JPH08323510A - Throw-away tip and throw-away type cutter - Google Patents

Abstract

(57) [Summary] [Purpose] Improves sharpness and discharge of spiral-shaped chips. [Structure] The main cutting edge 16 having an inclination angle β is provided on each side of the upper and lower surfaces of the negative throw-away tip 12, and the sub cutting edge 18 is provided at each corner.
To provide. A breaker groove 26 whose width gradually increases from the side of the auxiliary cutting edge 18 is provided between the main cutting edge 16 and the flat seating surface 25 having a height lower than that. The breaker groove 26 is provided with a rake surface 22 having a rake angle α and a first inclined surface 28, and the breaker groove 26
Further, a second inclined surface 29 that is gentler than the first inclined surface 28 is provided in the wide portion of the. Attach the tip 12 to the cutter 9,
Eject the spiral chips. Therefore, the chip 12
Is mounted so that the axial rake angle is -4 ° to -10 °, the corner angle is 25 ° to 60 °, the cutting edge tilt angle is 0 ° or more, and the true rake angle is in the range of -5 to -20 °. .

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 suitable for being attached to a throw-away type cutter for cutting, and a throw-away type cutter equipped with this throw-away tip.

[0002]

2. Description of the Related Art As a throw-away type cutter of this type, which produces spiral-shaped chips during cutting and can be suitably discharged, there is, for example, the one disclosed in Japanese Patent Publication No. 48-24462. This cutter will be described with reference to FIGS. 8 and 9. The throw-away tip 1 shown in FIG. 8 has a substantially flat plate shape of a parallel plate and has an upper surface 2
The ridgeline forming each side where the lower surface 3 and the side surface 4 intersect is defined as the main cutting edge 5. Each corner is notched in the vertical direction and chamfered, and each ridge line where the chamfered surface 6 and the upper and lower surfaces 2 and 3 intersect constitutes a sub cutting edge 7. Since the throw-away tip 1 is of the negative type, the number of effective cutting edges is twice as large as that of the positive type.

Such a throw-away tip is shown in FIG.
In the case of mounting and cutting on the cutter 9 of a rolling tool such as a milling cutter shown in Fig. 1, the tip 1 is mounted on the outer peripheral side of the tip of the cutter body 10, and the main cutting edge 5 located on the outer peripheral side has a corner angle CH. Then, the auxiliary cutting edge 7 is arranged so as to project to the tip side. In this case, the chip discharge state becomes a spiral winding,
Moreover, the axial rake angle A, the radial rake angle R, the cutting edge tilt angle I, and the true rake angle T of the cutting edge are set within a predetermined range in order to cleanly flow and discharge the processing surface without damaging it. It is an indispensable requirement. According to the test results, it is confirmed that the spiral-shaped chip discharge can be obtained only when the cutting edge inclination angle I is within a limited range of + 5 ° or more. In addition, the edge angle at which the cutting edge inclination angle I becomes a positive angle can be established even if the combination of the radial rake angle R and the axial rake angle A is negative, both positive, and positive and negative. It is clarified by the following calculation formula (the following formulas (1) to (4)). This justifies the possible angular range of the spiral-shaped chip ejection.

That is, the axial rake angle A, the radial rake angle R, the cutting edge inclination angle I, the true rake angle T, and the corner angle C
The relation of H is described by a calculation formula: tanT = tanR · cosCH + tanA · sinCH (1) tanI = tanA · cosCH−tanR · sinCH (2) tanA = tanI · cosCH + tanT · sinCH (3) tanR = tanT · cosCH−tanI · sinCH (4). The true rake angle T included in these formulas is important for cutting and mainly affects the cutting ability, but is usually used in the absolute value range of 0 to 20 °.

Further, considering the combination of the cutting edge angles for discharging the spiral-shaped chips by the above formula (2) on condition that the negative throw-away tip 1 having a large number of effective cutting edges is used, the cutting edge inclination angle I It has been clarified that is satisfied under the following conditions, where is a positive angle, axial rake angle A, and radial rake angle R are all negative angles. That is, it is necessary that the radial rake angle R, the axial rake angle A, and the corner angle CH satisfy the condition of tanA.cosCH> tanR.sinCH (5). When the axial rake angle A is -4 °, the relationship between the true rake angle T, the cutting edge inclination angle I, and the corner angle CH is calculated by the following equations (2) and (4): tanI = tanAsecCH-tanT FIG. 10 shows the result based on tanCH (6), and the practical effective range in which the chips form a spiral shape is that the cutting edge inclination angle I> 5 ° and the true rake angle T <| 20 ° | It is within the TI line. However, the true rake angle T is -5 ° to -20 as is clear from FIG.
Used in the range of °. Further, FIG. 11 shows the relationship among the radial rake angle R, the axial rake angle A, and the corner angle CH within the effective range. That is, R =
A curve a below -20 ° is a combination of R and CH with I = 5 ° or more, and an upper curve b is T = −.
It becomes larger than 20 ° (that is, the value of negative angle becomes smaller)
The limit combination of R and CH is shown, and the hatched area between the upper and lower curves a and b shows the range of usable numerical values.

Since the axial rake angle A uses a negative throw-away tip, it is the axial rake angle, that is, the clearance angle F of the front cutting edge portion, usually -4 ° to-.
It is used within the range of 10 °. Corner angle CH is usually 0
Although it is used in the range of up to 60 °, the corner angle CH in this configuration is such that the cutting edge inclination angle I is 5 ° or more and the axial rake angle A is -4 °. If the corner angle CH is 25 ° or less, the true rake angle T becomes a negative angle of -20 ° or less, resulting in poor sharpness and difficult cutting. When the corner angle CH exceeds 60 °, it can be angularly used, but it is not preferable because the cut amount per chip size becomes small, which is generally 60 ° or less. Therefore, in practice, the axial rake angle A is -4 to -10 ° and the corner angle CH is 25 to
When the cutting edge shape of the tip 1 is set in the range of 60 ° and the cutting edge inclination angle I is + 5 ° or more and mounted on the cutter 9, the negative throw-away tip 1 is used to discharge spiral-shaped chips. It is possible even if both the rake angle A and the radial rake angle R are negative.

[0007]

However, with such a configuration, since the throw-away tip 1 is a parallel plate negative type, when it is mounted on the cutter 9 for cutting as described above, it is axially cut. Rake angle A,
Since both of the true rake angles T are required to be negative, the chip discharging property and the sharpness were not always sufficient.

In view of the above problems, it is an object of the present invention to provide a throw-away tip capable of further improving chip discharging property and sharpness. Another object of the present invention is to provide a throw-away type cutter which is equipped with this throw-away tip and can further improve the chip discharging property and sharpness.

[0009]

A throw-away tip according to the present invention is a throw-away tip having a main cutting edge and a sub-cutting edge provided on ridge lines where upper and lower surfaces facing each other and side surfaces intersect with each other, The main cutting edge is inclined so as to gradually approach the opposing lower surface or upper surface side in the direction away from the sub cutting edge, and the rake surface of the main cutting edge is the opposing lower surface or upper surface side in the direction intersecting with this main cutting edge. The seating surface is flat and has a height lower than that of the main cutting edge via the breaker groove in the central direction intersecting the main cutting edge (upper surface and lower surface). It is characterized by being present. Further, the breaker groove is characterized in that it is gradually widened from the side of the auxiliary cutting edge along the main cutting edge. Further, the breaker groove is provided with a first inclined surface which is inclined upward in the central direction of the rake surface of the main cutting edge,
Further, the wide area of the breaker groove is characterized by being provided with a second sloped surface that is more gently sloped than the first sloped surface.

Further, the throw-away tip is a negative type, and the lower surface has the same shape as the upper surface and is rotationally symmetrical in the vertical direction. The seating surface is connected to the rake surface of the auxiliary cutting edge having a positive rake angle. Further, the throw-away tip has a substantially square plate shape.

The throw-away cutter according to the present invention is
A throw-away tip is attached so that the axial rake angle is -4 ° or less, the corner angle is 25 ° to 60 °, and the cutting edge tilt angle is 0 ° or more. In the throw-away type cutter configured to discharge, the throw-away tip has a throw-away tip.
The throw-away tip described in any one of 1.

The axial rake angle is preferably-
The angle is in the range of 4 ° to -10 °, and more preferably in the range of -5 ° to -7 °. The true rake angle is preferably -5.
Less than °, up to -20 °, more preferably -1
It is set within the range of 0 ° to -15 °. Further, a throw-away tip may be mounted so as to further satisfy the following equation: tanI = tanA.secCH-tanT.tanCH.

[0013]

According to the throw-away tip of the present invention,
The main cutting edge is inclined to the lower surface side in the direction away from the sub cutting edge, so that the chip discharging property is good, the rake angle is positive, and the sharpness is good, and moreover, it is flat on the center side of the upper and lower surfaces. Since the seating surface is provided, the seating stability is good when it is mounted on the cutter, the thickness of the entire chip is improved, and the chip strength is increased without cracking or chipping during cutting. Since this seating surface is lower than the main cutting edge, chip clogging is less likely to occur, the cutting load is reduced, and the chip discharge performance is further improved.

Further, at the time of low cutting, the thin chipping is curled without extending long due to the breaker groove having a narrow width, and is smoothly discharged, and at the time of deep cutting, the width of the breaker groove becomes wide, so that the flow of chips is increased. Will get better. Chips running along the rake face of the main cutting edge come into contact with the first inclined surface of the breaker groove at the time of low and medium cutting and are curled, and at deep cutting, the chips flow along the second inclined surface. It is preferably curled and ejected.

According to the throw-away type cutter of the present invention, it is possible to generate and discharge the spiral-shaped chips, and at that time, even when both the axial rake angle and the radial rake angle are negative. Yes, compared to the case where a parallel plate throw-away tip is mounted, both the substantial cutting edge tilt angle and the true rake angle can be made to be a positive angle. The sharpness is improved and the seating stability is good. Further, by mounting the throw-away tip of the present invention, both the substantial cutting edge tilt angle and the true rake angle are positive even when compared with the case where the parallel plate type throw-away tip is mounted under the same conditions. It is possible to make it larger in the forward direction such as making it into a corner, and the chip discharging property and sharpness are improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a perspective view of a throw-away tip according to an embodiment of the present invention, FIG. 2 is a plan view, FIG. 3 is a front view, FIG. 4 is a sectional view taken along line EE of the throw-away tip shown in FIG. 2, and FIG. Similarly, a sectional view taken along the line FF, and FIG.
FIG. 7 is a sectional view taken along line V-V of FIG. The throw-away tip 12 shown in FIGS. 1 to 7 is of a negative type and has, for example, a substantially square plate shape. The upper surface 13 and the lower surface 14 facing each other are formed with the same chip shape that is rotationally (reversed) symmetrical in the vertical direction. Therefore, the shape of the upper surface 13 (or the lower surface 14) will be mainly described, and the ridgeline that forms each side where the upper surface 13 and the side surface 15 intersect is the main cutting edge 16, and the chamfered surface is obtained by chamfering each corner in the vertical direction. A ridgeline at which 17 (included in the side surface) and the upper surface 13 intersect each other is a sub cutting edge 18.

The sub-cutting edges 18 formed at the respective corners of the upper surface 13 are located on the imaginary horizontal plane and have the same height. Further, the boundary between the chamfered surface 17 and the side surfaces 15 on both sides thereof is a chamfered surface 17a (included in the side surface) having an R-shaped curved surface.
The ridge lines intersecting with and are arc-shaped cutting edges 19, 19. Note that the chamfered surface 17a and the cutting edge 19 may be omitted, but it is preferable that they are provided at least between the sub cutting edge 18 and the main cutting edge 17 to prevent chipping. Further, one or both of the chamfered surfaces 17a, 17a may be flat. Then, each main cutting edge 16 is formed so as to be linearly inclined so as to gradually approach the lower surface 14 side in the direction away from the sub cutting edge 18 along the longitudinal direction thereof (inclination angle β:
(See FIG. 3), adjacent to the auxiliary cutting edge 18 in the corner, the auxiliary cutting edge 18 is inclined steeply upward and is connected to the adjacent auxiliary cutting edge 18. or,
A through hole 21 for screw clamping is formed in the center of the upper and lower surfaces 13 and 14.

On the upper surface 13, the rake face 22 of the main cutting edge 16 is inclined so as to gradually approach the lower surface side in the central direction (direction of the through hole 21) intersecting with the main cutting edge 16, and the rake angle α is It is substantially constant in the longitudinal direction of the cutting edge 16. In the plan view shown in FIG. 2, the rake face 22 is formed so that the width thereof becomes gradually narrower along the main cutting edge 16 from the side of the sub cutting edge 18 (constant width or gradually widening. Good). The rake face 22 is curved in the vicinity of the adjacent sub cutting edge 18 and is steeply inclined upward, and is connected to the rake surface 23a of the adjacent sub cutting edge 18. Also, sub cutting edge 1
8 and the cutting edge 19 between the main cutting edge 16 also has a rake face 23b
Are formed. The rake surfaces 23a and 23b of the auxiliary cutting edge 18 and the cutting edge 19 are also inclined so as to gradually approach the lower surface side in the central direction away from each cutting edge to form a positive rake angle.

Then, as shown in FIGS. 1 and 3, a flat seating surface 25, which is substantially in the shape of a girder in plan view, is formed around the through hole 21 in the upper surface 13, and the seating surface 25 is A substantially V-shaped ridge line portion 25a is provided so that the distance from each main cutting edge 16 gradually increases in the direction away from the sub cutting edge 18 and becomes narrower in the vicinity of the adjacent sub cutting edge 18. There is. The seating surface 25 is the rake surface 23 of the auxiliary cutting edge 18 at each corner.
a, 23b, etc. Main cutting edge 16 and seating surface 2
The region between 5 and 5 constitutes a breaker groove 26, and in this breaker groove 26, when viewed in a direction intersecting with the main cutting edge 16,
On the center side of the rake face 22, a concave curved portion 27 and a first sloped surface 28 having a gentle upward slope and having a planar shape are sequentially formed (see FIGS. 2, 4, 5, and 6). Face 28
Stands up on the seating surface 25 in a part of the area near the sub cutting edge 18. Further, in a region near the innermost portion of the ridge line portion 25a of the seating surface 25, which is away from the auxiliary cutting edge 18, between the first sloped surface 28 and the seating surface 25, the slope is gentler than the first sloped surface 28. An inclined, convex curved second upward slope 29 is formed.

The throw-away tip 12 constructed as described above is mounted on the throw-away type cutter 9 shown in FIG. 9, and for example, the same angle as in the above-mentioned prior art, that is, the axial rake angle A is -4 to -10.゜, corner angle CH is 2
Tip 1 in the range of 5 to 60 ° and cutting edge tilt angle I of + 5 ° or more
Set the blade edge angle of and install it so as to satisfy the formula (6) tanI = tanA · secCH−tanT · tanCH. In addition, as a precaution, the line of the main cutting edge serving as a reference for setting the axial rake angle and the like corresponds to the main cutting edge 5 of the parallel plate tip of the prior art, and the adjacent sub cutting edges of this embodiment. A virtual line connecting 18 and 18 is assumed.

Then, regarding the cutting edge inclination angle I, since the main cutting edge 16 of the chip 12 has the inclination angle β, the substantial cutting edge inclination angle becomes (I + β) in the positive direction, and the spiral cutting chips Emissions are improved. As for the true rake angle T, since the rake face 22 of the tip 12 has the rake angle α, the substantial true rake angle is (T + α), which also becomes large in the positive direction, resulting in sharpness. Will be improved. Then, by selecting each numerical value, both the substantial cutting edge inclination angle and the true rake angle can be made positive.

When the throw-away tip 12 according to the present embodiment is mounted on the cutter 9, numerical values of the respective angles are given as follows: the axial rake angle A is -5 ° 03 'and the radial rake angle R is -14 °. 46 ', corner angle CH is 44
47 °, true rake angle T is -14 °, cutting edge inclination I is 7
It becomes ゜. In this case, the substantial cutting edge inclination angle I is (+ β
)), The true rake angle T further increases by (+ α °) toward the conformal side.

In the throw-away tip 12 according to the present embodiment constructed as described above, the breaker groove 26 is gradually widened from the side of the auxiliary cutting edge 18 along the main cutting edge 16, so that at the time of low cutting depth. Since the breaker width is narrow, the thin chips that are produced tend to curl without extending for a long time.
At the time of middle cutting, the chips contact the first inclined surface and are curled, and at the time of deep cutting, the chips flow smoothly because the breaker width is wide, and moreover the second inclined surface 29 is gentler than the first inclined surface 28. The contact flow and the curl cause the chip flow to become smoother and prevent chip clogging, which has the advantage that the cutting load is small.
Further, since the seating surface 25 is located at a position lower than the main cutting edge 16 in both low, medium and deep cuts, chip clogging is unlikely to occur, and the flow smoothly flows out. Moreover, the throw-away tip 12 has the upper and lower surfaces 13,
The seating surfaces 25 provided on the respective 14 improve the thickness of the entire chip without causing cracks or chips.
High chip strength. In particular, since this seating surface 25 extends in the direction of the sub cutting edge 18 at each corner, the seating stability on the cutter and the chip strength near the corner are high. Moreover, since the negative type is used, there is an advantage that the die-press molding can be facilitated and the strength of the cutting edge can be maintained.

In the throw-away type cutter according to this embodiment, the rake face 22 of the main cutting edge 16 causes the rake angle α to increase.
The sharpness is improved and the inclination angle β is added to improve the chip discharge performance.Compared with the one equipped with the parallel plate throw-away tip,
The sharpness of the cutting blade 16 can be improved and the spiral-shaped chip discharging property can be improved without changing (may be changed) the mounting condition of the cutter 9 for discharging the spiral-shaped chips. . The indexable insert 12 having the upper and lower surfaces 13 and 14 provided with the main cutting edge 16, the sub cutting edge 18 and the like, respectively, has a plurality of sub cutting edges 18 on each surface located on the same virtual plane. It has the advantage that the blade shape and its position do not change even if the corner is changed.

When the throw-away tip 12 according to this embodiment is mounted on the cutter 9, the rake angle α and the inclination angle β of the main cutting edge 16 are set,
The same angle as the prior art, that is, the axial rake angle A is −
4 to -10 °, the corner angle CH is 25 to 60 °, and the cutting edge inclination angle I is set to + 5 ° or more, the tip angle of the tip 1 is set, and the equation (6) tanI = tanAsecCH-tanTtanC It is not always necessary to wear it in a satisfactory manner.

Next, the throw-away tip 1 of this embodiment.
The mounting condition for mounting the cutter 2 on the cutter 9 and improving the chip discharge property and the sharpness will be described. That is, if the formula (2) is transformed from the above-mentioned Kronenberg calculation formula,
The following expression (7) is obtained. tanR = (tanA * cosCH-tanI) * cosecCH (7) tanT = tanR * cosCH + tanA * sinCH (1) tanI = tanA * secCH-tanT * tanCH (6) tanR = tanT * cosCH-tanI * sinCH (4) And In the relationship between the above-mentioned conditions of the prior art and FIG. 11, the values of the axial rake angle A and the cutting edge inclination angle I or the true rake angle T are set as the conditions in Table 1 below, and the corner angle C is set.
When H = 25 °, 45 °, 60 °, and substituting in the above formulas (7), (1), (4), and (6), the radial rake angle R and the true rake angle T or The cutting edge inclination angle I is as shown in Table 1 below.

[0027]

[Table 1]

In Table 1, if the axial rake angle A is -4 °, the cutting edge inclination angle I is + 5 °, and the corner angle CH is smaller than 25 °, the left lower limit of the usable area in FIG. 11 is exceeded. This means that the true rake angle T is too small. As a condition, the axial rake angle A is −
At 4 °, the true rake angle T is -20 ° and the corner angle C is
When H is larger than 60 °, the radial rake angle R is as shown in FIG.
In the vicinity of the right upper limit of the usable area of, and the true rake angle T exceeds -20 °, it becomes too small.

By the way, according to the throw-away tip 12 of the above-described embodiment of the present invention, since the main cutting edge 16 is provided with a positive angle of the inclination angle β °, the cutting edge inclination angle I is further negative. Can be set to. That is, from the above-mentioned conventional technique, it is sufficient that β + I = + 5 °, and I = 5 ° -β (8). Then, when β = 5 ° is set, the angle of inclination of the cutting edge I is 0 °, and the tangled chips can be discharged. Moreover, by increasing the cutting edge inclination angle I toward the negative angle side, the amount of the negative angle of the true rake angle T that affects the sharpness can be reduced (see Table 2).

[0030]

[Table 2] However, if the cutting edge tilt angle I is set to a negative angle (for example, -4 °) as shown in the lower column of Table 2, the true rake angle T becomes too small and the clearance angle on the outer peripheral side becomes insufficient. Is not preferable.

Therefore, the cutting edge inclination angle I has a relationship with the axial rake angle A, but in use, as shown in Table 3 below, A = -6 ° and I = 0 ° is a preferable limit. It can be said that there is.

[Table 3]

In order to attach the throw-away tip 12 according to the embodiment of the present invention to the cutter 9 and discharge the spiral-shaped chips, the corner angle CH is 25 to 60 ° and the cutting edge inclination angle I is 0.
The axial rake angle A may be -4 ° or less, preferably -4 ° to -10 °, and more preferably -5 ° to -7 ° in the range of ≧ °. The true rake angle T is insufficient at the outer peripheral clearance at 0 °, but may be set to any negative angle (minus), preferably less than -5 ° and up to -20 °, more preferably -10 °. It is in the range of -15 °. In particular, if a numerical example of a practically effective wearing posture is shown, the corner angle CH = 45
Axial rake angle A = -6 ° and cutting edge tilt angle I near ゜
= 4 °, radial rake angle R = -11.3
1 °, true rake angle T = -12 ° 20 '. For the throw-away tip 12, the rake angle α = 25
When the inclination angle β of the main cutting edge 16 is 10 °, the substantial cutting edge inclination angle I is about 14 ° and the true rake angle T is about 13 °.

In the above embodiment, the throw-away tip 12 has a substantially square plate shape, but the present invention is not limited to this, and it is possible to use a substantially diamond plate shape, a substantially rectangular plate shape, a substantially parallelogram plate shape, or the like. It goes without saying that an appropriate polygonal shape such as a substantially quadrangular plate shape or a substantially triangular plate shape can be used. The first inclined surface 28 of the breaker groove 26 is not limited to a flat surface, but may be a concave curved surface or a convex curved surface.
Is not limited to a convex curved surface, but may be a concave curved surface or a flat surface.
Further, the main cutting edge 16 and the sub cutting edge 1 of the throw-away tip 12
Honing and flat lands may be provided on 8 and the like. Although the rake angle α is constant in the above-mentioned embodiment, the rake face 22 may be formed so as to gradually increase or decrease along the main cutting edge 16. Further, the inclination angle β is also made constant so that the main cutting edge 16 is formed to be linearly inclined. However, instead of this, the inclination angle β changes in the longitudinal direction of the main cutting edge 16. It may be configured to be gradually changed so as to be gradually inclined toward the lower surface in the direction away from the auxiliary cutting edge 18. For example, the main cutting edge 16
However, the inclination angle β may be changed to form a concave curve shape or a convex curve shape, and further, it may be configured to gradually approach the lower surface in a direction away from the auxiliary cutting edge 18. This makes it possible to appropriately adjust the degree of chip strength and chip discharge property.

[0034]

As described above, in the throw-away tip according to the present invention, the main cutting edge is inclined so that the main cutting edge gradually approaches the opposing lower surface or upper surface side in the direction away from the sub cutting edge, and the main cutting edge is scooped. The surface is inclined so as to gradually approach the opposing lower surface or upper surface side in the direction intersecting with the main cutting edge,
In the central direction that intersects the main cutting edge, through the breaker groove,
Since a flat seating surface that is lower in height than this main cutting edge is formed, sharpness and chip discharge performance are good, and since the seating surface is lower than the main cutting edge, chip clogging is less likely to occur and cutting The load is reduced, and the chip discharging property is further improved. Further, the seating surface provides good seating stability when mounted on the cutter, the thickness of the entire chip is improved, and the chip strength is high without cracking or chipping. Further, since the breaker groove is formed so as to gradually widen from the side of the auxiliary cutting edge along the main cutting edge, at the time of low cutting, the chip is curled without extending long due to the narrow breaker groove. , It is discharged smoothly, and the width of the breaker groove is widened at the time of deep cutting, so that the flow of chips is improved. Further, the breaker groove is provided with a first inclined surface in the upward direction in the central direction of the rake face of the main cutting edge, and in the wide area of the breaker groove, the second inclined surface with a gentler upward inclination than the first inclined surface is provided. Since the inclined surface is provided, the chips running along the rake surface of the main cutting edge are brought into contact with the first inclined surface of the breaker groove to be curled during low and medium cutting, and the chips are cut during deep cutting. The chips flow smoothly along the second inclined surface and are appropriately curled, the cutting load is reduced, and the chips are smoothly discharged.

The throw-away type cutter according to the present invention is
Axial rake angle is -4 ° or less, corner angle is 25
A throw-away type cutter that is equipped with a throw-away tip so that the angle of inclination of the cutting edge is 0 ° to 60 ° and is 0 ° or more, and that generates and discharges spiral-shaped chips during cutting. Since the insert is the throw-away insert according to any one of claims 1 to 3, it is possible to generate and dispose of a spiral-shaped chip, and at that time, the axial rake angle and the radial rake angle are different. It is possible even when both are negative, and compared to the case where a parallel plate-shaped throw-away tip is mounted, both the substantial cutting edge tilt angle and the true rake angle can be made positive, such as making it larger in the positive direction. Therefore, the chip discharging property and the sharpness are improved, chip clogging is less likely to occur, and the seating stability is good. Further, by mounting the throw-away tip of the present invention, both the substantial cutting edge tilt angle and the true rake angle are positive even when compared with the case where the parallel plate type throw-away tip is mounted under the same conditions. It is possible to make it larger in the forward direction such as making it into a corner, and the chip discharging property and sharpness are improved.
Moreover, the seating stability is good, the chip flow is smooth, and the cutting load is small.

[Brief description of drawings]

FIG. 1 is a perspective view of a throw-away tip according to an embodiment of the present invention.

2 is a plan view of the throw-away tip shown in FIG. 1. FIG.

3 is a front view of the throw-away tip shown in FIG. 1. FIG.

FIG. 4 is a sectional view of the throw-away tip shown in FIG. 2 taken along the line EE.

5 is a cross-sectional view taken along line FF of the throw-away tip shown in FIG.

6 is a cross-sectional view taken along line GG of the throw-away tip shown in FIG.

FIG. 7 is a sectional view taken along line VV of the throw-away tip shown in FIG.

FIG. 8 is a perspective view of a conventional throw-away tip.

9 is an explanatory view of a main part of a cutter to which the throw-away tip shown in FIG. 8 is attached.

FIG. 10 is a diagram showing a relationship among a cutting edge inclination angle, a true rake angle, and a corner angle.

FIG. 11 is a diagram showing a relationship between a radial rake angle and a corner angle.

[Explanation of symbols]

 12 Throw-away tip 13 Upper surface 14 Lower surface 16 Main cutting edge 18 Sub cutting edge 22 Rake surface of main cutting edge 25 Seating surface 26 Breaker groove 28 First inclined surface 29 Second inclined surface

Claims (4)

[Claims] 1. A throw-away tip in which a main cutting edge and a sub cutting edge are respectively provided on ridge lines where upper and lower surfaces and side surfaces facing each other intersect each other, wherein the main cutting edge is separated from the sub cutting edge. Direction, inclined so as to gradually approach to the opposing lower surface or upper surface side, the rake face of the main cutting edge is inclined so as to gradually approach to the opposing lower surface or upper surface side in the direction intersecting with the main cutting edge. A throw-away tip characterized in that a flat seating surface having a height lower than that of the main cutting edge is formed in a central direction intersecting the main cutting edge via a breaker groove. 2. The throw-away tip according to claim 1, wherein the breaker groove is formed so as to gradually widen from the auxiliary cutting edge side along the main cutting edge. 3. The breaker groove is provided with a first sloping surface that is upwardly inclined toward the center of the rake face of the main cutting edge, and the wide area of the breaker groove is more gently sloping than the first sloping surface. The throw-away tip according to claim 1 or 2, wherein a second inclined surface having an inclination is provided. 4. A throw-away tip is attached so that the axial rake angle is −4 ° or less, the corner angle is 25 ° to 60 °, and the cutting edge inclination angle is 0 ° or more, and it is a spiral coil at the time of cutting. A throw-away type cutter configured to generate and discharge chips, wherein the throw-away tip is the throw-away tip according to any one of claims 1 to 3.