JP2000334663A - Metal-coated abrasive grains, their production method and resin-bonded grinding wheels - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the holding strength of abrasive grains. SOLUTION: The surface of a superabrasive 1 is coated with a metal coating layer 11 made of copper, and the surface of the metal coating layer 11 is oxidized to form a surface layer 12 having a number of fine edges 12a standing up. , Constituting the metal-coated abrasive grains 10. A resin-bonded grindstone 2 is prepared by dispersing metal-coated abrasive grains 10 in a resin bonding phase 7.
Set to 0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal-coated abrasive grain dispersed and fixed in a binder phase in a resin-bonded grinding wheel or the like, a method for producing the same, and a resin-bonded grinding wheel provided with the metal-coated abrasive grain.

[0002]

2. Description of the Related Art Conventionally, for example, a resin-bonded grindstone is prepared by mixing a raw material powder of a thermoplastic resin such as a phenol resin or an epoxy resin with superabrasive grains such as diamond or CBN, and singly or together with a base metal as required. The resin-bonded abrasive grain layer was formed by embedding, press-forming and firing. Since the resin bond phase holding the superabrasive grains is relatively soft and low in strength, the resin-bonded grindstone wears off the tip of the superabrasive grains when grinding a relatively hard work material. Before the drop, the resin binder phase supporting the superabrasive grains is crushed, worn or deformed, and the superabrasive grains fall off. Resin bond whetstones tend to cause severe wear and to lose sharpness due to abrasive particles falling off. Therefore, in order to improve the holding power and heat resistance of the superabrasive grains in the resin binder phase, a metal such as copper or nickel is coated on the surface of the superabrasive grains 1 by electroless plating or the like as shown in FIG. The technique of forming the metal coating layer 2 to form the metal coating abrasive grains 3 is employed.
FIG. 10 shows a resin-bonded grindstone using such metal-coated abrasive grains 3. In this resin-bonded grindstone 4, an abrasive layer 6 is mounted on a base metal 5, and the abrasive layer 6 is made of thermoplastic resin. The metal-coated abrasive grains 3 are dispersed and arranged in a resin bonding phase 7 made of a resin.

[0003]

By the way, when grinding with such a resin-bonded grinding wheel 4, light metal grinding can prevent the metal-coated abrasive grains 3 from falling off, but heavy grinding requires a large load. Metal coating abrasive grains 3 on the surface of the abrasive layer 6
And the heat generated was too high to sufficiently suppress the grinding heat. The present invention has been made in view of the above problems, and provides a metal-coated abrasive grain having improved abrasive grain holding strength so as to withstand heavy grinding and improved heat resistance of the abrasive grain, a method of manufacturing the same, and a resin bond grinding wheel. The purpose is to provide.

[0004]

The metal-coated abrasive grains according to the present invention are obtained by coating the surface of the abrasive grains with a metal coating layer, and forming fine irregularities with sharp edges on the surface layer of the metal coating layer. It is characterized by becoming. By forming a surface layer by roughening the surface of the metal coating layer, the surface layer has a rough and fine uneven surface shape with a sharp edge on the entire surface, so anchoring when bonding with the resin binder phase The effect is large and the mechanical bond strength is larger than the conventional metal coating layer, even if a heavy load is applied to the abrasive grains during heavy grinding, the dropping of the abrasive grains is well suppressed,
High heat dissipation due to the large surface area of the surface layer.
The surface layer may be obtained by oxidizing and recrystallizing the metal coating layer. By oxidizing and recrystallizing the surface of the metal coating layer, many fine irregularities stand on the surface. Preferably, copper is used as the metal coating layer.

[0005] A resin-bonded grindstone according to the present invention is characterized in that the above-mentioned metal-coated abrasive grains are dispersed and fixed in a resin binder phase. Since the surface layer of the metal coating layer has a roughened surface with fine irregularities with sharp edges, it is intertwined with each other when bonding with the resin binder phase, and the anchor effect is large, so that the metal coating abrasive grains and the resin binder phase are combined. Mechanical bond strength is greater than conventional metal-coated abrasive grains, even if a heavy load is applied to the abrasive grains during heavy grinding, etc.
Due to the large surface area of the surface layer, it has high heat dissipation to grinding heat and high heat resistance.

Further, the method for producing metal-coated abrasive grains according to the present invention is characterized in that the surface of the abrasive grains is coated with a metal coating layer, and the metal coating layer is oxidized to form fine irregularities with sharp edges. Is formed. A metal coating layer is formed on the surface of the abrasive grains by electroless plating or the like, and then the surface of the metal coating layer is oxidized, so that the surface layer of the metal coating layer has a large number of fine uneven surface shapes as a whole. According to this manufacturing method, after coating the metal coating layer on the surface of the abrasive grains, the surface is oxidized by heat treatment or the like and roughened to obtain a surface layer having a high bonding strength with the resin binder phase. Easy to manufacture. Further, fine metal powder may be dispersed in the resin bonding layer. The metal powder further improves the heat conductivity and wear resistance during grinding.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, and the same or similar parts and members as those of the above-described prior art will be described using the same reference numerals. FIG.
FIG. 2 is an enlarged cross-sectional view of a superabrasive according to the embodiment, FIG. 2 is a partial longitudinal cross-sectional view of a resin-bonded grindstone in which an abrasive layer containing the superabrasive shown in FIG. 1 is mounted on a base metal, and FIG. , (B), (c) are diagrams showing a manufacturing process of metal-coated abrasive grains according to the present embodiment,
4A and 4B show the surface of the metal-coated abrasive grains. FIG. 4A is a diagram of the embodiment, FIG. 4B is a diagram of the conventional example, and FIG. Figures shown, FIGS. 6 to 8
FIG. 6 shows test results of the resin-bonded grindstone according to the embodiment and the resin-bonded grindstone according to the conventional example. FIG. 6 shows normal grinding resistance, FIG. 7 shows tangential grinding resistance, and FIG. FIG. Metal-coated abrasive grain 1 shown in FIG.
0 is provided with superabrasive grains 1 such as diamond and cBN inside,
On its outer surface, a metal coating layer 11 having a thickness of, for example, about 4 to 5 μm is formed, and this metal coating layer 11 is made of, for example, copper or a copper coating layer of copper oxide, cupric oxide, or the like. On the outer surface of the metal coating layer 11, a large number of fine edges 12 obtained by oxidizing the outer surface of the metal coating layer 11 made of copper, copper oxide, cupric oxide, or the like.
The surface layer 12 having a thickness of about 1 μm on which a is formed is formed as an oxide film.

The surface layer 12 has a height of, for example, 0.3 to 3 μm and an outer diameter of 0.5 to 3 μm when the surface of the copper metal coating layer 11 is oxidized in air and recrystallized. A large number of minute protrusions are formed as edges 12a, which protrude over the entire surface, so that the outer surface of the surface layer 12 has a rough texture (grening loss) as shown in FIG. Many fine irregularities are formed. On the other hand, the metal-coated abrasive grains 3 in which only the super-abrasive grains 1 are coated with copper as the metal coating layer 2 (11) are as shown in FIG. 8B, and the surface is relatively smooth. FIG. 2 shows a resin-bonded grindstone 20 according to the embodiment. The resin-bonded grindstone 20 is provided with an abrasive layer 21 on a base metal 5, and the abrasive layer 21 is made of a phenol resin or a polyimide resin. The metal-coated abrasive grains 10 are dispersed and fixed in the resin bonding phase 7. The metal-coated abrasive grains 10 are in a state of being intertwined with the resin bonding phase 7 because a large number of fine edges 12a are raised and roughened on a surface layer 12 covering the outer surface of the metal coating layer 11. Its mechanical bond strength is significantly higher than that of superabrasive grains 1 which are bonded and have a conventional metallization layer 2. As a result, the degree of bonding between the metal-coated abrasive grains 10 and the resin bonding phase 7 is further improved, so that the metal-coated abrasive grains 10 have a high abrasive grain holding strength that can withstand heavy grinding, and the surface layer 12 has a large surface area. The heat radiation effect of the abrasive grains 10 is increased.

Next, a method of manufacturing a metal-coated abrasive grain 10 and a resin-bonded grindstone 20 using the abrasive grain 10 according to the embodiment will be described with reference to FIG. First, the outer surface of the superabrasive grain 1 shown in FIG. 3A is coated with copper by electroless plating. In this case, the super abrasive 1 and the copper coating layer 1 as the metal coating layer
The copper constituting 1A is used at a weight ratio of, for example, 1: 1. The superabrasive obtained by this method and shown in FIG. 3B has the same configuration as the metal-coated abrasive 3 of the prior art. This is referred to as copper-coated abrasive grains 10A. Next, the copper-coated abrasive grains 10A are heated and oxidized in the air. The copper coated abrasive 10A is heated to a temperature of 400 to 600 ° C., for example, 500
When heated at 2 ° C. for 2 hours, the outer surface of the copper coating layer 11A is oxidized and thermally expanded, and only the surface expands in volume, so that stress is applied from the periphery as shown in FIG.
Due to the strain, the oxide film of the copper coating layer 11A is broken and the stressed portion rises, and the edges 12a stand.
If the heating temperature of the copper-coated abrasive grains 10A is lower than 400 ° C., the desired effect cannot be obtained because the edge of the copper coating layer 11A does not stand. It is not preferable because oxidation proceeds too much. In this way, the surface of the copper coating layer 11A is recrystallized to form the surface layer 12 on which many fine edges 12a stand.
The metal-coated abrasive grains 10 shown in FIG. 1 in which the copper-coated layer 11A becomes the metal-coated layer 11 and the surface layer 12 are manufactured. Next, the metal-coated abrasive grains 10 and a raw material powder of a thermoplastic resin or a thermosetting resin such as a phenol resin constituting the resin bonding phase 7 are mixed, and the mixture is molded together with the base metal 5 or alone.
Press molding and baking can form the resin bond grindstone 20 or the abrasive grain layer 21 thereof.

As described above, according to the present embodiment, the metal-coated abrasive grains 10 having the roughened surface layer 12 are used as the abrasive grains of the resin-bonded grinding stone 20, and the metal-coated abrasive grains 10 are bonded to the resin bonding phase 7. Since the resin binder phase is dispersed and mixed therein, the resin binder phase penetrates between a number of convex portions having the edges 12a of the surface layer 12 of the metal-coated abrasive grains 10 and is bonded, so that the mechanical bond strength is high. Therefore, even if a heavy load is applied to the metal-coated abrasive grains 10 during heavy grinding, for example, it is possible to prevent the metal-bonded abrasive grains 10 from falling off from the resin bonding phase 7 and to extend the life of the resin-bonded grindstone 20. Moreover, since the surface area of the surface layer 12 of the metal-coated abrasive grains 10 is large due to the edges 12a, the heat dissipation is high and the grinding heat generated in the metal-coated abrasive grains 10 during grinding can be efficiently released through the resin bonding phase 7. Also in this regard, the life of the resin bond grindstone 20 can be improved.

Next, a metal-coated abrasive grain 1 according to an embodiment of the present invention.
A grinding test was performed on the resin-bonded grindstones 0 and the resin-bonded grindstones 20 in which they were dispersed and mixed, the metal-coated abrasive grains 1 of the conventional example, and the resin-bonded grindstones 6 in which these were dispersedly mixed. In both the embodiment and the conventional example, the super-abrasive grains 1 are diamond and the metal coating layer 1
1 and 2 are made of copper, the resin binding phase 7 is made of phenol resin, the particle size of the superabrasive grains 1 is the same, and the total thickness of the metal coating layer 11 and the surface layer 12a and the thickness of the metal coating layer 2 are the same. I do. When the bending strength of the metal-coated abrasive grains 10 according to the example and the metal-coated abrasive grains 3 according to the conventional example is compared, as shown in FIG. 5, about 11.8 kgf in the example, and 9.1 in the conventional example.
It was about 9 kgf, and the bending strength of the present example was improved by about 20%. In addition, a grinding test was performed using the resin-bonded grindstone 20 according to the example and the resin-bonded grindstone 6 according to the conventional example.

The grinding test conditions are as follows. Resin bond whetstone: φ200 × 1 ^T × 3x × φ40 SD: $ 200/230 Concentration: 100 Work material: 90% alumina Table feed speed: 60 mm / min Cutting depth: 10 mm Cutting length: 100 mm Number of cutting: 30 Main wheel peripheral speed: 1500 mm / min

As shown in FIG. 6, the resin-bonded grinding wheel 20 according to the embodiment has a normal grinding resistance of about 36.7 kgf.
In the conventional example, it was about 32.0 kgf, and the tangential grinding resistance was about 6.7 kgf in the example and about 4.7 kgf in the conventional example as shown in FIG. The grinding ratio is about 687 in the embodiment as shown in FIG.
It was about 7 and the grinding wheel life was extended by about 15%. From these results, in the example, the bending strength of the metal-coated abrasive grains 10 was larger, and the life of the resin-bonded grindstone 20 was longer, thus confirming the effect.

Incidentally, a lubricant such as carbon may be contained and dispersed in the resin binder phase 7, thereby improving the heat conductivity and abrasion resistance during grinding. When the metal coating layer 11 is coated on the superabrasive grains 1, the metal coating layer 11 does not necessarily need to be coated by electroless plating, and may be formed by another method, for example, electroplating, PVD, CVD, or the like.

[0015]

As described above, in the metal-coated abrasive grains according to the present invention, the surface of the abrasive grains is coated with a metal coating layer, and the surface layer of this metal coating layer has fine irregularities with sharp edges. Since the surface layer has a rough surface shape with fine irregularities, it has a large anchor effect at the time of bonding with the binder phase, and the mechanical bonding strength is larger than that of the conventional metal coating layer. Even when a large load is applied to the abrasive grains during grinding, the abrasive grains are prevented from falling off, and the surface layer has a large surface area, so that it has high heat dissipation and high heat resistance.

In the resin-bonded grindstone according to the present invention, since the above-described metal-coated abrasive grains are dispersed and fixed in the resin binder phase, the surface layer of the metal-coated abrasive grains has a roughened shape with fine irregularities. Because of this, it is intertwined with each other when bonding with the resin binder phase, the anchor effect is large, the mechanical bond strength with the resin binder phase is larger than conventional metal-coated abrasive grains, and a large load is applied to the abrasive grains during heavy grinding Even when the applied voltage is applied, the removal of the abrasive grains is well suppressed, and the surface area of the surface layer is large, so that the abrasive has high heat dissipation to the grinding heat and can improve the life of the grinding wheel.

Further, according to the method of the present invention for producing metal-coated abrasive grains, the surface of the abrasive grains is coated with a metal coating layer, and the metal coating layer is oxidized to form fine surface irregularities with sharp edges. Is formed, the surface of the metal coating layer can be made into a surface layer having a large number of fine irregularities by simply oxidizing the surface of the metal coating layer, and processing is easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a metal-coated abrasive grain according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a resin-bonded grindstone provided with the metal-coated abrasive grains shown in FIG.

FIG. 3 is an explanatory view of a main part showing a method for producing metal-coated abrasive grains according to an embodiment.

4A and 4B show surfaces of metal-coated abrasive grains, wherein FIG. 4A is a diagram of an embodiment, and FIG. 4B is a diagram showing a conventional example.

FIG. 5 is a view showing the transverse rupture strength of metal-coated abrasive grains according to an example of the present invention and a conventional example.

FIG. 6 is a graph showing a normal grinding resistance of a resin-bonded grindstone according to an embodiment of the present invention and a conventional example.

FIG. 7 is a diagram showing tangential grinding resistance of a resin-bonded grindstone according to an embodiment of the present invention and a conventional example.

FIG. 8 is a diagram showing a grinding ratio of a resin-bonded grindstone according to an example of the present invention and a conventional example.

FIG. 9 is a cross-sectional view of a conventional metal-coated abrasive grain.

10 is a partial cross-sectional view of a resin-bonded grindstone provided with the metal-coated abrasive grains shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Super abrasive 7 Resin bonding phase 10 Metal-coated abrasive 11 Metal-coated layer 12 Surface layer 12a Edge 20 Resin bond whetstone 21 Abrasive layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsukasa Takahashi 246-1 Egoshi, Kurosuno, Izumi-cho, Iwaki-shi, Fukushima F-term in Mitsubishi Materials Corporation Iwaki Works (reference) 3C063 AA02 BB02 BB06 BB15 BC03 CC01 FF30

Claims (3)

[Claims] 1. A metal-coated abrasive in which a metal coating layer is coated on the surface of the abrasive, and fine irregularities with edges are formed on the surface layer of the metal coating. 2. A resin-bonded grinding wheel, wherein the metal-coated abrasive grains according to claim 1 are dispersed and fixed in a resin binder phase. 3. Production of metal-coated abrasive grains in which the surface of the abrasive grains is coated with a metal coating layer, and the metal coating layer is oxidized to form a surface layer on which fine irregularities with sharp edges are formed. Method.