JPWO2014098226A1 - CUTTING INSERT, CUTTING TOOL, AND CUTTING PRODUCT MANUFACTURING METHOD USING THE SA - Google Patents

Abstract

The cutting insert includes a cutting portion having a top surface, a bottom surface, a side surface connected to the top surface and the bottom surface, and a cutting blade located at a crossing portion between the top surface and the side surface. The first cutting edge is located on the tip side of the first cutting edge and has an outwardly convex arc shape, and the upper surface is located inward of the first cutting edge and is inclined downward as it goes inward. A breaker having a rake face that is adjacent to the rear end side with respect to the rake face, and a rising face that is inclined upward toward the rear end side. Has a wide portion having a largest width in a direction orthogonal to a virtual straight line extending from the rear end side to the front end side of the cutting portion on the rear end side with respect to both ends of the first cutting edge.

Description

  The present invention relates to a cutting insert, a cutting tool, and a method of manufacturing a cut workpiece using the cutting insert.

  In the cutting insert for grooving and profiling (hereinafter sometimes referred to as “insert”), the shape of the rake face for processing the chips of the insert in order to smoothly discharge the generated chips. Various studies have been made (see, for example, JP 2005-515905 A).

  In the insert described in this patent document, the cutting head has an arcuate cutting edge at the intersection of the chip surface on the upper surface side and the flank surface on the side surface side. And in a chip surface, it has a pair of bump-shaped part so that the chip fracture | rupture hollow provided in the front end side of the cutting head may be pinched | interposed.

  According to the insert having such a configuration, when grooving is performed, chips generated by the arc-shaped cutting blade are thick at the tip portion of the cutting blade and become thinner toward the rear end side. And since the curl diameter tends to become small in a thick part and the curl diameter tends to become large in a thin part, there exists a tendency for the cross-sectional shape of the chip | tip produced | generated in the said insert to become convex shape.

  However, since the chip breaking recess and the pair of bump-shaped portions are provided on the tip side of the cutting head, the function of guiding the convex chip cannot be sufficiently performed, and the chip is narrowed in the width direction. There was a risk of not being able to. As a result, there is a possibility that chips are entangled with the work material.

  Therefore, in the insert for grooving processing, the improvement of discharge | emission property of the chip | tip produced | generated with the cutting blade was calculated | required.

  One of the objects of the present invention is to provide a cutting insert and a cutting tool that are excellent in chip dischargeability, and a method of manufacturing a cut product using the cutting insert and cutting tool.

  A cutting insert according to an embodiment of the present invention includes an upper surface, a lower surface, a side surface connected to the upper surface and the lower surface, and a cutting portion having a cutting edge located at the intersection of the upper surface and the side surface, And a fixed portion positioned on the rear end side of the cutting portion when the cutting portion is viewed from above. When viewed from above, the cutting edge is located on the distal end side of the cutting portion and has an outwardly convex arc-shaped first cutting edge and a linear shape connected to both ends of the first cutting edge, respectively. And a pair of second cutting blades. The upper surface is positioned inward of the first cutting edge and is inclined downward toward the inner side, and is adjacent to the rear end side of the cutting portion with respect to the rake surface. And a breaker having a rising surface that is positioned and slopes upward toward the rear end side of the cutting portion. When viewed from above, the breaker has a width in a direction orthogonal to a virtual straight line extending from the rear end side of the cutting part toward the front end side toward the rear end side of the cutting part from both ends of the first cutting edge. Has the largest wide part.

It is a perspective view which shows the cutting insert which concerns on one Embodiment of this invention. It is a figure which shows the cutting insert of FIG. 1, (a) is the figure seen from the outer surface side, (b) is the figure seen from the inner surface. It is a figure which shows the cutting insert of FIG. 1, (a) is the whole figure which looked at one cutting part from the upper surface, (b) is the elements on larger scale which show the cutting part of (a). It is the elements on larger scale which show the cutting part of the cutting insert of FIG. It is a figure which shows each cross section in the cutting part of FIG. 4, (a) is an expanded sectional view divided | segmented along the AA line, (b) is an expanded sectional view divided | segmented along the BB line, c) is an enlarged cross-sectional view taken along the line CC. It is an expanded sectional view which expands and shows Drawing 5 (a). It is a figure which shows each cross section in the cutting part of FIG. 4, (a) is an expanded sectional view divided | segmented along the DD line, (b) is an expanded sectional view divided | segmented along the EE line, ( c) is an enlarged cross-sectional view taken along the line FF. It is a figure which shows each cross section in the cutting part of FIG. 4, (a) is an expanded sectional view divided | segmented along the GG line, (b) is an expanded sectional view divided | segmented along the HH line, c) is an enlarged cross-sectional view taken along the line II. It is a figure which shows the cutting tool which concerns on one Embodiment of this invention, (a) is a side view, (b) is a top view, (c) is a perspective view. It is an enlarged side view which expands and shows the front end side of the cutting tool of Fig.9 (a). It is a schematic explanatory drawing which shows the manufacturing method of the cut workpiece which concerns on one Embodiment of this invention. It is a top view which shows the cutting tool which concerns on other embodiment of this invention.

<Cutting insert>
Hereinafter, a cutting insert 1 (hereinafter simply referred to as an insert 1) according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 to 3 and the like, the insert 1 is generally positioned on the rear end side of the cutting portion 1a when the cutting portion 1a and the cutting portion 1a are viewed from above as shown in FIG. And a fixing portion 1b fixed to the holder. Then, as shown in FIG. 1, the cutting portion 1 a is formed by cutting the upper surface 2, the lower surface 3, the side surface 4 connected to the upper surface 2 and the lower surface 3, and the intersection portion between the upper surface 2 and the side surface 4. A blade 5 is provided.

  More specifically, in the present embodiment, the insert 1 has a triangular plate shape as shown in FIGS. 1 and 2, and has cutting portions 1 a at the corners of the triangle, A fixed portion 1b is provided in a region between the three cutting portions 1a. As an example of the size of the insert 1, for example, the diameter of a triangular inscribed circle is 9.52 to 12.7 mm, the side (blade width) is 0.33 to 5 mm, and the height (thickness) is 3 to 5 mm. be able to.

  The insert 1 is preferably made of a sintered body such as cemented carbide, cermet, or ceramic coated with a film. This film is for improving the wear resistance of the insert 1. Examples of the film composition include titanium compounds such as titanium carbide, titanium nitride, and titanium carbonitride, and alumina. The film may be at least one layer and may be composed of a plurality of layers. The insert 1 may be made of a sintered body that is not covered with a film.

  The insert 1 according to the present embodiment is an insert 1 that can be used for turning such as inner diameter grooving (inner diameter processing), outer diameter grooving (outer diameter processing), and parting off. is there. Hereinafter, details of each component will be described in order.

(About the cutting part)
The cutting part 1a is a main part that generates and discharges chips during cutting, and as shown in FIG. 3 and the like, the part on the tip 1af side of the cutting part 1a has an arc shape when viewed from above.

  The cutting edge 5 is a structure which has a main role in cutting a workpiece, and is located in the intersection part of the upper surface 2 and the side surface 4 as above-mentioned.

  In this embodiment, as shown in FIG. 3 (b), the cutting blade 5 includes an outwardly convex arc-shaped first cutting blade 5a located on the tip 1af side of the cutting portion 1a in top view. And a pair of second cutting blades 5b having a linear shape respectively connected to both ends of the first cutting blade 5a.

  Further, the pair of second cutting edges 5b may be configured not to be parallel to each other when viewed from above. As shown in FIG. 3, it is preferable that the pair of second cutting blades 5b be configured to approach each other toward the rear end side. In the insert 1 of the present embodiment, the first cutting edge 5a and the second cutting edge 5b are located with the line L5 in FIG. 3B as a boundary. The first cutting edge 5a and the second cutting edge 5b generally have an EE cross section line in FIG. 4 as a boundary.

  Since the cutting blade 5 according to the present embodiment has such a configuration, it performs turning such as inner grooving (inner diameter processing), outer grooving (outer diameter processing), and parting off. At this time, the work material is mainly cut using the first cutting edge 5a.

  As shown in FIG. 3B, the upper surface 2 has a land 7 and a breaker 6 (a rake surface 61 and a rising surface 62) located inward of the cutting edge 5 in a top view. Here, unless otherwise specified, “inward” in this specification means the center side of the cutting portion 1a when the cutting portion 1a is viewed from above.

  The land 7 is configured to mainly reinforce the cutting edge 5 and is located in a narrow area along the first cutting edge 5a as shown in FIGS. 3 and 5 to 7. In the present embodiment, the land 7 is located between the first cutting edge 5a and the rake face 61 and continuously to the first cutting edge 5a, and is separated from the first cutting edge 5a as shown in FIG. Accordingly, it is inclined at an inclination angle α1 with respect to the reference line S1a. It is preferable that the inclination angle α1 of the land 7 and the inclination angle α2 of the rake face 61 satisfy the relationship of α1 <α2.

  In the present embodiment, the land 7 is inclined downward as it moves away from the first cutting edge 5a. The inclination angle α1 of the land 7 is preferably set to 0 to 25 °, for example. In the present embodiment, as shown in FIG. 3B, in the top view, the length of the land 7 that is the distance between the first cutting edge 5a and the breaker 6 is the center 5af of the first cutting edge 5a. Is the shortest in the continuous part.

  The center 5af of the first cutting edge 5a in the present embodiment is located on the most distal end side in the cutting portion 1a. Therefore, the center 5af of the first cutting edge 5a can be said to be the tip of the first cutting edge 5a.

  In this specification, “inclination angle” means an angle inclined with respect to a predetermined reference line (surface) S1a as shown in FIG. More specifically, as shown in FIG. 10, the angle of inclination of the holder 21 to which the insert 1 is attached with respect to a reference line (surface) S1a parallel to the holder lower surface 213 in a state where the lower surface 213 of the holder 21 is left stationary. means. Then, it is determined that a so-called positive slope is positive and a so-called negative slope is negative.

  The breaker 6 is configured to have a role of adding deformation such as curling or squeezing in the width direction to chips generated by the cutting blade 5 and discharging the chips to the outside. Specifically, as shown in FIG. 3B and the like, the breaker 6 is positioned on the inside of the first cutting edge 5a, and a rake face 61 that is inclined downward as it goes inward. It has a rising surface 62 which is located adjacent to the rear end side of the surface 61 and which is inclined upward toward the rear end side. 3B and FIG. 4, the boundary Bo between the rake face and the rising face is shown. In the present embodiment, the boundary Bo has a curved shape that is convex toward the center 5af of the first cutting edge 5a in a top view, as shown in FIG.

  And in this embodiment, as shown in FIG.3 (b), the breaker 6 is a back end side of the cutting part 1a in the rear end side of the cutting part 1a rather than the both ends of the 1st cutting blade 5a in top view. The wide portion 6W having the largest width in the direction orthogonal to the imaginary straight line X extending toward the distal end side is provided. Here, the width (length) in the direction orthogonal to the virtual straight line X means the distance in the direction orthogonal to the virtual straight line X.

  Further, the direction extending from the rear end side to the front end side of the cutting portion 1a, which is the direction in which the virtual straight line X extends, means the direction in which the cutting portion 1a protrudes with reference to the fixed portion 1b in the cutting insert 1. Yes. In the cutting insert 1 of the present embodiment, the cutting portion 1a protrudes in a direction parallel to the outer surface 11b and the inner surface 12b of the fixed portion 1b shown in FIG. Therefore, when viewed from above, the direction in which the virtual straight line X extends is parallel to the outer surface 11b and the inner surface 11a. When viewed from above, the direction orthogonal to the virtual straight line X is orthogonal to the outer surface 11b and the inner surface 11a.

  According to this, also about the site | part produced | generated by the both ends of the 1st cutting blade 5a among chips, it can restrict | squeeze in the width direction by the rake face 61 in the wide part 6W of the breaker 6 located back. At the same time, the rising surface 62 of the breaker 6 can curl to a small diameter. Therefore, the insert 1 according to the present embodiment can exhibit excellent dischargeability with respect to chips generated by the outwardly convex arc-shaped first cutting edge 5a.

  Further, as shown in FIG. 3B, the breaker 6 has a length in the direction along the imaginary straight line X on the rear end side with respect to the center 5af of the first cutting edge 5a as viewed from above. It is the structure which becomes small as it goes to the part located in the rear-end side with respect to the both ends of the 1st cutting blade 5a from the existing part. In the present embodiment, the center 5af of the first cutting edge 5a is the same part as the tip of the first cutting edge 5a. Thereby, it can be made to change to a big diameter with respect to the thick part of center 5af among chips, and can be made to change to a small diameter with respect to the thin part of both ends. Therefore, it becomes possible to discharge | emit the chip | tip from which thickness changes with parts more effectively to the exterior.

  Furthermore, in this embodiment, the length in the direction along the imaginary straight line X is the rear end side with respect to the center 5af of the first cutting edge 5a in the top view in both the rake face 61 and the rising face 62. It becomes small as it goes to the part located in the rear-end side with respect to the both ends of the 1st cutting blade 5a from the part located in this. Thereby, the above-mentioned chip discharge | emission property can be exhibited more effectively.

  In addition, the breaker 6 passes through the center 5af of the first cutting edge 5a and is parallel to the imaginary straight line X in the top view, on the straight line, the lowest part (lowest part) 6L and the highest part (highest part) 6H. have. As a result, the chip can be deformed to a large diameter with respect to the thick part at the center, and can be deformed to a small diameter with respect to the thin part at both ends. It is possible to discharge to the outside. In FIG. 3B, since the virtual straight line X is positioned so as to include the center 5af of the first cutting edge 5a, in the top view, the lowest part (lowest part) 6L and the highest part (most) 6H is located on the imaginary straight line X.

  Here, “high” in the present specification means the relationship between the upper and lower positions when the insert 1 is mounted on the holder and the lower surface of the holder is left as a placement surface. In the present specification, “low” is a concept opposite to “high”.

  The rake face 61 is configured to have a role of mainly rubbing chips generated by the cutting blade 5 and flowing backward, and as shown in FIG. 6, the rake face 61 is positioned along the cutting blade 5 and inclines as it goes inward. It is inclined at α2. In the present embodiment, as shown in FIG. 6, the rake face 61 is inclined downward with respect to a reference line S1a described later as the distance from the first cutting edge 5a increases. The inclination angle α2 is preferably set to 5 to 30 °, for example.

  The rising surface 62 has a function of curling the chips mainly by directing upward the track of the chips scraped on the rake face 61. As shown in FIG. 6, the rising surface 62 is located adjacent to the rear end side of the rake face 61, and is inclined upward at an inclination angle α3 with respect to a reference line S <b> 1 a to be described later toward the rear end side. Yes. The inclination angle α3 is preferably set to 9 to 35 °, for example.

  In the present embodiment, the boundary between the rising surface 62 and the rake face 61 is a straight line that passes through the center 5af of the first cutting edge 5a and is orthogonal to the virtual straight line X when viewed from above as shown in FIG. The distance from X ′ is positioned so as to increase as the distance from the portion located behind the center 5af of the first cutting edge 5a increases. That is, the distance in the direction perpendicular to the tangent to the center 5af of the first cutting edge 5a has such a relationship.

  Further, as shown in FIG. 3B, the rising surface 62 has a length in a direction along the virtual straight line X when viewed from above, from a portion located behind the center 5af of the first cutting edge 5a. It becomes small as it goes to the part located in the back of the both ends of the 1st cutting blade 5a.

  As shown in FIG. 2, when viewed from the side, that is, when viewed from the inner surface 12b, at least a part of the rising surface 62 may be higher than the first cutting edge 5a.

  Moreover, it is preferable that the inclination angle α2 of the rake face 61 is smaller than the inclination angle α3 of the rising face 62.

  As described above, the side surface 4 is connected to the upper surface 2 and the lower surface 3 as shown in FIG. In the present embodiment, as shown in FIGS. 5 and 6, the side surface 4 is inclined inwardly from the upper surface 2 side toward the lower surface 3 side, and is a relief for avoiding contact with the work material. It has a role as a surface.

  As shown in FIG. 1, the lower surface 3 is located on the opposite side of the upper surface 2 with the side surface 4 interposed therebetween. In the present embodiment, the lower surface 3 is also inclined inwardly from the upper surface 2 side toward the lower surface 3 side, as shown in FIGS. 5 and 6, to avoid contact with the work material. It has a role as a flank. In the present embodiment, the lower surface 3 is planar and extends toward the adjacent cutting portion. As shown in FIG. 9, the lower surface 3 serves as a portion in contact with the holder 21 when the insert 1 is fixed to the holder 21.

(About fixed part)
The fixing part 1b is a part mainly having a role for fixing the insert 1 to the holder, and as shown in FIG. 1 and FIG. 2, three cuttings respectively located at the triangular corners of the insert 1 It is located in the area between the parts 1a. In other words, the fixing portion 1b is located on the rear end side of each cutting portion 1a.

  As shown in FIGS. 1 and 2, the fixing portion 1b has an outer surface 11b continuous with the side surface 4 of the cutting portion 1a and an inner surface 12b located on the opposite side of the outer surface 11b. In the present embodiment, as shown in FIG. 9, when the insert 1 is fixed to the holder 21, the inner surface 12 b of the fixing portion 1 b contacts the holder 21. Further, a surface obtained by extending the lower surface 3 of the cutting portion 1 a is also in contact with the holder 21.

  Moreover, the fixing | fixed part 1b has the through-hole 8 penetrated in a substantially perpendicular direction with respect to the outer surface 11b, as shown in FIG.

  The insert 1 is fixed to the holder by inserting a screw into the through hole 8 that passes between the outer surface 11b and the inner surface 12b, as will be described later.

<Cutting tools>
Next, the cutting tool 20 which concerns on one Embodiment of this invention is demonstrated in detail with reference to FIG. 9, FIG.

  As shown in FIGS. 9 and 10, the cutting tool 20 according to the present embodiment includes an insert 1 and a holder 21 to which the insert 1 is attached at the tip.

  The insert 1 is attached to the holder 21 such that the cutting edge 5 protrudes from the tip of the holder 21.

  In the present embodiment, attachment of the insert 1 to the holder 21 is performed by inserting a screw 22 from the through hole 8 of the insert 1 to a screw hole provided in the holder 21. The insert 1 is pressed and restrained by adjusting the restraining force with the screw 22.

  In place of the mounting method of the present embodiment, for example, a method of constraining the insert from the inner wall of the hole of the insert by the lever action of a substantially L-shaped lever by drilling a hole in the insert, or the shaft portion and the head The insert may be attached to the holder by using a pin that is eccentric and using a hole formed in the insert to restrain the insert.

<Manufacturing method of cut product>
Next, a method for manufacturing a cut product according to an embodiment of the present invention will be described with reference to FIG. 11, taking as an example a case where the insert 1 is attached and grooving is performed.

  The manufacturing method of the cut workpiece which concerns on this embodiment performed using the cutting tool 20 is equipped with the process of the following (i)-(iii).

  (I) A step of rotating the work material 100 in the direction of arrow A as shown in FIG.

  (Ii) As shown in FIG. 11 (b), the cutting tool 20 is moved in the direction of arrow B along the shape of the work material 100, and the cutting blade 5 of the cutting tool 20 is brought into contact with the rotating work material 100. Process. In this way, the workpiece 100 is cut (grooving).

  (Iii) A step of moving the cutting tool 20 in the direction of the arrow C and releasing the cutting tool 20 from the work material 100 as shown in FIG.

  By cutting the work material 100 as described above, a desired cut product can be obtained.

  In the step (i), the work material 100 and the cutting tool 20 may be relatively close to each other. For example, the work material 100 may be close to the cutting tool 20. Similarly, in the step (iii), the work material 100 and the cutting tool 20 need only be relatively distant from each other. For example, the work material 100 may be kept away from the cutting tool 20.

  Moreover, when continuing a cutting process, what is necessary is just to repeat the process of making the cutting blade 5 of the cutting tool 20 contact the different location of the workpiece 100, with the state which rotated the workpiece 100 maintained.

  In addition, the insert 1 has three corners as described above. Therefore, when the cutting blade 5 of the cutting part used is worn, the cutting blade 5 of another unused cutting part may be used.

  As mentioned above, although some embodiment which concerns on this invention was described, this invention is not limited to these embodiment, A various improvement and change are possible within the range as described in a claim. is there.

  For example, the insert according to the above-described embodiment is a so-called vertical type in which the through-hole penetrates between the outer surface and the inner surface that are continuous with the second cutting edge of the cutting portion. Instead, the insert is shown in FIG. Thus, you may apply to what is called a horizontal installation type insert.

  Specifically, the upper surfaces of the three cutting parts 1a may be formed in the same direction, and the through-hole 8 may penetrate from the upper surface side to the lower surface side of the cutting part 1a. According to this, when attaching the insert to the holder, the insert is placed on the upper surface of the holder, and a screw is inserted from the through hole 8 penetrating from the upper surface side to the lower surface side of the cutting portion 1a of the insert toward the lower surface side of the holder. Fix by doing.

  Also in this case, by making the structure of the cutting part 1a the same as the above-mentioned insert, even in the part generated near both ends of the first cutting edge of the chips, the rake face in the wide part of the breaker is used in the width direction. It can be squeezed and curled to a small diameter by the rising surface of the breaker. Therefore, it is possible to exhibit excellent discharge performance with respect to chips generated by the outwardly convex curved first cutting edge. Also in this insert 1, the three cutting parts 1a are rotationally symmetric about the center of the through hole 8.

  Moreover, in the above-mentioned embodiment, although the land was provided in the upper surface along the cutting edge, it may replace with this and you may make it the structure which does not provide a land. In this case, the rake face may be configured to be continuous with the first cutting edge. According to this, cutting resistance can be reduced more.

DESCRIPTION OF SYMBOLS 1 Cutting insert 1a Cutting part 1af Tip 2 Upper surface 3 Lower surface 4 Side surface 5 Cutting blade 5a 1st cutting blade 5af Center 5b 2nd cutting blade 6 Breaker 61 Rake face 62 Standing surface 6W Wide part 6L Lowest part 6H Highest part 7 Land 1b fixation Part 11b Outer surface 12b Inner surface (mounting surface)
8 Through-hole 20 Cutting tool 21 Holder 213 Holder lower surface 22 Screw 100 Work material S1a Surface parallel to the holder lower surface (reference surface)

A cutting insert according to an embodiment includes an upper surface, a lower surface, a side surface connected to the upper surface and the lower surface, and a cutting portion having a cutting edge located at a line of intersection between the upper surface and the side surface, and the cutting And a fixing portion located on the rear end side of the cutting portion when the portion is viewed from above. When viewed from above, the cutting edge is located on the distal end side of the cutting portion and has an outwardly convex arc-shaped first cutting edge and a linear shape connected to both ends of the first cutting edge, respectively. And a pair of second cutting blades. The upper surface is positioned inward of the first cutting edge and is inclined downward toward the inner side, and is adjacent to the rear end side of the cutting portion with respect to the rake surface. And a breaker having a rising surface that is positioned and slopes upward toward the rear end side of the cutting portion. When viewed from above, the breaker has a width in a direction orthogonal to a virtual straight line extending from the rear end side of the cutting part toward the front end side toward the rear end side of the cutting part from both ends of the first cutting edge. Has the largest wide portion and the lowest portion on a straight line passing through the center of the first cutting edge and parallel to the virtual straight line .

Claims (16)

A cutting portion having a top surface, a bottom surface, a side surface connected to the top surface and the bottom surface, and a cutting edge located at a line of intersection between the top surface and the side surface;
A cutting insert comprising a fixed portion located on a rear end side of the cutting portion when the cutting portion is viewed from above;
When viewed from above, the cutting edge is located on the distal end side of the cutting portion and has an outwardly convex arc-shaped first cutting edge and a linear shape connected to both ends of the first cutting edge, respectively. A pair of second cutting blades,
The upper surface is positioned inward of the first cutting edge and is inclined downward toward the inner side, and is adjacent to the rear end side of the cutting portion with respect to the rake surface. And a breaker having a rising surface that is located and slopes upward as it goes to the rear end side of the cutting part,
When viewed from above, the breaker has a width in a direction orthogonal to a virtual straight line extending from the rear end side of the cutting part toward the front end side toward the rear end side of the cutting part from both ends of the first cutting edge. A cutting insert having the largest wide part.   When viewed from above, the length of the breaker in the direction along the imaginary straight line extends from both ends of the first cutting edge from the portion located on the rear end side of the cutting portion with respect to the center of the first cutting edge. The cutting insert according to claim 1, which becomes smaller toward a portion located on the rear end side of the cutting portion with respect to the cutting portion.   3. The cutting insert according to claim 1, wherein the breaker has a lowest position on a straight line passing through a center of the first cutting edge and parallel to the virtual straight line when viewed from above.   Cutting in any one of Claims 1-3 which have the highest site | part on the straight line which passes along the center of the said 1st cutting blade, and is parallel to the said virtual straight line in the top view. insert.   The cutting insert according to any one of claims 1 to 4, wherein the pair of second cutting edges are not parallel to each other when viewed from above.   The cutting insert according to any one of claims 1 to 5, wherein the fixing portion has a through hole penetrating in a direction substantially perpendicular to a side surface continuous with the pair of second cutting blades.   The cutting insert according to any one of claims 1 to 6, wherein, in a top view, a boundary between the rising surface and the rake surface has a curved shape that protrudes toward the center of the first cutting edge.   In a top view, the length of the rising surface in the direction along the imaginary straight line is such that the length of the first cutting edge from the portion located on the rear end side of the cutting portion with respect to the center of the first cutting edge. The cutting insert in any one of Claims 1-7 which become small as it goes to the part located in the rear-end side of the said cutting part with respect to both ends.   The cutting insert according to any one of claims 1 to 8, wherein at least a part of the rising surface is higher than the first cutting edge in a side view.   The cutting insert according to any one of claims 1 to 9, wherein an inclination angle of the rake face is smaller than an inclination angle of the rising face.   The cutting insert according to any one of claims 1 to 10, wherein the upper surface further includes a land located between the first cutting edge and the breaker.   The cutting insert according to claim 11, wherein, in a top view, a length of the land, which is an interval between the first cutting edge and the breaker, is shortest at a portion continuous with a tip of the first cutting edge.   The cutting insert according to claim 11 or 12, wherein the land is inclined downward as it moves away from the first cutting edge.   The cutting insert according to claim 13, wherein an inclination angle of the land is smaller than an inclination angle of the rake face. The cutting insert according to any one of claims 1 to 14,
A cutting tool comprising: a holder to which the cutting insert is attached at a tip portion. A step of rotating the work material;
Contacting the rotating work material with the cutting edge of the cutting tool according to claim 15;
And a step of separating the work material from the cutting tool.

Images