JPS60104602A - Machining tool - Google Patents

Abstract

PURPOSE:To enable a ferrous material to be machined into a mirror-like surface by forming an edge on the monocrystalline piece of arsenic nitride which is fitted on the tip of the machining tool. CONSTITUTION:A conical hole 12 is formed on one end of a shank 11. A monocrystalline piece of arsenic nitride is placed at the bottom of the conical hole 12 with a supply of wax material 13. The shank 11 is heated so that a part of the monocrystalline piece 14 is pressed and buried into the shank 11. Then, after the wax material 13 is solidified by cooling of the shank 11, the monocrystalline piece 14 is machined and polished with the shank 11 to form a relief surface 5 and a rake 9. Thus a machining tool is obtained. Using this machining tool, a ferrous material can be machined into a mirror-like surface having a machined surface roughness of 0.05mumRmax.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a cutting tool for cutting, and particularly to a cutting tool that is capable of mirror-cutting a high-hardness iron-based material.

[Background of the invention]

2. Description of the Related Art Cutting tools using single crystal diamond in the cutting edge are known as cutting tools for precision cutting, mirror cutting, etc. of non-ferrous metal materials such as aluminum and copper.

When cutting ferrous materials such as hardened carbon steel or stainless steel with a diamond-based cutting tool, the cutting heat causes the diamond to react with the iron and form carbide, which causes the diamond to deteriorate. If the wear is severe υ, normal cutting will not be possible.

For this reason, cutting of iron-based materials uses a cutting tool in which a cutting edge is formed in a polycrystalline sintered body obtained by sintering boron nitride crystals. This cutting tool has a configuration as shown in FIG. 1, for example.

That is, a tip 3 formed of a polycrystalline sintered body is attached to a shank 1 via a base 6. A chamfer 1 and a flank 5 are formed on the cutting edge of the chip 3. With such a cutting tool, even if the flank surface 5, which affects the roughness of the cut surface, is polished to 0.05 μm Rmax or less, the cut surface will have a mirror finish of 0.1 μm Rmax. That was the limit.

The reason for this is that, as shown in FIG. 2, in the chip 5 made of a polycrystalline sintered body, the cutting edge 7 formed by the flank 5 and rake face 6 that constitute the cutting edge binds the crystal grains 8. This is because sharpness cannot be ensured due to the microchipping 10 of the binder 9.

[Purpose of the invention]

An object of the present invention is to provide a cutting tool that eliminates the drawbacks of the above-mentioned prior art and enables more advanced mirror cutting of iron-based materials.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized in that a single crystal of boron nitride is attached to the tip of a cutting tool, and a cutting edge is formed on this single crystal.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 shows the boron nitride single crystal used in the present invention.
The typical crystal habit of cubic boron nitride, which has the highest hardness, is shown. In these single crystals, all triangular and hexagonal faces are (November faces).

FIG. 4 to FIG. 6 show an example of the manufacturing process of a cutting tool according to the present invention. At one end of the shank 11,
A forest-like hole 12 is formed, and a brazing filler metal 13 is supplied to the bottom of the hole 12.

A boron nitride single crystal 14 is placed on the brazing filler metal 13. Then, while heating the shank 11 and melting the brazing filler metal 13, pressure is applied to the single crystal 14 in the axial direction of the shank 11, and a part of the single crystal 14 is press-fitted into the shank 11 (Fig. 4). and Figure 5). Next, after cooling the shank 11 and solidifying the brazing filler metal 15, the single crystal body 14 together with the shank 11 is cut and polished to form a flank face 5 and a rake face 6 as shown in FIG. Use as a cutting tool.

In the above embodiment, a brazing material 13 such as silver solder is used to join the boron nitride single crystal 14 and the shank 11, but since the single crystal 14 has poor wettability with metal, It is preferable to form a titanium coating on the single crystal body 14 by means such as plating. The shank 11 may also be made of a titanium-based material. FIG. 7 shows a cutting tool that is formed in the same process as in the above implementation and differs from the cutting tool shown in FIG. 6 only in the shape of the cutting edge. .

That is, the flank face 5 of the single crystal body 14 attached to the shank 11 is a cylindrical face, and the rake face 9 is a flat face, forming a sharp cutting edge 7.

Using this cutting tool, the quenched hardness is HRC5.
As a result of cutting the chromium alloy stainless steel tool steel No. 2, the cut surface was mirror-finished to a surface roughness of 1M or more with a surface roughness of 0.05 fine RmaxO.

This is because the cutting edge of the cutting tool is formed of the single crystal 14, eliminating microchipping in conventional cutting tools, thereby improving the machined surface roughness.

Note that the cubic boron nitride single crystal has a nine-opening property similar to the diamond single crystal. In particular, crystal planes that are prone to spacing are
It is a (11o) plane. For this reason, if the crystal orientation of the flank face of a cutting tool is not selected appropriately, the wear of the flank face will progress due to the crystal formation, causing chipping on the cutting edge, which will reduce the surface roughness of the cutting surface. let

That is, if the (1oo) crystal plane is used as a flank, chipping is likely to occur from any direction and it cannot be used as a flank.

Also, the <100> direction of the (11o) crystal plane and the (11
1) The <112> direction of the surface has less wear and less chipping.

Therefore, as a cutting tool, the rake face is the (
100) So, let's make the escape surface the (110) crystal surface,
Alternatively, by setting the rake face to be the (2〒) plane of the crystal plane and the flank face to be the (111) plane, it is possible to obtain a cutting tool that does not cause pitting and has less wear.

Incidentally, a plurality of cutting tools shown in the above embodiments may be attached to a tool holder and several places may be processed simultaneously.

However, it can also be used for milling by planting it in a tool holder like a face milling cutter with a planted blade.

〔Effect of the invention〕

As described above, according to the present invention, a ferrous material can be cut to a good mirror surface with a cut surface roughness of 0.5 μm Rmax.

[Brief explanation of the drawing]

Figure 1 is a side view of a conventional polycrystalline tool, Figure 2 is an enlarged view of the tip of a conventional polycrystalline tool, and Figure 6 is an enlarged view showing the crystals and texture of a single crystal of cubic boron nitride. , FIG. 4 to FIG. 6 show the manufacturing process of the cutting tool according to the present invention.
The figure is a perspective view showing a state in which a single crystal of boron nitride is embedded in the shank, Figure 5 is an enlarged sectional view showing the main part of Figure 4, and Figure 6 is a diagram of the cutting blade as a cutting tool. FIG. 7 is an enlarged view showing another example of the shape of the cutting edge of the cutting tool. 11...Shank, 14...Boron nitride single crystal. Representative Patent Attorney Akio Takahashi ＼ Figure 3 (α) (b) (C) Figure 4 l Figure s 2 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. A cutting tool comprising a tip on which a cutting edge for cutting is formed and a shank for holding the tip, wherein the cutting edge of the tip is made of a single crystal of boron nitride. A cutting tool characterized in that: 2. The cutting tool according to claim 1, wherein the single crystal of boron nitride is cubic boron nitride. 3. On the flank of the cutting edge, a single crystal of boron nitride (11
The cutting tool according to claim 1 or 2, characterized in that a 0) plane or a (111) plane is located.