JPH0871833A - Throw away tip - Google Patents

Abstract

PURPOSE: To enhance the cutting edge strength of a tip and improve the seating stability. CONSTITUTION: In a throw away tip of almost square plate shape, a corner cutting edge 14 is provided at each corner part of the upper face 12, and a main cutting edge 13 and an auxiliary cutting edge 15 inclined at a micro angle to the main cutting edge 13 are respectively provided between two adjacent corner cutting edges 14. The flank relief of the side face is formed into two stages. As the flank relief of the main cutting edge 13, the boundary to the first flank relief 21 of the corner cutting edge 14 has a clearance angle of 0 deg., the boundary to the first flank relief 19 of the auxiliary cutting edge 15 has a positive clearance angle θ1 , and the clearance angle is changed so as to be gradually larger as it goes away from the corner cutting edge 14 along the main cutting edge 13 so as to form a twisted flank relief. The second flank relief 24 of the main cutting edge 13 below is formed into plane shape with a clearance angle larger than θ1 so as to improve the seating stability.

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 mounted on a cutting tool such as a face mill and an end mill. The present invention relates to a throw-away tip capable of (90 degree shoulder wall scraping).

[0002]

2. Description of the Related Art Conventionally, as a throw-away tip of this type, for example, as shown in FIGS. 8 and 9, a rectangular plate-like tip 2 mounted on the outer peripheral side of the front end of a front milling cutter 1.
There is. As shown in FIG. 8, the throw-away tip 2 has an upper surface 4 that faces a lower surface 3 that forms a seating surface, and four side surfaces 5 have a flat surface that inclines outward from the lower surface 3 toward the upper surface 4. I am doing it. The ridge line where each side surface 5 and the upper surface 4 intersect forms a main cutting edge 6, and a sub cutting edge 7 is formed in the vicinity of a corner portion 4a on the same ridge line of each main cutting edge 6. Then, the upper surface 4 forms a rake surface, and the side surface 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 edge flank are on the same surface (side surface 5). Is formed in. A screw hole 8 is formed in the center 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 cut the work W with the cutter 1 at a right angle (90 degree shoulder wall), as shown in FIG. 9, the main cutting edge 6 located on the outer peripheral side of the cutter of the throw-away tip 2 The work piece W is cut so as to form a right-angled wall surface, and the auxiliary cutting edge 7 on the outer side of the ridge line located on the tip side is formed into a rectangular plate shape because the cutting angle is formed by the positive axial rake angle and the negative radial rake angle. Right angle shaving can be performed with the tip 2.

[0004]

However, the throw-away tip 2 as described above is mounted on the cutter so that the axial rake angle is positive and the radial rake angle is negative, and moreover, the main cutting edge 6 and the sub cutting edge are provided. Since the clearance angle of the blade 7 is on the same plane (side surface 5), the clearance angle of the main cutting edge 6 is excessively positive. As a result, the strength of the cutting edge is reduced and defects are likely to occur, resulting in a short life of the chip.

In view of the above situation, it is an object of the present invention to provide a throw-away tip which can be cut at a right angle and whose life can be greatly improved.

[0006]

A throw-away tip according to the present invention has a substantially rectangular plate shape, a ridge line portion of an upper surface facing a seating surface has a cutting edge, and a corner blade is provided at a corner portion of the ridge line portion. And the upper surface is a rake face,
In the throw-away tip in which the side surface from the seating surface to the upper surface is a flank, a sub cutting edge is provided near one corner blade of two adjacent corner blades,
A main cutting edge is provided toward the other corner blade, and as a flank of this main cutting edge, the relief angle is changed so that the clearance angle gradually increases as the distance from the corner blade increases along the main cutting edge. It is characterized in that a flank is provided.

This 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 between the twist flank and the seating surface is the clearance angle of the twist flank. It is characterized in that it is formed in a plane shape with a larger clearance angle. Further, the clearance angle of the twist flank is a negative surface of 0 degree in the boundary region with the corner blade, and the clearance angle is gradually increased in the direction away from the corner blade along the main cutting edge. .

The flanks of the sub-cutting blades extend from the sub-cutting blades in the thickness direction of the chip to a first flank with a predetermined width, and from the sub-cutting blades first flank in the seating surface direction. Then the secondary cutting edge
The second flank of the secondary cutting edge has a larger clearance angle than the flank, and the clearance angle of the first flank of the secondary cutting edge is set to be the same as the maximum clearance angle of the flank flank. The flank surface of the corner blade is the first flank surface of the corner blade which is set to have a predetermined width in the thickness direction of the insert from the corner blade, and the first flank surface of the corner blade extends from the first flank surface of the corner blade in the seating surface direction. It consists of the second flank of the corner blade with a larger clearance angle.
The clearance angle of the first flank of the corner blade is formed by gradually changing from the clearance angle of the first flank of the secondary cutting edge to the minimum clearance angle of the twist flank. The throw-away tip has an upper surface that is a rake surface and a lower surface that is a seating surface are parallel to each other, and has a substantially square plate shape in a plan view, and a main cutting edge and a sub cutting edge are respectively formed on ridge lines of four circumferences. It is characterized in that two adjacent main cutting edges are orthogonal to each other and a sub cutting edge is formed between two adjacent corner blades so as to incline toward the inside of the chip with respect to the main cutting edge by a small angle. In addition, one or a plurality of indexable inserts are mounted on the outer peripheral side of the tip of the tool body so that the radial rake angle becomes negative and the axial rake angle becomes positive. It is characterized in that it is the throw-away tip described in any of the above.

[0009]

When the throw-away tip according to the present invention is mounted on a cutting tool such that the radial rake angle becomes negative and the axial rake angle becomes positive, the main cutting edge forming the outer peripheral edge is the base from the tip side. It is inclined toward the end side in a direction closer to the rotation axis of the cutting tool,
In response to this, the twist flank of the main cutting edge changes so that the clearance angle gradually increases as it moves away from the tip corner blade toward the base side along the main cutting edge. The corner can be limited to the minimum required size according to its position, and the cutting edge strength of the main cutting edge is high.

By limiting the twist flank to a predetermined width,
Main cutting edge supported by the side surface support of the cutting tool seat 2nd
Since the flank can be formed in a flat shape and abuts at a position closer to the rake face, seating stability is high. In addition, the clearance angle of the twist flank is a negative surface of 0 degree at the tip which is the boundary area with the corner blade, and the cutting edge strength is the maximum, and it goes away from the corner blade along the main cutting edge. By gradually increasing the clearance angle, it is possible to avoid contact with the work wall surface of the work material.

Since the flank of the auxiliary cutting edge has a two-step structure, the conformity of the shape with the flank of the main cutting edge is ensured, and the clearance angle of the first flank of the secondary cutting edge is twisted and escaped. By setting it to the same size as the maximum clearance angle of the surface, the sub-cutting blade first flank located on the base end side of the outer circumference contacts the machined wall surface of the work material when mounted on the cutting tool. You can avoid contact. Since the flanks of the corner blades have a two-step structure, the conformity of the flanks on the side surface of the chip is ensured. When this throw-away tip is attached to the outer peripheral tip side of the cutting tool and used for cutting, the main cutting edge on the outer peripheral side performs right-angle wall surface cutting, and the sub cutting edge on the tip side performs incision cutting. Therefore, it is possible to perform right-angle cutting of the work material while maintaining high cutting edge strength.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. 1A and 1B show a throw-away tip according to this embodiment, wherein FIG. 1A is a plan view thereof, FIGS. 1B and 1C are side views corresponding to this plan view, and FIG. ) AA line sectional view, FIG. 3 is a partial sectional view taken along the line BB of FIG. 1A, FIG. 4 is an enlarged view of the corner portion of the throw-away tip plane, and FIG. 5 shows the throw-away tip according to the embodiment. 7 is a partially cutaway side view of the mounted front milling cutter, FIG. 6 is a side view of the front milling cutter of FIG. 5, and FIG.
FIG. 6 is a front view of the front milling cutter of FIG. 5. In FIG.
The throw-away tip 10 according to this embodiment has a substantially rectangular (substantially square in the figure) plate shape, and has an upper surface 12 facing a lower surface 11 forming a seating surface. A main cutting edge 13 is formed on each of the ridges forming the four sides of the upper surface 12, and an arc-shaped 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. 4).

Then, between the main cutting edge 13 and one of the corner cutting edges 14 at each ridge line, an inwardly small angle γ (for example, 1 to 5 degrees) with respect to the main cutting edge 13 is provided inside. An inclined sub cutting edge 15 is formed, and the sub cutting edge 15 is smoothly connected to the corner blade 14. The upper surface 12 is a rake surface, and the central portion of the upper surface 12 is a screw hole 1 for fixing a chip screw that penetrates to the lower surface 11.
6 is provided. A clamp surface or the like for pressing and fixing may be formed in this central portion. Also, the lower surface 11 and the upper surface 12
As shown in FIGS. 1 (b) and 1 (c), the four side surfaces 18 between and are two-step clearance angles in which the clearance angle increases gradually from the upper surface 12 to the lower surface 11 for each cutting edge region. Respectively constitute the flanks formed.

That is, on the side surface 18 in the region of each sub-cutting edge 15, a portion having a constant width (for example, about 1 mm) that intersects the sub-cutting edge 15 and extends along each sub-cutting edge 15 is constant. It is a flat auxiliary cutting edge first flank 19 having a clearance angle θ1 (for example, 15 degrees), and its lower region extends from the lower surface 11 toward the upper surface 12 while inclining outward to form the first flank surface. 1
The secondary cutting edge second flank 20 has a clearance angle θ2 (for example, 20 degrees) larger than 9. Then, on the side surface 18 in the area of each corner blade 14, a portion having a constant width (for example, about 1 mm) that intersects the corner blade 14 and extends along the corner blade 14 is adjacent to the adjacent sub-cutting edge 15 side. Toward the main cutting edge 13 of the side, it is a corner blade first flank 21 whose flank angle is gradually changed from θ1 (positive surface) to 0 degree (negative surface). In addition, the lower area is
Extends from the lower surface 11 toward the upper surface 12 while inclining outward,
It is a corner blade second flank 22 in which the same clearance angle θ2 as the auxiliary cutting edge first flank 20 is set. The corner blade first and second flanks 21, 22 are each formed in a cylindrical side surface shape.

On the side surface 18 in the area of the main cutting edge 13, a portion having a constant width (for example, about 1 mm) that intersects the main cutting edge 13 and extends along the main cutting edge 13 is called the main cutting edge 13. In the boundary area with the corner blade 14, the clearance angle θ3 is 0 degree (negative surface), and in the boundary area with the auxiliary cutting edge 15, the clearance angle θ3 is the clearance angle θ1 of the auxiliary cutting edge first flank surface 19. 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 the negative surface of 0 degree to θ1 to form a twist flank. Also, the main cutting edge No. 1
The lower region of the flank 23 extends obliquely outward from the lower surface 11 toward the upper surface 12, and is larger than the clearance angle θ3 of the main cutting edge first flank 23, which is the same as the sub cutting edge first flank 20. Plane-shaped main cutting edge second flank 24 set to clearance angle θ2
It is said that.

Therefore, the cutting edge angle of the main cutting edge 13 in the boundary region between the main cutting edge 13 and the corner edge 14 is as shown in FIG.
As shown in (c), negative surface with θ4 = 90 degrees (clearance angle is 0
2) in the central region of the main cutting edge 13 and the angle θ5 in the AA cross sectional view of FIG. 2, and in the boundary region with the sub cutting edge 15 the angle θ6 in the cross sectional view of the BB line in FIG. = 75 degrees (the clearance angle is 15 degrees). That is, the cutting edge angle of the main cutting edge 13 is set to gradually decrease with θ4>θ5> θ6 as the distance from the corner blade 14 increases.

A state in which such a throw-away tip 10 is mounted on the front milling cutter 1 is shown in FIGS. In the mounted state of the tip 10, as shown in FIG. 5, the auxiliary cutting edge 15 is located outside the tip surface as a front cutting edge, and the main cutting edge 13 of the adjacent ridge line portion on the outer peripheral tip side rotates the cutter body. The outer peripheral blade is located parallel to the axis L (in the figure). In addition, the throw-away tip 10 mounted on the seat portion 26 of the cutter body 1a has the two main side cutting edge second flanks 24 of the two adjacent side surfaces 18 of the seat portion 26. It is adapted to be positioned and fixed in a state in which 24 is in contact. Also, as shown in FIG. 6, the axial rake angle α is positive,
As shown in FIG. 7, the radial rake angle β is positioned to be negative.

In particular, in the tip 10 having the axial rake angle α shown in FIG. 6, with respect to the side surface 18 located on the outer peripheral surface side of the cutter 1, the main cutting edge 13 forming the outer peripheral edge is a right-angled wall surface of the work material W. To be formed, the auxiliary cutting edge 15 that is located on the tip end side in the axial direction and that is not involved in cutting is located on the base end side. Moreover, since the sub cutting edge first flank 19 which is the flank on the base end side is closer to the axis L than the main cutting edge first flank 23, the sub cutting edge first flank 19 has a clearance angle. By providing a positive clearance angle θ1 larger than the first cutting edge first flank 23 in which θ3 becomes gradually smaller toward the cutting edge tip direction, this flank surface 19 becomes a machining wall surface of the work material W during cutting. It is possible to avoid contact.

However, in the region of the main cutting edge 13, the clearance angle θ3 of the first flank 23 of the main cutting edge becomes smaller than that of the first sub cutting edge because it gradually moves away from the axis L from the base end side toward the tip direction. The clearance angle θ1 of the clearance surface 19 may be gradually decreased. For this reason, in the present embodiment, the main cutting edge first flank 23 is twisted so that the clearance angle θ3 gradually changes from the positive angle θ1 to 0 degrees from the base end side (the sub cutting edge first flank surface 19 side) to the tip direction. By using the flank, the necessary minimum clearance angle θ3 can be set, and the cutting edge angle of the main cutting edge 13 can be set as large as possible. In particular, on the tip side of the main cutting edge 13, since the boundary area with the corner blade 14 is set to the negative surface of 90 degrees,
The tip strength of the tip of the outer peripheral blade is extremely high. in this way,
The edge strength of the main cutting edge 13 can be gradually increased toward the tip side, and 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. Therefore, since the contact area with the work material W is large, the life of such an indexable insert 10 can be significantly improved.

Further, the second flank 24 of the main cutting edge is fixed at a constant angle θ2.
Since it is formed in a flat shape, the two adjacent side surface receivers 26a and 26b of the seat portion 26 of the cutter body 1a constitute a minimum necessary twist flank when supporting each side surface 18 of the throw-away tip 10. However, the seating stability can be secured. Further, the main cutting edge first flank 23, the sub cutting edge first flank 19 and the corner blade first flank 21 are
It is preferable that the width is the same in the chip thickness direction, and for example, it is set to about 0.5 to 1.5 mm. Moreover, the chip 10 that abuts on the side surface receivers 26a and 26b of the seat portion 26
Since it is preferable to set the receiving portion on the side surface of the main cutting edge to a position closer to the rake surface in order to secure the seating stability, the width of the main cutting edge first flank 23 is limited and the main cutting edge second flank is limited. Surface 2
The width of 4 can be set large.

As described above, according to the present embodiment, the clearance angle of the small-width main cutting edge first flank 23 extending along the main cutting edge 13 is set to the clearance of the sub-cutting edge first flank 19. Since it is formed in a twist flank shape that gradually decreases from the positive angle θ 1 which is the same as the angle to the boundary area with the first flank 21 of the corner blade to a negative, it affects the shoulder wall scraping ability by 90 degrees. Without this, the clearance angle θ3 of the main cutting edge 13 can be limited to the necessary minimum, and especially the edge strength of the main cutting edge portion can be increased, and the life of the tip can be greatly improved. Further, when the chip 10 is fixed, the main cutting edge second flank 24 supported by the side surface receivers 26a and 26b of the sheet portion 26 is formed in a flat shape, and the width in the thickness direction is set to be large. Since it can be supported in a region close to the rake face, it is possible to further secure seating stability.

Further, in each of the above-mentioned embodiments, the corner blade 14 is formed in an arc shape in a plan view, but it may be formed in a chamfer. In this case, the 2nd flank 22 may be formed in the shape of a plane. Although the flanks of the sub cutting edge 15 and the corner blade 14 are made to have the same flank shape as that of the main cutting edge 13 so as to form the side surface shape of the tip smoothly, it is not limited to this configuration. Without auxiliary cutting edge 15
Each flank of the corner blade 14 may have one step or three steps or more, or may have a curved surface shape. In this case, it may be formed so that the clearance angle θ1 is not exceeded in the flank surface area of the auxiliary cutting edge. Further, the rake face does not necessarily have to be a flat face and can be formed in an appropriate shape, for example, a breaker groove or the like may be provided.

[0023]

As described above, in the throw-away tip according to the present invention, the auxiliary cutting edge is provided near one of the two adjacent corner blades, and the main cutting edge is directed toward the other corner edge. The flank of this main cutting edge is a twist flank formed so that the clearance angle gradually increases as it moves away from the corner blade along the main cutting edge. In addition, it is possible to limit the clearance angle of the flank of the main cutting edge to the necessary minimum, in particular it is possible to increase the edge strength of the main cutting edge portion, and it is possible to greatly improve the life of the tip. . or,
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 between the twist flank and the seating surface has a clearance angle larger than that of the flank. Since it is formed in a flat shape, when the throw-away tip is mounted on the cutter body, the side seat of the seat portion comes into contact with the second flank of the main cutting edge, so that the seating stability of the tip can be secured. In addition, by limiting the width of the twist relief surface, the side surface receiver of the seat portion can be brought into contact with a position close to the rake surface, and the seating is more stable. The clearance angle of the twist flank is a negative surface of 0 degrees in the boundary area with the corner blade, and the clearance angle gradually increases in the positive direction along the main cutting edge in the direction away from the corner blade. The cutting edge angle can be maximized to increase the cutting edge strength,
In particular, when mounted on a tool, the edge strength near the corner blade is further enhanced. In addition, the clearance angle of the first flank of the secondary cutting edge is set to the same size as the maximum clearance angle of the twist flank, so that the clearance of the secondary cutting edge located on the outer peripheral side when mounted on a tool The surface can be prevented from coming into contact with the machined surface of the work material. The clearance angle of the first flank of the corner blade is
Since the auxiliary cutting edge is formed by gradually changing from the flank angle of the first flank to the minimum flank angle of the twist flank, the flank shape of the tip can be formed smoothly.

[Brief description of drawings]

FIG. 1 shows a throw-away tip according to an embodiment of the present invention, in which (a) is a plan view, (b), (c).
[Fig. 3] is a side view corresponding to a plan view.

FIG. 2 is a cross-sectional view taken along line AA of the throw-away tip plan view shown in FIG.

FIG. 3 is a partial sectional view taken along the line BB of the throw-away tip plan view shown in FIG.

FIG. 4 is an enlarged view of a corner portion of the throw-away tip plan view shown in FIG.

FIG. 5 is a partially cutaway side view showing a state in which the throw-away tip according to the embodiment is mounted on the front milling cutter.

FIG. 6 is a side view of a state in which the throw-away tip is attached to the front milling cutter as seen from the outer peripheral side.

FIG. 7 is a front view of the front milling cutter shown in FIG. 6.

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

FIG. 9 is a partial cross-sectional view showing a state in which a conventional milling cutter is mounted on a front milling cutter at a right angle.

[Explanation of symbols]

1 ... Face mill, 10 ... Throwaway 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, 20 ... Sub cutting edge second flank, 21 ... Corner blade first flank, 23 ... Main cutting edge first flank, 24 ... Main cutting edge second flank.

Claims (7)

[Claims] 1. A substantially rectangular plate shape, wherein a ridge line portion of the upper surface facing the seating surface forms a cutting edge, a corner blade is provided at a corner portion of the ridge line portion, and the upper surface is a rake face, In throw-away inserts whose flanks from the seating surface to the top surface are flanks, a sub-cutting blade is provided near one corner blade of the two adjacent corner blades and a main cutting edge is provided toward the other corner blade. A cutting edge is provided, and as a flank of this main cutting edge, a twist flank is formed so that the clearance angle gradually increases along with the distance from the corner blade along the main cutting edge. Throw-away tip featuring. 2. 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 between the twist flank and the seating surface is the twist flank. The throw-away tip according to claim 1, wherein the throw-away tip is formed in a plane shape with a clearance angle larger than the clearance angle. 3. The clearance angle of the twist flank is a negative surface of 0 degree in the boundary region with the corner blade, and the clearance angle gradually increases along the main cutting edge in the direction away from the corner blade. The throw-away tip according to claim 1 or 2. 4. The flank surface of the sub-cutting edge is a sub-cutting blade first flank surface having a predetermined width in the thickness direction of the tip from the sub-cutting edge.
The sub-cutting blade first flank extends in the seating surface direction and has a sub-cutting blade second flank having a larger clearance angle than the sub-cutting blade first flank, and the sub-cutting blade first flank escapes. The throw-away tip according to any one of claims 1 to 3, wherein the corner is set to have the same size as the maximum clearance angle of the twist flank. 5. The flank surface of the corner blade has a first flank surface of the corner blade which is set to have a predetermined width in the thickness direction of the tip from the corner blade, and extends from the first flank surface of the corner blade in the seating surface direction. It consists of a corner blade second flank having a larger flank angle than the corner blade first flank, and the flank angle of the corner blade first flank is from the flank angle of the auxiliary cutting blade first flank to the minimum flank flank. The throw-away tip according to any one of claims 1 to 4, wherein the throw-away tip is formed so as to gradually change to a corner. 6. The throw-away tip has an upper surface which is a rake surface and a lower surface which is a seating surface are parallel to each other, and has a substantially square plate shape in plan view, and the main cutting edge and the sub cutting edge are respectively formed on four ridge lines. A blade is formed, and two adjacent main cutting edges are orthogonal to each other, and a sub-cutting edge is formed between the two adjacent corner cutting edges inclining toward the inside of the tip with respect to the main cutting edge by a small angle. 6. The method according to claim 1, wherein
Throw-away tip described in any of. 7. One or more throw-away chips,
In a cutting tool which is mounted on the outer peripheral side of the tip of the tool body such that the radial rake angle becomes negative and the axial rake angle becomes positive, the throw-away tip is the throw according to any one of claims 1 to 6. A cutting tool that is an away tip.