JPS60118469A - Manufacturing method of metal bond grindstone - Google Patents

Abstract

PURPOSE:To form the pore in a grindstone and promote an autogeny function of the grindstone, by mixing a material whose melting point is above the determined degree, and which is fusible in a solvent whose main component part is such as water, and the super abrasive, in a metal bond powdered matrix, after sintering them, taking off the fusible material by stepping the sintered body in the solvent. CONSTITUTION:A pore-forming material such as sodium chloride, whose melting point is above 500 deg.C, and which is fusible in a solvent whose masin component parts are more than one kind of material, selected from a group of materials, such as water, alcohol, acetone, ammonia and acetic acid, and super abrasive 3 such as diamonds, are mixed in a matrix 2 which consists of metal bond powder, such as bronze powder. After the mixture is sintered, pores 4 are formed in the sintered body, by taking off the pore-forming material from the sintered body, by steeping it in the said solvent, such as water. In this way, a work difficult to grind as it is hard and brittle, can be precisely processed, because the material of the sintered body without the porse, maintains it's combining power, as the dense mixture was sintered while the sintering processing was performed, and an autogeny function of a grindstone is raised, as the pores are formed after the sintering.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a metal bonded grindstone using a sintering method.

Natural or synthetic diamond abrasive grains or cubic boron nitride abrasive grains (
A metal bond grindstone is known as a grindstone suitable for superabrasive grains such as CBN. Compared to resin bonded grindstones and vitrified bonded grindstones, metal bonded grindstones have a stronger ability to retain abrasive grains, and therefore have the advantage that abrasive grains are less likely to fall off even during grinding or cutting, where a fairly strong force is applied. are doing. Metal bonded grindstones also have the advantage of generally having a long life because the bond itself has strength and heat resistance.

However, conventional metal bonded whetstones have a disadvantage in that due to their structural characteristics, there is little self-sharpening action of the whetstone, resulting in significant deterioration of sharpness. In other words, metal bonded grindstones are usually manufactured from powder by sintering methods (hot press method, cold press method, etc.), but conventional sintering methods of this type cannot form pores in the grindstone. There wasn't. For this reason, conventional metal bond grindstones do not have pores. As a result, conventional metal bonded whetstones do not have the self-growth effect of the whetstone due to pores, and the abrasive grains fall off and separate, causing the whetstone surface to become clogged or crushed during grinding or cutting operations. It was easy.

For this reason, although conventional metal bonded grindstones have the advantages mentioned above, it is difficult to cut hard and brittle + A materials such as semiconductor wafers, lenses, and ferrite. However, its scope of application was very limited compared to resin bonded grindstones.

The present invention was made in view of these problems, and by forming pores in the metal bond grindstone, the self-sharpening action of the grindstone is promoted, and materials that are conventionally difficult to grind or cut can be processed. It is an object of the present invention to provide a method for manufacturing a metal bond grindstone that can be easily ground or cut.

This object is achieved according to the invention as follows. That is, according to the present invention, a substance soluble in a solvent containing at least one selected from the group consisting of water, alcohol, acetone, ammonia, and acetic acid as a main component and having a melting point of 500'C or higher and superabrasive grains are combined. is mixed into a matrix of metal bond powder, this mixture is sintered, and the sintered body is immersed in the solvent to remove the substance, thereby forming pores in the sintered body.

In the present invention, bronze powder is preferably used as the metal bond material constituting the 7 trix. However, other metal bond materials such as copper, tin,
It is also possible to use a mixture or a single substance of metal powders such as cobalt, nickel, iron, silver, and tungsten.

As abrasive grains, those generally called super abrasive grains, for example,
Natural or synthetic diamond abrasive grains or cubic boron nitride abrasive grains (
CBN).

In the present invention, a pore-forming substance is mixed into the matrix together with the abrasive grains prior to sintering. and,
After sintering, the sintered body is immersed in a predetermined solvent to dissolve and remove the pore-forming substance.

With this configuration, a densely packed mixture is sintered during sintering, and after sintering, pores are formed at the sites where the pore-forming substance has been dissolved and removed.

Sintering may be performed by a conventionally known pot press method or cold press method. In either method, the mixture is pressurized during sintering (approximately 100 to 50
0 kg/cA, approximately 3 to 10 tons in the case of cold press method
/cn+) and heated (about 500°C or higher). Therefore, even if there are pores in the mixture, they are all crushed during sintering. This is a necessary condition for obtaining a dense sintered body. Therefore, in the method according to the present invention, in order to maintain the bonding strength of the parts other than the pores in the final product, the grinding wheel, during sintering, a dense mixture without pores is sintered, and after sintering, By dissolving and removing the pore-forming substance mixed in this sintered body, pores are formed in the grindstone.

Water is the most common solvent for dissolving and removing pore-forming substances, but other solvents such as alcohol (in the present invention, ethyl alcohol, methyl alcohol, etc.) are also used. It is also possible to use acetone, ammonia or acetic acid. Alternatively, a mixed solvent of these may be used.

The pore-forming substance that is dissolved and removed by these solvents must not melt during sintering, and therefore must have a melting point of 500° C. or higher. Examples of pore-forming substances that can be used in the present invention (corresponding solvents are listed in parentheses) include sodium aluminate (water), potassium chloride (water), calcium chloride (water,
ethyl alcohol, acetic acid, acetone), ferrous chloride (water, ethyl alcohol, acetone), magnesium chloride
(water, ethyl alcohol), sodium chloride (water), potassium chromate (water), sodium silicate (water), barium oxide (ethyl alcohol), potassium bromide (water, ethyl alcohol), calcium bromide (water, ethyl alcohol, acetone), sodium bromide (water, ethyl alcohol, ammonia), magnesium bromide (water, ethyl alcohol, methyl alcohol), sodium carbonate (
water), potassium sulfide (water, ethyl alcohol), sodium sulfide (water), potassium sulfate (water), sodium sulfate (water), etc. Of course, even substances other than those exemplified here can be used as long as they are soluble in the above-mentioned solvents and have a melting point of 500°.
If it is C or higher, it can be used as necessary.

The particle size of the pore-forming substance is preferably about 46 to 600 in terms of U, S, and mesh numbers, which will be described later. If this particle size is too small, the self-growth effect of the grinding wheel will be reduced;
If it is too large, the whetstone will become brittle, which is not preferable. Further, the volume fraction (porosity) of pores formed in the grindstone is preferably about 5 to 50%, and about 10 to 40%.
It is more preferable that If this volume fraction is outside the above range, it is not preferable for the same reason as mentioned above. The porosity in the grindstone can be adjusted by adjusting the amount of the pore-forming substance mixed therein.

The shape of the grindstone manufactured by the method of the present invention is not particularly limited, and it can be applied to various types, such as straight type, segment type, and those with or without alloy.

Unlike conventional grinding wheels, the metal-bonded grinding wheel manufactured by the method of the present invention is porous, which allows for better removal of cutting chips and circulation of cooling water, and the properties of the bond are relatively soft. , which promotes the spontaneous shedding of worn diamond abrasive grains, etc. Through these mutual and synergistic effects, it becomes possible to easily cut materials that were previously difficult to cut.

It has been experimentally confirmed that in the metal bonded grindstone manufactured by the method of the present invention, pores are distributed substantially uniformly up to a thickness sufficient for practical use, for example, approximately 3 m.

The present invention will be explained in detail below.

In the following examples, the particle sizes of the abrasive grains and the pore-forming substance are defined by U, S, and mesh numbers (hereinafter indicated by the symbol "#"). The particle size is defined by the side length of the square aperture of the mesh that corresponds to U, S, and the mesh number. For example, #320 corresponds to the side length of the rectangular opening of the mesh of U, S, and mesh number 320 of 44μ.

Example 1 and Comparative Example 1 100 g of bronze powder as metal bond material, 11 g of #1000 synthetic diamond as abrasive grain, 15 g of thorium chloride #180-320 as pore-forming material
was used. Mix these and use the hot press method (800
℃, 300 kg/c for 1 hour), and then immersed in water at room temperature for 8 hours to dissolve and remove sodium chloride.

A donut-shaped grindstone with an outer diameter of 52 m1, an inner diameter of 40 mm, and a thickness of 0.211 mm was obtained (the volume fraction of pores was about 32%).

On the other hand, as a comparative example, a grindstone with the same dimensions was created from 160 g of the same bronze-based powder and 1 g of synthetic diamond by the hot press method under the same conditions as above.

These grindstones were used to groove glass-bonded single crystal ferrite. The grooving speed (feeding speed) was 1 m/sec, and the grooving depth was 2.0 m/sec. As a result, the grindstone according to the embodiment of the present invention has 0.
While it was possible to leave the pillars in No. 211, in the comparative example, the pillars were broken due to grinding, and it was impossible to leave the pillars in place.

"Troublesome 2 and Comparative Example 2 100 g of the same bronze powder as in Example 1, 16 g of #4000 synthetic diamond, #220 to 400 sodium chloride], Og, and a donut-shaped grindstone of the same size as in Example 1. (The volume fraction of pores is approximately 23%)
).

On the other hand, as Comparative Example 2, a similar grindstone was created from 140 g of the same bronze-based powder and 16 g of synthetic diamond.

Grooving of single crystal ferrite was performed using these grindstones. The grooving speed was 3 van/see, and the grooving depth was 0.31. As a result, the chipping of the grindstone according to the example of the present invention was 1μ or less, whereas the chipping of the grindstone of the comparative example was 3μ or more.

As is clear from the above examples, the metal bonded grindstone manufactured by the method of the present invention is capable of precision machining of hard, brittle, and difficult-to-machine materials, which was impossible with conventional grindstones.

Using 100 g of the same bronze powder as in Example 1, 1.1 g of #800 synthetic diamond, and 15 g of #180-320 sodium chloride, an outer diameter of 52 Texture, inner diameter 40
A donut-shaped grindstone with a thickness of +n and a thickness of 3.0 fins was prepared.

A cross section of this grindstone 1 is shown in the attached drawing, and diamond abrasive grains 3 of about 20 μm are held in a matrix 2 made of bronze-based powder. In the grindstone 1, pores 4 of about 40 to 100 microns were distributed almost uniformly up to the deepest part. These pores 4 are traces of sodium chloride dissolved and removed by water, and communicate with the surface of the grindstone 1. The pores 4 occupied approximately 1/3 of the volume of the grinding wheel.

In addition, a small amount of sodium chloride 5 remained in the matrix 2, which was not dissolved and removed because it did not communicate with the surface. Such sodium chloride 5 can be dissolved and removed by, for example, immersing the whetstone 1 in water again after it has been used for some time. Further, when water is used as a solvent, the grinding is usually performed while water is being applied for cooling, so that the material is automatically dissolved and removed at this time. Such a method of use is effective, for example, when a fairly thick grinding wheel is manufactured by the method of the present invention 1 and the pore-forming substance is present at such a depth that it cannot be dissolved and removed by the initial immersion. It is.

[Brief explanation of the drawing]

The drawing is a partially enlarged sectional view of a grindstone according to an embodiment of the present invention. In addition, in the symbols used in the drawings, 2 -------------------- Matrix 3 ----------Diamond abrasive grain 4 - -------------------It is a single pore. Agent Saturn Katsunekane Yoshio Sugiura Toshiki 2

Claims (1)

[Claims] A substance that is soluble in a solvent and whose main component is at least one selected from the group consisting of water, alcohol, acetone, ammonia, and acetic acid and has a melting point of 500"C or more and superabrasive grains are placed in a matrix made of metal bond powder. and sintering the mixture, the sintered body is immersed in the solvent to remove the substance, thereby forming pores in the sintered body. Manufacturing method of bonded whetstone.