JPS60238214A - Rotary cutting tool - Google Patents

Abstract

PURPOSE:To improve the cutting performance and spread the use of a cut material by coating the surface of a share-point part with a hard coated layer with high adhesion strength through physical evaporation method. CONSTITUTION:The share-point part 3 of a rotary cutting tool 1 is made of the superhard alloy such as WC, TiC, TiN, etc., and the surface part of a basic material having WC particles is coated by a hard coated layer 4 prepared through PVD method, and said coated layer 4 is made of TiC, TiN, Al2O3, etc., and formed as a single layer or the double layer consisting of two layers or more. The reason of adopting the PVD method is that since the share-point part 3 is brazed onto a shank part, the low-temperature coating treatment below a brazing temperature is suitable, and a kind of diffusion layer 5 having a thickness of 0.05-1mum is formed onto the surface side on the interface between the hard coated layer 4 and the surface part of the share-point part 3 corresponding to the underground. Therefore, the adhesion strength between the share-point part and the hard coated layer 4 is increased, and exfoliation of the hard coated layer 4 is eliminated, and high-speed cutting is enabled, and the cutting life can be prolonged, and the tool can be adopted for the cutting of hardened steel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary cutting tool used for chamfering work, welding bead cutting, die engraving work, etc.

[Conventional technology]

Conventionally, this type of rotary cutting tool was manufactured by, for example, the Japanese Patent Publication No. 48-3
As disclosed in Publication No. 7552, a hole is drilled at the rear end of the cutting edge made of cemented carbide, the tip of the shank is inserted into the hole, and both are brazed together. That's what I do. The structure disclosed in this publication improves the structure of the attachment between the cutting edge and the shank by forming a slit at the tip of the shank, and the attachment is intended to improve strength. It is.

[Problem that the invention seeks to solve]

However, in this type of rotary cutting tool, the objectives are to improve cutting performance and expand the range of applications for workpiece materials, and there is a demand for the development of a tool that has both of these objectives.

[Means for solving problems]

3 The present invention was made in view of the above points, and the steel shank portion has a cutting edge portion made of a cemented carbide base material.
In rotary cutting tools that are brazed, the surface of the cutting edge is coated with a hard coating layer created by physical vapor deposition (PVD) to increase adhesion strength, thereby improving cutting performance and stiffening the material. The present invention provides a rotary cutting tool that can be used for a wide range of applications.

〔Example〕

Hereinafter, one embodiment of the rotary cutting tool of the present invention will be described.
This will be explained with reference to the figures.

In Figures 1 to 3, (1) is a rotary cutting tool used for chamfering work, mold cutting work, etc. This rotary cutting tool (1) has a steel shank part (2) and a carbide shank part (2). It has a cutting edge part (3) made of an alloy, and these reconsiderations are
Integrated by brazing.

As mentioned above, the cutting edge portion (3) is made of cemented carbide, and its composition is determined depending on the type of material to be stiffened, cutting conditions, cutting speed, etc., mainly taking into consideration toughness and wear resistance. things are selected. For example, WC type, TiC type, TiN type, etc.

In addition, as can be seen from the explanatory diagram in FIG. 3 and the microscopic photograph in FIG. (4) is coated. (In Figure 4, the hard coating layer (
4) has a band-like shape in the above portion. ) The composition of this hard coating layer (4) is, for example, T.
iC, TiN, T1CN, TiC: No.

It is made of Al2O5 or the like and is formed as a single layer or a multilayer of two or more. (A single layer is formed in Fig. 3 and Fig. 4.) In this case, the PVD method was adopted because the cutting edge portion (3) is brazed to the shank portion (2). This is because low-temperature coating treatment below the temperature is suitable for brazing.

Furthermore, at the interface between the hard coating layer (4) and the surface portion of the blade edge portion (3) corresponding to the base, 0.0
A kind of diffusion layer (5) of the order of 5-1 μm is produced.

This is the surface part of the cutting edge part (3) and the hard coating layer (4).
This is designed to increase the adhesion strength between the hard coating layer (4) and prevent peeling of the hard coating layer (4). In other words, as clearly shown in FIG. 4, this diffusion layer (5) extends over a certain depth on the surface of the cutting edge portion (3) by WC, T i C+ T a C+ T , which forms part of the base material. A layer of a compound with reduced nonmetallic components (e.g. C, N) such as iN or a layer of a non-stoichiometric compound forms a bonding layer between the cutting edge portion (3) corresponding to the base and the hard coating layer (4). It fulfills several functions. In other words, it means that the non-metallic components on the surface of the blade edge portion (3) diffuse toward the hard coating layer (4).

According to various experimental results, the thickness of this diffusion layer (5) is preferably 0.1 to 0.5 μm.

In order to obtain such a diffusion layer (5), it is necessary to apply the PVD method by thoroughly cleaning the surface of the cutting edge part (3) of the rotary cutting tool (1). It becomes possible. This cleaning is performed, for example, as follows.

The first step is the cutting edge portion (3) where the cutting edge (6) is formed by grinding.
) is thoroughly cleaned with a nonionic surfactant to completely remove dirt, oil, etc. from the surface.

At this time, it is effective to brush the surface of the cutting edge portion (3). Note that the surfactant used needs to be nonionic. This is because, in the case of a cationic or anionic surfactant, these ions may remain on the surface of the cutting edge portion (3).

The second step is a step of cleaning the surface of the cutting edge portion (3) in an acid solution. At this time, it is effective to use ultrasonic cleaning. The acid solution is preferably hydrochloric acid, dilute nitric acid, etc., and its pH is generally preferably 5 to 6 PH. If the binder phase component such as Go present on the surface of the cutting edge portion (3) is oxidized and contaminated by this second step, the oxide is dissolved and removed.

The third step is a step of ultrasonic cleaning in pure water to completely remove the activator, acid solution, etc. remaining in the first and second steps. At this time, the pure water used is treated with an ion exchange resin to completely remove trace amounts of metal components in the water.

The fourth step is to put the cutting edge part (3) into an organic solvent,
This is a process of ultrasonic cleaning and replacing water with an organic agent. At this time, a volatile organic agent is used. Specifically, methyl alcohol, ethyl alcohol, acetone, and ether are suitable. The co-rotating cutting tool (1) thus cleaned is finally dried.

Next, a rotary cutting tool (1) having a cleaned cutting edge portion (3) is installed.
), the surface of the cutting edge portion (3) is coated with a hard coating layer (4) using the PVD method. The PVD method to be applied is
For example, an appropriate method such as an ion blasting method, a sputtering method, or a coating method using a gas reaction in plasma can be employed. Although the temperature varies depending on the type of hard coating layer (4), 200 to 700°C is usually suitable.

[Example 1] The rotary cutting tool (1) has the following components as the cutting edge portion (3):
A composition of 94% WC-6% Co by weight was applied. The cutting edge shape of the cutting edge portion (3) is one that has a linear cutting edge ridge (6) on the outer circumferential side as shown in Fig. 1, and a nick (7) as shown in Fig. 5. Each has a straight cutting edge (6) with an outer diameter of 10
It was set as mg. Then, the hard coating layer (4) was coated with TiN to a thickness of about 2 μm using the PVD method after the above-mentioned cleaning process and drying process.

Note that the applied PVD method is specifically as follows. First, after evacuating the inside of the device to 10-' Torr, a high vacuum of 10-4 Torr or higher is maintained, and the cutting edge portion (3) is gradually heated to a final temperature of 500°C.
And so. Next, the surface of the blade edge portion (3) was bombarded with high-purity argon gas for 40 minutes, and then nitrogen gas was introduced to set the partial pressure of nitrogen gas in the device to 0.13 Pa to perform a coating treatment. The precipitation rate at this time is 1.3 x 10-3
It was μm/sec.

The rotary cutting tool (1) having the hard coating layer (4) thus constructed was attached to a hand grinder and applied to cutting cast iron and steel materials at 15D00r, P, and m, respectively. As a result, due to the differences in the shape of the cutting edge, chip discharge, sharpness, etc., the one shown in Fig. 1 was suitable for cutting cast iron, and the one having the nicks (7) shown in Fig. 5 was suitable for cutting steel materials. Further, in comparison with the conventional example without the hard coating layer (4), the cutting life was at least twice as long, and the wear state was normal wear, thus achieving the object of the present invention.

In addition, at the stage when the cutting life was reached, some pieces showed minute chipping, but due to the presence of the diffusion layer (5), hardly any peeling of the hard coating layer (4) was observed.

[Example 2] The rotary cutting tool (1) has the following components in the cutting edge portion (3):
80%WC-12%Tic-8%TaC-8% by weight
One with a composition of Co was selected. As shown in FIG. 6, the shape of the cutting edge is an intermittent cutting edge (6) exhibiting an uneven shape due to intersecting nicks (7), which is called a diamond pattern. In addition, the hard coating layer (4) is made of 1.
Each of these is coated with N by the PVD method.

Then, this rotary cutting tool (1) was attached to a milling machine to cut the side surface of the hardened steel. As a result, the hard coating layer (
4) The cutting life was approximately 4 times longer than that of the conventional example without the above. In this case, some peeling of the hard coating layer (4) was observed on the flank side, but this had almost no effect on cutting performance and surface roughness.

As explained above, the present invention provides a rotary cutting tool in which the cutting edge portion (3) is coated with the hard film layer (4), and therefore has the following specific effects.

First, cutting performance is improved. This is because, due to the presence of the hard coating layer (4), high-speed cutting is possible and the cutting life is at least twice as long compared to conventional products that do not have this layer. be.

Second, no peeling of the hard coating M(4) was observed. This is because a diffusion layer (5) exists at the interface between the hard coating layer (4) and the surface of the cutting edge (3).
) This is due to the fact that the adhesive strength is increased by cocooning.

Thirdly, cutting applications are expanded. This is because conventional rotary cutting tools are often unsuitable for cutting hardened steel, whereas the rotary cutting tool of the present invention is fully applicable.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the rotary cutting tool of the present invention, Fig. 2 is a side view thereof, Fig. 3 is an explanatory enlarged sectional view of the cutting edge portion (3), and Fig. 4 is , cutting edge part (3)
FIG. 5 is a micrograph showing the interface state between the hard coating layer (4) and the surface portion of the cutting edge portion (3), and FIG. 5 shows a modification of the rotary cutting tool of the present invention, in which the cutting edge portion (3) is FIG. 6 is a partially enlarged front view of the cutting edge portion (3) similarly showing a modification. (1)・・・Rotary cutting tool, (2)・・・・・・
Shank part (3)...Blade tip part (4)...
...Hard film layer (5) ...Diffusion layer (6)
・・・・・・Cutting Edge Patent Applicant Toshiba Tungaloy Co., Ltd. 5 Figure 5 Re) Procedural Amendment 1” (Method) % Formula % [1 Commissioner of the Patent Office Shige Gakudon 2 Name of the invention Rotary cutting Tool 3: Relationship with the case of the person making the amendment Patent applicant 3111-1 Tsukagoe, 1-7, Saiwai-ku, Yozaki-shi, Kanagawa Prefecture, July 1982 (1) "..." on page 10, line 20 of the specification Microscope photograph showing the interface state,] is corrected to 1...Microscope V-1 showing the crystal structure of the interface.

Claims (2)

[Claims] (1) In a rotary cutting tool in which a cutting edge portion made of cemented carbide is brazed to a steel shank portion, the cutting edge portion is coated with physical vapor deposition (PVD) on its surface portion.
A rotary cutting tool characterized in that it is coated with a hard coating layer formed by a method, and that a diffusion layer is formed on the surface side of the interface between the hard coating layer and the surface of the cutter portion corresponding to the base. (2) The rotary cutting tool according to claim 1, wherein the diffusion layer is made of a compound or a non-stoichiometric compound having a thickness of 0.1 to 0.5 μm.