JPH11156608A - Cutting insert - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably discharge curled chips and provide good chip discharging performance by forming a breaker groove immediately after the nose tip of a cutting insert to be recessed with respect to both side parts and specifying the rake angle or the like of a side cutting edge. SOLUTION: A cutting insert 10 is formed in a rhombic shape where the included angle of a nose part 4 is relatively larger, and a cutting edge 3 composed of a tip cutting edge 3a and a side cutting edge 3b is formed in an edge side between a face 1 and a flank 2. A breaker groove 6 is formed in the nose part 4 to be continuous from the cutting edge 3, and a breaker projection 8 is formed in the center part of the breaker groove 6. In this case, the breaker groove 6 is formed to be recessed with respect to both side parts. Then, the rake angle (α) of the side cutting edge 3b is set equal to 5 deg. or more, and the side cutting edge 3b is set to have a down angle β=4 deg. to 8 deg. in the direction of being shifted from the nose tip. Thus, chip resistance in the nose tip is reduced, and chips are surely curled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting insert for metal working, which is used for a material such as hot-rolled soft iron or a cold-rolled plate, which is not cut when cutting and is likely to be continuous. .

[0002]

2. Description of the Related Art Conventionally, in order to cut such a material having high ductility by cutting, a breaker groove and a breaker projection connected to the breaker groove are provided near the tip of a nose of a polygonal plate. Formed ones have been used.

[0003] In such a cutting insert, the shape of the nose is such that the step between the cutting edge and the bottom surface of the breaker groove gradually decreases from the tip of the cutting edge nose R to the outside thereof, and the rake angle increases. Was also gradually getting smaller.

Typically, the distance from the tip of the nose to the rise of the breaker projection is about 0.4 mm, the depth of the breaker groove is 0.1 mm, and the rake angle of the rake face in the breaker groove is about 15 °. Has been used.

However, the above-mentioned conventional cutting insert does not completely solve the problem that the chips are discharged without being bent by the breaker projections while being extended. In particular, when machining the step portion of the shaft, In addition, the extension of the chips was a great problem.

[0006] This is because the R surface remains at the corner of the step,
When the processing direction is changed from the horizontal direction to the vertical direction or the opposite direction, the cutting amount temporarily increases. For this reason, the result is that the cutting processing is performed beyond the chip processing capacity.

[0007] When the chips are extended as described above, serious problems are caused, such as entanglement with the rotating center of the machine tool, interrupting the work, or entanglement with the cutting edge, causing a cutting edge defect. .

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, even in a material such as a hot-rolled soft iron or a cold-rolled plate, which is easy to be continuously cut without cutting, the cutting blade is surely curled in a spiral shape. An object of the present invention is to provide a cutting insert that can be stably discharged.

[0009]

In order to solve the above-mentioned problems, the present invention comprises forming a cutting edge on a ridge between a rake face and a flank, and forming a curved tip cutting edge and horizontal cutting edges on both sides thereof. A cutting insert comprising a nose portion having a nose portion and a breaker projection formed at a central portion in the breaker groove of the nose portion, wherein a breaker groove immediately behind the tip of the nose is concave with respect to both lateral portions thereof. In addition, a cutting insert having a rake angle α of the horizontal cutting edge of 5 ° or more and a downward angle β of 4 ° to 8 ° in a direction away from the nose tip is provided. It is.

[0010]

According to the cutting insert of the present invention, the breaker groove immediately behind the tip of the nose is concave with respect to both lateral portions. As a result, the chip resistance at the tip of the nose, which receives the largest cutting resistance, is reduced, the contact area between the chip and the breaker groove surface in the vicinity thereof is reduced, and the cutting resistance from the chips is also reduced.

Further, the rake angle of the horizontal cutting edge is made as large as 5 ° or more, and in addition, the horizontal cutting edge is formed at a downward angle of 4 ° to 8 ° in a direction away from the tip of the nose, so that R machining and learning can be performed. In a type of machining, such as machining, in which cutting variation is likely to occur, even a chip having a large cutting amount and flowing easily can be surely curled in a spiral shape at the horizontal cutting edge portion.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 4 show a cutting insert 10 of the present embodiment. The entire shape of the cutting insert 10 is a rhombus shape in which the nose portion 4 has a relatively large cutting edge angle.
A cutting edge 3 is formed on a ridge between the rake face 1 and the flank 2.

The nose portion 4 has a breaker groove 6 connected to the cutting edge 3 and a breaker projection 8 connected to a seating surface 7 at a central portion of the breaker groove 6.

FIG. 2 is an enlarged plan view of a region Y in FIG. 1. As shown in FIG. 2, the nose portion 4 has a straight cutting edge 3b on both sides of a curved tip cutting edge 3a. .

FIGS. 3A to 3C are an AA diagram, a BB diagram, and a CC diagram in FIG. 2, respectively, from the nose tip D and the nose tip D, respectively. Tip cutting edge 3
A cross-sectional view at the intermediate point E and the transverse cutting edge 5b is shown.

As shown in FIGS. 3A and 3B, the step J between the cutting edge 3 at the tip D of the nose and the breaker groove 6 is at the intermediate point E (from the tip D of the nose to the tip cutting edge 3a). ) Is larger than the step K between the cutting edge 3 and the breaker groove 6. That is, the breaker groove 6 right behind the tip D of the nose is concavely deeper with respect to both lateral portions. As a result, the chip resistance at the leading edge D of the nose which receives the largest cutting resistance is reduced, and the contact area between the chip and the groove surface of the breaker groove 6 in the vicinity thereof is reduced, so that the cutting resistance from the chip is also reduced. The horizontal cutting edge 3b does not increase the rake angle α ° to 5 ° or more as shown in FIG. 3 (c), and also moves the horizontal cutting edge 3b away from the nose tip D as shown in FIG. By forming at a downward angle β = 4 ° to 8 °, even in the case of cutting that is likely to cause cutting fluctuations, such as R processing and learning processing, even chips that have a large cutting amount and are easy to flow, spiral at the horizontal cutting edge part Make sure it curls. In other words, even in the processing of pulling or the processing of pushing, wide chips that flow easily flow diagonally along the breaker projection 8 in the direction away from the workpiece, rather than trying to exceed the breaker projection 8, and as a result, The flow of the chips is smooth, the curl is helically curled, and the chips are easily cut, and the cutting resistance is small.
Therefore, in the cutting insert 10, the chips reliably hit the breaker projections 8 in both the pulling process and the pressing process, and are curled and discharged stably.
Even when the amount of cutting changes rapidly, such as when processing a corner portion of a stepped portion, chips are satisfactorily processed.

Incidentally, the step J, K between the cutting edge and the bottom surface of the breaker groove at the midpoint E from the tip of the nose to the lateral end F of the tip cutting edge, and J = 0. 0.04 mm and (JK) = 0.0
It is preferable to satisfy the formula of 2 to 0.06 mm.

If K is less than 0 mm (positive), the cutting resistance tends to be large, and the chips may be easily elongated. On the other hand, if it is larger than 0.06 mm, chip processing may be defective.

If (JK) is less than 0.02 mm, chip processing may be poor, and if it is larger than 0.06 mm, chip processing may be poor.

Next, with respect to the rake angle α ° of the transverse cutting edge 3b, when α ° is smaller than 5 °, chips are removed from the breaker projection 8.
Might be easier to get over. Note that this α ° is 15
If the angle exceeds °, burrs may be generated. The rake angle α ° of the transverse cutting edge 3b is preferably larger than the rake angle γ ° of the nose tip D (see FIG. 3A).

This is because if α ° and γ ° satisfy α ° ≦ γ °, there is a possibility that the chips may not easily flow in the direction away from the workpiece.

The downward angle β ° of the transverse cutting edge 3b is 4 °.
If it is less than 8 °, or if it is more than 8 °, chip processing may be deteriorated.

The embodiment of the present invention has been specifically described above. However, the present invention is not limited to this embodiment, and may take any form without departing from the object of the invention. Needless to say.

Embodiment In the cutting insert 10 shown in FIGS.
Step K between the cutting edge 3 at the tip cutting edge 3a and the breaker groove,
J, (JK), the rake angle α ° of the transverse cutting edge 3b and the rake angle γ ° of the nose leading edge D were prepared as shown in Table 1, and processing tests were performed under the following cutting conditions. Was.

Cutting conditions V = 400 m / min d = 1-4 mm f = 0.7 mm / rev. Work material: SPHE (JIS) Tool shape: CNMG120408 Cutting fluid: Yes

[0027]

[Table 1]

The downward angle β ° of the transverse cutting edge 3b is 6 °.
It was fixed. The processing mode was both R processing and copying processing.

In these processes, the magnitude of the cutting resistance and the ability to treat chips were observed and evaluated. The cutting resistance was evaluated as large (blue), medium (brown), and small (blue) by the color of the chips. The cutting performance was evaluated on a four-point scale: good, good, poor, and bad.

As is clear from Table 1, Samples 1 to 4 had a step K between the cutting edge 3 and the breaker groove 6 at the intermediate point E of the tip cutting edge 3a of less than 0, and neither the cutting resistance nor the cutting treatment ability was satisfactory. . Further, in all of Samples 5, 9, and 13, the step J between the cutting edge 3 and the breaker groove at the leading edge D of the nose was 0 or more and was smaller than the step K, and neither the cutting resistance nor the cutting treatment ability was satisfactory. Next, in Samples 10, 14, and 15, the step J was smaller than the step K, and neither the cutting resistance nor the cutting performance was good. Sample 16 has a step K of 0.0
8 and the chip disposal ability was not good. In sample 21, the rake α ° of the transverse cutting edge 3b was as large as 20 °, and the chip disposal ability was not good.

On the other hand, samples 6 to 8, 1
Samples Nos. 1, 12, 17 to 20 had good cutting resistance and cutting performance. Among them, the sample 8 has a rake angle γ ° of the nose tip D larger than the rake angle α of the transverse cutting edge 3b.
(JK) was as large as 0.10 mm, and the chip treating ability was slightly inferior to other products of the present invention.

Next, as shown in Table 2, the steps K, J, J-
K and the rake angles α ° and γ ° are fixed,
The same test was performed on samples 22 to 26 in which only the down angle β was different. Table 2 shows the results.

[0033]

[Table 2]

As apparent from Table 2, the descending angle β °
Of the present invention (samples 23 to 25) having an angle of 4 ° to 8 ° had good chip disposal performance, whereas those of the present invention (sample 2)
2,26) was not good.

[0035]

As described above, according to the present invention, the breaker groove just behind the tip of the nose is concave with respect to both lateral portions. As a result, the chip resistance at the tip of the nose, which receives the largest cutting resistance, is reduced, the contact area between the chip and the breaker groove surface in the vicinity thereof is reduced, and the cutting resistance from the chips is also reduced. Also, make the rake angle of the horizontal cutting edge 5
° or more, and in addition, by forming the transverse cutting edge at a downward angle of 4 ° to 8 ° in the direction away from the tip of the nose, in types of processing where cutting variation easily occurs, such as R processing and learning processing, Even cutting chips that have a large cutting depth and flow easily are reliably curled in a spiral at the horizontal cutting edge.
In other words, even in the process of pulling or pushing, wide chips that are easy to flow flow diagonally along the breaker protrusion in the direction away from the workpiece, rather than trying to exceed the breaker protrusion, and as a result, The flow is smooth,
It is easily curled in a spiral shape and has low cutting resistance. Therefore, the chips reliably hit the breaker projections and curl and are stably discharged. Further, the chips can be satisfactorily processed even when the amount of cutting changes suddenly, for example, when machining a corner portion of a step.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cutting insert of the present invention.

FIG. 2 is an enlarged top view of a region Y in FIG.

3 (a) to 3 (c) respectively show A-
It is an A diagram, a BB diagram, and a CC diagram.

FIG. 4 is an enlarged side view of a region Y in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cutting insert 1 Rake surface 2 Flank 3 Cutting edge 3a Tip cutting edge 3b Horizontal cutting edge 4 Nose part 6 Breaker groove 7 Seating surface 8 Breaker projection Y area α, γ Cutting rake angle β Down angle D Nose edge ED Intermediate point from to F F Side edge of the cutting edge

Claims (2)

[Claims] 1. A cutting edge is formed at a ridge between a rake face and a flank, and a nose portion having a curved tip cutting edge and lateral cutting edges on both sides thereof is provided, and a breaker groove of the nose portion is provided. A cutting insert formed with a breaker projection at the center of the inside of the nose, the breaker groove immediately behind the tip of the nose is concave with respect to both lateral parts, and the rake angle α of the horizontal cutting edge is 5 ° or more. A cutting insert having a horizontal cutting edge formed at a downward angle β = 4 ° to 8 ° in a direction away from the tip of the nose. 2. A step J, K between the cutting edge and the bottom surface of the breaker groove at an intermediate point E from the tip of the nose to the lateral end F of the tip cutting edge, and J = 0 to 0. .
04 mm and (JK) = 0.02 to 0.06 mm
2. The cutting insert according to claim 1, wherein the following formula is satisfied.