JPH0976104A - Throwaway tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the strength of a cutting edge, to decrease the honing angle, and to decrease cutting resistance by forming a honing part into a round shape and smoothly linking the honing part to a land part. SOLUTION: A honing part 2 is in contact with a flat land part 3 by the constant radius of curvature R1, the ratio of the length (a) of the honing part from the contact and the length (b) of the land part is set to 1 to 1.5 to 3, the length (a) of the honing part is set in the range of 0.1 to 0.3mm, and the radius of curvature R1 is set to (3 to 5.5) (a). When (a) is set in the range of 0.1 to 0.3mm in the expression of R1=(3 to 5.5) (a), the tangential angle of the honing part 2 in the cutting edge part can be formed in the range of 10 to 30 deg.. When the tangential angle is set to about 30 deg. or more, cutting resistance is increased, chattering occurs in high angle or high feed angle cutting, and the work clamping state is deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip in which a cutting edge used for turning is honed, and more particularly to a throw-away tip capable of reducing cutting resistance and enhancing cutting edge strength. .

[0002]

2. Description of the Related Art In the turning process accompanied by severely interrupted cutting, the actual cutting method is 53-12.
No. 2790 discloses a chip in which the negative honing is provided on the cutting edge portion to enhance the strength of the cutting edge.
However, in the case of negative honing, the work material is always in contact with the honing surface at a negative honing angle in the range from the cutting edge portion to the end of the land, which increases cutting resistance. On the other hand, the conventional round honing has a small angle and width and low resistance, but at the cutting edge, the tangential angle of contact with the work material is large, and R is increased to strengthen the cutting edge strength. Then, the back force increases, which causes chattering and deterioration of machining accuracy, and thus the shape does not consider the cutting resistance.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a throw-away tip which improves cutting performance deterioration due to cutting resistance and enhances cutting edge strength. .

[0004]

In order to achieve the above object, the present consideration has the following constitutional requirements. That is, it has a polygonal plate shape, a cutting edge is formed on at least one of the ridges of the upper and lower surfaces, a honing portion and a land portion are formed along the cutting edge, and the cutting edge faces inward from the land portion. In a throw-away tip in which a breaker groove is formed in the breaker groove, a length a of the honing portion and a length b of the land portion are taken in a cross section orthogonal to the cutting edge.
And the ratio a: b is 1: on the same plane as the land surface.
1.5-3, the length of the honing part is 0.1-0.3
mm and an arc having a constant radius of curvature R1 in contact with the land, R1 = 3 to 5.5 mm, and the intersection of the land and the breaker groove has a radius of curvature R2 of 0.3.
It is achieved by forming the convex R of 1.0 mm.

[0005]

With the above structure, even when the cutting resistance is increased by strengthening the cutting edge strength, the cutting resistance generated in the land portion can be reduced and the processing accuracy can be maintained. Hereinafter, the operation, the reason for limiting the numerical values, and the like will be described in detail based on Examples.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, FIG. 1 shows a throw-away tip according to an embodiment of the present invention, and FIG. 2 shows a side view thereof. 1 and 2, the throw-away tip has a triangular shape and is provided with a cutting edge portion 1 on three sides thereof. A honing portion 2 is provided along the cutting edge portion 1 and a land portion 3 in contact with the honing portion 2 is provided to separate the breaker. The groove 4 is formed. FIG. 3 is a cross-sectional view of FIG.
In the enlarged view of the cutting edge portion in the A section, the honing portion 2 is
It is in contact with the flat land portion 3 with a constant radius of curvature R1,
From the contact point P, the length a of the honing portion and the length b of the land portion
And the ratio of a to b is 1: 1.5 to 3, the length a of the honing portion is 0.1 to 0.3 mm, and the radius of curvature R1 is R1 = (3 to 5.5) a. And

The above R1 = (3 to 5.5) a is a = 0.
When it is set to 1 to 0.3 mm, the tangent angle θ2 of the honing portion 2 in the cutting edge portion can be formed to be 10 to 30 °, which means that the cutting edge strength (defective tool life) in FIG. When the tangent angle θ2 is set to 30 ° or more at an angle of 10 ° to 50 ° which is sufficient for strengthening, cutting resistance increases, and chattering and work clamp state are deteriorated in high cutting depth and high feed cutting. Therefore, 10 °
-30 °. The cutting test shown in FIG. 4 (life of missing tool) was 100 m / min for cutting speed and 0.5 for feed speed.
mm / rev, depth of cut 2 mm, work material SCM440
It is evaluated based on the presence or absence of damage to the cutting edge such as chipping, chipping, etc. by inserting four grooves in a (hardened) round bar and turning the chip to give it a mechanical impact.

Secondly, the width of honing was similarly evaluated under the same cutting specifications as in FIG. The result is shown in FIG. From FIG. 5, by making the length a of the honing portion larger than 0.1, the length is sufficient to strengthen the cutting edge strength in impact resistance, and when the length a of the honing portion exceeds 0.3. Since burr on the machined surface is severely generated, it is set to 0.1 to 0.3 mm.

Further, in the present invention, as shown in FIG. 3, by forming the flat land 3 in contact with the honing portion 2, in the case of only the curved surface honing like the conventional cutting edge shape shown in FIG. During cutting with a large feed amount, the chip 5 crosses the honing portion 2 and comes into contact with the breaker 4. Therefore, the force H received from the chip 5 causes cracks 6 from the vicinity of the contact surface between the breaker 4 and the chip 5. And the cutting edge is easily damaged. On the other hand, as shown in FIG. 7 as an example of the invention of the present application, the force H received from the chips 5 at the contact portion between the flat land portion 3 and the chips 5 acts in the chip thickness direction, so that the cutting edge strength is increased. There is nothing wrong with it. Therefore, the ratio of the length a of the honing portion to the length b of the land portion is set to a: b = 1: 15 to 3. If it is less than 1.5 times, it is not possible to prevent the occurrence of the crack 8, and 3
If it exceeds twice, the length of a + b becomes too long, so a:
b = 1: 15 to 3 was set.

Thirdly, in the present invention, as shown in FIG. 8, in the cutting in which the cutting depth and the feed amount are both large, the convex portion R of 0.3 mm or more is smooth at the intersection of the land portion 3 and the breaker 4. By connecting to the chip, the chip disposability can be made good without interrupting the chip flow. If R2 is less than 0.3 mm, it becomes convex and is likely to cause defects, and if it exceeds 1 mm, the length of the land portion 3 is lengthened, and 0.3 to 1 is required for good chip disposal. It was set to 0.0 mm. In addition, a convex R having a radius of curvature of about 0.03 to 0.1 mm may be provided at the intersection of the honing portion and the cutting edge.

Fourth, in the cutting of the throw-away tip of the present invention shown in FIG. 9, the tangent angle θ1 at the contact point between the honing portion 2 and the land portion 3 and the tangent line at the contact point between the honing portion 2 and the cutting edge portion 1 The relationship with the angle θ2 will be described. FIG. 10 shows a conventional example of negative honing, and FIG.
Shows the relationship of round honing as a conventional example. In the example of the present invention of FIG. 9, the honing has a curved surface shape, and when it is smoothly connected to the land portion 3, the tangent angle θ1 thereof is θ shown in FIG.
1 below, the angle becomes the same as θ1 shown in FIG.
Allows cutting with low resistance.

[0012]

As described above, the cutting edge strength can be strengthened by forming the honing portion into an R shape and smoothly connecting it to the land portion, and by further forming the R shape, the honing angle can be reduced. It was possible to reduce the cutting resistance.

[Brief description of drawings]

FIG. 1 shows a front view of a throwaway tip of an example of the present invention.

FIG. 2 shows a plan view of FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 shows tangential angle and tool life test results.

FIG. 5 shows honing width and tool life test results.

FIG. 6 is a cross-sectional view of a cutting edge of a throw-away tip according to a conventional example, and is an explanatory view schematically showing chip discharge during cutting.

FIG. 7 is a cross-sectional view of a cutting edge of a throw-away tip according to an example of the present invention, which is an explanatory view schematically showing chip discharge during cutting.

FIG. 8 is a cross-sectional view of a cutting edge of a throw-away tip according to an example of the present invention, which is an explanatory view schematically showing chip discharge during cutting.

FIG. 9 shows an enlarged cross-sectional view of the cutting edge of the example of the present invention.

FIG. 10 is a conventional cutting edge (negative honing).
FIG.

FIG. 11 is an enlarged cross-sectional view of a conventional cutting edge (round honing).

[Explanation of symbols]

 1 Cutting edge part of throw-away tip 2 Honing part 3 Land part 4 Breaker groove 5 Chips 6 Crack a Length of honing part b Length of land part R1 Radius of curvature at intersection of honing part and land part R2 Land part and Curvature radius of crossing of breaker groove θ1 Tangent angle between honing part and land part θ2 Tangent angle between cutting edge part and honing part H Force received from chip 5 H

Claims (2)

[Claims] 1. A polygonal plate shape, a cutting edge is formed on at least one ridge line portion of upper and lower surfaces, a honing portion and a land portion are formed along the cutting edge, and from the land portion. In the throw-away tip in which the breaker groove is formed toward the inside, in the cross section orthogonal to the cutting edge, the ratio a: b of the length a of the honing portion and the length b of the land portion is 1: 1.5 to 3 on the same plane as the surface, and the length of the honing portion is 0.1 to 3.
0.3 mm and a constant radius of curvature R that contacts the land
A throw-away tip characterized in that the relationship of R1 = (3 to 5.5) a is satisfied with an arc of 1. 2. The throw-away tip according to claim 1, wherein the intersection of the land portion and the breaker groove is formed by a convex R having a radius of curvature R2 of 0.3 to 1.0 mm. A throw-away tip to do.