JPH0215321B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a throw-away chip, and particularly to a throw-away chip that can be easily obtained, having a through hole for fixing it to a holder of a cutting tool. Relating to a manufacturing method.

[Conventional technology]

Tools having a cutting edge portion containing a sintered body containing high-pressure phase boron nitride have been studied for some time.

Most sintered tools containing high-pressure phase boron nitride have a structure in which a sintered body containing high-pressure phase boron nitride is laminated and bonded onto a cemented carbide substrate.

For this purpose, the manufacturing method was to place raw material powder of high-pressure phase boron nitride on a cemented carbide substrate and sinter it under high temperature and high pressure in an ultra-high pressure apparatus to obtain a sintered body.

[Problem that the invention seeks to solve]

When the sintered body obtained by such a manufacturing method is used as a throw-away chip, especially when used as a throw-away chip that has a through hole for fixing to a cutting tool holder, it is difficult to drill holes with the required dimensions. However, since the sintered body layer containing the high-hardness, high-pressure phase boron nitride must also be drilled, there is a problem in that the machining time is long and the tool used to drill the holes is extremely worn out.

Therefore, in order to eliminate the need for hole processing after sintering, it is possible to sinter so that holes of the required size are obtained during sintering, but since sintering is performed under high temperature and high pressure, the holes before and after sintering are It was very difficult and impossible to predict the dimensional changes of

An object of the present invention is to provide a method for manufacturing a throw-away chip that eliminates the drawbacks of the conventional method and makes it extremely easy to process holes after sintering.

[Means for solving problems]

The present invention is a method for manufacturing a throw-away chip, in which a molded body is formed, which has a convex part in the center, a high melting point substance is interposed inside the convex part, and the other part is made of cemented carbide. , containing high-pressure phase boron nitride, has a hole in the center corresponding to the convex part, has a thickness of 0.3 mm to 2 mm, and has a width of 1 mm from the outer edge to the hole.
A plate-shaped molded body having a hole in the center having a diameter of mm to 9 mm is molded, and the molded body having the convex portion and the plate-shaped molded body having a hole in the center are stacked and the convex portion and the hole are fitted. After that, it is sintered at high temperature and high pressure in an ultra-high pressure device.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

1a to 1c show an example of a molded product having a convex portion in the manufacturing method of the present invention, FIG. 1a is a plan view thereof, FIG. 1b is a front view thereof, and FIG.
Figure c shows a sectional view taken along line AA in Figure 1b. Moreover, FIGS. 2a to 2c show an example of a plate-shaped molded body having a hole in the center in the manufacturing method of the present invention,
Fig. 2a shows a plan view thereof, Fig. 2b shows a front view thereof, and Fig. 2c shows a sectional view taken along line BB in Fig. 2b.

First, in the present invention, a molded body 1 having a convex portion 2 as shown in FIGS. 1a to 1c and a second
A plate-shaped molded body 5 having a hole 6 in the center as shown in Figures a to 2c is formed.

The molded body 1 having convex portions of this example has convex portions 2 on each of the upper and lower surfaces, but when a sintered body containing high-pressure phase boron nitride is provided on either the upper surface or the lower surface of the throw-away chip. Correspondingly, the convex portion 2 may be formed on either the upper or lower surface.

Here, the high-pressure phase boron nitride means known cubic boron nitride or wurtzite boron nitride.

A high melting point substance 3 is disposed inside the convex portion 2 and can be easily removed by cutting or machining after sintering. The high melting point substance 3 is a substance that does not melt during sintering or generate gas and prevent sintering, such as graphite, hexagonal boron nitride, iron,
These materials include nickel, molybdenum, tantalum, tungsten, titanium, and zirconium.

This high melting point substance 3 is interposed inside the convex portion 2 so that the size of the hole is slightly smaller than the desired size after sintering. If the throw-away tip remains around the hole and has sufficient strength to fix the throw-away chip to the cutting tool, it is acceptable even if the size of the intervening high melting point material 3 after sintering is larger than the hole size. do not have.

The other portion of the molded body 1 having the convex portion is made of a known cemented carbide 4 typified by, for example, tungsten carbide and cobalt.

On the other hand, the plate-shaped molded body 5 having a hole 6 in the center of this example contains high-pressure phase boron nitride, and other components include well-known cobalt, nickel, iron, copper, titanium, silicon, magnesium, zirconium, hafnium,
Aluminum, Groups 4a, 5a, and 5a of the periodic table
It is molded containing at least one component such as boride, nitride, oxide, silicon carbide, boron carbide, etc. of group 6a elements.

In the plate-shaped molded body 5 having a hole in the center, the hole 6 is provided corresponding to the convex portion 2 of the molded body 1 described above. Further, the thickness of this plate-shaped molded body 5, that is, t is 0.3 mm to 2 mm, and the width from the outer edge to the hole 6,
That is, d is 1 mm to 9 mm. Thickness less than 0.3mm,
If the width is less than 1 mm, there will be less area that can be used as a tool, and the applications will be extremely limited, which is undesirable. If the thickness exceeds 2 mm and the width exceeds 9 mm, the cemented carbide forming the throwaway tip will As the number of parts decreases, the toughness of the throw-away tip decreases, which is disadvantageous when used as a tool. In other words, this type of throw-away chip has a structure in which a sintered body containing high-pressure phase boron nitride, which has high hardness but low transverse rupture strength, is reinforced with a cemented carbide having a higher transverse rupture strength. It is from.

The molding method for these molded bodies is a method in which predetermined raw material powder is placed in a mold and molded using a press or the like.

Further, when the high melting point substance 3 inside the convex portion 2 is made of metal, a hole may be made in the molded body afterwards and a predetermined metal rod may be embedded in the hole.

In the drawings, a cylindrical shape is illustrated as an example of the shape of the molded body, but the shape can be appropriately selected depending on the requirements, such as a triangular prism shape or a quadrangular prism shape.

The molded bodies obtained as described above are stacked one on top of the other so that the protrusions and holes fit together, and then placed in a container made of a known metal such as stainless steel, titanium, zirconium, molybdenum, or nickel. In a known ultra-high pressure device such as a belt type, 2GPa or more,
Throwaway chips are manufactured by sintering at a known high temperature and pressure of 1000°C or higher.

The resulting throw-away chip is drilled at the corresponding position of the hole and reamed to the final dimensions, resulting in a throw-away chip with a through hole that can be easily fixed to a cutting tool holder. It will be done.

FIGS. 3 to 5 are diagrams showing each example of the throw-away chip manufactured as described above, and FIG. 3a is a plan view showing an example of an equilateral triangular throw-away chip. FIG. 3b shows a side view thereof, and FIG. 3c shows a sectional view taken along the line C--C in FIG. 3a.

FIG. 4a is a plan view showing an example of a rectangular throw-away tip, FIG. 4b is a side view thereof, and FIG. 4c is a sectional view taken along line DD in FIG. 4a. In this example, the hole portion is made of metal, and a portion of it is left as is.

Similar to FIG. 3a, FIG. 5a is a plan view showing an example of an equilateral triangular throw-away tip;
The figure shows the side view, and Figure 5c shows the E-E of Figure 5a.
Each shows a cross-sectional view. In this example, unlike the example shown in FIG. 3a, the central part of the sintered body is entirely replaced with metal, and a hole is provided in the central part.

In the examples shown in FIGS. 3 to 5, the sintered body containing high-pressure phase boron nitride is provided on both the upper and lower surfaces of the throw-away chip. It may be something that has been prepared for.

In the figure, 4', 4'', 4 are cemented carbide, and 6', 4 are cemented carbide.
6'', 6 are holes, 7', 7'', 7 are sintered bodies containing high-pressure phase boron nitride, etc., and 8, 8' are metals, respectively.

〔Example〕

Next, the present invention will be specifically explained using examples.

Example 1 Wurtzite boron nitride with particle size of 2 μm or less86
Weight% and aluminum particle size of 10μm or less14
% by weight were mixed in a cemented carbide ball mill for 24 hours. The mixed powder was put into a mold and press-molded into a ring shape with an outer diameter of 13 mm, an inner diameter of 7 mm, and a thickness of 2 mm, and two molded bodies were prepared.

Meanwhile, tungsten carbide 90% by weight, cobalt 10
A cemented carbide consisting of % by weight was press-formed into a shape as shown in FIG. Next, a hole with a diameter of 5 mm is drilled in the center of this molded body in a direction perpendicular to the top surface, and a stainless steel round rod with a diameter of 5 mm and a length of 6 mm is embedded in the hole. 5
A depression with a diameter of 1 mm and a depth of 1 mm was filled with a compact of iron powder press-formed to the same size.

Next, the previously prepared annular molded body was fitted into the upper and lower convex portions of the molded body made of cemented carbide and stainless steel, overlapped, and placed in a titanium capsule with a thickness of 0.5 mm. , sealed with a lid made of the same material, and heated at 6.2GPa and 1400℃ in an ultra-high pressure device.
Pressure was applied for 20 minutes and then returned to normal temperature and pressure.

When the sintered body inside the capsule was removed from the ultra-high pressure equipment and ground with a silicon carbide grindstone, the part containing wurtzite boron nitride, the cemented carbide part, and the stainless steel part were firmly bonded. It was a good sintered body. Also, its shape is
It was in the shape of a disc measuring 11 mm and 3.2 mm thick, and a sintered body containing wurtzite boron nitride with a width of 3.5 mm and a thickness of 1 mm was provided in an annular shape on the upper and lower edges of the disc. .

Next, a hole with a diameter of 4 mm was drilled in the stainless steel part at the center of the sintered disk so that it could be attached to a lever lock type handle. The machining was extremely easy, similar to drilling for ordinary stainless steel, and was completed within one minute.

Comparative Example 1 A mixture of wurtzite boron nitride and aluminum having the same composition as in Example 1 was press-molded into a disk shape with an outer diameter of 13 mm and a thickness of 2 mm, and a tungsten carbide
Cemented carbide powder consisting of 90% by weight and 10% by weight of cobalt was press-molded into a disk shape of 13 mm in diameter and 4 mm in thickness, which was stacked on top of each other and sintered in the same manner as in Example 1.

The obtained sintered body has a thickness of 1 mm on the top and bottom surfaces of the cemented carbide.
It is covered with a sintered body containing wurtzite boron nitride of mm.

In order to provide a hole in the center of this sintered disk, the diameter is 4
I tried drilling holes with a mm diamond-handled grindstone. A grindstone rotating at 10,000 revolutions/minute was pressed against the surface of the center of the disk for 5 minutes, but the grindstone was crushed and only a small depression was formed on the surface of the sintered body. I also tried ultrasonic processing, but it did not work at all.

〔Effect of the invention〕

In the present invention, since a high melting point substance is pre-interposed in the center of the cemented carbide part, that part can be easily removed after sintering, and therefore a through-hole for fixing it to a cutting tool holder is provided. It is possible to easily manufacture a throw-away tip having the following properties.

[Brief explanation of drawings]

Fig. 1 shows an example of a molded article having a convex portion in the manufacturing method of the present invention, Fig. 1a shows its plan view, Fig. 1b shows its front view, and Fig. 1c shows its 1b
FIG. 2 shows an example of a plate-shaped molded product having a hole in the center according to the manufacturing method of the present invention, FIG. 2a shows a plan view thereof, and FIG. FIG. 2c shows a front view, FIG. 2c shows a sectional view taken along line BB in FIG. 2b, and FIGS. 3 to 5 show examples of throwaway chips obtained by the manufacturing method of the present invention. Figures 3a, 4a, and 5a are front views, Figures 3b, 4b, and 5b are side views, and Figures 3c, 4c, and 5c are sectional views. 1... Molded body having a convex portion, 2... Convex portion, 3...
...High melting point substance, 4, 4', 4'', 4... Cemented carbide, 5... Plate shaped body having a hole in the center, 6,
6', 6'', 6... hole, 7, 7', 7'', 7...
Sintered body containing high-pressure phase boron nitride, 8,8'...metal.

Claims (1)

[Claims] 1. A method for manufacturing a throw-away chip, comprising: a molded article having a convex portion in the center, a high melting point substance interposed inside the convex portion, and the other portion made of cemented carbide; and a hole corresponding to the convex part in the center part, the thickness is 0.3 mm to 2 mm, and the width from the outer edge to the hole is 1 mm to 9 mm. After stacking the molded body having the convex portion and the plate-like molded body having a hole in the center and fitting the convex portion and the hole, the molded body is heated in an ultra-high pressure device. A method for producing a throw-away chip characterized by sintering at high temperature and high pressure.