JP3226632B2 - Manufacturing method of axial grinding tool blank with superabrasive layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a blank for an axial rotary grinding tool, such as a drill, an end mill, a router or the like, having a cutting edge at the tip of a cemented carbide substrate, or other similar tools, especially for increasing the joining force between the two parts. Tool blank.

[0002] As a shaft-shaped grinding / polishing tool, a tool formed entirely of a cemented carbide, including a cutting edge portion, and a sintered body of diamond or cubic boron nitride (c-BN) disposed at the cutting edge portion. Such a configuration is known and used in a wide range of industrial fields. In the electronic component industry, a tool having a carbide cutting edge having a diameter of about 3 mm or less, particularly 1.6 mmφ or less, is widely used for drilling holes in a printed circuit board. This tool has a very short life and is liable to cause troubles due to frictional heat. Therefore, diamond or c-BN has been used for the cutting edge portion.

[0003] However, such a tool configuration has conventionally been
For example, after each of the cutting blade portion and the base portion are created in advance,
A step of joining by brazing is employed. However, with this method, it is difficult to obtain a strong bonding force and high accuracy,
Also, it is difficult to apply to small-diameter tools.

On the other hand, Japanese Patent Application Laid-Open No. Sho 58-79879 discloses a method in which both the steps of producing these superabrasive sintered bodies and joining them to a superhard substrate portion are performed by a single high-temperature and high-pressure treatment. Is described. It is also known to cut out a composite block having a super-hard substrate and a flat diamond tip layer as a cylinder by wire cutting or the like (for example, Japanese Patent Publication No. 4-9754). In these cases, however, since the smallest cross section perpendicular to the axis is used as the joint surface between the diamond and the carbide portion, the diamond layer is also used in this configuration, especially for small-diameter tools. The bonding strength with the base was not always sufficient.
In particular, when a brazing operation is involved, heat is accumulated on the boundary surface and peeling often occurs. Further, since the thickness of the diamond layer is uniform over the entire surface, there is a defect that an arbitrary cutting edge thickness cannot be obtained.

Accordingly, an object of the present invention is to solve such a problem of the prior art by improving a bonding portion between a superabrasive layer and a substrate. A grinding tool blank having a cemented carbide base body and a tip adjacent to the base and containing sintered superabrasive grains, and having a generally axial shape, a boundary between the base and the tip. An axial grinding tool blank characterized in that the plane is inclined with respect to a plane perpendicular to the axis of the axial body. Here, the term “axial” refers to a column or frustum having a cross section of a circle, an ellipse, a triangle, a polygon, or the like, or a three-dimensional shape in which these are combined, and has an axial length of at least three times the major diameter of the end face or the longest diagonal line. Say things.

In the present invention, the boundary surface between the superabrasive layer and the superhard substrate is inclined at 5 to 45 °, particularly preferably 15 to 30 °, with respect to the vertical plane. If the angle of inclination is less than 5 °, an increase in bonding strength cannot be expected, and if it exceeds 45 °, the use of diamond is increased more than necessary, which is wasteful.

[0007] The tool blank of the present invention is preferably produced as follows. That is, the second gist of the present invention is to form a cemented carbide mass having a generally cylindrical shape and having an end surface essentially perpendicular to the cylinder axis, and forming the mass with diamond or cubic at the end surface. Contact with an aggregate containing superabrasives selected from polycrystalline boron nitride, mounted on a high-pressure device, and set the thermodynamically stable temperature and temperature of the corresponding superabrasives
Manufacturing a shaft-shaped grinding tool blank characterized by sintering the whole by applying it to a pressure area, collecting it from a high-pressure device, and then cutting it out by a physical means as a shaft inclined with respect to the axial direction of the mass. In the law. Next, the present invention will be described with reference to the drawings.

FIG. 1 shows a grinding tool blank made in accordance with the present invention, FIG. 2 shows a cemented carbide / diamond composite block as an intermediate product produced halfway in the practice of the present invention, and FIG. 3 shows this composite block. It is a sectional view and a partial enlarged view (in an upper circle) of a main part of a high-pressure and high-temperature device which can be used for making.

As illustrated in FIG. 1, the axial grinding tool blank 1 of the present invention is a rotary type (a), (b) used by rotating around an axis, and a non-rotary type (c) tool not used. It can also be created for use. In the case of the rotary type, the cross section perpendicular to the axis is circular (columnar), and in the case of the non-rotary type, other polygons or triangles, as well as circles, ellipses, etc. are formed in addition to the illustrated squares. The boundary surface between the diamond layer 2 and the super-hard base portion 3 at the end face is inclined at an angle of 45 ° or less with respect to the axis. These are finished to the final shape of the blank by conventional precision polishing. Such a grinding tool blank of the present invention is preferably prepared by the following operation.

At the bottom of a can 4 made of a high melting point metal (Ta, Mo, Zr, etc.), an abrasive powder 5 composed of diamond alone or a mixture with a solvent metal (iron-based) is spread to a uniform thickness. Then, a sintered or sintered cemented carbide (W)
(C-Co type) block 6 is packed, and covered with a metal plate 7 of the same quality. As described in Japanese Patent Application Laid-Open No. Sho 62-15081, the whole is surrounded by a NaCl molded body 8 as a pressure transmitting material, a tubular heating body 9, refractory discs 10 and 11, and a limestone sleeve 12. Metal plate 13 for energizing both ends,
14 and metal rings 15 and 16, and refractory insulating plates 17 and 18 are arranged in the rings, and the whole is a pair of anvils 19 and 20, and gaskets 21 and
22 is mounted in a reaction chamber of a high-temperature and high-pressure apparatus constituted by an annular die 24 in which a high-rigidity sintered alumina tubular body 23 is inscribed. In the apparatus shown here, protectors 25 and 26 made of metal plates are sandwiched between each anvil and the gasket. The inside of the can 4 is subjected to pressure and temperature conditions within the thermodynamically stable region of diamond to complete the sintering of the diamond layer and the joining with the cemented carbide block. The composite material recovered from the high-temperature and high-pressure apparatus is polished and removed from the refractory adhering to the surroundings to form a cylindrical body 27, which is subjected to wire cutting. Using a jig, tilt and fix to the table,
For example, cutting is performed along a line as shown. The resulting columnar body such as a cylindrical body is processed into a final blank shape by polishing the side surface and the inclined end surface.

[0011]

Example 1 Diamond powder 15 having a particle size of 3 to 8 μm
g was distributed almost uniformly over the entire bottom surface of a Ta can having a diameter of 80 mm, and a sintered carbide block (WC-13% Co) having a diameter of 80 mm and a thickness of 15 mm was placed thereon. This was assembled as shown in FIG. 2 and loaded into an anvil cylinder type high temperature and high pressure apparatus as shown in FIG. The sintering was completed by treating at 6GPa and 1550 ° C. for 5 minutes, and the carbide block taken out of the device was mounted on a wire cutting device (DIAX DWC90B type manufactured by Mitsubishi Electric Corporation) with an inclination of 30 °.
Fifty cylinders having a diameter of 1.60 mm and a total length of 17 mm were cut out. This polished the sides and the top of the sloping diamond layer, respectively, to form end faces perpendicular to the axis, and finally obtained a 1.5 mm diameter microdrill blank as shown in FIG.

[0012]

Example 2 The above example was repeated to produce a composite block having a diameter of 80 mm and a thickness of 12 mm including a diamond layer having a particle size of 10 μm. It was attached to a wire cutting device at an inclination of 15 °, and a prismatic body was cut out from this, and a non-rotating tool blank of 7 mm × 7 mm was prepared by finish polishing.

As described above, in the blank according to the present invention, the boundary surface between the superabrasive layer and the substrate is inclined with respect to the plane perpendicular to the axis of the shaft-like body (such as the cylinder axis or the prism axis). . With this configuration, the heat-peeling resistance is improved, and the effect of improving the bonding force by increasing the bonding area is obtained. In addition, since the thickness of the layer of superabrasive grains can be partially increased significantly, a tool that has a long cutting surface in the axial direction and achieves a smooth polished surface,
Obtained easily.

Although the above description has been made exclusively with respect to diamond, even when cubic boron nitride is used as the superabrasive,
Obviously, a similar tool blank is obtained.

[Brief description of the drawings]

FIG. 1 shows a grinding tool blank according to the invention.

[Fig. 2] Carbide / diamond composite material block of intermediate product

FIG. 3 is a cross-sectional view of a main part of an ultra-high pressure device that can be used for producing an intermediate product.

[Description of Signs] 1 Grinding tool blank 2 Diamond layer 3 Super hard base 4 High melting point metal can 5 Abrasive powder 6 Cemented carbide block 7 Metal plate 8 NaCl molded body 9 Tubular heating body 10 Refractory disk 11 Fire resistant Object disk 12 Rockstone sleeve 13 Metal plate 14 Metal plate 15 Metal ring 16 Metal ring 17 Refractory insulating plate 18 Refractory insulating plate 19 Anvil 20 Anvil 21 Gasket 22 Gasket 23 Sintered alumina cylindrical body 24 Ring die 25 Protector 26 Protector 27 Cylindrical body

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B24D 7/18 B23P 15/28 B24D 3/00 310 B24D 3/00 320 B24D 3/00 340 B24D 18/00

Claims (1)

(57) [Claims] (1) an overall cylindrical shape, and with respect to a cylindrical axis;
To produce cemented carbide mass with essentially vertical end faces
And the mass is diamond or cubic
Contact with aggregates containing superabrasives selected from boron nitride
High-pressure equipment, and thermodynamically
Sinter the whole by subjecting it to a stable temperature and pressure range.
After collecting from the high pressure device,
Cut out as an axial body inclined to the axial direction of the mass
Production of axial grinding tool blank with super abrasive layer
Construction method.