JPH09174323A - Throw-away tip and throw-away type cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high cutting performance, increase strength of cutting edges, and improve the service life of a tip. SOLUTION: Main cutting edges 13 and sub-cutting edges 15 are respectively formed in an almost square plate shape in a ridgeline part of an upper surface 12 by sandwiching corner edges 14. A first flank relief 23 of the main cutting edges 13 is formed in the same as a relief angle of a first flank relief 19 of the sub-cutting edges as a twisted flank relief where a relief angle gradually becomes large from a negative on the corner edge 14 side, and a second flank relief 24 of a plane is arranged on the under surface side. Cutting faces 33 of the main cutting edges increas as a relief angle increases, and its width gradually becomes narrow. This tip 10 is installed on the tip outer peripheral side of a cutter main body so that a radial rake angle becomes negative and an axial rake angle becomes positive, and performs right-angled cutting.

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 which are mounted on a throw-away type cutter such as a face mill and an end mill.

[0002]

2. Description of the Related Art Conventionally, for example, as shown in FIGS. 12 and 13, as a throw-away tip of a kind that can be mounted on the outer peripheral portion of the tip of a throw-away type cutter and can cut a work material at a right angle (90 degree shoulder wall cutting). As shown in, there is a substantially square plate-shaped chip 2 attached to the tip outer peripheral side of the face milling cutter 1. As shown in FIG. 12, the throw-away tip 2 has an upper surface 4 that faces a lower surface 3 that forms a seating surface, and its four circumferential side surfaces 5 are flat surfaces that incline outward from the lower surface 3 toward the upper surface 4. I am doing it. The ridgeline where each side surface 5 and the upper surface 4 intersect forms a main cutting edge 6, and each main cutting edge 6
Sub cutting edges 7 are formed in the vicinity of the corners 4a on the same ridge line. Then, the upper surface 4 forms a rake surface, and the side surface 5
Form flanks of the main cutting edge 6 and the sub cutting edge 7, and the main cutting edge flank and the sub cutting edge flank are formed on the same surface (side surface 5). A screw hole 8 is formed in the central portion of the upper surface 4 so as to penetrate the upper and lower surfaces and mount and fix the chip 2 on the face mill 1.

When attaching such a throw-away tip 2 to the seat portion at the outer peripheral side tip of the front milling cutter 1,
The cutter body is positioned with a positive axial rake angle so as to form a positive angle α with respect to the rotation axis L of the cutter body. Moreover, the cutter body is positioned with a negative radial rake angle so as to form a negative angle β with respect to the radial axis M of the cutter body. When attempting to perform a right-angle cutting (90 degree shoulder wall cutting) cutting of the work material W with such a cutter 1, as shown in FIG. 13, with the main cutting edge 6 located on the cutter outer peripheral side of the throw-away tip 2, The workpiece W is cut so as to form a right-angled wall surface, and the auxiliary cutting edge 7 on the outer side of the ridgeline located on the tip side is cut with a positive axial rake angle and a negative radial rake angle. Right angle shaving can be performed with the chip 2.

[0004]

However, in the throw-away tip 2 as described above, the cutter 1 has a positive axial rake angle and a negative radial rake angle.
Since the clearance angles of the main cutting edge 6 and the sub cutting edge 7 are on the same plane (side surface 5), the clearance angle of the main cutting edge 6 becomes excessively positive. Therefore, the cutting edge angle is small over the entire length of the cutting edge, the strength of the cutting edge is small, and chipping is likely to occur, so that there is a drawback that the life of the tip is short.

In view of such circumstances, an object of the present invention is to provide a throw-away tip which has high cutting performance, can increase the cutting edge strength, and can greatly improve the life thereof. To do. Another object of the present invention is to provide a throw-away tip and a throw-away cutter capable of sharpening a right angle, having high cutting performance, increasing the cutting edge strength, and greatly improving the life thereof. To provide.

[0006]

A throwaway tip according to the present invention has a ridge line portion where a first surface and a second surface intersect with each other, and the first surface is a rake surface,
The throw-away tip having the second surface as the flank is characterized in that the rake angle of the rake face increases as the clearance angle of the flank increases along the cutting edge. With regard to this cutting edge, both the clearance angle and the rake angle are small on the low cutting side and the cutting edge strength is high, the cutting resistance is relatively large but the cutting depth is shallow, so there is no problem, and sharpness on the deep cutting side improves. The cutting resistance does not increase and the life of the tip is improved.

In the throw-away tip according to the present invention, the ridge line portion of the upper surface facing the seating surface forms a cutting edge, the upper surface is a rake surface, and the side surface between the seating surface and the upper surface is a flank surface. In the throw-away tip, a sub-cutting edge is provided on one of the two ridges that connect to the corners of the upper surface, and a main cutting edge is provided on the other, along the main cutting edge as the flank of this main cutting edge. The flank is formed so that the flank angle is gradually increased, and the rake face corresponding to the flank flank with the main cutting edge sandwiched between the flank angle increases as the flank angle increases. It is characterized in that it is formed so that the rake angle is gradually increased. The auxiliary cutting edge and the main cutting edge that sandwich the corner of the throw-away tip have an angle slightly larger than a right angle. When this throw-away tip is attached to the cutter so that the radial rake angle is negative and the axial rake angle is positive, the main cutting edge that forms the outer peripheral blade rotates the throw-away type cutter from the tip side to the base end side. It is inclined in a direction closer to the axis, and accordingly,
The twist flank of the main cutting edge is changed so that the flank angle gradually increases along the main cutting edge from the tip to the base end side, so that this flank comes into contact with the machining wall surface of the work material. Since the rake angle of the rake face of the main cutting edge is gradually increased accordingly, the cutting edge strength is high because the relief angle and the rake angle are both small on the low cutting side, and the cutting edge angle is large. The cutting resistance is comparatively large, but the depth of cut is shallow, so there is no problem. On the deep cutting side, sharpness is improved and cutting resistance does not increase. Therefore, the life of the chip is improved as compared with the conventional chip.

Further, the clearance angle of the twist flank face is set to 0 degree negative in the boundary area with the corner portion, and gradually increases in the positive direction along the main cutting edge in the direction away from the corner portion. Good. By minimizing the clearance angle of the twist flank face according to its position, the cutting edge angle of the main cutting edge used at the time of low cutting can be set larger and the cutting edge strength can be increased. The rake face is formed as a downward slope from the main cutting edge side of the breaker groove formed on the upper surface along the main cutting edge to the center direction of the upper surface, and the width of the rake surface is directed toward the direction where the rake angle increases. It may be gradually narrowed. Since the width of the rake face is gradually narrowed from the low-cut side to the deep-cut side, the chips flowing on the rake face tend to curl.
Also, the bottom of the breaker groove (surrounding plane) following the rake face is
It is a plane parallel to the seating surface of the tip. Since the bottom of the breaker groove is parallel to the seating surface, reduction in chip strength is suppressed and strength is secured.

A flat land having a small width is formed on the ridge of the upper surface, and the flat land is formed wide from the auxiliary cutting edge to the corner. The flat land can increase the strength of the cutting edge, and by forming the auxiliary cutting edge wide from the corner portion, it is possible to strengthen the auxiliary cutting edge that is easily damaged during cutting. Further, on the descending inclined surface forming the rake surface, a convex portion protruding from the wide flat land into the breaker groove may be formed. Since the convex portion is formed on the descending inclined surface of the wide portion, the chips generated at the time of low cutting can be easily curled. The twist flank is set with a predetermined width in the thickness direction of the tip from the main cutting edge, and the second flank of the main cutting edge formed between this twist flank and the seating surface is more than the clearance angle of the flank flank. It may be formed in a flat shape with a large clearance angle. By limiting the twist flank to a predetermined width, the second main flank of the main cutting edge can be made large, and if this is used as the side surface receiving portion of the seat portion when the chip is mounted, it will contact at a position closer to the rake face. Therefore, the seating stability is good. The throw-away tip according to the present invention has a substantially quadrangular plate shape in a plan view, a main cutting edge and a sub-cutting edge are formed on the ridges of the four edges of the upper surface, and a corner blade is formed on each corner, and they are adjacent. It is characterized in that the two main cutting edges are orthogonal to each other, and the auxiliary cutting edge is formed inclining toward the inside of the chip by a small angle with respect to the main cutting edge between two adjacent corner cutting edges. This throw-away tip has a secondary cutting edge sandwiching a corner blade and a main cutting edge at an angle slightly larger than 90 degrees, and can be used for right-angle cutting and can also be used for four corners.

The throw-away type cutter according to the present invention is
In the throw-away type cutter, one or a plurality of throw-away tips are mounted on the outer peripheral side of the tip of the cutter body so that the radial rake angle becomes negative and the axial rake angle becomes positive, and the throw-away tip is as described above. A throw-away tip according to any one of (claims). When this throw-away tip is attached to the tip of the outer circumference of the throw-away type cutter and used for cutting,
The main cutting edge on the outer peripheral side performs right-angle wall surface cutting, and the auxiliary cutting edge on the tip side performs incision cutting, enabling right-angle cutting of the work material.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention.
11 to 11, the same parts as those of the above-described conventional art are designated by the same reference numerals and the description thereof will be omitted. FIG.
Is a perspective view of the throw-away tip according to the present embodiment,
2 is a plan view of the throw-away tip shown in FIG. 1, FIG.
Is a side view, FIG. 4 is a sectional view taken along line AA of FIG. 2, FIG. 5 is a sectional view taken along line BB of FIG. 2, and FIG. 6 is a sectional view taken along line CC of FIG.
7 is a sectional view taken along line D-D of FIG. 2, FIG. 8 is an enlarged view of a corner portion of a throw-away tip plane, and FIG. 9 is a partially cutaway side view of a front milling cutter having a throw-away tip according to an embodiment. 10 is another side view of the front milling cutter of FIG. 9, and FIG. 11 is a front view of the front milling cutter of FIG. FIG.
3, the throw-away tip 10 according to the present embodiment has a substantially quadrangular (substantially square in the figure) plate shape, and has a lower surface 11 forming a seating surface and an upper surface 12 facing the lower surface 11. A main cutting edge 13 is formed on each of the ridges forming the four sides of the upper surface 12, and an arcuate corner blade 14 is provided on each corner. The main cutting edges 13 of two adjacent ridge lines are orthogonal to each other (see FIG. 8).

Then, between the main cutting edge 13 and one of the corner blades 14 at each ridge line portion, an inner side of the upper cutting edge 13 is formed by a small angle γ (eg, 1 to 5 degrees) with respect to the main cutting edge 13. An inclined auxiliary cutting edge (cleaning blade) 15 is formed, and the auxiliary cutting edge 15 is smoothly connected to the corner blade 14. Also, the four side surfaces 18 between the lower surface 11 and the upper surface 12 have the upper surface 12 for each cutting edge region as shown in FIG.
From the bottom surface 11 to the bottom surface 11, two flanks having a larger clearance angle are formed.

That is, on the side surface 18 in the area of each sub-cutting edge 15 shown in FIG. 3, each sub-cutting edge 1 intersects with the sub-cutting edge 15 and
5 with a constant width t (for example, 0.5 to 1.5 m)
m) is a constant clearance angle θ1 (for example, 15
Is a planar sub-cutting edge having a first flank 19 and a lower region thereof has a larger clearance angle θ2 than the first flank 19.
(For example, 20 degrees) Secondary cutting edge second flank 20 set
It has been. Then, on the side surface 18 in the area of each corner blade 14, the corner blade 14 intersects with the corner blade 14 and
A portion having a constant width t extending along the adjacent sub-cutting edge 1
From the 5 side toward the main cutting edge 13 side of the adjacent side, the clearance angle is θ
The corner flank first flank 21 is gradually changed from 1 (positive surface) to 0 degree (negative surface). Further, the lower region thereof is a corner blade second flank 22 in which the same clearance angle θ2 as that of the auxiliary cutting edge first flank 20 is set. still,
The corner blade first and second flanks 21 and 22 are each formed in a cylindrical side surface shape that is inclined outward.

Then, on the side surface 18 in the region of the main cutting edge 13, a portion having a constant width t that intersects the main cutting edge 13 and extends along the main cutting edge 13 is the main cutting edge 13 and the corner edge 14. The clearance angle θ3 is set to 0 degree (negative surface) in the boundary area, and the clearance angle θ3 is the clearance angle θ1 (positive surface) of the secondary cutting edge first flank 19 in the boundary area with the auxiliary cutting edge 15. The main cutting edge first flank 23 is gradually changed so as to coincide with.
That is, the main cutting edge first flank 23 has a clearance angle along the main cutting edge 13 from the boundary area with the corner blade first flank 21 to the boundary area with the sub cutting edge first flank 19. Is formed so as to smoothly change from 0 degree to θ1 to form a twist flank. Further, the lower region of the main cutting edge first flank 23 is larger than the clearance angle θ3 of the main cutting edge first flank 23,
It is a flat main cutting edge second flank 24 which is set to the same clearance angle θ 2 as the auxiliary cutting edge first flank 20.

Further, on the upper surface 12, a flat land (rake surface land) 26 having a small width and parallel to the lower surface 11 is formed over the entire circumference from the ridge line portion of the entire circumference forming each cutting edge toward the center side. Moreover, the land 26 is formed with a wide land portion 26a in which a substantially trapezoidal shape and a concave arc are continuously formed in a plan view from the area of each sub cutting edge 15 to the corner blade 14. As shown in the sectional view taken along the line AA in FIG. 4, a recess 27 is formed in the inner region of the flat land 26 on the upper surface 12, and the recess 27 is formed on the entire circumference following the flat land 26. A sloped descending slope 28 and a peripheral flat surface 29 formed from the lowermost part of the slope 28 to the entire circumference and having the same height.
a, an upslope 29b having a small upslope on the center side thereof, and a center bottom surface 30 following the upslope 29b and having a substantially square shape in plan view and parallel to the lower surface 11.
As shown in FIGS. 1 and 2, the ascending slope 29b is formed by arranging convex or concave surfaces in the height direction having an arcuate cross section, for example, to reduce the area of contact with traveling chips. The central bottom surface 30 has a smaller distance from the lower surface 11 than the ridgeline portion of the main cutting edge 13 and the like, and a screw hole 16 for fixing a chip screw is formed in the center thereof (a clamping surface or the like may be used).

Further, the boundary line between the descending inclined surface 28 and the peripheral flat surface 29a is a minute angle about the screw hole 16 with respect to the ridge line forming each cutting edge of the upper surface 12 in the plan view shown in FIG. It is located in a rotating position. Further, the region from the descending inclined surface 28 to the ascending inclined surface 29b constitutes the breaker groove 31, and the peripheral flat surface 29a constitutes the bottom of the breaker groove. Further, the downward inclined surface 28 is provided with a convex portion 32 having a substantially inverted truncated pyramid shape protruding from the wide land portion 26a of each sub cutting edge 15 toward the lowermost portion thereof. The area of the descending sloped surface 28 corresponding to the wide land portion 26a has a radius R and a convex portion 32 forming a truncated pyramidal convex curved surface from the side of the auxiliary cutting edge 15 toward the corner blade 14.
The concave curved surface 32a of 1 is continuously formed, and constitutes a breaker for curling chips when the low cutting depth is cut by the main cutting edge 13.

Further, the descending inclined surface 2 corresponding to each main cutting edge 13
When the region of 8 is the main cutting edge rake face 33, the main cutting edge rake face 33 has a clearance angle of the first cutting edge first flank (twist flank) 23 from the corner blade 14 side to the sub cutting edge 15. As the λ gradually increases, the rake angle δ gradually increases, so that the cutting edge angle μ gradually decreases. That is, in the boundary area between the corner blade 14 and the main cutting edge 13, the clearance angle λ1 of the main cutting edge flank 23
Is set to the minimum 0 degree (negative surface), and the rake angle δ of the main cutting edge rake face 33 corresponding to this is set to the minimum δ1 (see FIG. 5). Then, in the cross section near the center of the main cutting edge 13 (see FIG. 4), the clearance angle λ of the main cutting edge first flank 23
Is λ2 (> λ1), and the rake angle δ of the main cutting edge rake face 33 is δ2 (> δ1). Further, in the boundary region with the auxiliary cutting edge 15 (see FIG. 6), the clearance angle λ of the first flank 23 of the cutting edge is λ3 (= 15 degrees> λ2), and this rake angle δ is δ3.
(> Δ2).

Therefore, as the main cutting edge 13 moves from the boundary with the corner blade 14 toward the boundary with the sub cutting edge 15, the clearance angle λ of the first cutting edge first flank 23 is λ1 (= 0) <λ2 < λ3
(= 15) and correspondingly the main cutting edge rake face 33
The rake angle δ also increases as δ1 <δ2 <δ3. Therefore, the cutting edge angle μ of the main cutting edge 13 is maximum (= μ1) on the low cutting side, and μ2 (<μ1) near the center,
At the boundary with the sub-cutting edge 15, the minimum is μ3 (<μ2), and the cutting edge strength gradually decreases from the low cutting side toward the deep cutting.
Further, the main cutting edge rake face 33 has a maximum width in a boundary area (low cutting side) of the main cutting edge 13 with the corner blade 14, and has a minimum width in a boundary area with the sub cutting edge 15 (deep cutting side). Are formed so as to become (linearly) gradually.

A state in which such a throw-away tip 10 is mounted on the front milling cutter 1 is shown in FIGS. 9 to 11. As shown in FIG. 9, in the mounted state of the tip 10, the auxiliary cutting edge 15 is located on the outer side of the tip as a front cutting edge, and on the outer peripheral tip side, the main cutting edge 13 of the ridge line portion adjacent to the corner edge 14 with the corner blade 14 interposed therebetween. Is the outer peripheral blade positioned parallel to the rotation axis L of the cutter body (in the figure). Also, the chip 10 is
As shown in FIG. 10, the positive axial rake angle α
Then, as shown in FIG. 11, it is positioned so as to have a negative radial rake angle β. In particular, in the chip 10 having the axial rake angle α shown in FIG. 10, with respect to the side surface 18 located on the outer peripheral surface side of the cutter 1, the main cutting edge 13 serving as the outer peripheral blade should form a right-angled wall surface of the work material W. The auxiliary cutting edge 15 that is located on the tip end side in the axial direction and does not participate in cutting is located on the base end side (rear end side). Moreover,
Since the auxiliary cutting edge first flank 19 which is the flank on the proximal end side is closer to the axis L than the main cutting edge first flank 23, the auxiliary cutting edge first flank 19 has a main cutting edge first flank 19. Since the positive clearance angle θ1 is larger than that of the first clearance surface 23, it is possible to prevent the clearance surface 19 from coming into contact with the machining wall surface of the workpiece W during cutting.

In the area of the main cutting edge 13, the clearance angle λ of the primary cutting edge first flank 23 is set to the primary cutting edge first flank 23 because it gradually moves away from the axis L from the base end side toward the tip end direction. It may be gradually smaller than the clearance angle θ1 of the clearance surface 19. Therefore, in the present embodiment, the clearance angle λ of the first cutting edge first flank 23 gradually changes from the base end side (the sub cutting edge first flank surface 19 side) to the tip direction from the positive angle θ1 to 0 degree. By using a twist flank, the minimum necessary clearance angle λ can be set. Moreover, the main cutting edge rake face 33 corresponding to the main cutting edge first flank 23 with the main cutting edge 13 interposed therebetween has the rake angle δ from the base end side toward the tip direction, and the main cutting edge first flank face is formed. As the clearance angle λ of 23 decreases (λ3 to 0 degree), gradually decreases (δ3 to δ1 degree)
Since the cutting edge angle μ of the main cutting edge 13 is large at the low cutting depth, the cutting edge strength at the time of cutting is high. In this case, the cutting resistance is relatively large, but since the cutting depth is shallow, it does not hinder the cutting. Further, at the time of deep cutting, the cutting edge angle μ is gradually reduced, but the rake angle δ is gradually increased, so that the sharpness is improved and the cutting resistance is gradually reduced. Therefore, the cutting resistance of the entire main cutting edge 13 does not increase. In particular, the main cutting edge 13 has a larger length than the sub cutting edge 15 and forms a right-angled wall surface by cutting, so that the work material W is formed.
Since the contact area with is large, the life of the throw-away tip 10 can be greatly improved.

Further, the second flank 24 of the main cutting edge is fixed at a constant angle θ2.
The cutter body 1a shown in FIG.
Two adjacent side surface receivers 35a, 35 of the seat portion 35 of
In b, when supporting each side surface 18 of the throw-away tip 10, the seating stability can be ensured even if a minimum necessary twist escape surface is provided.

As described above, according to the present embodiment, due to the mounting posture of the throw-away tip 10 on the throw-away type cutter 1, the main cutting edge No. 1 of the main cutting edge 13 (which forms the outer peripheral edge). (1) The clearance angle λ of the flank 23 gradually increases from the tip end side toward the base end side, and the rake angle δ of the main cutting edge rake face 33 gradually increases. Since the edge angle μ of 13 is large, the edge strength at the time of cutting is high. At that time, the cutting resistance is relatively large, but the depth of cut is shallow, so that there is no obstacle to cutting. Further, at the time of deep cutting, the cutting edge angle μ is gradually reduced, but the rake angle δ is gradually increased, so that the sharpness is improved and the cutting resistance is gradually reduced. Therefore, the cutting resistance of the entire main cutting edge 13 does not increase. Therefore, as compared with the conventional one, the life of the throw-away tip 10 for right angle cutting can be improved.

Further, by forming the wide land portion 26a in the area of the sub cutting edge 15 of the flat land 26, the sub cutting edge 15 which is likely to be damaged during cutting to the corner blade 14 of the nose portion.
The strength of the cutting edge can be increased over time. Moreover, by providing the convex portion 32 from the wide land portion 26a to the descending inclined surface 28, it is possible to curl the chip as a breaker at the time of the low cutting by the main cutting edge 13 and improve the chip discharging property. . Further, even when making a deep cut, the projection 32 is formed, so that the chips can be curled and guided to the base end side, and the chip discharge performance is good. Moreover, since the main cutting edge rake face 33 is wide on the low cutting side and gradually narrows on the deep cutting side, chips are likely to curl during cutting. Further, when the chips are discharged, the ascending sloped surface 29b of the breaker groove 31 is formed as an uneven surface, so that the contact area with the chips is small, and the traveling of the chips and the suppression of heat generation of the chip can be improved. In addition, the peripheral flat surface 29 forming the bottom of the breaker groove
Since a is parallel to the seating surface 11, it is possible to suppress a decrease in chip strength.

Further, although the corner blade 14 is formed in an arc shape in a plan view in the above-mentioned embodiment, it may be formed in a chamfer. In the embodiment, the flank of the main cutting edge 13 has a two-step configuration, but the present invention is not limited to this, and the main cutting edge first flank 23 has a one-step configuration extending to the lower surface 11, or A structure with three or more steps may be used (sub cutting edge 15
And the corner blade 14 as well).

[0025]

As described above, the throw-away tip according to the present invention is formed so that the rake angle of the rake face increases as the clearance angle of the flank increases along the cutting edge. With regard to this cutting edge, by making both the clearance angle and the rake angle small on the low cutting side, the cutting edge strength is high, the cutting resistance is relatively large, but the cutting depth is shallow, so it does not hinder cutting and deep cutting. Sharpness is improved when cutting, and cutting resistance does not increase. Further, the throw-away tip according to the present invention is provided with a sub-cutting edge on one of the two ridge line portions connected to the corners of the upper surface and a main cutting edge on the other side, and as a flank of this main cutting edge, a main cutting edge is provided. Formed so that the clearance angle gradually increases along the blade,
Since the rake face is formed so that the rake angle increases gradually as the clearance angle of the rake face increases, the throw-away tip has a positive axial rake angle. When attached to the cutter so that the radial rake angle becomes negative,
The main cutting edge that forms the outer peripheral edge is inclined from the tip end side to the base end side in a direction closer to the rotation axis of the throw-away type cutter, and accordingly, the twist relief surface of the main cutting edge is Since the clearance angle gradually increases along the direction from the tip to the base side, it is possible to avoid this clearance surface coming into contact with the machined wall surface of the work material, and the rake angle of the rake surface of the main cutting edge Therefore, the cutting angle is large on the low cutting side and the cutting edge strength is high, and the cutting resistance is comparatively large, but the cutting depth is shallow, so it does not become an obstacle, and the cutting resistance is good when cutting deep. Does not grow.

Further, since the clearance angle of the twist flank is a negative of 0 degree in the boundary region with the corner portion and gradually increases in the positive direction along the main cutting edge in the direction away from the corner portion, the twist flank clearance By minimizing the clearance angle of the surface,
The cutting edge angle of the main cutting edge used at the time of low cutting can be set to be larger, and the cutting edge strength can be increased. Since the width of the rake face gradually narrows in the direction of increasing the rake angle, the chips flowing through the rake face are likely to curl. A small flat land is formed on the ridge of the upper surface, and this flat land is formed wider from the sub cutting edge to the corner, and rises from the wide flat land into the breaker groove on the downward slope that forms the rake face. Since the convex portion is formed, the cutting edge strength can be increased by the flat land, and by forming the width from the auxiliary cutting edge to the corner portion wide, it is possible to strengthen the auxiliary cutting edge that is easily damaged during cutting. The chips generated at the low depth of cut can be easily curled. Since the second main cutting edge flank formed between the twist flank and the seating surface is formed in a plane shape with a clearance angle larger than the clearance angle of the twist flank, the second main cutting edge flat If the flank surface is used as the side surface receiving portion of the seat portion when the tip is mounted, the seating stability is good because the flank surface abuts at a position closer to the rake surface.

The throw-away type cutter according to the present invention is
Since the throw-away tip is the throw-away tip according to any one of claims 2 to 6, the main cutting edge on the outer peripheral side of this throw-away tip is used to perform right-angle wall milling, and the auxiliary cutting edge on the tip side. Incision cutting will be performed, and the work material can be cut at right angles.

[Brief description of the 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 side 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 AA.

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

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

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

FIG. 8 is an enlarged view of a corner portion of the throw-away tip shown in FIG.

FIG. 9 is a partially cutaway side view of the front milling cutter to which the throw-away tip according to the embodiment is attached.

FIG. 10 is another side view of the front milling cutter shown in FIG. 9.

FIG. 11 is a front view of the front milling cutter shown in FIG. 9.

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

FIG. 13 is a partial cross-sectional view showing a state of right-angle cutting by a front milling cutter equipped with a conventional throw-away tip.

[Explanation of Codes] 1 ... Face milling machine, 10 ... Throw-away tip, 11
... Lower surface, 12 ... Upper surface, 13 ... Main cutting edge, 14 ... Corner blade, 15 ... Sub cutting edge, 18 ... Side surface, 19 ... Sub cutting edge first flank, 23 ... Main cutting edge first flank, 24 ... Main cutting edge second flank surface, 28 ... Downward sloping surface, 26 ... Flat land, 26a ... Wide land portion, 32 ... Convex portion, 33 ... Main cutting edge rake surface.

Claims (7)

[Claims] 1. A ridge line portion where a first surface and a second surface intersect forms a cutting edge, and the first surface is a rake surface,
In the throw-away tip in which the second surface is a flank, the rake angle of the rake face is formed to increase as the clearance angle of the flank increases along the cutting edge. Throw away tip. 2. A throw-away tip in which a ridge line portion of an upper surface facing a seating surface forms a cutting edge, the upper surface is a rake surface, and a side surface between the seating surface and the upper surface is a flank surface, A sub-cutting edge is provided on one of the two ridge lines connected to the corners of the upper surface and a main cutting edge is provided on the other, and the relief angle of this main cutting edge is gradually increased along the main cutting edge. And a rake face, wherein the rake face is formed such that the rake angle thereof gradually increases as the clearance angle of the twist flank face increases. A throw-away tip to do. 3. The clearance angle of the twist flank is negative at 0 degrees in the boundary region with the corner portion, and gradually increases in a positive direction along the main cutting edge in a direction away from the corner portion. The throw-away tip according to claim 2. 4. The rake face is formed as a descending slope of a breaker groove formed on the upper surface along the main cutting edge from the main cutting edge side toward the center of the upper surface, and the width of the rake surface is the rake surface. The throw-away tip according to claim 2 or 3, wherein the throw-away tip is configured to be gradually narrowed in a direction in which the angle is increased. 5. A flat land having a small width is formed on the ridge portion of the upper surface, and the flat land is formed wider from the sub-cutting edge to the corner portion, and the flat land has a large width on the downward inclined surface forming the rake face. The throw-away tip according to any one of claims 2 to 4, wherein a protrusion protruding from a flat land into the breaker groove is formed. 6. The twist flank is set to have a predetermined width in the thickness direction of the tip from the main cutting edge, and the second flank of the main cutting edge formed between the twist flank and the seating surface is twisted. The throw-away tip according to any one of claims 2 to 5, wherein the throw-away tip is formed in a plane shape with a clearance angle larger than the clearance angle of the clearance surface. 7. One or more throw-away chips,
7. A throw-away type cutter mounted on the outer peripheral side of the tip of the cutter body so that the radial rake angle becomes negative and the axial rake angle becomes positive, wherein the throw-away tip is any one of claims 2 to 6. A throw-away type cutter characterized by a throw-away tip.