamond or CBN sintered bodies, abrasive grains, and single crystals into uniform particle sizes without containing impurities in a short time. be.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a crushing device used in the crushing method of the present invention, FIGS. 2 and 3 both show conventional devices, FIG. 2 is a plan view of a beater mill, and FIG. It is a side view of the crushing part of the air hammer in the air gun method.

Claims (1)

[Claims] A metal hard ball having a radius almost the same as that of the hemisphere is inserted into a metal cylindrical outer frame with a cylindrical center and hemispherical ends. After adding fine powder and vibrating the outer frame and hard ball to form a hard layer of fine powder on the inner wall surface of the cylindrical outer frame and the outer peripheral surface of the hard ball,
A diamond or cubic boron nitride object to be crushed is placed in the cylindrical outer frame, and vibration is applied to the cylindrical outer frame and the rigid sphere to crush the object between them. A method of crushing cubic boron nitride.