JPH07241716A - Rotary tool with superhigh pressure sintered compact - Google Patents

Abstract

PURPOSE:To provide a rotary tool with superhigh pressure sintered compact of high brazing strength between the extreme end part and the shank part. CONSTITUTION:This rotary tool is formed by brazing the extreme end part 2 integratedly sintering a superhigh pressure sintered compact 6 and the shank part 3 made of super hard alloy to a base material 5 made of superhard alloy. The solder material is silver solder containing Ti of 1-5wt.%. Wettability to the superhigh pressure sintered compact part 6 is improved, and the rotary tool hardly generating breakage is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a drill, an end mill,
The present invention relates to a rotary tool with an ultra-high pressure sintered body such as a reamer, and particularly to a rotary tool having a high brazing strength between a tip portion and a shank portion.

[0002]

2. Description of the Related Art A round bar material made of cemented carbide as a base material and integrally sintered with a super-high pressure sintered body such as diamond or cubic boron nitride is used to bond a super-high pressure sintered body chip to the base material. It is more suitable for rotating tools with ultra-high pressure sintered bodies such as drills, end mills, reamers, etc. because it has better mechanical and thermal strength than those used. Furthermore, it can be said that the integrally sintered material is a more suitable application target for a rotary tool that employs a helical blade to improve cutting performance, a rotary tool having a relatively long blade length, and the like.

Regarding the above-mentioned materials, for example, there is one disclosed in Japanese Patent Laid-Open No. 3-2771212.
Then, the tip portion made of such a material and the shank portion are joined by brazing to form a rotary tool. Conventionally, silver solder has been generally used as a brazing material.

[0004]

However, according to the observation results of the inventors of the present invention, the conventional silver braze has a cemented carbide at the end face of the tip and an end face of the shank made of the cemented carbide facing the cemented carbide. It was found that the bonding was poor and gaps were formed because the wettability of the ultra-high pressure sintered body portion was poor only by joining.

This result is particularly problematic for a small diameter rotating tool having a small brazing area and a rotating tool having a large number of blades and a large area ratio of the ultra-high pressure sintered body to the brazing end surface. It also contributes to breakage from the layers.

[0006]

The present invention has been made in view of the above problems, and relates to a rotary tool having a tip portion and a shank portion joined by brazing. The tip portion is formed from a material obtained by integrally sintering a cemented carbide base material and an ultrahigh pressure sintered body filled in a groove provided in the outer peripheral portion thereof. A groove end is opened in the brazing end surface of the tip portion, which becomes the exposed surface of the ultra-high pressure sintered body. Here, a silver solder containing 1 to 5% by weight of Ti is used as a brazing filler metal for brazing.

[0007]

As described above, by adding a trace amount of Ti to the silver braze, selective adsorption of Ti on the interface of the ultra-high pressure sintered body or formation of a Ti compound and improvement of the wettability of the brazing material are considered. As a result, normal joining of the ultra-high pressure sintered body and the cemented carbide of the shank portion becomes possible. As a result,
The brazing area will increase.

The increase in the brazing area directly leads to an increase in the force against the shearing force. In addition, the improvement of brazing around the outer peripheral part is several times stronger than bending and twisting, and the notch effect prevention effect due to the elimination of the gap is also great, and the brazing strength and breakage are high. A rotating tool that is difficult to do is realized.

If the amount of Ti to be added is less than 1% by weight, the effect of the addition is not exhibited, and if it exceeds 5% by weight, the brazing layer becomes hard and brittle, which is not preferable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotary tool with an ultra-high pressure sintered body of the present invention will be described below with reference to the drawings.

Although FIG. 1 shows an embodiment of a twisted blade end mill, a straight blade end mill may be used. The rotary tool may be a drill, a reamer, or the like.

In FIG. 1, an end mill 1 has a tip 2
The shank portion 3 and the shank portion 3 are joined by brazing. The tip portion 2 is molded from a material 4 as shown in FIG. The material 4 is a round bar-shaped base material 5 made of cemented carbide.
And an ultra-high pressure sintered body 6 made of diamond or cubic boron nitride filled in four twist grooves provided on the outer periphery of the sintered body 6
Are obtained by sintering together with a binder at ultrahigh pressure and high temperature.

The brazing end surface which constitutes the one end surface of the material 4 is usually ground in a V shape so that the brazing area becomes large. This end face is formed by the base material 5 made of cemented carbide and the super-high pressure sintered body 6 exposed at the groove end. Then, one end surface of the shank portion 3 made of cemented carbide facing the tip portion 2 is also ground into a V shape and brazed. After that, the outer surface of the shank portion 3 is ground, the chip pocket 7 is ground, and the cutting edge 8 is formed.
Grinded for creation and commercialized.

For the brazing material, a silver brazing material containing 1 to 5% by weight of Ti is used for the purpose of improving the wettability with the ultra-high pressure sintered body 6 and increasing the brazing area. At this time, in order to prevent the oxidation of Ti, the brazing operation is preferably performed in vacuum or in argon gas.

Next, a practical example of the present invention will be introduced.

In the end mill 1 shown in FIG. 1, the diameter is 5 mm and the number of blades is 4. The composition of the silver solder used was 72% by weight Ag, 26% by weight Cu, and 2% by weight Ti. Brazing was performed in a vacuum. Further, FIG. 3 is manufactured by a conventional method for comparison, and has exactly the same specifications except that silver braze containing no Ti is used as a brazing filler metal in the end mill.

When the brazing layer 9 was observed, the end mill 1 shown in FIG. 3 was found to have a wax break 10 at the portion 6 of the ultra-high pressure sintered body, but the end mill 1 shown in FIG. It was not observed at all. As a result, the end mill 1 of FIG.
Then, it became possible to almost avoid the breakage from 9 parts of the brazing layer within the range of the normal use cutting conditions of the end mill with the ultra-high pressure sintered body.

[0018]

As described above, in the rotary tool with the ultra-high pressure sintered body of the present invention, the brazing material wets the ultra-high pressure sintered body portion by the action of the silver braze containing 1 to 5% by weight of Ti. Improves resistance and eliminates wax cuts and gaps. As a result, a rotary tool with an ultra-high pressure sintered body that is unlikely to break is realized.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a rotary tool with an ultra-high pressure sintered body of the present invention.

FIG. 2 is a perspective view of a tip end material of the rotary tool shown in FIG.

FIG. 3 is a front view showing an example of a conventional rotary tool with an ultra-high pressure sintered body.

[Explanation of symbols]

 1 End Mill 2 Tip Part 3 Shank Part 4 Material 5 Base Material 6 Ultra High Pressure Sintered Body 8 Cutting Edge 9 Wax Layer

Claims (1)

[Claims] 1. A tip end made of a material obtained by filling a groove formed in the outer periphery of a cemented carbide base material in the shape of a round bar with a super-high pressure sintered body and integrally sintering the material, and forming a round bar shape. A cemented carbide shank part is brazed and joined, which is a rotary tool formed so that a cutting edge is formed in the ultra-high pressure sintered body, and a groove end is opened in a brazed end face of the tip part, In the rotary tool with the ultra-high pressure sintered body, which is the exposed surface of the ultra-high pressure sintered body, silver braze containing 1 to 5% by weight of Ti is used for the brazing. A rotary tool with an ultra-high pressure sintered body.