JPH0825141A - Drilling tool - Google Patents

Abstract

PURPOSE:To a improve cutting performance by forming a cutting edge forming part of high hardness hard quality sintered compact and forming a base material of cemented carbide or tool steel, and integrally sinter connecting these forming part and base material to each other by a plasma discharge sintering method, so as to perform manufacture at a low cost and further easily. CONSTITUTION:A columnar unit 1, forming one end part into a cone by cermet, is formed also to form a cylindrical drill base material 2 of cemented carbide. Next by a plasma discharge sintering method, the columnar unit 1 and the drill base material 2 are integrally sinter secured (sinter connection secured part is shown by code Y). Further in the case of sinter securing, by considering securing sureness, powder of Ni, Co, Ni-Co is preferable left as interposed between the columnar unit 1 and the drill base material 2. Successively, a shank S is brazed to the drill base material 2. At last, when formed point end edges 10 and a twist groove M in the columnar unit 1 and the drill base material 2 by polishing work and electric discharge machining, a drill D is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool such as a drill and a reamer used in a machine tool (this cutting tool is referred to as a drilling tool in this specification).

[0002]

BACKGROUND OF THE INVENTION Structural carbon steel forgings used for automobile parts have a high hardness (HB 130 or more) and hard metal carbide particles are mixed in the structure. One of them is. When this forged product is bored with various tools, the following problems occur. . When the tool is composed of high-speed rope When the tool is fed at high speed and high speed, the impact of the collision between the metal carbide and the cutting edge causes fatigue of the cutting edge, which easily causes wear and chipping (small chip). , The tool life will be very short. In other words, considering the tool life, low-speed low-feeding is required, resulting in poor productivity. . When the tool is made of cemented carbide, when the tool is fed at high speed and high speed, the wear is relatively small,
The impact force generated by the collision between the metal carbide and the cutting edge causes chipping or chipping of the cutting edge, resulting in poor surface roughness of the formed hole. Therefore, there is a problem that productivity is low as in the case of.

As a means for solving the above problems when the tool is fed at high speed and high speed, it is conceivable that the cutting edge of the tool is made of cermet or ceramic.
It has not been put to practical use for the following reasons. . Cutting edge part made of cermet When brazing a cutting edge made of cermet to a tool body made of tool steel or cemented carbide, the coefficient of thermal expansion between cermet and tool steel and cemented carbide Due to the difference between the two, thermal cracks and strains occur, and therefore they have not been put to practical use. . The cutting edge is made of ceramic. Since an ultrahigh pressure and high temperature generator is required for joining the ceramic and the metal, the tool itself becomes very expensive and therefore has not been put into practical use.

[0004]

Therefore, according to the present invention, the manufacturing cost is low and the manufacturing is easy, and the cutting performance is excellent.
An object is to provide a drilling tool having a long tool life.

[0005]

The drilling tool of the present invention comprises:
The part where the cutting edge is formed is a high hardness hard sintered body, the base material is made of cemented carbide or tool steel, respectively,
These are integrally sintered and joined together by the plasma discharge sintering method.

The high hardness and hard sintered body is preferably made of cermet.

Further, it is preferable that the high hardness hard sintered body is made of a ceramic containing an oxide, a carbide, and a nitrogen substance with a metal.

[0008]

The present invention operates as follows.

Since a high hardness hard sintered body serving as a cutting edge and a cemented carbide or tool steel as a base material are sintered and bonded by a plasma discharge sintering method, it can be manufactured at a low cost.

Since the cutting edge is formed of a high hardness hard sintered body made of cermet or ceramic, the cutting edge is hardly fatigued, worn or chipped by the impact force caused by the collision between the metal carbide and the cutting edge. That is, the tool life is long and the cutting performance is excellent.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described with reference to the drawings shown as embodiments. [Embodiment 1] FIG. 1 shows an embodiment in which the present invention is applied to a drill D. In this drill D, the tip portion of the drill including the tip blade 10 is made of cermet.
The symbol M shown in FIG. 1 is a twist groove, and the symbol L is a land portion.

This drill D can be manufactured in the following order. First, a cylindrical body 1 whose one end is conical with a cermet
And the cylindrical drill base material 2 is formed of cemented carbide (see FIG. 2). Next, by the plasma discharge sintering method shown in FIG. 3, the cylindrical body 1 and the drill base material 2 are integrally sintered and fixed in the mode shown in FIG. 2 (in FIGS. Indicated by Y). In addition, at the time of the above-mentioned sinter fixation, Ni, Co, Ni between the cylindrical body 1 and the drill base material 2 is taken into consideration in consideration of the certainty of fixation.
It is preferable to interpose powder of —Co. Then, the shank S is brazed to the drill base material 2 in the manner shown by the chain double-dashed line in FIG. Finally, when the tip blade 10 and the spiral groove M are formed in the cylindrical body 1 and the drill base material 2 by polishing or electric discharge machining,
The drill D shown in is completed. [Embodiment 2] FIGS. 4 and 5 show another embodiment in which the present invention is applied to a drill D. A plate-like tip 3 (commercially available) composed of a cermet as shown in FIG. ) Is used to form the tip blade 30 of the drill as shown in FIGS. 5 and 6.

The drill D can be manufactured in the following order. First, a drill base material 4 made of cemented carbide having a split groove at its tip is manufactured (see FIG. 7). Next, as shown in FIG. 7, the plate-shaped chip 3 is housed in the split groove of the drill base material 3, and the side surface of the split groove and the side surface of the plate-shaped chip 3 are plasma-discharge-sintered as shown in FIG. The sinter-bonding-fixed portion is indicated by reference numeral Y in FIG. 7 by the method. In addition, at the time of the sinter fixation, Ni, N
It is preferable to interpose powders of Co and Ni—Co. Subsequently, the shank S is brazed to the drill base material 4 in the manner shown by the chain double-dashed line in FIG. 7 (in FIG. 4, this brazed portion is indicated by reference symbol Z). Finally, the plate-shaped chip 3 and the drill base material 4 are polished.
When the tip blade 30 and the twist groove M are formed in
The drill D shown in is completed.

Although the present invention is applied to the drill in the above embodiment, the present invention is not limited to this and can be applied to a reamer.

In the above embodiment, the cylindrical body 1 and the plate-shaped tip 3 are made of cermet. However, the present invention is not limited to this, and is made of ceramic containing oxides, carbides, and nitrogens with metals. You may allow it.

[0016]

From the contents described in the section of operation, it is possible to provide a drilling tool which can be manufactured inexpensively and easily, has excellent cutting performance, and has a long tool life.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of a drill according to an embodiment of the present invention.

FIG. 2 is a side view of the intermediate body of the drill before polishing.
The figure which shows a cylinder, a drill base material, and a shank material.

FIG. 3 is a schematic explanatory view of a plasma discharge sintering method used when manufacturing the drill of the present invention.

FIG. 4 is a side view showing a main part of a drill according to another embodiment of the present invention.

FIG. 5 is a view of the drill shown in FIG. 4 when viewed from one end side.

6 is a perspective view of a plate-shaped tip used in the drill shown in FIG.

7 is a side view of the intermediate body before the polishing process of the drill shown in FIG. 4, showing a plate-shaped tip, a drill base material, and a shank material.

[Explanation of symbols]

 D drill S shank material 1 cylindrical body 2 drill base material 3 plate-shaped tip 4 drill base material 10 tip blade 30 tip blade

Claims (3)

[Claims] 1. A portion where a cutting edge is formed is made of a high hardness hard sintered body and a base material is made of cemented carbide or tool steel, and these are integrally sintered by a plasma discharge sintering method. A drilling tool characterized by being joined. 2. The drilling tool according to claim 1, wherein the high hardness hard sintered body is composed of cermet. 3. The high hardness hard sintered body is an oxide with a metal,
The drilling tool according to claim 1, which is made of a ceramic containing a carbide and a nitrogen.