JP3410438B2 - Super abrasive wheel for high speed grinding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a superabrasive grindstone for high speed grinding using superabrasive grains such as diamond grains and CBN grains.

[0002]

2. Description of the Related Art This type of superabrasive grindstone is composed of a superabrasive layer containing diamond grains and CBN grains and a base for holding the superabrasive layer. The abrasive layer itself has high hardness and toughness, and has excellent high-speed grindability, so the superabrasive layer can be used as a base for a superabrasive wheel with stable performance, that is, high-speed rotation. It is required to have characteristics such as having sufficient strength against the stress acting by the force of time, having little deformation, having uniform deformation, and being lightweight. In order to obtain such characteristics, recently, C-FRP having excellent mechanical strength and thermal strength and a small specific gravity has been used as the base material for the whole base or a part thereof. For example, the applicant of the present invention is Japanese Patent Application No. 4-23.
No. 9437, a base of a superabrasive grindstone for high-speed grinding, in which carbon fibers are spirally wound and laminated in a circumferential and cylindrical direction on the surface of a metal base and the resin is hardened and molded with a resin such as an epoxy resin. Have already proposed.

[0003]

However, in the structure in which the whole base or a part thereof is molded with C-FRP as described above, it is sure that it has excellent performance as a base due to the characteristics of the material itself. However, on the other hand, there is a problem that the price of the superabrasive grindstone becomes very high. In order to reduce the cost of the grindstone, it has been a problem to select an alternative material whose strength against centrifugal damage is comparable to that of C-FRP. Therefore, the present invention provides a superabrasive grindstone for high-speed grinding, which can significantly reduce the price of the superabrasive grindstone while maintaining the strength against centrifugal fracture, which is an excellent performance as a base of C-FRP. The purpose is to do.

[0004]

In order to solve the above-mentioned problems, the present invention is a superabrasive grain grindstone in which a superabrasive grain layer is fixed to the outer peripheral surface of a disc-shaped base. Is a Ti alloy and is used under a grinding condition of a grinding wheel peripheral speed of 120 m / sec or more, which is a superabrasive grindstone for high-speed grinding. The base is made of Ti alloy, C-FR
Compared to P, the material price is lower and the price of the superabrasive grindstone can be reduced. Not only that, but the value of the specific strength, which is an index of strength against centrifugal fracture, is high, and it has excellent mechanical properties suitable for high-speed rotation at a grinding wheel peripheral speed of 120 m / sec or more.

[0005]

[Table 1]

Table 1 compares the mechanical characteristic values of a base made entirely of Ti alloy, a base made entirely of steel, and a base made entirely of C-FRP. As is clear from Table 1, the specific strength, which is an index of strength against centrifugal fracture, is higher in the base made entirely of Ti alloy than in the base made entirely of steel, and the whole base made of C-FRP is used. It shows that it is comparable to the stand.

The Ti alloy used for the base is preferably a Ti-Al-V type alloy, a Ti-Al-V-Sn type alloy, or a Ti-Al-Mo-V type alloy. Is. Specifically, Ti-6Al-6V-2S
An n alloy, Ti-6Al-4V alloy, or the like can be used, but is not limited to these.

Then, Cu is added to the interface between the base and the superabrasive layer.
It is characterized by having a brazing material layer as a component . By providing the superabrasive grain layer through the brazing material layer containing Cu as a component, the adhesive strength between the superabrasive grain layer and the base, which can sufficiently withstand high-speed grinding, is obtained. To fix a resin-bonded superabrasive grain layer on the surface of a base material made of conventional steel or aluminum alloy, "the resin bond adheres to the base metal (base) with its own adhesiveness. A method is used in which unevenness is provided on the surface of the base metal to increase the adhesion area and a strong adhesive is applied. ”(Edited and issued by the Diamond Industry Association; Diamond Tool Manual; 1979)
Issued annually; page 189) is known. Also,
In order to bond the metal-bonded superabrasive layer to the surface of the base material made of steel, there is known a technology in which the surface of the base is pre-plated with Cu and the metal bond is sintered and bonded to the base at the same time. Has been. However, especially for metal bond Ti
In order to bond to a base made of an alloy, it is impossible to bond directly, so a brazing material layer containing Cu as a component is indispensable. If a super-abrasive grain layer is formed by metal bonding, and Ti cannot be sufficiently bonded due to the reaction between Ti of the substrate and Cu of the brazing material component during sintering, in order to suppress this reaction, the substrate is previously It is preferable that the surface of is plated with Ni. As the Ni plating, either electroplating or chemical plating may be applied, and the thickness of the Ni plating is 5
It is preferably at least μm.

The brazing material containing Cu as the component used in the present invention is preferably one having a low brazing temperature and high fluidity,
Not only the Ti alloy used as a base, but also Ag-, which has particularly excellent wettability with diamond and provides high adhesion.
Cu-Ti based activated brazing material is most suitable. To form the brazing material layer, it is suitable to use a pasty brazing material. Here, the pasty brazing material is generally a brazing material powder kneaded with a binder and has an appropriate viscosity, so that it is easy to work. In an actual operation, first, a paste-like brazing material is applied to the grinding surface of the base, and when the brazing material is dried and no longer flows, it is placed in a furnace and heated to melt the brazing material. Then, it is cooled in the furnace to complete the formation of the brazing material layer.

To form a superabrasive grain layer on the surface of the brazing material layer, the surface of the brazing material layer is treated by sandblasting or the like to form fine irregularities, and the superabrasive grain layer is formed on the surface of the brazing material layer. It is preferable because a strong adhesive force with the layer can be obtained. In the case of metal bond, since it is usually sintered at a high temperature of 600 ° C. or higher, the brazing material layer can be formed simultaneously with sintering. For example, in order to manufacture a metal bond grindstone for high-speed grinding, a paste of Ag-Cu-Ti-based activated brazing material is uniformly applied to the surface of a base and put in a drying oven to dry until it does not flow. After drying, assemble the base into the mold,
This can be heated and pressed to simultaneously sinter the metal bond and form the brazing material layer.

The superabrasive grain layer contains diamond abrasive grains,
It contains CBN abrasive grains or mixed abrasive grains of diamond abrasive grains and CBN abrasive grains, and the average grain size is 10 μm to 1
It is characterized in that it is 000 μm. Depending on the type and hardness of the work piece, the type of machine, the grinding conditions, the required surface roughness, etc., the type of super-abrasive grains to be used, the grain size,
Determine the degree of concentration as appropriate. The average grain size of superabrasive grains generally used for high-speed grinding is in the range of 50 μm to 800 μm, and the concentration tends to be 100 or more with high concentration.

The superabrasive layer can be selected from binders such as resin bonds, metal bonds, electrodeposition bonds and vitrified bonds. Type of work piece and its hardness,
The optimum bond can be selected depending on the grinding conditions, required surface roughness, and the like. However, the grinding wheel peripheral speed is 200 m / se
When performing high-speed grinding of c or more, a bond material having high strength is required, and therefore it is safer to select metal bond or electrodeposition bond.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the invention will be described in the section of Examples.

[0014]

EXAMPLES (Example 1) FIG. 1 is an external view of a superabrasive grain grindstone for high-speed grinding according to an example. Since this whetstone is for cutting, the whetstone thickness is very thin and therefore the structure is such that it is sandwiched by the whetstone flanges. Whetstone outer diameter D = 250 mm, inner diameter d = 25.
4 mm, superabrasive layer thickness T = 1.2 mm, base thickness t = 1
mm, whetstone flange outer diameter f = 220 mm, whetstone flange thickness (one side) = 10 mm, diamond grain average particle size 1
80μm, concentration 150, metal bond composition is 85C
u-15Sn, the composition of the base material is Ti-6Al-6V-
It was a 2Sn alloy. An Ag-Cu-Ti-based activated brazing material layer was provided at the boundary between the Ti alloy base and the superabrasive layer.
In order to confirm the effect of the present invention, as a comparative example, using a conventional steel (SKD) as the base and C-FRP, the grinding wheel peripheral speed is 200 m / sec, 250 m / sec, 300 m /
A rotation test was performed at sec, 350 m / sec, and 400 m / sec, and the strain amount Δ of the base when the grindstone flange was removed was compared by the three persons. The measurement results are shown in Table 2.

[0015]

[Table 2]

As shown in Table 2 above, in the Ti alloy base of the present invention, the circumferential velocity of the grindstone causing the strain shown in FIG.
It is higher than the steel base and is comparable to the C-FRP base. The production cost of the Ti alloy base was about 30% that of the C-FRP base.

(Embodiment 2) The base size and specifications of the superabrasive grain layer are the same as those of the embodiment 1, and the outer diameter D of the grindstone D = 250 mm, the inner diameter d = 25.4 mm, and the superabrasive grain layer thickness T = 1.2 mm. , Base thickness t = 1 mm, whetstone flange outer diameter f = 220 mm, whetstone flange thickness (one side) = 1
0 mm, average grain size of diamond grains 180 μm, concentration degree 150, metal bond composition was 85Cu-15Sn, and base material composition was Ti-6Al-6V-2Sn alloy. The surface of the base is preliminarily plated with Ni having a thickness of 5 μm, and the boundary between the Ni plating and the superabrasive grain layer is Ag—Cu.
A Ti-based activated brazing material layer was provided. In order to confirm the effect of the present invention, as a comparative example, the base is made of conventional steel (SK
D) and C-FRP, grinding wheel peripheral speed 200 m / s
ec, 250m / sec, 300m / sec, 350m
/ Sec, 400 m / sec, a rotation test was performed, and when the grindstone flange was removed, the strain amounts Δ of the bases were compared by the three parties, and the same good results as in Example 1 were obtained.

As described above in detail, since the base of the present invention is made of Ti alloy, it is possible to reduce the cost of the grindstone while maintaining the strength against the centrifugal fracture of the grindstone.
Further, by forming an Ag—Cu—Ti-based activated brazing material layer or the like at the interface between the Ti alloy base having a thickness of 5 μm or more and Ni plating in advance and the superabrasive grain layer, The joint strength with the grain layer can be improved, and safe high-speed grinding is possible.

[Brief description of drawings]

FIG. 1 shows a perspective view of an embodiment.

FIG. 2 is a schematic diagram showing a strain amount of a base.

[Explanation of symbols]

1 Ti alloy base 2 flange 3 Flange tightening holes Dc whetstone outer diameter Outer diameter of Df flange Δ distortion amount

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B24D 3/00 B24D 5/00

Claims (3)

(57) [Claims] 1. A super-abrasive grinding wheel comprising fixed superabrasive layer in a disc-like base outer peripheral surface of said base is made of Ti alloy subjected to Ni plating on the surface, the super abrasive Cu is added to the boundary between the grain layer and the Ni plating.
Has a brazing material layer, and the peripheral speed of the grindstone is 120 m / sec
A superabrasive grindstone for high-speed grinding, which is used under the above grinding conditions. 2. The Ti alloy is a Ti-Al-V type alloy, a Ti-Al-V-Sn type alloy, or a Ti-Al-Mo-type alloy.
The superabrasive grindstone for high-speed grinding according to claim 1, which is a V-based alloy. 3. The superabrasive layer is diamond abrasive, C
The superabrasive grindstone for high speed grinding according to claim 1 or 2, which contains BN abrasive grains or mixed abrasive grains of diamond abrasive grains and CBN abrasive grains, and has an average grain diameter of 10 µm to 1000 µm. .