JPS6076902A - Highly hard material cutting tool - Google Patents

Abstract

PURPOSE:To increase tool life by dividing a flank into a primary flank including a cutting edge and a secondary flank below the primary flank, and defining the scope of the clearance angle of the primary flank. CONSTITUTION:A tool A consists of a primary flank 3, in which a cutting edge is included, and a secondary flank 3' which follows immediately below it. The primary flank is formed in such a way that, when this tool is set on a machine tool rest, the clearance angle theta is in the scope of, -3 deg.<=theta<=0 deg.. Accordingly, an actual cutting is made in a condition that the primary flank is brought into contact with a workpiece B. When continuous cutting or the cutting of the thick wall section of a highly hard material is carried out using a tool of such a shape, the tool becomes hard to be broken, and its life is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a tool suitable for cutting and RIJ processing a high hardness material such as hardened steel using a hard sintered tool. Various ultra-high pressure hard sintered bodies Ae mainly made of diamond and high-pressure phase type boron nitride have been developed and put into practical use. Cutting of hardened steel mechanical parts, such as automobile transmission gears, is attracting attention and is being used on a considerable scale. Further, the practical application of cutting high hardness materials such as ceramics and rocks using diamond sintered tools is being considered.

Now, cutting of a hardened steel part using a CBN sintered body tool will be explained below as an example, but the content of the explanation generally applies to the case of cutting a high-hardness material using a hard sintered body.

Cutting of hardened steel parts using CBN sintered tools has attracted attention as a highly efficient processing method that replaces grinding, and is currently used for machining the inner and outer diameters and end faces of gears and shafts for various machines and vehicles, including automobiles. It is widely used, etc. When machining such parts, there are many cases where completely continuous cutting is performed without any notches on the work surface, but it is also possible to perform interrupted cutting such as oil immersion, key grooves, or the outer circumference of spline shafts, or fluctuations in the amount of cutting, that is, deviations in the finishing allowance. There are more parts that cut meat. In grinding, you don't have to worry as much about chipping or cracking of the grinding wheel even with such interrupted machining or uneven thickness machining, but when cutting with a CBN sintered tool, the cutting edge often breaks, which is a problem. It is. In particular, the cutting resistance is high due to the high hardness of the rigid material, and the stiffness of OBN sintered tools is lower than that of cemented carbide, so continuous cutting b
In many cases, the tool life was much shorter than that of u.

Carbide tools and ceramic tools are treated with various shapes of cutting edge in order to improve the strength of the cutting edge for such interrupted cutting, and OBN sintered tools are also treated with various shapes as shown in Figure 1. It is used with a special cutting edge treatment,
Although it was effective to some extent in preventing chipping of the cutting edge, it was still insufficient.

Also, in Japanese Patent Publication No. 57-42442, as a "finishing tool blade", the width from the cutting edge is within the range of 0.02 to 0.1 wg between the F flank and the cutting edge, and An invention entitled "A finishing tool blade having a flank-equivalent surface with an equivalent clearance angle of around 0°" is disclosed. This known invention is similar to the present invention at first glance, but its intended use and use are completely different from the present invention, making it a different invention. That is, the known invention relates to a cutting tool used for cutting and finishing steel thread materials, and the finishing tool blade is capable of suppressing the formation of built-up edges and obtaining a good finished surface in cutting at low speeds. We aim to provide the following.

On the other hand, the object of the present invention is to dramatically extend the tool life when cutting a hard rigid material using a hard sintered tool, especially when performing interrupted cutting.

Further, in the known invention, it is said that a width dimension of the flank face equivalent surface where the clearance angle equivalent angle is around 0° is preferably in the range of 0.02 to 0.1 m, but in the present invention, as will be explained later, There is almost no effect when the width of one flank is in the range of 0.02 to 0.1 fin, and it is more effective when it is greater than 0.1 square and less than 0.5 inch.

The present invention provides a tool that has a long life equivalent to continuous cutting even in interrupted cutting and uneven thickness cutting of hard materials.

The present invention provides a cutting tool that has a hard sintered body in its cutting edge and is used for cutting hardened steel and other high-hardness materials. The area and the area are the 1st
When the clearance angle of the flank surface is actually cut, the clearance angle e is 13°≦O≦
This is a tool for cutting high hardness materials, characterized in that it is formed to fall within the range of 0.09.

The contents of the present invention will be explained below based on the drawings.

FIG. 2 shows a cross section of the cutting edge of the machined AA according to the present invention, and the flank is formed of a first flank 3 including the cutting edge etching and a second flank 3' below the first flank 3. The first flank is formed such that the clearance angle θ is within the range of 13°≦θ≦0° when the tool is set on the machine tool post.

Therefore, during actual cutting, the first flank comes into contact with the rigid material as shown in FIG. It was discovered that when a tool with this shape is used for interrupted cutting or uneven thickness cutting of high-hardness materials, the tool becomes less likely to break, and the tool life is significantly longer than that of conventional tools. This invention is based on this discovery.

The reasons for this can be considered as follows.

Tool breakage in interrupted cutting is thought to be primarily due to the impact force applied to the tool when the tool breaks away after biting during interrupted cutting, but in interrupted cutting of hardened steel using a CBIJ sintered tool, chipping does not occur at the initial stage of cutting. Very few, and often chipped after cutting a certain amount.

Considering this, tool breakage in interrupted cutting is not only due to the impact force during biting and KW release (the vibration between the tool and the rigid material caused by this impact causes fatigue fracture of the tool material). Therefore, it is thought that the tool life can be extended by suppressing the vibration caused by this impact in some way.

By the way, as shown in FIG. 3, the tool of the present invention cuts with the first flank surface 3 of the tool A in contact with the workpiece B, so the workpiece and the tool are restrained from each other by this surface. Therefore, the degree of freedom of vibration is reduced accordingly. In order to investigate this point, we conducted an interrupted cutting test on the outer periphery of longitudinally adjacent round bars and measured the principal component forces, and the results shown in Figure 4 were obtained. That is, in the conventional tool, vibration continues for one cycle (C in the figure) after the impact during intermittent biting, whereas in the tool of the present invention, the vibration is almost zero in almost every cycle. For this reason, it is considered that the tool life of the tool of the present invention is significantly extended by intermittent cutting. Furthermore, the tool of the present invention is thought to have another effect.

That is, in the tool of the present invention, as shown in Fig. 3, the first flank is intentionally brought into contact with the P4u material, so a large back force N acts through the first flank. However, as shown in FIG.
becomes. Diamond and OBN sintered tools are generally brittle materials, which are weak against tensile stress but very strong against compressive stress. Therefore, it is very advantageous for these hard sintered tools to have such a compressive stress field at the cutting edge.

Now, for this reason, the tool of the present invention has a long life in interrupted cutting, and it is preferable that the angle and width of the first flank face are in the following ranges. From the viewpoint of the effect of the tool of the present invention as described above, it is preferable that the angle is such that the first flank abuts the rigid material as accurately as possible. This range is -5°≦0≦09. -3°
If it is less than that, the cutting edge of the tool will not bite into the rigid material, which is inappropriate.

If it is 06 or more, the width at which the first flank comes into contact with the rigid material becomes small, which is still inappropriate.

The width of the first flank is preferably greater than 0.1 and preferably 0.5 mm or less. If it is less than 0.1■, the effects of vibration suppression and compressive stress field described above are insufficient. Also 0.51+ll11
If it exceeds c, the thrust force becomes too large, which is not good, as it becomes difficult for the tool to bite into the rigid material, resulting in adverse effects such as deterioration of the machining dimensional accuracy of the rigid material.

The cutting tool of the present invention having the above configuration is particularly suitable for interrupted cutting of hardened materials such as hardened steel having a Rockwell C scale hardness of 45 or more, high hardness cast iron having a Shore hardness of 60 or more, and ceramics.

The present invention will be explained in more detail with reference to Examples below.

〔Example〕

A 5NG452 type indexable tip was prepared by brazing one corner of the OBN tool SUMIBORON 13N200, and the shape of the cutting edge was set as shown in Table 1.

Table 1 Using each tip in Table 1, diameter 30 + o +, length 200
rxm spline shaft (Material 50M420. Hardness HRO
65) was subjected to interrupted circumferential turning. Cutting conditions are cutting speed 1
00m/min, depth of cut 0.2mm, feed rate 0.1wa
/rev, dry type. The test results are shown in Table 2.

Table 2 Test results As shown in Table 2, with the standard cliff 1 chip, chipping occurred after 40 chips were cut, and then large chips occurred after 50 chips were cut in total of 10 chips, making regrinding impossible. On the other hand, although there are some differences between Chip Shops 5 and 5, all of them can cut up to around 500 chips, and the chips do not chip significantly, so they can be used for re-grinding, and a remarkable effect is recognized. Also, a chip flat 2 in which the first flank surface is smaller than the preferred range.
Although the chip has a slightly longer lifespan than a normal chip, its effectiveness is insufficient.

Similarly, chip 7 in which the width of the first flank is larger than the preferred m radius
Although fL6 can be cut, the dimensional accuracy is unstable and it cannot be used. The chip plate 7 whose first clearance surface has a clearance angle of 15°50/ is not bitable and therefore cannot be used. The chip A8 with a clearance angle of +50', which is also outside the range, also has a slightly longer life than the standard chip A1, but only by a small amount.

As explained above, the present invention provides a tool for cutting high-hardness materials that exhibits a stable and long life equivalent to continuous cutting even in interrupted cutting or uneven thickness cutting of high-hardness materials.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a cutting tool whose cutting edge has been treated by a conventional method, the second cause is a cross-sectional view of a cutting tool according to the present invention, and Fig. 5 is a cross-sectional view of a cutting tool in which a cutting tool A of the present invention is used to cut a rigid material. Fig. 4 (aJ, (bJ) is a conceptual diagram showing the actual state of the main component force t- The fifth graph is a conceptual diagram showing the stress state in the cutting tool of the present invention. Agents 1) Akira Agent Ryo Hagiwara - Time - Kaiichi Mato

Claims (1)

[Claims] In a cutting tool that has a hard #, solid body on the cutting edge and cuts hardened steel and other high-hardness materials, the flank surface is the first flank surface that includes the cutting blade nip. It is divided into the second relief surface below, and the first
When cutting the clearance angle of the flank surface, the clearance angle θ is 15°≦θ≦
A tool for cutting high hardness materials, characterized in that the tool is formed to have a hardness in the range of 0.00. 2) The hard sintered body is diamond or high pressure phase nitrided 8
Claim No. (υ term H
A tool for cutting high-hardness materials. 3) Clause #E (1) or + of the patent claim where the high hardness material is hardened steel with a hardness of 45 or more on the Rockwell C scale.
23! High hardness material cutting tool 4) Claim J1 in which the high hardness material is cast iron with a Shore hardness of 60 or more. The tool for cutting 16 hardness material according to item 11) or item (2). 5) A tool for cutting a high hardness material according to claim 1 or 2, wherein the high hardness material is a ceramic material. 6) The width of the first flank from the cutting edge is thicker than 0.1 (0,
Claims Nos. (1) to M within the range of 5 m or less
(High-hardness material cutting tool according to any one of item 57.