JPH0543918A - Material for cutting tool and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide tool material for drills with a large lip height and small diameter and to adapt a small diameter drill and an end mill to their making in a large diameter. CONSTITUTION:The material for cutting tools is in the shape of a bar and consists of an extra high pressure sintered material layer 4 stuck sintered through an intermediate layer 5 in a groove part 3 provided in a shank 2 and one end of the shank 2. The extra high pressure sintered material layer 4 consists of diamond, cubic boron nitride, etc., and the intermediate layer 5 consists of Ni, Co or Ni-Co alloy 0.1-0.5mm thick. The reason the intermediate layer 5 is interposed in that the relaxation of residual stress generated between the shank 2 and the extra high pressure sintered material layer 4 is taken into consideration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for a cutting tool such as a small-diameter drill or end mill, and a method for manufacturing the same, and particularly to reduce cracks generated in a cutting edge element made of an ultrahigh pressure sintered body. It is a thing.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a material for a cutting tool of this type is disclosed in, for example, Japanese Patent Laid-Open No. 62-124833. This is to form parallel grooves or lattice-shaped grooves on a disc made of cemented carbide, and sinter and fix a super-high pressure sintered body layer made of diamond, cubic boron nitride, etc. in this groove, A tool material is obtained by dividing the united layer portion into a round bar shape.

[0003]

However, in the manufacturing method disclosed in the above-mentioned publication, when the depth of the ultra-high pressure sintered body layer becomes greater than the width, cracks are likely to occur in this sintered body layer. Therefore, this manufacturing method has a problem that a small diameter drill having a high lip height or a drill having a diameter of 3 mm or more cannot be manufactured.

In view of the above, the present invention seeks to improve the depth of the ultra-high pressure sintered body layer in the groove so as to be large.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an ultrahigh pressure sintered body layer provided at one end of a cemented carbide shank is bonded through an intermediate layer in a groove portion. Thus, the material for the cutting tool is configured. In this case, the intermediate layer is Ni, having a thickness of 0.1-0.5 mm,
It is made of Co or Ni-Co alloy.

Further, in the manufacturing method of the cutting tool element, a disk made of cemented carbide is used as a starting material, and Ni and C are contained in the groove.
o or Ni-Co alloy foil is placed, and the mixed powder of the ultra-high pressure sintered body is packed in the foil and sintered under ultra-high pressure and high temperature.
Finally, it is cut out by wire cutting or the like.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the material for a cutting tool of the present invention and its manufacturing method will be described below with reference to the drawings.

1 (a) (b) and FIG.
Is a round bar material for cutting tools, and is applied to small diameter drills, end mills, and the like. And
This cutting tool material 1 is a shank 2 made of cemented carbide.
And a super-high pressure sintered body layer 4 in a groove portion 3 in the shape of a letter or a cross provided at one end of the shank 2. In this case, the ultra-high pressure sintered body layer 4 is formed by sintering a mixed powder of diamond, cubic boron nitride, a binder and the like at ultra-high pressure and high temperature.

However, in the sintering of the ultra-high pressure sintered body layer 4 under the ultra-high pressure and high temperature, the intermediate layer 5 is interposed, as clearly shown in FIG. The intermediate layer 5 has a thickness of 0.1
Ni, Co or Ni-Co having a thickness of 0.5 mm
It is made of alloy. The intermediate layer 5 is interposed
This is to reduce the occurrence of cracks in the ultra-high pressure sintered body layer 4. That is, when the ultra-high pressure sintered body layer 4 and the shank 2 are directly sintered and fixed, residual stress is generated due to the difference in thermal expansion coefficient between them, and therefore the intermediate layer 5 is interposed in order to alleviate the residual stress. It is a thing. And Ni,
The intermediate layer 5 made of Co or Ni—Co alloy is selected because it can absorb residual stress by plastic deformation and does not react with diamond or cubic boron nitride to form a carbide or a nitride. It is because it is expensive.

Further, the thickness of the intermediate layer 5 is 0.1 to 0.
5 mm is a suitable range. This is because if it is thinner than 0.1 mm, the residual stress relaxation effect is not sufficient, and if it exceeds 0.5 mm, there is a residual stress relaxation effect, but when it is processed into a drill and used, only this part is worn. This is because it has a drawback that it is easily scooped out.

In the cutting tool material 1 thus constructed, the groove 3 is formed in the rod-shaped shank 2, and the intermediate layer 5 is formed.
The ultra-high pressure sintered body layer 4 may be sinter-bonded under ultra-high pressure and high temperature. However, in many cases, it is more efficient to obtain the cutting tool material 1 by the manufacturing method of the present invention as shown in FIG.

FIG. 3 shows a starting material 10 used in the method for producing a material for a cutting tool according to the present invention. The starting material 10 is made of cemented carbide, and a circular end face thereof is provided with a groove portion 11 in a parallel relationship. It was set up. Specifically, the outer diameter is 23 m
m, a cemented carbide made of WC-5.5% Co having a height of 10 mm is applied, and the groove portion 11 has a depth = 4 mm and an opening end width =
It is 2.06 mm and the bottom radius = 0.75 mm. The cross-sectional shape of the groove 11 is preferably U-shaped or V-shaped.

A foil made of Ni, Co or a Ni alloy forming the intermediate layer 5 is placed in the groove portion 11 of the starting material 10 and then mixed powder forming the super high pressure sintered body layer 4 is filled therein. The capsule 12 as shown in FIG. 4 is applied and exposed to ultra-high pressure and high temperature to sinter the mixed powder. In the specific example in this case, as the foil forming the intermediate layer 5, a 200 μm Ni foil and a capsule 12 made of Zr were applied.

As the mixed powder forming the ultra-high pressure sintered body layer 4, a mixed powder of diamond and / or cubic boron nitride and a binder may be used, or diamond and / or cubic boron nitride powder. A solvent metal may be placed on top of and infiltrated. In addition, a thick Ni alloy was previously installed as an intermediate layer material, and a part of this was set as diamond and / or
Alternatively, it may be infiltrated into cubic boron nitride powder. Specifically, after the starting material 10 is inserted into a capsule 12 made of Zr, diamond particles having an average particle size of 3 to 6 μm are filled in the groove portion 11, and a Co plate 13 and a lid 14 made of Zr are placed on the groove portion 11. Then, it was placed in an appropriate high-temperature and high-pressure apparatus and sintered under the conditions of a pressure of 55 Kb and a temperature of 1500 ° C. for 10 minutes.
After cooling and decompressing, the capsule 1 made of Zr
2. When the lid 14 made of Zr is removed by grinding, Ni
A composite sintered body having the mid layer 5 was obtained. The Co plate 13 described above is infiltrated into the diamond particles and serves as a binder. With regard to the above-mentioned sintering conditions, a sufficient pressure is applied so that diamond and / or cubic boron nitride does not change into a low-pressure phase, and an ultra-high pressure sintered body containing diamond and / or cubic boron nitride is further added. Sufficient to form layer 4 and intermediate layer 5
The temperature and time must be selected so that the thickness does not become thinner than 0.1 mm due to diffusion.

The composite sintered body thus obtained was wire-cut by an array as shown in FIG.
A cutting tool material 1 as shown in FIG. In this case, the presence of cracks was not observed in the ultrahigh pressure sintered body layer 4.

[0016]

As described above, the present invention is a raw material for a cutting tool in which the super-high pressure sintered body layer 4 is sinter-fixed through the predetermined intermediate layer 5 and a manufacturing method thereof. Therefore, the occurrence of cracks in the ultra-high pressure sintered body layer 4 is reduced, and the length in the depth direction is large, so that it can be applied to a drill with a high lip height, a drill with a large diameter, an end mill, etc. Has the advantage that

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment (a) and (b) of a material for a cutting tool of the present invention, respectively.

FIG. 2 is a partially enlarged sectional view.

FIG. 3 is a perspective view showing a starting material in a method for manufacturing a cutting tool material according to the present invention.

FIG. 4 is a conceptual cross-sectional view in which a starting material is inserted into a capsule.

FIG. 5 is a plan view illustrating a cutting pattern from the obtained composite sintered body.

[Explanation of symbols]

 1 Material for Cutting Tool 2 Shank 3 Groove 4 Ultra High Pressure Sintered Body Layer 5 Intermediate Layer 10 Starting Material 11 Groove 12 Capsule

Claims (3)

[Claims] 1. An ultrahigh pressure sintered body layer 4 made of diamond, cubic boron nitride or the like is provided at one end of a rod-shaped cemented carbide shank 2 so as to present a single letter shape or a cross shape, as a cutting element. In the material for a cutting tool, the ultra-high pressure sintered body layer 4 is bonded to the shank via an intermediate layer 5, and the intermediate layer 5 has a thickness of 0.1 to 0.5 m.
A material for a cutting tool, which is made of Ni, Co, or a Ni-Co alloy having a thickness of m. 2. A method for producing a material for a cutting tool, characterized in that the material for a cutting tool according to claim 1 is produced by the following steps. (A) Ni or Co is formed on the inner surface of the parallel or lattice-shaped groove portion 11 provided on one end surface of the starting material 10 made of cemented carbide.
Alternatively, a step of disposing a foil made of a Ni—Co alloy. (B) A step of filling the groove portion 11 in which the foil is arranged with a mixed powder of diamond, cubic boron nitride, a binder and the like. (C) A step of sintering the mixed powder by exposing the starting material 10 obtained in the step (b) to high temperature and high pressure. (D) A cutting step of cutting the composite sintered body obtained in the step (c) by wire cutting or the like to obtain the material for a cutting tool according to claim 1. 3. A method of manufacturing a material for a cutting tool, which comprises a step of placing a thin plate of a solvent metal on a mixed powder in addition to the filling step described in claim 2 (b).