JP6576338B2 - Cutting insert and cutting edge exchangeable cutting tool - Google Patents

Description

  The present invention relates to a cutting insert and a cutting edge exchangeable cutting tool to which the cutting insert is detachably mounted.

  Conventionally, the thing of the shape currently disclosed by patent document 1 is known as a cutting insert of a blade-tip-exchange-type cutting tool. The cutting insert of patent document 1 has the main cutting edge part which inclines below as it leaves | separates from a cutting corner in side view. In order to obtain a cutting insert that can be used by both the left and right sides, the main cutting edge is inclined downward at the same angle from all the cutting corners. They are connected at an intermediate point between them, forming a symmetrical V-shape. Therefore, it is possible to perform the same cutting process on both the left and right sides regardless of which cutting corner is used. At this time, of course, in the main cutting edge of this cutting insert, only the downwardly inclined main cutting edge part connected to the cutting corner involved in cutting is used for cutting (that is, the downwardly inclined main cutting edge part and , And the main cutting edge part of the upward slope connected to it is not used for cutting at the same time).

JP 2011-104738 A

  However, in the cutting insert of patent document 1, the following problem arises by the structure which connects two main cutting edge parts in V shape. Chips generated by the main cutting edge part participating in cutting (that is, the main cutting edge part of the downward slope connected to the cutting corner participating in cutting) may curl depending on the material of the work piece. However, it may be discharged, resulting in a relatively large curl radius. The chip having the increased curl radius is adjacent to the main cutting edge portion having an upward inclination connected to the main cutting edge portion having a downward inclination (that is, the main cutting edge portion not used for cutting). May collide with the side. As will be described in detail later, the unused main cutting edge portion is inclined upward, so that chips easily collide with adjacent side surfaces. When the chips collide, the side surface is scratched, or deposits such as chip fragments and welded materials adhere to the side surface, thereby reducing the surface accuracy of the side surface. Since the side surface of the cutting insert as disclosed in Patent Document 1 functions as an abutting surface that comes into contact with the insert seat of the tool body, when the surface accuracy of this portion is reduced, the side surface becomes an abutting surface with the insert seat. When it does, the fixing property of a cutting insert will worsen and it will become easy to produce problems, such as shakiness and chatter at the time of cutting.

  The present invention has been made in view of the above problems, and is fixed by scraping side surfaces of chips even though the main cutting edge portion having the downward inclination and the main cutting edge portion having the upward inclination are connected in the central region. It aims at providing the cutting insert which can suppress a fall of property, and the blade-tip-exchange-type cutting tool provided with the same.

The present invention provides a first end face (2), a second end face (3) facing the first end face (2), and a side face connecting the first end face (2) and the second end face (3). (4) In the cutting insert (1) having the main cutting edge (8) and the main cutting edge (8) at the intersecting ridge line between the first end surface (2) and the side surface (4). Two secondary cutting edges (9) adjacent to both ends are formed, and the main cutting edge (8) is separated from one of the secondary cutting edges (9), and the second end face (3). The first main cutting edge portion (8a) adjacent to the first main cutting edge portion (8a) is connected to the first main cutting edge portion (8a) and moves away from the second end face (3) as it approaches the other sub cutting edge (9). A second main cutting edge portion (8b), and the first main cutting edge portion (8a) and the second main cutting edge portion. 8b) from the central point (C) between the two secondary cutting edges (9) toward the secondary cutting edges (9), the central point (C) and the secondary cutting edges ( 9), and the first main cutting edge portion (8a) and the second main cutting edge portion (8b) are viewed from the first end face (2) side. Cutting that is straight and has a constrained portion (12) that is concave toward the inside of the cutting insert (1) is formed on the side surface (4) adjacent to the main cutting edge (8). An insert (1) is provided.

  The present invention also provides a tool body (21, 21 ′), at least one insert seat (22) formed on the tool body (21, 21 ′), and a detachable attachment to the insert seat (22). In the cutting edge exchangeable cutting tool (20, 20 ′) composed of at least a cutting insert to be cut, the cutting insert is the cutting insert (1), and the insert seat (22) has a tool rotation. It is comprised from the bottom face (221) which faced the direction front, and the side part (222) which protrudes, The said side part (222) of the said insert seat is the said to-be-restrained part of the said cutting insert (1) Provided is a cutting edge-exchangeable cutting tool (20) that abuts on (12).

  According to the present invention, the first main cutting edge portion (8a) having a downward inclination and the second main cutting edge portion (8b) having an upward inclination as the distance from one of the sub cutting edges (9) is a central point ( C) In the cutting insert including the main cutting edge (8) having a configuration connected in the region near C), a concave portion (restraint portion) is formed on the side surface, and the side surface of the cutting insert (1) is only in that portion. The tool body (21) is in contact with and restrained. For this reason, when the first main cutting edge portion (8a) is used for cutting, the surface accuracy of the side surface is reduced because the chips collide with the side surface region connected to the second main cutting edge portion (8b). However, when the region of the side surface is used for fixing the cutting insert, the fixability does not deteriorate.

1 shows a perspective view of one embodiment of a cutting insert of the present invention. FIG. The side view which looked at the cutting insert shown by FIG. 1 from the direction which opposes the side surface adjacent to the main cutting edge is shown. The perspective view of one Embodiment of the blade-tip-exchange-type cutting tool of this invention using the cutting insert of FIG. 1 is shown. FIG. 4 shows a side view of the tool body shown in FIG. 3. The figure explaining the cutting edge used when the cutting insert of FIG. 1 performs a cutting process is shown. The figure for demonstrating the growth of the chip | tip which generate | occur | produces when the cutting insert of FIG. 1 performs a cutting process is shown. The perspective view of other embodiment of the blade-tip-exchange-type cutting tool of this invention using the cutting insert of FIG. 1 is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, terms such as “upper”, “lower”, “right”, and “left” that can be used in relation to a surface and the like are convenient expressions for easy understanding of the explanation. It does not indicate an absolute positional relationship.

  As shown in FIGS. 1 and 2, the cutting insert 1 of the present embodiment is a first end surface (upper surface) 2 having a substantially square shape, a first end surface (upper surface) 2 facing the upper surface 2 and having substantially the same shape as the upper surface 2. It is basically composed of two end surfaces (lower surfaces) 3 and side surfaces 4 connecting the upper surface 2 and the lower surface 3. A mounting hole 5 provided so as to penetrate the upper surface 2 and the lower surface 3 is provided in the approximate center of the upper surface 2 and the lower surface 3. The central axis IA of the cutting insert 1 is determined so as to pass through the center of the mounting hole 5 and perpendicularly intersect the upper surface 2 and the lower surface 3 in a top view. The cutting insert 1 of the present embodiment has an outer shape that is 90 ° rotationally symmetric with respect to the central axis IA. The side surface 4 intersects the upper surface 2 and the lower surface 3 substantially perpendicularly. Therefore, although the cutting insert 1 of this embodiment is what is called a negative type, it is not limited to this.

  The upper surface 2 has a substantially square shape as an overall basic shape, but has a short side portion 6 that is cut out so that the corner region is chamfered. Therefore, the upper surface 2 has a shape in which four short side portions 6 and four long side portions 7 having a relatively longer length than the short side portion 6 are alternately connected. However, the shape of the upper surface 2 is not limited to this, and may be another polygonal shape. Further, since the upper surface 2 and the lower surface 3 have the same outer shape, detailed description of the outer shape of the lower surface 3 is omitted. In other words, the description of the configuration made with respect to the upper surface 2 is also applicable to the lower surface 3 hereinafter.

  A cutting edge is formed at the intersecting ridge line between the upper surface 2 and the side surface 4. The cutting edge is composed of a main cutting edge 8 and a secondary cutting edge 9. The main cutting edge 8 is formed on the intersecting ridge line between the long side portion 7 and the side surface 4 of the upper surface 2, and the sub cutting edge 9 is formed on the intersecting ridge line between the short side portion 6 of the upper surface 2 and the side surface 4. When the cutting insert 1 is involved in cutting, the main cutting edge 8 has a function of cutting the side wall surface of the workpiece processing surface. On the other hand, the auxiliary cutting edge 9 has a function of cutting the bottom wall surface of the work surface. In the present embodiment, the top surface 2 of the cutting insert 1 has a substantially square shape, and the angle formed by the two main cutting edges 8 sandwiching one corner is 90 °. However, the present invention is not limited to this.

  Here, as shown in FIG. 2, in a side view of the cutting insert 1, a virtual plane represented by a virtual line that intersects the central axis IA perpendicularly at an intermediate point between the upper surface 2 and the lower surface 3. , Defined as plane M. In the side view, the auxiliary cutting edge 9 is formed in parallel with the plane M and is arranged at a position farthest from the plane M. The main cutting edge 8 connected to the sub cutting edge 9 approaches the plane M as it is separated from the sub cutting edge 9, and is closest to the plane M at the center point C at the central point between the adjacent sub cutting edges 8. It is formed to do. In the present embodiment, since the main cutting edge 8 is inclined not in a straight line but in a concave curve shape, the main cutting edge 8 has a gentle U-shape as a whole. Further, the main cutting edge 8 is formed to have a bilaterally symmetric shape with a reference line passing through the center point C and parallel to the central axis IA as viewed from the side. Further, the upper surface 2 and the lower surface 3 are formed to have a 180 ° symmetrical shape with respect to the plane M. Therefore, the cutting insert 1 of this embodiment can be used even if it is turned over and attached to the body of the cutting tool.

  The upper surface 2 is connected to the inclined portion 10 and the inclined portion 10 that approaches the plane M as it advances from each of the cutting edges 8 and 9 inward of the cutting insert 1 (that is, toward the central axis IA), and A flat surface 11 parallel to the plane M is formed. Since the cutting insert 1 according to the present embodiment has cutting edges 8 and 9 formed on both the upper surface 2 and the lower surface 3 and can be used upside down, the flat surface 11 has a tool body 21 (FIG. 3). It also functions as a seating surface in contact with.

  Here, in the main cutting edge 8 arranged between the adjacent sub cutting edges 9, a portion from one sub cutting edge 9 side to the center point C is defined as a first main cutting edge portion 8a, and the other sub cutting edge. A portion from the 9 side to the center point C is defined as a second main cutting edge portion 8b. In the present embodiment, when the cutting insert 1 is used for cutting, when the cutting tool is viewed from the base end side connecting to the machine tool, the cutting tool rotates in the clockwise direction (FIG. 3). In the case of a left hand in which the first main cutting edge portion 8a and the sub cutting edge 9 are combined as one set and the rotation direction is counterclockwise (FIG. 7), the second main cutting edge portion 8b and the sub cutting edge 9 Is involved in cutting as one set. Therefore, in the cutting insert 1 of this embodiment, it is possible to perform the same cutting process with a cutting edge having the same shape, which is inclined so as to move away from the sub-cutting edge 9, in either right or left. is there. Therefore, it is possible to sufficiently reduce the cutting resistance while being usable in both left and right sides. In the present embodiment, there are 8 sets of the first main cutting edge portion 8a and the sub cutting edge 9 in the vertical direction, and the set of the second main cutting edge portion 8b and the sub cutting edge 9 is the vertical alignment. There are 8 pairs. That is, the right-handed cutting can be performed 8 times, and the left-handed cutting can be performed 8 times. However, the present invention is not limited to this, and the number of usable cutting edges can be appropriately changed. Moreover, the 1st main cutting edge part 8a and the 2nd main cutting edge part 8b may be the shape which combined either or both of the straight line or the curve.

  As shown in FIG. 2, the side surface 4 has a concave portion recessed toward the inside of the cutting insert 1 in an intermediate region between the upper surface 2 and the lower surface 3 in a side view of the cutting insert 1. A restraint portion 12 is formed. The constrained portion 12 is a portion of the side surface 4 that comes into contact with the tool body 21. In the present embodiment, the constrained portion 12 includes a first flat surface 12a that is inclined inward of the cutting insert 1 from the upper surface 2 side toward the lower surface 3 side, and the cutting insert 1 from the lower surface 3 side toward the upper surface 2 side. And a second flat surface 12b inclined inward. The first plane 12a and the second end face 12b are formed to be symmetric with respect to the plane M described above. The constrained portion 12 is provided between the main cutting edge 8 on the upper surface 2 and the main cutting edge 8 on the lower surface 3 in a side view of the cutting insert 1. In addition, a fixed gap G is provided between the first plane 12 a and the upper surface 2 and between the second plane 12 b and the lower surface 3. The number of constrained portions 12 provided in the cutting insert 1 of the present embodiment is four corresponding to the number of side surfaces connected to the long sides of the substantially squares of the upper surface 2 and the lower surface 3, but of course. Depending on the basic shape adopted for the upper surface 2 and the lower surface 3, this can be changed as appropriate.

  The shape of the constrained portion 12 is not limited to that described above, and may be another shape capable of achieving the intended purpose as the concave constrained portion 12. As long as it is concave, it may be composed of, for example, a combination of a plurality of planes instead of a single plane. Moreover, it may be comprised from the curved surface and the shape which combined the plane and the curved surface may be sufficient. Furthermore, a clear gap G may not appear between the first plane 12a and the second plane 12b, and the two may be smoothly connected.

  The cutting insert 1 can be made of a hard material such as cemented carbide, cermet, ceramic, or ultra-high pressure sintered body containing diamond or cubic boron nitride, or a coating thereof.

  Next, the blade-tip-exchangeable cutting tool 20 equipped with the cutting insert 1 of the present embodiment will be described.

  As shown in FIG. 3, an embodiment of the cutting edge-exchangeable cutting tool 20 using the cutting insert 1 of the above-described embodiment is provided with a right-hand tool body 21 of a front milling cutter having a rotation center axis TA. A plurality of cutting inserts 1 are mounted such that one main cutting edge portion 8a is involved in cutting. The cutting insert 1 is mounted on the distal end side of the tool body 21, and the proximal end side of the tool body 21 is connected to a machine tool. As shown in FIGS. 3 and 4, the tool body 21 is formed with a plurality of insert seats 22 and corresponding chip pockets 23 so as to open to the tool front end side of the outer peripheral surface. . The insert seat 22 is a part for fixing the cutting insert 1, and the chip pocket 23 is a space for discharging chips generated in the cutting process.

  As shown in FIG. 4, all the insert seats 22 are composed of a bottom surface 221 facing forward in the tool rotation direction and a protruding side surface portion 222. When the cutting insert 1 is mounted on the insert seat 22, the bottom surface 221 contacts the upper surface 2 or the lower surface 3 of the cutting insert 1, and the side surface portion 222 contacts the constrained portion 12 of the cutting insert 1. A screw hole 24 for attaching the cutting insert 1 with, for example, a fixing screw is provided at the center of the bottom surface 221. The side surface portion 222 includes a first side surface portion 222a located on the tool center axis TA side and a second side surface portion 222b located on the tool outer peripheral side when viewed from the direction facing the bottom surface 221. Have. The first side surface portion 222a faces the tool outer peripheral direction and the tool tip direction, and the second side surface portion 222b faces the tool center axis TA direction and the tool tip direction. Further, in the present embodiment, the first side surface portion 222a and the second side surface portion 222b are arranged so that the planes including each intersect at an angle of about 90 ° when viewed from the direction facing the bottom surface 221. Has been. This is because the cutting insert 1 of this embodiment is substantially square when viewed from the end face. That is, when the secondary cutting edge on the diagonal line of the secondary cutting edge 9 connected to the first primary cutting edge portion 8a involved in cutting is indicated by reference numeral 9a in FIG. 3, two pieces sandwiching the secondary cutting edge 9a are sandwiched. This is because the two side surface parts connected to the main cutting edge 8 or the restrained parts 12 form 90 °. However, the present invention is not limited to this, and it is needless to say that the angle formed by the first side surface portion 222a and the second side surface portion 222b can be appropriately determined according to the basic shape of the end surface.

  When the cutting insert 1 is mounted on the insert seat 22, the first side surface portion 222 a and the second side surface portion 222 b of the insert seat 22 and the two adjacent constrained portions 12 provided on the side surface 4 of the cutting insert 1 are Abut. In the cutting edge replacement type cutting tool 20 of the present embodiment, the first side surface portion 222a of the insert seat 22 abuts only on the first flat surface 12a of the constrained portion 12, and the second side surface portion 222b of the insert seat 22 is constrained portion. It is comprised so that it may contact | abut only the 12 2nd plane 12b. However, the contact relationship between the first side surface portion 222a and the second side surface portion 222b of the insert seat 22 and the first flat surface 12a and the second flat surface 12b of the constrained portion 12 is not limited to this. Various combinations may be adopted. Further, the protruding shape of the side surface portion 222 of the insert seat 22 and the concave shape of the constrained portion 12 of the cutting insert 1 are portions that form a complementary shape in which the cutting insert 1 is appropriately restrained in accordance with the contact between the two. What is necessary is just to have.

  By removing the fixing screw and rotating the cutting insert 1, the constrained portion 12 that contacts the side surface portion 222 of the insert seat 22 can be changed. When the constrained portion 12 that contacts the side surface portion 222 of the insert seat 22 changes, the cutting edges 8 and 9 involved in cutting also change. This makes it possible to sequentially determine the cutting edges 8 and 9 involved in cutting. In addition, as described above, the cutting insert 1 of the present embodiment can be used in either right or left mode.

  Next, the operation and effect of the cutting insert 1 of the present embodiment and the cutting edge-exchangeable cutting tool 20 equipped with the cutting insert 1 will be described.

  The main cutting edge 9 of the cutting insert 1 of the present embodiment includes a first main cutting edge portion 8a connected to one of the adjacent sub cutting edges 9 and a first main cutting edge 9 connected to the other sub cutting edge 9. And two main cutting edge portions 8b, each of which is inclined so as to approach the plane M as it is separated from each sub cutting edge 9, and has a shape that connects at the center point C between the sub cutting edges 9. Yes. A concave constrained portion 12 is formed on the side surface 4 adjacent to the main cutting edge 8. With such a configuration, the following effects can be obtained.

  For example, as shown in FIG. 5, the first main cutting edge portion and one of the sub cutting edges used for cutting in relation to the configuration of the cutting edge replacement cutting tool 20 of FIG. When a second main cutting edge portion and a side surface portion connected to the second main cutting edge portion and the side portion connected to the second main cutting edge portion that are not used for cutting are denoted by reference numerals 8b 'and 4', respectively, a chip having a relatively large curl radius is represented by the first main cutting edge portion 8a ' Is generated, the chip tends to collide with the side surface portion 4 ′ adjacent to the second main cutting edge portion 8b ′. This is because, since the curl radius is large in the first place, as indicated by the arrow in FIG. 6, the chips tend to extend (grow) in a spiral shape so as to wrap around the side surface portion 4 ′. At the same time, the inclination in the direction away from the plane M with increasing distance from the center point C, that is, the inclination in which the tip of the chip is allowed to extend so as to avoid the side face 4, and the direction in which the hitting area increases. The second main cutting edge portion 2b ′ provided with the inclination (upward inclination) exists over a wide area up to the other sub cutting edge. Accordingly, the tip of the chip having a large curl radius is likely to collide with the side portion 4 ′ of “uphill slope” provided over a wide range. The surface accuracy of the side surface 4 ′ is deteriorated due to scratches or deposits caused by the collision of the chips. However, in the configuration of the present embodiment, the constrained portion 12 is formed in an intermediate region between the upper surface 2 and the lower surface 3, that is, in a region away from the main cutting edge 8 and recessed toward the inside of the cutting insert 1. Therefore, the chips hardly reach the inside of the constrained portion 12 having a concave shape. In the present embodiment, the cutting insert 1 is held so as to contact the tool body 21 at the concave constrained portion 12 instead of the side surface 4 ′ itself. Therefore, the fixing property of the cutting insert 1 is not affected by the surface accuracy of the side surface 4 ′, so that high fixing property can be maintained regardless of chip collision.

  Although the above description has been described with respect to the usage mode in which only the first main cutting edge portion 8a 'is involved in cutting, the present invention is not effective only in the usage mode. That is, since the main cutting edge 8 of the present embodiment has a gentle U-shape as a whole, a process of cutting from the first main cutting edge portion 8a ′ to the middle of the second main cutting edge portion 8b ′ ( That is, processing with a large cutting amount) is also possible. Even in such a mode of use of the cutting insert, there is a situation where chips easily collide with the side surface portion 4 ′ of the second main cutting edge portion 8 b ′. In such a usage mode, since the second main cutting edge portion 8b ′ is used, it is difficult to use as a two-sided cutting insert, but when the other first main cutting edge portion 8a is involved in cutting. The present invention is effective because the side surface 4 ′ with reduced surface accuracy may be attached to face the side surface portion 222 a or 222 b of the insert seat 22.

  Moreover, in the cutting insert 1 of this embodiment, although the 1st main cutting edge part 8a and the 2nd main cutting edge part 8b are connected in the center point C, it is not limited to this. The connection point between the first main cutting edge portion 8a and the second main cutting edge portion 8b is a third of the distance between the central point C and the sub cutting edge 9 from the central point C toward each sub cutting edge 9. It suffices to be within an area. This is because the above-described chip collision is likely to occur only when the connection point is in this region. That is, the inclination in the direction away from the plane M with increasing distance from the connection point, that is, the inclination in the direction in which the chip hits, not the inclination in the direction allowing the chip to extend so as to avoid the side surface 4. This is because the second main cutting edge portion 2 b provided with the inclination exists over a wide area up to the other sub cutting edge 9. When the connection point exceeds one third, the region of the second main cutting edge portion 8b becomes considerably small, and the possibility that chips will collide with the side surface 4 adjacent to the second main cutting edge portion 8b is reduced. The present invention is effective when the connection point is in the above region. However, when the cutting insert 1 is used for cutting both sides, it is preferable that the connection point is on the center point C. For the same reason, the main cutting edge 8 is preferably formed so as to be symmetrical with respect to a reference line passing through the center point C and parallel to the central axis IA in a side view.

  As shown in FIG. 7, the cutting insert 1 of the above embodiment can be used by being attached to a blade-tip-exchangeable cutting tool 20 ′ in the form of a face mill having a left-handed tool body 21 ′. The present invention is effective. That is, the case where the first main cutting edge portion 8a is mainly involved in cutting has been described so far (FIG. 3), but of course, the case where the second main cutting edge portion 8b is mainly involved in cutting (FIG. 3). In 7), on the contrary, chips easily collide with the region of the side surface 4 adjacent to the first main cutting edge portion 8a. That is, the present invention can obtain the same effect as described above even when the second main cutting edge portion 8b is mainly involved in cutting.

  In addition, although the said blade-tip-exchange-type cutting tool 20,20 'and tool body 21,21' illustrated the thing of the form of a face mill, this invention is not limited to this. That is, the present invention can be applied to a turning tool such as a rotary cutting tool or a bite having another shape such as an end mill or a drill.

  While typical embodiments of the present invention have been described above, the present invention can be modified in various ways, and substitutions and modifications can be made without departing from the spirit and scope of the present invention defined by the claims of the present application. Is possible.

Claims (6)

A first end face (2), a second end face (3) facing the first end face (2), and a side face (4) connecting the first end face (2) and the second end face (3). In a cutting insert (1) having
The intersecting ridge line between the first end face (2) and the side face (4) has a main cutting edge (8) and two linear sub cutting edges (9 adjacent to both ends of the main cutting edge (8). ) And are formed at least,
The main cutting edge (8) includes a first main cutting edge portion (8a) that is closer to the second end surface (3) as the distance from one of the sub cutting edges (9) increases, and the first main cutting edge portion. A second main cutting edge portion (8b) that is connected to (8a) and moves away from the second end face (3) as it approaches the other sub cutting edge (9); and
The connecting portion between the first main cutting edge portion (8a) and the second main cutting edge portion (8b) is connected to each of the sub cutting edges from a center point (C) between the two sub cutting edges (9). Towards (9), in a region within one third of the distance between the center point (C) and the secondary cutting edge (9),
The first main cutting edge portion (8a) and the second main cutting edge portion (8b) are linear when viewed from the first end face (2) side, and are U-shaped when viewed from the side surface (4) side. By making a shape, the first main cutting edge part (8a) is configured to be able to cut into the middle of the second main cutting edge part (8b),
Of the side surface (4), the portion connected to the first main cutting edge portion (8a) and the second main cutting edge portion (8b) is a single plane,
On the side surface (4) adjacent to the main cutting edge (8), a constrained portion (12) having a concave shape toward the inside of the cutting insert (1) is seen from the side surface (4) side, etc. In the width and at both ends, the main side is connected to the plane connected to one of the side cutting edges (9) and the plane connected to the other side cutting edge (9) of the side surface (4). It is formed corresponding to the entire cutting edge (8),
The cutting insert (1) characterized by the above-mentioned. The second end face (3) also has a main cutting edge (8) and two sub cutting edges (9) connected to both ends of the main cutting edge (8) at the intersecting ridge line with the side face (4), Has at least a formed structure,
Regarding the configuration on the second end face (3) side,
The main cutting edge (8) has a first main cutting edge portion (8a) that is closer to the first end surface (2) as it is separated from one of the sub cutting edges (9), and the first main cutting edge portion. A second main cutting edge portion (8b) that is connected to (8a) and moves away from the first end face (2) as it approaches the other sub cutting edge (9),
The connecting portion between the first main cutting edge portion (8a) and the second main cutting edge portion (8b) is connected to each of the sub cutting edges from a center point (C) between the two sub cutting edges (9). Towards (9), in the region within one third of the distance between the central point (C) and the secondary cutting edge (9),
Cutting insert (1) according to claim 1, characterized in that. The connecting portion is the center point (C) between the auxiliary cutting edges ( 9 ).
Cutting insert (1) according to claim 1, characterized in that. The first main cutting edge portion (8a) and the second main cutting edge portion (8b) are formed symmetrically with respect to the center point (C) in a side view of the cutting insert (1). Yes,
Cutting insert (1) according to claim 3 , characterized in that. A tool body (21, 21 ′), at least one insert seat (22) formed on the tool body (21, 21 ′), and a cutting insert detachably attached to the insert seat (22); In the cutting edge exchangeable cutting tool (20, 20 ′) composed of at least
The cutting insert (1) according to any one of claims 1 to 4,
The insert seat (22) is composed of a bottom surface (221) facing forward in the direction of tool rotation and a protruding side surface portion (222).
The side surface portion (222) of the insert seat abuts on the constrained portion (12) of the cutting insert (1).
A cutting edge exchangeable cutting tool (20) characterized by the above. Using the cutting insert (1) according to claim 1,
Performing a process of cutting from the first main cutting edge portion (8a) to the middle of the second main cutting edge portion (8b);
Causing the chips generated by the machining to collide with the portion of the single plane connecting the first main cutting edge portion (8a) and the second main cutting edge portion (8b);
Cutting method including.

Images