JPH08155702A - Cutting tool with chip breaker and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To combine a cutting tool with a cutting edge made of ultra-high hardness sintered body with high cutting edge strength and excellent chip disposal performance in finish cutting. [Structure] A chamfered portion 8 having a height H is provided at an intersection of each upper surface and side surface of an ultra-high hardness sintered body 3 containing cubic boron nitride as a main component and a tool main body 1 joined with the ultra-high hardness sintered body 3. The hardness sintered body 3 is provided with a chip breaker 5 for moving the cutting edge downward by h. The relationship between H and h is H> h, and the chamfered portion 6 for strengthening that is formed by a part of the surface of the chamfered portion 8 is generated at the cutting edge portion. Also,
After the chip breaker of the optimum size for finish cutting is formed at the optimum position, the size of the chamfered portion 6 can be secured without any shortage by adjusting the value of H, and the above-mentioned purpose can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a cutting edge formed of an ultra-high hardness sintered body containing cubic boron nitride or the like as a main component, and the sintered body is provided with a chip breaker for chip disposal and a strengthened cutting edge. A chamfered cutting tool and a manufacturing method for forming the tool into an ideal shape.

[0002]

2. Description of the Related Art For example, a tool used for finish cutting of carburized and hardened steel having a hardness of about 40 to 60 HRc and induction hardened steel, of course, has a cutting edge of high hardness and high strength.
A chip breaker for chip disposal is also needed. In order to meet this requirement, an ultra-high coating tool and a ceramic tool can be easily attached by a technique such as embossing a chip breaker, but they lack hardness and strength.

Therefore, cubic boron nitride (CB) is used for the cutting edge.
The number of cases in which an ultra-high hardness sintered body containing N) as a main component is adopted is increasing.

As shown in FIG. 6, a tool adopting this ultra-high hardness sintered body is provided with a seat groove 2 at the tip corner portion of a tool body (the base metal of a throw-away tip) 1 in which a super groove is formed. The high hardness sintered body 3 is joined. Reference numeral 4 denotes a back plate which is integrated during the production of the ultra-high hardness sintered body, and the sintered body is fixed to the tool body 1 by brazing.

The chip breaker 5 provided on the ultra-high hardness sintered body 3 cannot be formed by embossing, and therefore is attached by electric discharge machining or polishing after joining the sintered bodies.

In a tool for processing a high hardness work material such as hardened steel, it is indispensable to strengthen the chamfer of the cutting edge. The chamfering can be easily applied by mechanical polishing without any shortage in size and stable in size and shape, but it is not possible to process the chamfer for strengthening the cutting edge only on the effective cutting edge after installing the chip breaker. Since the chip breaker can no longer be machined, the chamfered portion 6 in FIG. 6 is subjected to honing with a brush or manual work, and it is impossible to uniformly chamfer the cutting edge.

As shown in FIG. 7, it is also possible to incline the ultra-high hardness sintered body 3 in the direction in which its rear part falls and form a breaker wall of the chip breaker 5 with a part of the surface of the seat groove 2. . In this case, since the breaker wall is formed by a part of the seat groove 2 and the surface of the ultra-high hardness sintered body has no unevenness, chamfering for strengthening the cutting edge can be performed by machining.

[0008]

The chamfered part for brush honing or manual cutting for strengthening the cutting edge after the chip breaker processing cannot secure a sufficient size and its shape is difficult to be fixed. Therefore, the tool shown in FIG. 6 has insufficient edge strength when cutting a high hardness work material, and cannot exhibit a long life.

The tool shown in FIG. 7 can be provided with a relatively large chamfering portion 6 for strengthening before or after joining the ultra-high hardness sintered bodies, but the distance from the cutting edge to the breaker wall (breaker width) becomes large. Therefore, the setting range of cutting conditions is narrow, and effective chip disposal cannot be expected in finish cutting.

Therefore, it is an object of the present invention to provide a cutting tool with a chip breaker which achieves both a desirable cutting edge strengthening treatment and a good chip treatment in finish cutting, and a method for manufacturing the tool.

[0011]

A cutting tool with a chip breaker of the first invention provided as a solution to the above-mentioned problems has an ultra-high hardness that is joined to a tool body and a seat groove of a tip corner portion of the body. A chamfered portion is formed at the intersection of the upper surface and the side surface of each sintered body, and the height H of the chamfered portion is larger than the amount h of cutting edge of the cutting edge from the upper surface of the ultra-high hardness sintered body by chip breaker processing. The surface of the chamfered portion for strengthening the cutting edge is constituted by a part of the surface of the chamfered portion having the height H.

This tool uses an ultra-high hardness sintered body containing cubic boron nitride as a main component in the cutting of hardened steel, and in the finish cutting, it is used as the upper surface of the chamfered portion of height H. The angle θ formed by 15 ° <θ <45 °, the width W of the chip breaker
Is 0.3 mm to 2.0 mm and the chip breaker depth t is 0.
2mm-0.8mm, width w of chamfer for strengthening the cutting edge is 0.02mm
It is preferable that each is set in the range of 0.2 mm.

Next, there are two manufacturing methods of the second invention for manufacturing the cutting tool of the first invention. One of them is to form a chamfered portion of the above-mentioned height H after joining an ultra-high hardness sintered body to a seat groove formed on the upper surface of the tip corner of the tool body, and then to form an upper surface on the ultra-high hardness sintered body. Is a method of forming a chip breaker for moving the cutting edge downward from the core by h, and the other is a method of forming a chip breaker and forming a chamfered portion having a height H in the reverse order of the above.

[0014]

The amount h of the tip of the cutting edge is determined by the depth of the chip breaker. Further, when the height of the chamfered portion for strengthening the cutting edge is h ₁ , this value is obtained from the required strength of the cutting edge. Therefore,
Design H such that h + h ₁ = H. Since the chamfered portion having the height H can be freely set in size, the height H can be secured as designed. When a chamfered portion of this height H is formed and then a chip breaker of a required size is formed, h ₁ is formed at the cutting edge portion.
The surface of the height remains, and the required cutting edge strength is secured.
Even when the chamfered portion having the height H is formed after the chip breaker is formed, the surface having the height h ₁ is newly formed and the same result is obtained. Therefore, according to the present invention, the optimum size for finish cutting is obtained. The tip breaker can be provided at an optimum position to achieve the purpose of ensuring sufficient cutting edge strength.

Further, since the chamfered portion having the height H can be processed by mechanical polishing, the edge strengthening portion can be homogenized.

Next, it is preferable that θ is from 15 ° to 45 °. If θ is smaller than 15 °, the effect of strengthening the cutting edge becomes small, and the cutting edge is frequently broken during cutting. Become. On the other hand, if it is larger than 45 °, the cutting resistance at the time of cutting becomes large, the machining dimension becomes unstable, and the cutting edge is damaged due to excessive cutting resistance, which is not preferable. Further, when θ is 45 ° or more, when the chamfer width w for strengthening the cutting edge is large, the thickness of the ultra-high hardness sintered body is limited. Therefore, the actual cutting edge is formed only by the ultra-high hardness sintered body. It is not done, and it is out of the purpose of the present application.

Regarding the width W of the chip breaker,
The preferred range of 0.3 mm to 2.0 mm is W
If is less than 0.3 mm, the chips will tend to become clogged in the chip breaker during cutting, and the cutting edge may be damaged. If it is 2.0 mm or more, the width of the chip breaker becomes too wide, and it becomes impossible to obtain a good chip control.

The same applies to the depth t of the chip breaker. The reason why t is preferably 0.2 mm to 0.8 mm is as follows.
If it is less than 0.2 mm, chips are likely to be clogged in the chip breaker during cutting, and the cutting edge is broken.
On the other hand, if the thickness exceeds 0.8 mm, not only the chip disposal becomes worse, but also the depth becomes larger than the thickness of the ultra-high hardness sintered body, and the ultra-high hardness sintered body disappears from the cutting edge 7.

The width w of the reinforced edge chamfer is from 0.02 mm to
It should be in the range of 0.2 mm. If it is smaller than 0.02 mm, the effect of strengthening the cutting edge is small as is the case with the angle θ, and it may be broken during use. On the other hand, if w is larger than 0.2 mm, there is no particular adverse effect on actual cutting, but if the angle θ is large and the depth t of the chip breaker is deep, this w
In order to increase the value, the thickness of the ultra-high hardness sintered body must be increased. This is not preferable because the expensive ultra-high hardness sintered body becomes more expensive as the thickness increases.

[0020]

FIG. 1 shows an example in which the present invention is applied to a throw-away tip.

In the figure, reference numeral 1 denotes a tool body (polygonal base metal) made of cemented carbide or the like, and a super-hard sintered body 3 is formed in a seat groove 2 formed at a tip corner portion of the body. The back plate 4 integrated with is brazed and joined. Further, a chip breaker 5 is attached to the upper surface of the tip corner portion of the ultra-high hardness sintered body 3. 6 is a chamfered portion for strengthening the cutting edge provided along the cutting edge 7, 8 is a chamfered portion at the intersection of each upper surface and side surface of the main body 1 and the ultra-high hardness sintered body 3 (referred to in the present invention. Height H
Chamfered portion), 9 is a central hole for chip mounting.

As shown in FIG. 2 (b), the chamfered portion 6 for strengthening the cutting edge has one of the surfaces of the chamfered portion 8 made smaller than the height H of the chamfered portion 8 by reducing the centering amount h of the cutting edge. The part is left and it is composed of the left side.

A tool for finish-cutting hardened steel or the like using a super-hard sintered body 3 containing cubic boron nitride as a main component is shown in FIG. 2 (b) at θ, W, t ( It is recommended to choose the numerical ranges mentioned above for r and w). Within this range, the sharpness and strength of the cutting edge can be secured in a good balance, and the chip disposal effect in the finishing region can be enhanced.

FIG. 3 shows an example of a manufacturing process of the throw-away tip of FIG. The ultra-high hardness sintered body 3 is joined to the tool body 1 (FIG. 2 (a)), and then the chamfered portion 8 of height H is machined on the two sides of the upper surface including the body {FIG. )} After that, the chip breaker 5 is processed so that the chamfered portion 6 for strengthening the cutting edge is left {FIG.

The chip breaker 5 may have a shape with a rake angle as shown in FIG. 4 or a so-called oblique grinding shape that is biased to one side as shown in FIG.

Further, the tool body 1 may be a shank supported by a holder.

Further, in the case of a tool using an ultra-high hardness sintered body containing polycrystalline diamond as a main component as a cutting edge, there are few cases where the cutting edge is strengthened in consideration of its application, but this tool also has a chip breaker. The present invention can be effectively applied to the case where the blade edge is strengthened.

A performance comparison test between the cutting tool of the present invention and a conventional cutting tool will be described below.

The tools used are the product of the present invention having the shape shown in FIG. 1 and the conventional product shown in FIGS. 6 and 7. The cutting edge materials of these tools are cubic boron nitride sintered bodies. did. The dimensional specifications of the product of the present invention are as follows: W = 0.8 m in FIG.
m, w = 0.1 mm, r = 0.3 mm, θ = 45 °, h
(T) = 0.3 mm. The tool of FIG. 6 has a very small w of about 0.03 mm because the cutting edge is manually strengthened. The tool shown in FIG. 7 can have w of 0.1 mm, but W is 5.0 mm, which is extremely large.

The test conditions are as follows. Work Material: S48C Induction Hardened Steel (HRc41-4
Equivalent to 8) Cutting style: Peripheral cutting Cutting conditions Cutting speed: 110 m / min Feed: 0.12 mm / rev Depth of cut: 0.17 mm * Test result The conventional tip of Fig. 7 had no problem with the cutting edge condition, but chip treatment In regard to the above, although it curled to some extent, it was entangled in the holder without breaking, and it interfered with the processing. On the other hand, in the product of the present invention, the chips were curled to an appropriate size, finely cut, and smoothly discharged. Further, the product of the present invention had no damage on the cutting edge and could continue the cutting stably. On the other hand, the conventional tip of FIG. 6 showed the same performance as the product of the present invention with respect to chip disposal, but the life of the chip was shorter than that of the product of the present invention due to the chipping of the cutting edge.

[0031]

As described above, in the cutting tool of the present invention, a chamfer having a large height H is provided at the intersection of the upper surface and the side surface including the area other than the effective blade portion, and a part of the surface is provided. Since the chamfered part for strengthening the cutting edge is configured with, it is possible to install a chip breaker of the optimum size at the optimum position to obtain a sufficient cutting edge strength, and the cutting edge strength and excellent chip disposal are required. It can be expected to have a great effect when used for finish processing of hardened steel, especially boring processing in automatic machine lines and shaft processing of induction hardened steel.

[Brief description of drawings]

1A is a perspective view of a throw-away chip to which the present invention is applied, FIG. 1B is a plan view of the same chip as above, and FIG. 1C is a side view of the same chip as above.

2A is an enlarged plan view of the cutting edge of the tip of FIG. 1, and FIG. 2B is an enlarged side view of the cutting edge.

3 (a) to (c): a diagram showing a manufacturing procedure of the chip of FIG.

FIG. 4A is an enlarged plan view of a main part showing a modified example of the chip breaker. FIG. 4B is a side view of the same.

5 (a): Enlarged plan view showing still another example of the chip breaker (b): Side view of the above

FIG. 6A is a plan view showing an example of a conventional throw-away tip. FIG. 6B is a side view of the tip.

FIG. 7A is a plan view showing another example of a conventional throw-away tip. FIG. 7B is a side view of the above tip.

[Explanation of symbols]

 1 Tool Main Body 2 Seat Groove 3 Super Hard Sintered Body 4 Back Plate 5 Chip Breaker 6 Chamfering Edge Strengthening Edge 7 Cutting Edge 8 Chamfering Height H 9 Center Hole

Claims (4)

[Claims] 1. An ultra-high hardness sintered body is joined to a seat groove formed on the upper surface of the tip corner of a tool body, and a cutting edge, a chip breaker, and a chamfered portion for strengthening the cutting edge are attached to the ultra-high hardness sintered body. In the provided cutting tool with a chip breaker, a chamfered portion is formed at the intersection of the upper surface and the side surface of each of the tool body and the super-hard sintered body, and the height H of the chamfered portion is an ultra-high level obtained by the chip breaker processing. The chip breaker is characterized in that the surface of the chamfered portion for strengthening the blade edge is formed by a part of the surface of the chamfered portion having the height H, which is larger than the amount h of descending the blade edge from the upper surface of the hardness sintered body. Cutting tool with. 2. The ultra-high hardness sintered body contains cubic boron nitride as a main component, and an angle θ formed by an upper surface of a chamfered portion having a height H is 15 ° <θ <45 °, Chip breaker width W
Is 0.3 mm to 2.0 mm and the chip breaker depth t is 0.
2mm-0.8mm, width w of chamfer for strengthening the cutting edge is 0.02mm
The cutting tool with a chip breaker according to claim 1, wherein the cutting tool is defined in the range of 0.2 mm to 0.2 mm. 3. An ultra-high hardness sintered body is joined to a seat groove formed on the upper surface of the tip corner of the tool body, a chamfered portion having the height H is formed, and then the ultra-high hardness sintered body is formed. 2. The method for manufacturing a cutting tool with a chip breaker according to claim 1, wherein a chip breaker is provided which moves the cutting edge downward from the upper surface by h-core. 4. An ultra-high hardness sintered body is joined to a seat groove formed on the upper surface of the tip corner of the tool body, and then a chip breaker is formed on the ultra-high hardness sintered body to move the cutting edge h-core down from the upper surface. The method for manufacturing a cutting tool with a chip breaker according to claim 1, wherein a chamfered portion having the height H is formed thereafter.