JP2001009628A - Throw-away tip and throw-away type cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform excellent finish cutting machining even when a tip mounting attitude deviates. SOLUTION: At the corner part 14 of a tip upper surface, a main cutting edge 13 is formed on one side of a corner blade 15 and an auxiliary cutting edge 16 on the other side. The corner blade 15 is parallel to a tip under surface, the clearance angle of a corner blade first flank 21 is varied and gradually changed such that a central part is negative and the angles at two ends are brought into 15 deg.. The auxiliary blade 16 is gradually increased in height throughout a portion extending from a connection point (a) to the main cutting edge 13 to a connection point (d) to the corner blade 15, and formed approximately in an arcuate shape where a protrusion toward the outside is formed in a plan. An auxiliary cutting edge first flank has a clearance angle varied and gradually increased throughout a portion extending from the corner blade first flank 21 to the connection point (a) and forming a positive clearance angle. When a tip is mounted on a cutter, the auxiliary cutting blade 16 forms a face cutting edge.

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 and a throw-away type cutter, such as a face mill or an end mill, to which the throw-away tip is mounted. The present invention relates to a throw-away tip and a throw-away type cutter capable of performing right-angle cutting (cutting a shoulder wall by 90 degrees) of a work material.

[0002]

2. Description of the Related Art Conventionally, as this kind of indexable insert, for example, as shown in FIGS. 12 and 13, there is an approximately square plate-shaped insert 2 attached to the outer peripheral side of the front end of a face mill 1. This indexable tip 2 is shown in FIG.
As shown in FIG. 2, the upper surface 4 is opposed to the lower surface 3 forming the seating surface, and the four peripheral side surfaces 5 form a plane inclined outward from the lower surface 3 toward the upper surface 4. Each side 5 and top 4
Each of the ridges formed by ridge lines intersecting with each other forms a main cutting edge 6, and a sub-cutting edge 7 is formed near the corner 4a on the same ridge of each main cutting edge 6. The upper surface 4 forms a rake face, the side face 5 forms a flank of the main cutting edge 6 and the sub-cutting edge 7, and the main cutting edge flank and the sub-cutting flank are on the same plane (side face 5). Is formed. In the center of the upper surface 4,
An insertion hole 8 is formed through the upper and lower surfaces to mount and fix the chip 2 to the front milling cutter 1.

When such a throw-away tip 2 is attached to a mounting seat at the outer peripheral end of the face mill 1, a positive angle α (not shown) is formed with respect to the rotation axis O of the cutter body 1a. Position with an axial rake angle. In addition, a negative angle β (not shown) is formed with respect to the radial axis of the cutter body 1a.
Position it with a negative radial rake angle.
When the work material W is to be cut at a right angle (90 ° shoulder wall cutting) with such a cutter 1, as shown in FIG. 13, the work is cut by the main cutting edge 6 located on the outer peripheral side of the cutter of the indexable insert 2. It is cut so as to form a right-angled wall surface of the material W, and the sub cutting edge 7 outside the ridge portion located on the tip side has a cutting angle defined by a positive axial rake angle and a negative radial rake angle. The right angle cutting can be performed with the plate-shaped chip 2.

[0004]

However, in the face milling machine 1 as described above, since the indexable insert 2 is arranged so that the sub cutting edge 7 is formed in a straight line and is subjected to finish cutting, the indexable insert 2 has a front face. If the auxiliary cutting edge 7 is mounted so as to be parallel to the processing surface to be finished in the state where the chip is mounted on the milling cutter 1, finishing can be performed with high precision. However, when the chip is mounted, the mounting position of the chip 2 may be slightly inclined. When the cutter W is mounted at a wrong angle, the cutter W is fed in a direction perpendicular to the rotation axis O of the cutter main body 1a, and is intermittently cut. The problem that remarkably worsens occurs. In addition, in such a case, there is a disadvantage that the sub cutting edge 7 and the corner blade are easily damaged and the life of the chip is shortened.

In view of such circumstances, the present invention provides a throw-away insert and a throw-away type cutter which have a good finished surface roughness even if the mounting position to the cutter is shifted and which can prolong the cutting edge life. The purpose is to provide.

[0006]

In the indexable insert according to the present invention, the ridge of the upper surface facing the seating surface forms a cutting edge, and the cutting edge is provided on one side with the corner blade provided at the corner of the ridge. In a throwaway chip in which a main cutting edge is provided and a sub cutting edge is provided on the other side, and a top face is a rake face and a side face from the seating face to the top face is a flank face, the sub cutting edge is viewed in plan. And is formed in a convex curve shape. When cutting the work material with the indexable insert attached to the cutter, even if the mounting angle of the indexable insert with respect to the cutter is slightly displaced when performing finishing cutting etc. with the sub-cutting edge, the work surface of the work material Since the sub-cutting edge having a convex curve comes into contact with the sub-cutting edge to perform the cutting process, the shape of the cutting area of the sub-cutting edge hardly changes, so that good cutting can be performed.

In the side surface, the first flank of the sub-cutting edge connected to the sub-cutting edge may be a torsion flank whose clearance angle gradually increases from the connection with the corner blade toward the other end of the sub-cutting edge. Good. Regarding the sub-cutting edge, the area closer to the corner cutting edge where the cutting is performed has a smaller clearance angle, so that the cutting edge angle is larger and the fracture resistance is higher. The secondary cutting edge may be inclined so that the distance from the connection with the corner blade to the other end gradually decreases with respect to the seating surface. When the incision cutting is performed, the workpiece gradually contacts from the corner blade toward the sub-cutting edge for performing the finish cutting, so that even when used in intermittent cutting, the impact is small and the fracture resistance is high.

[0008] Further, a twisted flank may be provided so that the clearance angle gradually increases from the center of the first flank of the corner blade connected to the corner blade to the first flank of the sub cutting edge.
By gradually increasing the clearance angle from the corner blade performing the incision cutting to the sub-cutting edge performing the finish cutting, the angle of the tool near the center of the corner blade increases, and the fracture resistance is high. Another main cutting edge may be connected to the other end of the sub cutting edge, and the sub cutting edge may project outward (upper surface) from the other main cutting edge in plan view. At the time of finish cutting with the sub-cutting edge, the other main cutting edges not used for cutting connected to the sub-cutting edge do not come into contact with the processing surface and do not deteriorate the finished surface roughness. The main cutting edge is formed so as to gradually approach the seating surface from the connection with the corner blade toward the connection with the other sub-cutting edge, and the flank of the main cutting edge is the main cutting edge. The flank of the sub-cutting edge has a flank and a second flank of the main cutting edge, and the flank of the sub-cutting edge has a sub-cutting edge first flank and a sub-cutting second flank having a smaller flank angle. The flank may have a larger clearance angle than the second flank of the main cutting edge, and the side closer to the seating surface may be formed wider.

[0009] The indexable cutter according to the present invention comprises:
A throw-away type cutter which is mounted on the outer periphery of the tool body such that one or more indexable inserts have a radial rake angle of negative (negative angle) and an axial rake angle of positive (positive angle). , Wherein the throw-away tip is the throw-away tip according to any one of claims 1 to 5. Attach the indexable insert to the cutter body so that the corner part is located at the outer peripheral part of the tip and cut and cut, the main cutting edge connected to one end of the corner blade as the outer peripheral blade, and the sub cutting edge connected to the other end as the front blade. Can be used for shoulder milling.

[0010]

FIG. 1 is a block diagram showing an embodiment of the present invention.
11 to FIG. 11, the same parts as those in the above-described conventional technique are denoted by the same reference numerals, and description thereof is omitted. FIG.
2 is a side view, FIG. 3 is a bottom view, FIG. 4 is a side view of a main part of the sub cutting edge viewed from the flank direction, and FIG. 5 is a corner portion. FIG. 6 is a cross-sectional view taken along the line AA in a direction intersecting the sub cutting edge at the corner shown in FIG. 5, FIG. 7 is a cross-sectional view taken along the line BB, FIG. 9 is a side view showing a longitudinal section of a part of the face milling machine equipped with the chip according to the embodiment, FIG. 10 is a side view of the face milling machine shown in FIG. 9, and FIG. 11 is a side view of the face milling machine shown in FIG. It is a bottom view.
In FIGS. 1 to 3, the throw-away tip 10 according to the present embodiment has a substantially polygonal plate shape, for example, a substantially quadrangular (substantially square) plate shape, and a lower surface 11 serving as a seating surface.
And an upper surface 12 facing the same. Main cutting edges 13 are respectively formed on the ridges of the ridges forming substantially four sides of the upper surface 12, and arc-shaped corner blades 15 are provided on the four corners 14, respectively. The main cutting edges 13, 13 of two adjacent ridges are substantially orthogonal to each other (see FIG. 1).

In each corner 14, a main cutting edge 13 is disposed on one ridge connected to the corner blade 15, and the other ridge is substantially convex curved in plan view, for example, having a large diameter. A sub-cutting edge 16 having a substantially circular arc shape having a radius r (for example, r = 200 mm) is formed. This sub-cutting edge 16 is connected to another main cutting edge 13 at a connection point a at the same ridge. Moreover, the main cutting edge 13 and the sub cutting edge 16 forming the same ridge are arranged such that the main cutting edge 13 is retracted toward the center of the upper surface 12 with respect to the sub cutting edge 16 in plan view. Next, the upper surface 12 has a recess gradually inclined toward the lower surface 11 so that the inner side of each ridge provided with the main cutting edge 13, the sub-cutting edge 16, and the corner blade 15 becomes smaller in distance from the lower edge 11 than the ridge. A positive or rake face 12 </ b> A having a curved or planar shape is provided, and an insertion hole 18 for tip screw penetration penetrating to the lower surface 11 is formed in the center of the inside of the rake face 12 </ b> A. Note that a clamp surface or the like for pressing and fixing with a clamp member may be formed at the center. In addition, the four circumferential side surfaces 19 between the lower surface 11 and the upper surface 12 form a plurality of, for example, two-stage flank surfaces having different clearance angles from the upper surface 12 to the lower surface 11 as shown in FIG.

In the corner portion 14 shown in FIGS. 4 and 5, the side surface 19 in the area of each corner blade 15 has a constant width (for example, about 1 mm) crossing the corner blade 15 and extending along the corner blade 15. The portion is the first flank 21 of the corner blade, and the clearance angle θ1 from the center portion to the connection portion with the adjacent sub-cutting blade 16 changes from a negative (θ = 0 °) to a positive angle (eg, θ1 = 15). (°) gradually changes to form a twist relief surface, and is set at a negative clearance angle from the center of the corner blade 15 to the connection with the main cutting blade 13 on the adjacent side. The corner blade 15 is formed at the same distance from the lower surface 11 over the entire length and in parallel with the lower surface 11. The lower area of the first flank surface 21 of the corner blade extends outwardly from the lower surface 11 toward the upper surface 12 and is connected to the first flank surface 21 of the corner blade, and has a positive constant clearance angle θ2 (which is larger than the clearance angle θ1). (For example, θ2 = 15 °). The corner blade second flank 22 is formed in a cylindrical side surface shape.

On the side face 19 in the region of the sub-cutting edge 16 adjacent to the corner cutting edge 14, a small-width sub-cutting first flank 24 intersecting with and extending along each sub-cutting edge 16.
Is formed, and the first flank 24 of the secondary cutting edge is
Connection point a between the sub cutting edge 16 and the main cutting edge 13
Is formed, for example, in a substantially triangular shape so that the width gradually decreases toward. Therefore, the sub-cutting edge 16 is vertically inclined so that the distance from the connection point d with the corner blade 15 to the connection point a with the main cutting edge 13 is gradually reduced so as to gradually decrease the distance from the lower surface 11. The inclination angle changes at a bending point b provided in the vicinity of the connection point a. Here, a portion between the connection point a and the bending point b of the sub cutting edge 16 is defined as an auxiliary sub cutting edge 16a. The secondary flank first flank 24 is a positive flank having a variable flank angle θ3, and at the connection with the corner flank first flank 21, the clearance angle θ3 is equal to θ1 (= 15 °). It gradually increases toward the connection point a with the cutting edge 13 and at the bending point b, for example, 30
°, and the auxiliary flank 24 from the bending point b to the connection point a
The area a is set to a torsional flank having the same clearance angle θ3 (= 30 °). The sub-cutting edge 16 and the sub-cutting first flank 24 are the auxiliary sub-cutting edge 16a and the sub-cutting flank 24.
a may not be provided, and in this case, the sub cutting edge 16 forms a connection point a connected to the main cutting edge 13 at the position of the bending point b.

In the plan view of the corner portion 14 shown in FIG. 5, for example, a cross section taken along the line AA passing through a connection portion d between the sub cutting edge 16 and the corner blade 15, and a BB passing through an intermediate point e of the sub cutting edge 16 are shown.
The line cross section and the cross section taken along line CC passing through the bending point b are shown in FIGS.
7 and 8, the clearance angle θ of the first flank 24 of the sub cutting edge is shown.
3 is a clearance angle θ3 (= θ1) = 15 ° in a cross section taken along line AA,
The clearance angle θ3 = 22.05 ° in the cross section along the line BB, and the clearance angle θ3 = 30.00 ° when the line CC is broken. The sub cutting edge 16 reduces the width thereof while gradually increasing the clearance angle θ3 from the connection point d on the corner blade 15 side to the connection point a, thereby reducing the width of the sub cutting edge 16 as described above. It is formed in a substantially arc shape with a large radius r projecting outside the upper surface 12. The area below the sub-cutting first flank 24 extends obliquely outward from the lower surface 11 toward the upper surface 12, for example, a positive clearance angle θ4 (for example, θ4 = 15 °) equal to or less than the clearance angle θ3.
Is set as the secondary flank second flank 25. The secondary flank second flank 25 is formed in a substantially trapezoidal plane so as to gradually increase in width from the connection region with the secondary flank first flank 24 toward the lower surface 11.

Next, on the side surface 19 in the area of the main cutting edge 13,
A substantially triangular region that intersects with the main cutting edge 13 and extends along the main cutting edge 13 and gradually decreases in width from a connection portion with the corner blade 15 to a connection point a with the sub cutting edge 16 is formed. The main cutting edge is a first flank 26. The clearance angle θ5 of the first flank 26 of the main cutting edge is set to negative (0 °) at the connection with the first flank 21 of the corner blade, and the clearance angle θ3 at the connection point a with the sub cutting edge 16. Therefore, the clearance angle θ5 is 0
It is a torsional flank that changes gradually from ° to θ3. The main cutting edge 13 is formed to be inclined in the vertical direction so that the distance from the connection with the corner blade 15 to the connection point a with the sub cutting edge 16 with the lower surface 11 gradually decreases. The area below the first flank 26 of the main cutting edge extends from the lower surface 11 to the upper surface 12.
And a main cutting edge second flank 27 extending outwardly to a connection region with the main cutting edge first flank 26, the clearance angle θ6 of which is, for example, 12 °, and the main cutting edge first flank. It is larger than the clearance angle θ5 of the surface 26, but smaller than the clearance angle θ4 of the secondary flank 25. The second flank 27 of the main cutting edge forms a substantially trapezoidal plane whose width gradually decreases from the connection area with the first flank 26 of the main cutting edge toward the lower surface 11.

A boundary line 28, which is a boundary between the second flank 27 of the main cutting edge and the second flank 25 of the sub cutting edge, extends on the side surface 19 at an angle with respect to the lower surface 11, and extends along the first cutting edge. Flank 24
And intersects with a perpendicular line b1 lowered from the bending point b to partition the auxiliary flank 24a. Therefore, the main flank second flank 27 extends to the area of the auxiliary flank 24 a of the auxiliary flank first flank 24. Note that the indexable insert 10 has four corner portions 14, that is, four corners, and a main cutting edge 13, a sub cutting edge 16, and a corner cutting edge 15 are provided on each ridge side portion, and the side surface 19 is provided on each side surface 19. Flank surfaces 21, 22, 24, 25, 26 and 27. Honing 28 may be formed on the main cutting edge 13, the sub cutting edge 16, and the corner blade 15 at each ridge.

FIGS. 9 to 11 show a state in which such a throw-away tip 10 is mounted on the front milling machine 1. FIG. When the tip 10 is mounted on the bottom surface 30a of the mounting seat 30 of the cutter body 1a with the lower surface 11 serving as a seating surface, as shown in FIG. The main cutting edge 13 on the ridge side adjacent to the outer peripheral tip side with the blade 15 interposed therebetween is an outer peripheral edge positioned substantially parallel to the rotation axis O of the cutter body (on the drawing). In addition, the indexable insert 10 mounted on the mounting seat 30 of the cutter body 1a is configured such that two adjacent side face supports 30b, 30c of the mounting seat 30 are attached to the main cutting edge second flank 27, 27 is positioned and fixed in a state where it abuts. Further, as shown in FIG. 10, the positioning is performed so that the axial rake angle α is positive, and as shown in FIG. 11, the radial rake angle β is negative.

In particular, the axial rake angle α shown in FIG.
With respect to the side surface 19 located on the outer peripheral surface side of the cutter 1, the main cutting edge 13 serving as the outer peripheral edge is located on the distal end side in the rotation axis O direction so as to form a right-angled wall surface of the workpiece W. The sub cutting edge 16 not involved in the cutting is located at the end side. In addition, since the sub-cutting edge second flank 25, which is the flank on the base end side, has a larger flank angle than the main cutting edge second flank 27, this side surface 19 is formed on the machined wall surface of the workpiece W during cutting. Contact can be avoided. Further, since the main cutting edge 13 is inclined with respect to the lower surface 11, the axial rake angle α can be set to be larger than the inclination angle of the chip 10 itself, and the sharpness can be improved.

Then, the main cutting edge 13 which is an outer peripheral edge is fed in a direction substantially perpendicular to the rotation axis O of the cutter body 1a while performing main cutting to form a right-angled wall surface of the work material W, so that the front edge is moved. Finish cutting of the processing surface is performed with the auxiliary cutting edge 16 to be formed. At this time, the mounting seat 30 of the throw-away tip 10
Even if the mounting posture of the workpiece W is slightly inclined and inclined, the auxiliary cutting edge 16 has a large-diameter arc shape, so that the shape of the contact area with the processing surface of the workpiece W is substantially reduced. Good finish cutting with little change. In particular, the sub cutting edge 16 has a clearance angle θ3 at a connection point d with the corner blade 15.
Is the same as the clearance angle θ1 of the corner blade 15, and the clearance angle θ3 gradually increases as the distance from the corner blade 15 increases. Can be suppressed.

As described above, according to the present embodiment, since the sub-cutting edge 16 is formed to protrude in a substantially arc shape, even if the mounting posture of the throw-away tip 10 with respect to the mounting seat 30 of the cutter body 1a is slightly deviated, the sub-cutting blade 16 can be covered. The finishing process of the sub-cutting edge 16 on the machined surface of the work material W can be performed well, and the finished surface roughness is good. Moreover, the sub cutting edge 16 is non-parallel to the lower surface 11 and rises in a substantially arc shape so that the distance from the connecting point a to the main cutting edge 13 to the connecting point d to the corner blade 15 gradually increases with the lower surface 11. Each cutting edge 1 of the corner portion 14 is inclined and smoothly connected to the corner blade 15 parallel to the lower surface 11 at the time of cutting such as cutting or biting.
The impact on 5 and 16 can be suppressed, and loss can be suppressed. Moreover, in the corner portion 14, the clearance angles θ1 to θ3 extend from the center of the corner blade 15 to the connection point a of the sub-cutting edge 16.
That is, since the angle gradually changes from negative (0 °) to 15 ° to 30 ° to the positive side, the corner blade 15 having the largest impact is used.
The edge strength at the center of the steel is high and the fracture resistance is high. Further, since the sub cutting edge 16 is formed so as to protrude with respect to the main cutting edge 13 at the same ridge side portion, the main cutting edge 13 adjacent to the sub cutting edge 16 to be finish-cut does not come into contact with the processing surface. The finished surface roughness is also good in terms of point.

Each of the flank surfaces of the main cutting edge 13, the sub cutting edge 15, and the corner blade 14 is formed in two steps. However, the present invention is not limited to this structure.
Alternatively, each of the second flank surfaces 22, 25, 27 and thereafter may have a curved surface configuration. In addition, the rake face 12A does not need to be a concave curved face or a flat face, and can be formed in an appropriate shape. For example, a breaker or the like may be provided. The throw-away tip 10 according to the present invention is not limited to a substantially square plate-like shape, but may employ a variety of polygonal-shaped tips having corner portions 14. Also, the cutter to which the indexable insert 10 according to the present invention is mounted is not limited to the face mill 1 but can be applied to various rolling tools such as an end mill.

[0022]

As described above, in the indexable insert according to the present invention, since the sub cutting edge is formed in a convex curve shape in plan view, the throw away tip with respect to the cutter is used for finishing cutting with the sub cutting edge. Good machining with little change in the shape of the cutting area of the sub-cutting edge because the convex curved sub-cutting edge comes into contact with the processed surface of the work material even if the mounting angle of the tip is slightly shifted Can be performed.

In the side surface, the first flank of the minor cutting edge connected to the minor cutting edge is a torsion flank whose clearance angle gradually increases from the connection with the corner blade toward the other end of the minor cutting edge. Since the clearance angle is smaller in the area near the corner blade where the cutting is performed, the blade angle is large and the fracture resistance is high. Also, since the secondary cutting edge is inclined so that the distance from the seating surface gradually decreases from the connection with the corner blade toward the other end, when cutting, the workpiece is gradually cut from the corner blade toward the secondary cutting edge. Since it comes into contact, the impact is small and the fracture resistance is high.

Further, since the flank is formed so as to gradually increase the clearance angle from the center of the first flank of the corner blade to the corner flank to the first flank of the sub-cutting edge, the flank is formed near the center of the corner blade. The blade angle increases and the fracture resistance is high. Another main cutting edge is connected to the other end of the sub cutting edge, and the sub cutting edge protrudes outward from the main cutting edge in plan view. The cutting edge does not contact the machined surface and does not deteriorate the finished surface roughness.

The indexable cutter according to the present invention comprises:
Since the throw-away tip is the throw-away tip according to any one of claims 1 to 5, the throw-away tip is attached to the cutter body so that the corner portion is located at the outer periphery of the tip, and the main tip is connected to one end of the corner blade. The cutting edge can be used as an outer peripheral edge and the auxiliary cutting edge connected to the other end can be used as a front edge for shoulder cutting.

[Brief description of the drawings]

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

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

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

FIG. 4 is a perspective view of a corner portion of the throw-away tip according to the embodiment.

FIG. 5 is a plan view of a corner portion.

FIG. 6 is a vertical sectional view taken along line AA of a corner shown in FIG. 5;

FIG. 7 is a vertical sectional view taken along the line BB of the corner shown in FIG. 5;

FIG. 8 is a vertical sectional view taken along the line CC of the corner shown in FIG. 5;

FIG. 9 is a side view showing the front milling cutter equipped with the indexable insert according to the embodiment in a partially broken state.

FIG. 10 is a side view of a front milling machine equipped with a throw-away tip according to the embodiment.

FIG. 11 is a bottom view of the front milling cutter to which the throw away tip according to the embodiment is attached.

FIG. 12 is a perspective view of a conventional throw-away tip.

FIG. 13 is an explanatory view showing a state in which shoulder milling is performed by a front milling machine to which the throw away tip shown in FIG. 12 is attached.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Face mill 10 Indexable insert 13 Main cutting edge 14 Corner part 15 Corner blade 16 Secondary cutting edge 24 Secondary flank first flank 25 Secondary flank second flank

Continued on the front page (72) Inventor Hiroaki Hayashizaki 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Pref. F-term in Mitsubishi Materials Corporation Tsukuba Works (Reference)

Claims (6)

[Claims] 1. A ridge portion on an upper surface facing a seating surface forms a cutting edge, and a main cutting edge is provided on one side and a sub cutting edge is provided on the other side with a corner blade provided at a corner portion of the ridge portion interposed therebetween. Provided, in a throwaway tip in which the upper surface is a rake surface and the side surface from the seating surface to the upper surface is a flank, the sub-cutting edge is formed in a convex curve shape in plan view. A featured throwaway tip. 2. In the side surface, the first flank of the minor cutting edge connected to the minor cutting edge is a torsion flank whose clearance angle gradually increases from a connection portion with the corner blade toward the other end of the minor cutting edge. The indexable tip according to claim 1, wherein 3. The throw according to claim 1, wherein the sub-cutting edge is inclined so that a distance from a connecting portion with the corner blade to the other end thereof gradually decreases from a connection portion with the corner blade. Away tip. 4. A torsional flank so that a flank angle gradually increases from a central portion of the corner flank first flank connected to the corner blade to a sub cutting edge first flank. 4. The throw-away tip according to any one of 1 to 3. 5. The other main cutting edge is connected to the other end of the sub cutting edge, and the sub cutting edge projects outward from the other main cutting edge in a plan view. The throw-away tip according to any one of 1 to 4. 6. The one or more indexable inserts,
6. A throw-away type cutter mounted on a tip outer peripheral side of a tool body such that a radial rake angle becomes negative and an axial rake angle becomes positive, wherein the throw-away tip is any one of claims 1 to 5. A throwaway type cutter characterized by being a throwaway tip.