JP7119781B2 - Cutting inserts and indexable cutting tools - Google Patents

Description

The present invention relates to a cutting insert that is detachably attached to an indexable cutting tool, and an indexable cutting tool that is detachably attached to the outer circumference of the tip of a tool body in which the cutting insert rotates around an axis. be.

As such a cutting insert, for example, Patent Document 1 discloses a substantially hexagonal plate-like insert body having three main corners and three sub corners alternately on the upper and lower surfaces, and the three main corners on the upper surface. In order from the first major corner toward two adjacent minor corners, a corner edge, a linear minor cutting edge that slopes downward as it moves away from the corner edge, and a minor cutting edge as it moves away from the minor cutting edge. A so-called no-handed cutting insert is described in which a main cutting edge that slopes toward the lower surface at a large angle is formed, and portions extending from these first major corners toward two adjacent minor corners have the same shape. ing. In addition, in Patent Document 1, the main cutting edge is concave on the lower surface side in a side view, and is inclined downward so as to gradually approach the lower surface as it goes from the end of the minor cutting edge to the end on the minor corner side. It is also stated that

Such a cutting insert has an insert mounting seat formed at the tip of the tool body of an indexable cutting tool that rotates around the axis, and the corner edge is located on the outer periphery of the tip of the tool body. A pair of minor cutting edge and major cutting edge connected to the blade is positioned on the outer peripheral side of the tool body, and another pair of minor cutting edge and major cutting edge is positioned on the tip side of the tool body and detachably attached. . In the cutting insert attached to the tool body in this way, a set of minor cutting edge and main cutting edge located on the outer peripheral side of the tool body performs wall cutting with a relatively large depth of cut, and the cutting insert located on the tip side of the tool body performs wall cutting with a relatively large depth of cut. Finish cutting of the bottom surface is performed by another set of minor cutting edges and the minor cutting edge of the major cutting edge.

Japanese Patent No. 5715688

By the way, in cutting a relatively large depth of cut with such a cutting insert, it is necessary to have a low cutting resistance so as not to cause chattering vibration in work materials such as thin plates, and to have a high-precision finished surface with good surface quality ( wall surface, bottom surface), and good chip dischargeability capable of preventing chips from being bitten. In addition, unless it is possible to obtain good chip discharge performance by controlling the direction of chip discharge, cutting resistance is increased due to chip bite, and the bitten chip damages the work material. As a result, the wall surface and bottom surface are damaged, and the quality and accuracy of the finished surface are impaired.

The present invention has been made under such a background, and by controlling the discharge direction of chips generated by the main cutting edge positioned on the outer peripheral side of the tool body, cutting is performed while preventing the chips from being caught. It is an object of the present invention to provide a cutting insert capable of suppressing resistance and ensuring high quality and precision on a finished surface, and an indexable cutting tool to which the cutting insert is detachably attached.

In order to solve the above problems and achieve such an object, the cutting insert of the present invention comprises first and second polygonal faces facing opposite sides, and the first and second polygonal facets. The insert body has a polygonal plate-shaped insert body having a plurality of side surfaces arranged around the surface, and the first corner portion of the corner portions of the first polygonal surface of the insert body is provided with this A corner cutting edge having a corner rake face is formed on the first polygonal face, and extends from the corner cutting edge to a second corner portion adjacent to the first corner portion in the circumferential direction of the first polygonal face. has a main rake face on the first polygonal face that is continuous with the corner rake face, and a main cutting edge extending from the first end of the corner cutting edge is formed, the main cutting edge being the corner cutting edge side, a convex curve in a side view facing the main flank face intersecting the main rake face among the plurality of side faces as it goes from the first end portion of the corner cutting edge toward the second corner portion side. , the corner edge extends toward the second polygonal surface after leaving the second polygonal surface while drawing a said first end projecting more than a second end of said corner edge opposite said first end, said insert body extending in a direction projecting away from said first end; 1. It has an insert centerline passing through the center of the second polygonal face, and the first polygonal face has a secondary rake face connected to the corner rake face on the opposite side of the main rake face. on the first polygonal face and extending from a second end of the corner edge opposite the first end of the corner edge, the minor cutting edge is a plurality of side surfaces of the insert body, in a side view facing a secondary flank that intersects the secondary rake face via the secondary cutting edge, the second characterized by extending toward the polygonal surface side of the

Further, in the indexable cutting tool of the present invention, the insert mounting seat is formed on the outer periphery of the tip of the tool body that rotates around the axis. and the major cutting edge extending from the first end of the corner edge is located on the outer peripheral side of the tool body, and the corner rake face and the main rake face are connected to the corner edge and the major cutting edge. It is characterized in that it is detachably attached with its surface facing the direction of rotation of the tool.

In the cutting insert and the indexable cutting tool configured as described above, the main cutting edge on the corner edge side moves from the first end of the corner edge toward the second corner portion. in a side view facing the main flank that intersects the main rake face among the side surfaces of the above, so that it extends toward the second polygonal surface after separating from the second polygonal surface while drawing a convex curve. Therefore, the tip of the chip on the corner edge side is elongated into a convex curved cross-sectional shape along the convex curve formed by the main cutting edge, and is generated thinly, so that the tip of the chip is thin. The curl radius can be made smaller than the trailing end to make it easier to roll.

For this reason, the chips flow away from the main cutting edge as they go from the front end to the rear end, that is, in the direction toward the inner circumference as they go toward the rear end of the tool body, and curl in the same direction. It is discharged while being curled so that it will be done. Therefore, since the chip discharge direction is controlled away from the wall surface cut by the main cutting edge, it is possible to prevent chips from being caught between the wall surface of the work material cut and the insert body. It is possible to prevent the finished surface (wall surface) from being damaged by such biting of chips and impair the quality and accuracy of the finished surface, and it is possible to suppress the increase in cutting resistance. .
Furthermore, by forming the corner edge so as to extend in a direction projecting away from the second polygonal surface toward the first end, the tip portion of the major cutting edge is formed from the corner edge. It is possible to make it easier to discharge the chips generated along the way toward the inner peripheral side as it goes toward the rear end side of the tool body.
The insert body has an insert centerline passing through the centers of the first and second polygonal faces, and the first polygonal face has a a minor cutting edge having a minor rake face on the first polygonal face that is contiguous with the corner rake face and extending from a second end of the corner cutting edge opposite to the first end of the corner cutting edge; The second end of the corner cutting edge in a side view facing the minor flank that intersects the minor rake face through the minor cutting edge among the plurality of side surfaces of the insert body. By forming the chip so as to extend toward the second polygonal face side as it separates from the edge, the curl radius of the leading edge of the chip is made smaller than that of the trailing edge even by this minor cutting edge. It becomes possible to guide chips in the direction of the line.

Here, in a side view facing the main flank, the radius of curvature of the convex curve drawn by the main cutting edge is within the range of 3 mm to 10 mm, and is at least 1.0 mm from the first end of the corner edge. It is desirable that the main cutting edge draws a convex curve within the range of . If the radius of curvature of the convex curve drawn by the main cutting edge is less than 3 mm, there is a risk that chipping or the like may easily occur in this portion of the main cutting edge. There is a risk that the effect of controlling the discharge direction of the Moreover, even if the range in which the major cutting edge draws the convex curve is shorter than the range of 1.0 mm from the first end of the corner edge, the effect of controlling the chip discharge direction can be sufficiently exhibited. may disappear.

Further, a boundary line between the main rake face and the corner rake face extending from the first end of the corner cutting edge to the inside of the first polygonal face is It is desirable that the main cutting edge is intersected at an intersecting angle within the range of 20° to 60°. The main rake face and the corner rake face intersect at such an intersection angle to form a region of gradually increasing rake angle on the main rake face, which allows chips to be dissipated along the boundary line between the main rake face and the corner rake face. By guiding, it is possible to more reliably control the discharge direction in the direction away from the main cutting edge, that is, in the direction toward the inner peripheral side toward the rear end side of the tool body.

That is, when the crossing angle of this boundary line with the main cutting edge in plan view is less than 20°, the chip discharge direction is surely controlled in the direction toward the inner peripheral side toward the rear end side of the tool body. may not be possible. Conversely, if the crossing angle exceeds 60°, it becomes difficult for the chips to be discharged to the rear end side of the tool body, and the chips that have flowed out to the inner peripheral side of the tool body hit the wall surface of the chip pocket of the tool body and hit the outer peripheral side. There is a risk that it will flow into the gap between the main cutting edge and the cut wall surface of the work material.

By forming the corner cutting edge in a concave curved shape in a side view facing the corner flank that intersects the corner rake face through the corner cutting edge among the plurality of side surfaces of the insert body, the corner cutting edge To more effectively prevent chips from being bitten by surely curling the tip of generated chips around the center line toward the inner peripheral side as it goes toward the rear end side of a tool body as described above. becomes possible.

In addition, when the corner edge is formed to extend in a direction projecting away from the second polygonal face toward the first end, the first end of the corner edge is , a corner flank of a plurality of side surfaces of the insert body that intersects the corner rake face through the corner cutting edge with respect to a second end of the corner cutting edge opposite the first end; It is desirable that the projection amount is in the range of 0.05 mm to 0.15 mm when viewed from the side facing the . If the protrusion amount is less than 0.05 mm, the effect of controlling the chip discharge direction toward the inner peripheral side toward the rear end side of the tool body may decrease as described above. , the crossing angle between the corner edge and the major cutting edge at the first end becomes small, and chipping or the like may easily occur.

In this case, it is desirable that the minor cutting edge has an inclination angle of 0° to 15° with respect to a plane perpendicular to the center line of the insert when viewed from the side facing the minor flank. . When this inclination angle is less than 0° and the minor cutting edge extends away from the second end of the corner edge toward the opposite side of the second polygonal surface, the chip curl center line As it moves toward the rear end of the tool body, it moves toward the outer peripheral side, which may make it impossible to reliably prevent chips from being bitten. Further, if the inclination angle of the minor cutting edge exceeds 15°, it becomes difficult for the chips to be discharged to the rear end side of the tool body, and there is a risk that chips may be jammed.

Further, the insert body has a rotationally symmetrical shape of 120 degrees around an insert centerline passing through the centers of the first and second polygonal faces, and is symmetrical with respect to the first and second polygonal faces. It is formed in a hexagonal plate shape, and three each of the first and second corner portions are alternately arranged in the circumferential direction on the first and second polygonal faces, and the are arranged opposite to each other in the direction of the insert centerline, and between the first and second polygonal faces, the first end of the corner cutting edge and the When the second end of the corner cutting edge is arranged on the opposite side of the insert body in the circumferential direction, the first and second polygonal faces (hexagonal faces) on the front and back sides can be formed by one insert body. ) It is possible to use a corner edge, a major cutting edge or a minor cutting edge a total of 6 times, 3 times each.

Furthermore, in this case, if the side surface of the insert body is formed to extend parallel to the center line of the insert to form a negative type cutting insert, the corner edge, the major cutting edge, or the minor cutting edge can be secured to improve the strength of the cutting edge.

As described above, according to the present invention, the curl radius at the tip of the chip on the corner edge side is made smaller than that at the rear end, so that the chip curls toward the inner peripheral side as it goes toward the rear end of the tool body. By curling around the center line, it is possible to control the direction of chip ejection away from the wall surface of the work piece formed by the main cutting edge, so that the chips are caught between the wall surface and the main cutting edge. Since it is possible to prevent entrapment, it is possible to improve the quality and accuracy of the finished surface and to suppress an increase in cutting resistance.

It is a perspective view showing one embodiment of the cutting insert of the present invention. FIG. 2 is a plan view of the embodiment shown in FIG. 1 viewed from a direction facing a polygonal surface (hexagonal surface); FIG. 3 is a side view seen in the direction of an arrow V in FIG. 2; FIG. 3 is a side view seen in the direction of an arrow W in FIG. 2; FIG. 3 is a side view seen in the direction of an arrow X in FIG. 2; FIG. 3 is a side view seen in the direction of arrow Y in FIG. 2 ; FIG. 3 is a side view seen in the direction of an arrow Z in FIG. 2; FIG. 2 is an enlarged view of part A in FIG. 1; 4 is an enlarged view of part A in FIG. 3. FIG. 5 is an enlarged view of part A in FIG. 4. FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2; FIG. 3 is a cross-sectional view taken along line BB in FIG. 2; 3 is a cross-sectional view along CC in FIG. 2; FIG. 3 is a cross-sectional view along DD in FIG. 2; FIG. 3 is a cross-sectional view along EE in FIG. 2; FIG. 3 is a cross-sectional view along FF in FIG. 2; FIG. 3 is a cross-sectional view along GG in FIG. 2; FIG. 3 is a cross-sectional view taken along line HH in FIG. 2; FIG. FIG. 3 is a sectional view taken along line II in FIG. 2; FIG. 3 is a cross-sectional view taken along JJ in FIG. 2; 1 is a perspective view of a tool body in one embodiment of an indexable cutting tool of the present invention; FIG. 22 is an enlarged perspective view of the periphery of the insert mounting seat of the tool body shown in FIG. 21; FIG. 1 is a perspective view showing an embodiment of an indexable cutting tool of the present invention; FIG. Figure 24 is a bottom view of the embodiment shown in Figure 23; Figure 24 is a side view of the embodiment shown in Figure 23; FIG. 24 is an enlarged side view of the periphery of the insert mounting seat of the embodiment shown in FIG. 23; 24 is an enlarged perspective view of the periphery of the insert mounting seat of the embodiment shown in FIG. 23; FIG. 2 shows a state in which chips are generated by the cutting insert of the embodiment shown in FIG. 1; Fig. 2 shows the state in which chips are generated by a cutting insert with a constant rake angle of the main cutting edge.

1 to 20 show one embodiment of the cutting insert of the present invention. 21 and 22 show a tool body of an indexable cutting tool to which the cutting insert of this embodiment is attached, and FIGS. 1 shows an embodiment of the indexable cutting tool of the present invention to which the cutting insert of . Furthermore, FIG. 28 shows a state in which chips are generated by the cutting insert of this embodiment, and FIG. It shows the state in which chips are generated by

The cutting insert of this embodiment has an insert body 1 made of a hard material such as a cemented carbide in the shape of a polygonal plate, particularly a plate of an irregular hexagon. 1, a second polygonal surface 2) and a plurality (six) of side surfaces 3 arranged around these hexagonal surfaces 2; A mounting hole 4 having a circular cross section penetrating through the insert body 1 is opened at the center of the two hexagonal faces 2 .

The insert body 1 is rotationally symmetrical about an insert centerline C passing through the center of the mounting hole 4 by 120°, and is also inverted symmetrically about the two hexagonal faces 2 . An annular flat portion 2a perpendicular to the center line C of the insert is formed around the opening of the mounting hole 4 on the two hexagonal surfaces 2. As shown in FIG. Moreover, the length of each side of the hexagonal surface 2 when viewed from the direction of the center line C of the insert is approximately equal.

The six corner portions of each of the two hexagonal faces 2 are alternately arranged in the circumferential direction of the hexagonal face 2 as first corner portions C1 and second corner portions C2. The included angle between the two edges of the hexagonal surface 2 that intersect at the first corner C1 is made smaller than the included angle between the two edges of the hexagonal surface 2 that intersect at the second corner C2. , and is therefore less than 120° and is set at approximately 90°.

In addition, between the two hexagonal faces 2, the first corner portion C1 of the other hexagonal face 2 is located on the opposite side of the first corner portion C1 of one hexagonal face 2 in the insert center line C direction. , the second corner portion C2 of the other hexagonal face 2 is located on the opposite side of the second corner portion C2 of the one hexagonal face 2 in the insert center line C direction. A plurality of side surfaces 3 of the insert body 1 are planar parallel to the insert centerline C, and the cutting insert of this embodiment is a negative type cutting insert.

A corner cutting edge 5 having a corner rake face 5a on each hexagonal face 2 is formed in the first corner portion C1. The corner edge 5 is formed in a convex curved shape such as a convex circular arc in plan view facing the hexagonal surface 2 seen from the direction of the center line C of the insert. Therefore, of the side faces 3 of the insert body 1, the intersection ridges of the two side faces 3 that intersect the corner rake face 5a through the corner edge 5 are formed into a convex curved surface such as a cylindrical surface parallel to the insert centerline C. and the corner flank 5b.

Further, the corner rake face 5a, the main rake face 6a and the sub rake face 7a described below are formed on the inner side of the hexagonal face 2 on which the corner rake face 5a, the main rake face 6a and the sub rake face 7a are formed. , the plane is inclined toward the hexagonal surface 2 opposite to the hexagonal surface 2 with respect to the plane perpendicular to the center line C of the insert.

The hexagonal surface 2 is formed from the first end (counterclockwise end of the corner edge 5 centered on the center line C of the insert in FIG. 2) 5A, which is one end of the corner edge 5. A main cutting edge 6 having a main rake face 6a continuous with the corner rake face 5a on each hexagonal face 2 is formed to the second corner portion C2 adjacent to the first end portion 5A side in the circumferential direction of the . Since the plurality of side surfaces 3 of the insert body 1 are planar, the main cutting edge 6 is formed linearly in plan view facing the hexagonal surface 2 seen from the insert centerline C direction. Of these, the side surface 3 intersecting the main rake face 6a through the main cutting edge 6 is used as the main flank 6b of the main cutting edge 6. As shown in FIG.

Furthermore, the second end (clockwise end of the corner cutting edge 5 centered on the insert centerline C in FIG. 2), which is the other end of the corner cutting edge 5 opposite to the first end 5A ) 5B to the second corner portion C2 adjacent to the second end portion 5B in the circumferential direction of the hexagonal face 2, each hexagonal face 2 has a secondary rake face 7a that also continues to the corner rake face 5a. A cutting edge 7 is formed. Like the major cutting edge 6, the minor cutting edge 7 is also formed linearly in plan view facing the hexagonal surface 2 seen from the direction of the insert centerline C. A side surface 3 that intersects the secondary rake face 7a through the cutting edge 7 serves as a secondary flank 7b of the secondary cutting edge 7. As shown in FIG.

Therefore, in the cutting insert of this embodiment in which the insert body 1 has a symmetrical shape with respect to the two hexagonal faces 2, the corner edge 5, the major cutting edge 6 and the minor cutting edge 7 extend in opposite directions in the circumferential direction of the insert body 1 . That is, one side surface 3 of the insert body 1 is formed with a major cutting edge 6 at the ridge line crossing the hexagonal surface 2 on one side, and is used as a main flank 6b of the major cutting edge 6, A minor cutting edge 7 is formed at an intersection ridge with the hexagonal face 2, and serves as a minor flank 7b of the minor cutting edge 7. As shown in FIG.

The corner edge 5 extends in a direction projecting away from the hexagonal surface 2 opposite to the hexagonal surface 2 on which the corner edge is formed as it goes from the second end 5B toward the first end 5A. ing. That is, when the corner edge 5 is formed on the first polygonal face (one hexagonal face 2), the corner edge 5 extends from the second end 5B to the first end 5A. , in a direction projecting away from the second polygonal face (the other hexagonal face 2).

Here, the first end 5A of this corner cutting edge 5 lies in a plane perpendicular to the insert centerline C with respect to the second end 5B of the corner cutting edge 5 opposite this first end 5A. As shown in FIG. It protrudes with a protrusion amount t within the range of 0.05 mm to 0.15 mm. The corner cutting edge 5 is formed to have a concave curved shape as shown in FIGS. 5 and 8 when viewed from the side facing the corner flank 5b.

The major cutting edge 6 continuing to the first end 5A of the corner edge 5 is located on the corner edge 5 side from the first end 5A of the corner edge to the first edge 6 with the major cutting edge 6 therebetween. In a side view vertically facing the main flank 6b intersecting with the main rake face 6a among the plurality of side faces 3 of the insert body 1, toward the second corner C2 opposite to the corner C1. As shown in 9 and FIG. 10, after leaving the hexagonal surface 2 opposite to the hexagonal surface 2 on which the main cutting edge 6 is formed while drawing a convex curve such as a convex circular arc, the main cutting edge 6 is It extends toward the hexagonal surface 2 side opposite to the formed hexagonal surface 2 .

That is, when the major cutting edge 6 is formed on the first polygonal face (one hexagonal face 2), this major cutting edge 6 is the second edge of the corner edge 5 on this first polygonal face. From the end 5B toward the second corner C2, while drawing a convex curve such as a convex arc on the corner edge 5 side, after leaving the second polygonal surface (the other hexagonal surface 2), the second , extending toward the polygonal surface (hexagonal surface 2) side of the .

Here, in a side view perpendicularly opposed to the main flank 6b, the curvature radius R of the convex curve drawn by the main cutting edge 6 on the corner edge 5 side is within the range of 3 mm to 10 mm. The main cutting edge 6 draws a convex curve in a range of at least 1.0 mm from the end 5A of 1. In addition, on the second corner portion C2 side of this range, the main cutting edge 6 may extend toward the opposite hexagonal surface 2 side while drawing a convex curve in the side view, or may be linearly opposite to the hexagonal surface 2 side. may extend toward the hexagonal surface 2 of the , or may draw a concave curve.

On the other hand, the minor cutting edge 7 has a corner edge 5 when viewed from the side perpendicularly facing the minor flank 7b intersecting the minor rake face 7a through the minor cutting edge 7 among the plurality of side faces 3 of the insert body 1. or along a plane P perpendicular to the insert centerline C from the second end 5B of the corner edge 5, or the minor cutting edge 7 is formed as the distance from the second end 5B of the corner edge 5 increases. It is formed so as to extend toward the side of the hexagonal surface 2 opposite to the hexagonal surface 2 that is formed. In this embodiment, as shown in FIGS. 3 and 9, the corner cutting edge 5 is formed so as to extend toward the opposite hexagonal surface 2 as the distance from the second end 5B increases.

That is, when the minor cutting edge 7 is formed on the first polygonal face (one hexagonal face 2), in this embodiment the minor cutting edge 7 is formed on the corner edge 5 of the first polygonal face. It extends toward the second polygonal surface (the other hexagonal surface 2) as it goes from the second end 5B toward the second corner portion C2. The minor cutting edge 7 has an inclination angle α with respect to a plane P perpendicular to the insert center line C in the range of 0° to 15° in a side view facing the minor flank 7b. If the minor cutting edge 7 extends along a plane P perpendicular to the insert centerline C, this inclination angle α is 0°.

The major cutting edge 6 extends from the first end 5A of the corner edge 5 to the second corner C2 on the side of the first end 5A. extends from the second end 5B of the corner edge 5 toward the second corner C2 on the second end 5B side in a range shorter than the major cutting edge 6. As shown in FIG. In the portion from the end of the minor cutting edge 7 opposite to the second end 5B of the corner edge 5 to the second corner portion C2, the intersection ridge between the hexagonal surface 2 and the side surface 3 is the minor cutting edge. 7 is inclined toward the opposite hexagonal surface 2 at an angle larger than the inclination angle α, and this portion is not used for cutting.

Furthermore, the corner rake face 5a, the main rake face 6a, and the minor rake face 7a are arranged on the corner edge 5 side, the major cutting edge 6 side, and the minor cutting edge 7 side, respectively, in FIGS. In a cross section orthogonal to the corner edge 5, the major cutting edge 6, and the minor cutting edge 7 in plan view viewed from the direction facing the hexagonal face 2 along the insert centerline C as shown in 20, the corner rake face 5a , the main rake face 6a, and the secondary rake face 7a toward the opposite hexagonal face 2 side toward the inner side of the hexagonal face 2 at a gentle constant inclination angle with respect to the plane perpendicular to the insert centerline C. Extending lands 5c, 6c, 7c are provided.

Furthermore, between the lands 5c, 6c, 7c of the corner rake face 5a, the main rake face 6a, and the minor rake face 7a and the corner edge 5, the major cutting edge 6, and the minor cutting edge 7, these lands The honing portions 5d, 6d, and 7d tend toward the opposite side of the hexagonal surface 2 toward the inner side of the hexagonal surface 2 at a gentler inclination angle with respect to the plane perpendicular to the insert centerline C than the portions 5c, 6c, and 7c. is formed. The honing portions 5d, 6d and 7d are narrower than the land portions 5c, 6c and 7c in the cross section. These honing portions 5d, 6d, and 7d may be formed along a plane perpendicular to the center line C of the insert in the same cross section.

The corner rake face 5a, the main rake face 6a, and the sub rake face 7a are linearly in contact with the land portions 5c, 6c, and 7c in the above cross section, forming convex curves on the inside of the hexagonal face 2. It extends toward the opposite hexagonal surface 2 as it goes, forms a concave curve, and is formed so as to be in contact with the flat portion 2a of the hexagonal surface 2. As shown in FIG.

In this embodiment, as described above, the corner cutting edge 5 forms a concave curved shape in a side view facing the corner flank 5b, and protrudes toward the first end 5A away from the second end 5B. Therefore, the corner rake face 5a and its land portion 5c also extend from the boundary line L between the secondary rake face 7a and its land portion 7c to the boundary line M between the main rake face 6a and its land portion 6c. It is formed so as to protrude in the insert centerline C direction while drawing a concave curved surface as it goes.

Further, in the present embodiment, the main cutting edge 6 has a side surface facing the main flank 6b as it goes from the first end 5A of the corner edge 5 toward the second corner portion C2 on the corner edge 5 side. In view, the main rake face 6a and its land portion 6c also extend toward the opposite hexagonal face 2 after leaving the opposite hexagonal face 2 while drawing a convex curve. From the boundary line M with the land portion 5c, it forms a convex curved surface toward the second corner portion C2 side, and after separating from the opposite hexagonal surface 2, extends toward the opposite hexagonal surface 2 side. It will be.

A boundary line M between the main rake face 6a and its land portion 6c extending from the first end portion 5A of the corner cutting edge 5 to the inside of the hexagonal face 2 and the corner rake face 5a and its land portion 5c is shown in FIG. , intersects the main cutting edge 6 at an intersection angle β within the range of 20° to 60° in a plan view viewed from the direction facing the hexagonal surface 2 along the direction of the insert center line C is doing.

Furthermore, in the cutting insert of the present embodiment, the main cutting edge 6 has a main rake face at least on the corner edge 5 side and from the first end portion 5A of the corner edge 5 toward the second corner portion C2 side. A gradually increasing rake angle region 6e is provided in which the rake angle .theta. That is, in this rake angle gradually increasing region 6e, the main rake face 6a in the cross section perpendicular to the main cutting edge 6 is aligned with the insert centerline C when viewed from the direction facing the hexagonal face 2 along the insert centerline C. The rake angle θ, which is the angle formed with the perpendicular plane, gradually increases along the main cutting edge 6 from the first end 5A of the corner edge 5 as shown in FIGS. 11 to 14 .

Here, in the present embodiment, the rake angle gradually increasing region 6e is 1.0 mm to It is formed within a range N of 2.0 mm. Further, in the present embodiment, the rake angle θ of the main rake face 6a is constant on the second corner portion C2 side of the gradually increasing rake angle region 6e. Furthermore, the amount of gradual increase in the rake angle θ in the gradually increasing rake angle region 6e, that is, the difference between the first end 5A of the corner cutting edge 5 and the terminal end of the gradually increasing rake angle region 6e on the side opposite to the first end 5A The difference between the rake angles θ of the main rake face 6a is 5° or more.

21 and 22, the cutting insert configured as described above is attached to the insert mounting seat 12 formed on the outer periphery of the tip portion of the tool body 11 in an embodiment of the indexable cutting tool of the present invention as shown in FIGS. 21 and 22. 13 to form the indexable cutting tool (indexable milling cutter) of the above embodiment as shown in FIGS. 23 to 27 .

In this embodiment, the tool main body 11 is formed in a substantially disc-shaped outer shape centered on the axis O with the tip portion (lower portion in FIG. 25) having a large diameter. A chip pocket 14 extending to the side is formed, and the insert mounting seat 12 is formed on the wall surface of the chip pocket 14 facing the tool rotation direction T as a recess opening to the wall surface and the tip end surface and the outer peripheral surface of the tool body 11. formed. In this embodiment, a plurality (four) of chip pockets 14 and insert mounting seats 12 are formed at regular intervals in the circumferential direction.

As shown in FIGS. 21 and 22, the insert mounting seat 12 has an annular flat bottom surface 12a facing in the tool rotation direction T, and an outer periphery of the tip of the tool body 11 that rises perpendicularly to the bottom surface 12a in the tool rotation direction T side. It has a wall surface 12b facing the side and a wall surface 12c facing the inner peripheral side of the tip. The bottom surface 12a is slightly inclined in the tool rotation direction T toward the rear end of the tool body 11, and a screw hole 12d into which the clamp screw 13 is screwed is formed in the center thereof. Between the bottom surface 12a and the wall surfaces 12b and 12c, and between the bottom surface 12a and the tip surface and outer peripheral surface of the tool body 11, relief portions are formed to prevent interference with the insert body 1. .

With such an insert mounting seat 12, the cutting insert of the above-described embodiment has one hexagonal face 2 of the insert body 1 directed in the tool rotation direction T, and one corner edge 5 of this one hexagonal face 2. As shown in FIGS. 23 and 25, the tip end of the tool body 11 is protruded to the outer periphery, and the main cutting edge 6 connected to the corner edge 5 is protruded to the outer periphery of the tool body 11 as shown in FIG. As shown in FIG. 25, the minor cutting edge 7 connected to the corner edge 5 protrudes toward the tip side of the tool body 11 so as to extend in the opposite direction to the tool rotation direction T toward the rear end side as shown in FIG. and is seated on a plane perpendicular to the axis O or so as to extend slightly toward the rear end side toward the inner peripheral side of the tool body 11 .

The other hexagonal surface 2 opposite to the hexagonal surface 2 of the insert body 1 has the flat portion 2a at the center thereof in close contact with the bottom surface 12a of the insert mounting seat 12, and the tool body The two side faces 3 of the insert body 1 are formed with secondary flanks 7b connecting to the remaining two minor cutting edges 7 on the one hexagonal face 2 other than the minor cutting edges 7 directed toward the tip side of the insert. The seat 12 is brought into contact with the wall surfaces 12b and 12c. The wall surface between these wall surfaces 12b and 12c does not come into contact with the insert body 1 seated in this way, and a small distance is provided between the facing side surface 3 and the wall surface.

The clamp screw 13 inserted through the mounting hole 4 is screwed into the screw hole 12d so that the flat portion 2a of the other hexagonal surface 2 becomes the bottom surface 12a. , and the two side surfaces 3 are pressed against the wall surfaces 12 b and 12 c respectively, fixed to the insert mounting seat 12 , and mounted to the tool body 11 .

In the cutting insert configured as described above and the indexable cutting tool to which the cutting insert is attached, the main cutting edge 6 is located on the corner edge 5 side where the rake angle gradually increasing region 6e of the main rake face 6a is formed. From the first end portion 5A of the corner cutting edge 5 toward the second corner portion C2 side, in a side view facing the main flank 6b, the opposite hexagonal surface 2 (second polygonal ), and extends toward the opposite hexagonal surface 2 side.

For this reason, the chip is generated thin by being elongated in the shape of a convex curve in cross section along the convex curve formed by the main cutting edge 6 at the tip portion on the corner edge 5 side, so that the chip is easily rolled into a small curl radius. . As a result, the curl radius at the tip of the chip can be made smaller than the curl radius at the trailing edge, and the center line of the curl moves away from the major cutting edge 6 as it goes from the tip to the trailing edge of the chip. The direction, that is, the discharge direction of the chips can be controlled so that the chips are directed toward the inner peripheral side toward the rear end side of the tool body 11 .

Therefore, according to the cutting insert and the indexable cutting tool configured as described above, the chips generated by the main cutting edge 6 come into contact with the cut wall surface of the work material, or get caught between the insert body 1 and the cutting tool. You can avoid getting caught. For this reason, even under cutting conditions with a large depth of cut, it is possible to prevent the finished surface (wall surface) from being damaged by such biting of chips, and it is possible to suppress an increase in cutting resistance, resulting in high-quality cutting. In addition, it is possible to prevent chattering from occurring even in the cutting of thin plates.

In this way, the main cutting edge 6 draws a convex curve from the first end portion 5A toward the second corner portion C2 side in a side view facing the main flank 6b on the corner edge 5 side, while forming a convex curve in the opposite direction. In the cutting insert having the above configuration that extends toward the opposite hexagonal surface 2 after separating from the hexagonal surface 2, the curvature radius R of the convex curve drawn by the main cutting edge 6 as in this embodiment is 3 mm to 10 mm. Within the range, it is desirable to form a convex curve within a range of at least 1.0 mm from the first end 5A of the corner cutting edge 5 .

If the radius of curvature R of the convex curve drawn by the main cutting edge 6 is less than 3 mm, the main cutting edge 6 may protrude at this portion, and chipping or the like may easily occur. If it exceeds, the convex curve becomes flat, and the effect of controlling the chip discharge direction as described above may be impaired. Moreover, even when the range where the main cutting edge 6 draws a convex curve is shorter than the range of 1.0 mm from the first end 5A of the corner edge 5, the effect of controlling the direction of chip discharge can be sufficiently exhibited. may not be possible.

Further, in the present embodiment, on the side of the corner edge 5 on the tip side of the tool body 11 of the main cutting edge 6 that protrudes to the outer peripheral side of the tool body 11 , from the first end 5A of the corner edge 5 to the tool body 11 . A gradually increasing rake angle region 6e is provided so that the rake angle .theta. there is

Therefore, the chips generated by the main cutting edge 6 from the corner edge 5 side flow along the main rake face 6a with a large rake angle θ on the rear end side of the main cutting edge 6, and are more likely to move in the tool rotation direction than on the tip side. Since a large space on the T side is secured on the trailing end side, the major cutting edge 6 is curled with a larger radius on the trailing end side than on the tip end side. Accordingly, the chips are also directed in a direction away from the main cutting edge 6 as the center line of the curl goes from the front end to the rear end, that is, in a direction toward the inner peripheral side as it goes toward the rear end side of the tool body 11. It flows out and is discharged while being curled in the same direction.

Here, FIG. 28 shows a state in which chips are generated by the cutting insert of the above embodiment, and FIG. It indicates the state in which the These figures show cutting conditions of cutting speed: 160 m/min, depth of cut: 2.0 mm, feed per tooth: 0.2 mm/t, diameter of main cutting edge 6 around axis O: 80 mm. The radius of curvature R of the convex curve formed by the corner edge side portion of the cutting edge viewed from the direction facing the main rake face is 5.2 mm, and the simulation is performed for cutting the work material: SCM440. 28 and 29 are diagrams of the insert body viewed from the direction of rotation of the tool, and the diagrams on the right side are views viewed from the outer peripheral side of the tool body.

From the results of FIGS. 28 and 29, in FIG. 29 where the rake angle of the main cutting edge is constant, the chips have a large radius of curl on the tip side of the main cutting edge (lower side in each figure of FIG. 29). , the curl radius is smaller on the rear end side (upper side of each drawing in FIG. 29), and the center line of the curl is closer to the outer peripheral side of the tool body (on the right side of each left drawing in FIG. 29) toward the rear end side. extends to For this reason, it can be seen that chips may come into contact with the wall surface of the work material formed by the main cutting edge, or chips may be caught between the wall surface and the main cutting edge.

On the other hand, in FIG. 28, contrary to FIG. 29, the chips have a smaller curl radius on the tip side of the main cutting edge (lower side in each figure in FIG. 28) and 28), the radius of the curl increases, and the center line of the curl extends toward the inner peripheral side of the tool body (to the left in each left-hand drawing of FIG. 28) toward the rear end side. In other words, it can be seen that the chip discharge direction is controlled so as to leave the wall surface of the work cut by the main cutting edge. Note that in FIG. 28, the rake angle gradual increase region extends approximately 1.0 mm from the first end of the corner edge, and the rake angle θ gradually increases from 20° to 30°.

Further, in the present embodiment, the rake angle gradually increasing region 6e is within a relatively short range N of 1.0 mm to 2.0 mm from the first end 5A of the corner cutting edge 5 in plan view facing the hexagonal surface 2. is formed in Even within such a short range N, if the rake angle gradually increasing region 6e is formed, the chip curl radius can be reduced on the tip end side (corner edge 5 side) of the major cutting edge 6 as shown in FIG. It is possible to control the direction in which the chips are discharged by giving the above-described curly curl. If the rake angle gradual increase region 6e is shorter than 1.0 mm from the first end 5A of the corner cutting edge 5, it may not be possible to sufficiently impart such a curl to the chips.

Moreover, in the present embodiment, the rake angle of the main rake face 6a is less than the second corner portion C2 side of the gradually increasing rake angle region 6e beyond 2.0 mm from the first end portion 5A of the corner cutting edge 5. Since θ is constant, the edge angle of the main cutting edge does not become unnecessarily small on the rear end side of the main cutting edge 6 (on the side of the second corner portion C2). It is possible to prevent the blade 6 from being chipped or chipped. However, the rake angle .theta.

Further, in the present embodiment, the amount of gradual increase of the rake angle θ of the main rake face 6a in the region 6e of gradually increasing rake angle is set to 5° or more. It is possible to surely give a curl that makes the curl radius small. That is, when the amount of gradual increase in the rake angle θ in this gradual increase in rake angle region 6e is less than 5°, the curl diameter of the chips is reduced on the corner edge 5 side of the main cutting edge 6, and the discharge direction is directed toward the tool body as described above. There is a possibility that it may become difficult to reliably adhere to the chips in a direction toward the inner peripheral side toward the rear end side.

In this embodiment, the land portion 6c and the honing portion 6d are formed on the main rake face 6a on the main cutting edge 6 side. The inclination angle, ie, the rake angle, may gradually increase away from the first end 5A of the corner cutting edge 5 in conjunction with the rake angle gradual increase region 6e of the main rake face 6a, or may be constant.

Furthermore, in the present embodiment, the boundary line M between the corner rake face 5a and the main rake face 6a extending from the first end portion 5A of the corner cutting edge 5 toward the inside of the hexagonal face 2 extends along the centerline C of the insert. In a plan view viewed from the direction facing the hexagonal face 2, the main rake face 6a intersects the major cutting edge 6 at an intersecting angle β within the range of 20° to 60°. Thus, it extends from the boundary line M inclined with respect to the main cutting edge 6 . Therefore, it is possible to more reliably control the discharge direction of chips in the direction away from the main cutting edge 6, thereby preventing the occurrence of biting.

That is, when the intersection angle β is smaller than 20°, the boundary line M is too close to the main cutting edge 6 in plan view, and the chip discharge direction cannot be reliably controlled away from the main cutting edge 6. It can be difficult. On the other hand, if the crossing angle β exceeds 60°, it becomes difficult for chips to be discharged to the rear end side of the tool body 11, and the chips flowed out to the inner peripheral side of the tool body 11 are discharged into the chip pocket. It hits the wall surface facing the outer periphery of the tool body 11 of 14 and flows to the outer periphery, and there is a possibility that it may be caught between the main cutting edge 6 and the wall surface of the work material formed by the main cutting edge 6 .

On the other hand, in the present embodiment, the corner edge 5 moves away from the hexagonal face 2 opposite to the hexagonal face 2 on which the corner edge 5 is formed as it goes toward the first end 5A thereof, and the insert centerline C It is formed so as to extend in a direction projecting in the direction. For this reason, the curl radius is set to be smaller so that the tip of chips generated from the corner edge 5 by the tip of the main cutting edge 6 is slightly entangled, and the curl radius is further directed toward the inner peripheral side as it goes toward the rear end side of the tool body 11 . It is possible to control the discharge direction as follows.

Moreover, in this embodiment, the corner cutting edge 5 is formed in a concave curved shape when viewed from the side facing the corner flank 5b, and the tip of chips generated along this concave curved line is curled to a smaller radius. In addition, since the corner rake face 5a is also formed into a concave curved surface, the tip of the chip can be curled to a smaller radius. Therefore, it is possible to control the discharge direction so that the center line of the curl of the chips is more reliably separated from the main cutting edge and directed toward the inner peripheral side as it moves toward the rear end side of the tool body 11, thereby preventing the chips from being bitten. can be effectively prevented. However, as long as the first end portion 5A protrudes from the second end portion 5B, the corner cutting edge 5 may be linear in the side view.

Further, in this embodiment, when the corner cutting edge 5 is formed to extend in the direction of protruding in the direction of the insert centerline C toward the first end 5A as described above, the first end 5A is , with respect to the second end portion 5B of the corner cutting edge 5 on the opposite side, the protrusion amount t in the direction of the insert center line C in a side view facing the corner flank 5b is in the range of 0.05 mm to 0.15 mm. Inside. As a result, the chip discharge direction can be controlled more effectively, and the corner edge 5 and the major cutting edge 6 can be prevented from being chipped at the first end portion 5A.

That is, if the protrusion amount t is smaller than 0.05 mm, the effect of controlling the chip discharge direction toward the inner peripheral side toward the rear end side of the tool body 11 may decrease as described above. be. On the other hand, if the protrusion amount t exceeds 0.15 mm, the intersection angle between the corner edge 5 and the major cutting edge 6 at the first end 5A of the corner edge 5 becomes small, and the first edge In the portion 5A, the corner edge 5 and the main cutting edge 6 may be easily damaged or chipped.

Furthermore, in the cutting insert of this embodiment, the insert body 1 has an insert centerline C passing through the centers of the front and back hexagonal faces 2 (first and second polygonal faces), and these The hexagonal face 2 has a secondary rake face 7a continuous with the corner rake face 5a on the side opposite to the main rake face 6a of each hexagonal face 2 and on the side opposite to the first end 5A of the corner cutting edge 5. A minor cutting edge 7 extending from the second end 5B of is formed, and the minor cutting edge 7 can smoothly finish the bottom surface of the machined surface of the work material.

In the present embodiment, the minor cutting edge 7 is formed in the direction of the distance from the second end 5B of the corner edge 5 in a side view facing the minor flank 7b. It is formed so as to extend toward the side of the hexagonal surface 2 opposite to the square surface 2, and the minor cutting edge 7 cuts chips continuous from the corner edge 5 to the inner peripheral side of the tool body 11 into the tool body. 11 can be generated in such a manner as to be pulled into the inner peripheral side. Therefore, it is possible to more reliably guide the center line of the chip curl toward the inner peripheral side as it moves toward the rear end side of the tool body 11, thereby controlling the discharge direction.

When the minor cutting edge 7 is formed in this way, in the reference example, the minor cutting edge 7 extends from the second end 5B of the corner edge 5 in a side view facing the minor flank 7b. may be formed along a plane P perpendicular to the insert centerline C, with an inclination angle α with respect to this plane P of 0°, i. It is sufficient if it is not formed in a direction away from the square face 2 so that chips are pushed out to the outer peripheral side of the tool body 11 . However, if the inclination angle α is too large, the chips will be drawn into the inner peripheral side of the tool body 11 too much, making it difficult to discharge them to the rear end side, and they will remain in the chip pocket 14 and tend to be bitten. Preferably, the angle α is 15° or less.

Furthermore, in this embodiment, the insert body 1 is rotationally symmetrical by 120° around the insert center line C passing through the centers of the two hexagonal faces 2, which are the first and second polygonal faces. The two hexagonal faces 2 are formed in a hexagonal plate shape that is symmetrical about the front and back with respect to the two hexagonal faces 2, and each of the two hexagonal faces 2 has three first and three second corner portions C1 and C2 in the circumferential direction. The two hexagonal faces 2 are arranged alternately and on opposite sides in the direction of the insert centerline C, and the first end 5A and the second end 5B of the corner edge 5 are arranged on opposite sides of the insert body 1 in the circumferential direction, so that the major cutting edge 6 and the minor cutting edge 7 are formed on the front and back hexagonal faces 2 from the first and second ends 5A and 5B. are formed to extend in opposite directions.

That is, the cutting insert of this embodiment is a handed cutting insert, and the corner edge 5, the major cutting edge 6, and the corner edge 5, the major cutting edge 6, and the The use of minor cutting edges 7 may be possible.

In addition, the cutting insert of this embodiment has a negative flank 3 formed so that the side surface 3 on which the corner flank 5b, the main flank 6b, and the sub-flank 7b of the insert body 1 are formed extends parallel to the center line C of the insert. Since it is a cutting insert of this type, it is possible to secure a large edge angle of the corner edge 5, the major cutting edge 6, and the minor cutting edge 7, thereby improving the cutting edge strength. As a result, the corner edge 5, the major cutting edge 6, and the minor cutting edge 7 can be prevented from being chipped or damaged.

1 insert body 2 hexagonal faces (first and second polygonal faces)
3 side face 4 mounting hole 5 corner edge 5A first end of corner edge 5 5B second end of corner edge 5 5a corner rake face 5b corner flank face 6 main cutting edge 6a main rake face 6b main flank face 6e rake face Gradual angle region 7 Minor cutting edge 7a Minor rake face 7b Minor flank face 11 Tool body 12 Insert mounting seat 13 Clamp screw C Insert centerline L Corner rake face 5a and its land portion 5c and its minor rake face 7a and its land portion 7c M Boundary line between the corner rake face 5a and its land portion 5c and the main rake face 6a and its land portion 6c N Range where the rake angle gradually increasing region 6e is formed P From the second end portion 5B of the corner cutting edge 5 A plane perpendicular to the extending center line C of the insert t Projection amount of the first end 5A of the corner edge 5 from the second end 5B R Projection of the convex curve drawn by the main cutting edge 6 in a side view facing the main flank 6b Curvature radius O Axis of the tool body 11 T Tool rotation direction α Inclination angle of the minor cutting edge 7 with respect to the plane P in a side view facing the minor flank 7b β Plan view seen from a direction facing the hexagonal surface 2 θ The rake angle of the main rake face 6A in the gradually increasing rake angle region 6e

Claims (9)

It has a polygonal plate-like insert body having first and second polygonal faces facing opposite sides and a plurality of side faces arranged around the first and second polygonal faces. ,
A corner cutting edge having a corner rake face on the first polygonal face is formed at the first corner of the corners of the first polygonal face of the insert body,
From this corner cutting edge to the second corner portion adjacent to the first corner portion in the circumferential direction of the first polygonal surface, the main rake surface continuous with the corner rake surface is formed on the first polygonal surface. a main cutting edge having and extending from the first end of the corner edge;
On the corner edge side, the main cutting edge has a main flank surface that intersects the main rake surface among the plurality of side surfaces as it goes from the first end portion of the corner edge toward the second corner portion side. , extending toward the second polygonal surface after separating from the second polygonal surface while drawing a convex curve ,
The corner edge extends in a direction protruding away from the second polygonal surface toward the first end, the first end being opposite the first end. protruding from the second end of the corner blade of
The insert body has an insert centerline passing through the centers of the first and second polygonal faces,
The first polygonal face has a secondary rake face connected to the corner rake face on the side opposite to the main rake face and connected to the first end of the corner cutting edge. is formed with a minor cutting edge extending from a second end of the corner edge opposite the
The minor cutting edge is separated from the second end of the corner edge in a side view facing the minor flank that intersects the minor rake face through the minor cutting edge among the plurality of side surfaces of the insert body. and extending toward the second polygonal face according to the above . In a side view facing the main flank, the radius of curvature of the convex curve drawn by the main cutting edge is in the range of 3 mm to 10 mm, and the radius of curvature is in the range of at least 1.0 mm from the first end of the corner edge. 2. The cutting insert according to claim 1, wherein said main cutting edge has a convex curve. A boundary line between the main rake face extending from the first end of the corner cutting edge to the inside of the first polygonal face and the corner rake face is the main rake face in plan view facing the first polygonal face. 3. The cutting insert according to claim 1, wherein the cutting edge intersects at an intersecting angle within the range of 20° to 60°. The corner cutting edge is formed in a concave curved shape in a side view facing a corner flank surface that intersects the corner rake face through the corner cutting edge among the plurality of side surfaces of the insert body. Cutting insert according to any one of claims 1 to 3 . A first end of the corner cutting edge is directed toward a second end of the corner cutting edge opposite the first end from one of the plurality of side surfaces of the insert body through the corner cutting edge. Any one of claims 1 to 4, characterized in that, in a side view facing a corner flank that intersects with the corner rake face, it protrudes by a protrusion amount within a range of 0.05 mm to 0.15 mm. The cutting insert described in . 2. The angle of inclination of the minor cutting edge with respect to a plane perpendicular to the center line of the insert is within a range of 0° to 15° in a side view facing the minor flank. 6. The cutting insert according to any one of claims 5 . The insert body is rotationally symmetrical about an insert center line passing through the centers of the first and second polygonal faces by 120°, and is symmetrical with respect to the first and second polygonal faces. It is formed in a hexagonal plate shape,
Three each of the first and second corner portions are arranged alternately in the circumferential direction on each of the first and second polygonal surfaces, and are arranged on opposite sides in the insert centerline direction. and
Between the first and second polygonal faces, a first end of the corner cutting edge and a second end of the corner cutting edge opposite to the first end define the insert body. 7. The cutting insert according to any one of claims 1 to 6 , characterized in that it is arranged circumferentially opposite the . 8. The cutting insert according to claim 7 , wherein the side surfaces of said insert body extend parallel to said insert centerline. The cutting insert according to any one of claims 1 to 8 is mounted on an insert mounting seat formed on the outer periphery of the tip portion of the tool body that rotates about the axis, and the cutting insert is attached to the tip of the tool body. The main cutting edge extending from the first end of the corner edge is positioned on the outer peripheral side of the tool body, and the corner rake face and the main cutting edge that are connected to the corner edge and the main cutting edge are positioned on the outer peripheral side of the tool body. An indexable cutting tool characterized by being detachably mounted with a rake face facing the direction of rotation of the tool.

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