JP7057152B2 - Manufacturing method of cutting inserts, cutting tools and cutting materials - Google Patents

Description

This aspect relates to a method for manufacturing a cutting insert, a cutting tool, and a cutting object.

As a cutting tool used when cutting a work material such as metal, for example, a cutting insert having a tip breaker described in Patent Document 1 is known. The chip breaker in the cutting insert described in Patent Document 1 has two breaker surfaces having a symmetrical shape with the bisector of the nose as a boundary.

International Publication No. 2005/06817

In the chip breaker in the cutting insert described in Patent Document 1, since the two breaker surfaces are located apart from the nose, the behavior of chips may become unstable during cutting with a low depth of cut.

The insert in one embodiment has a convex curved corner having a constant radius of curvature in the top view, an upper surface having a linear first side and a second side in the top view extending from the corner, and the upper surface. It has a lower surface located on the opposite side of the above surface and a side surface located between the upper surface surface and the lower surface surface. Further, the upper surface has a first surface located along the corner, a second surface separated from the first surface, and located farther from the lower surface than the first surface, and the above. It has a third surface that is located between the first surface and the second surface and is inclined with respect to each of the first surface and the second surface. In top view, the third surface has a first inclined surface located on the side of the first side and a second inclined surface located on the side of the second side of the first inclined surface. The first inclined surface is a cutting insert in contact with the corner in the top view.

The cutting insert of the above aspect has good chip evacuation.

It is a perspective view which shows the cutting insert of the embodiment of this disclosure. It is an enlarged view which shows the region A1 in FIG. It is a top view of the cutting insert shown in FIG. It is an enlarged view which shows the region A2 in FIG. It is a modification of the cutting insert shown in FIG. FIG. 3 is a side view of the cutting insert shown in FIG. 3 as viewed from the B1 direction. It is an enlarged view which shows the region A3 in FIG. FIG. 3 is a side view of the cutting insert shown in FIG. 3 as viewed from the B2 direction. It is an enlarged view which shows the region A4 in FIG. FIG. 3 is a side view of the cutting insert shown in FIG. 3 as viewed from the B3 direction. It is an enlarged view which shows the region A5 in FIG. It is sectional drawing which shows the cross-section of C1-C1 in FIG. It is sectional drawing which shows the cross-section of C2-C2 in FIG. It is a top view which shows the cutting tool of embodiment of this disclosure. It is a figure which showed one step in the manufacturing method of the cut product of the embodiment of this disclosure. It is a figure which showed one step in the manufacturing method of the cut product of the embodiment of this disclosure. It is a figure which showed one step in the manufacturing method of the cut product of the embodiment of this disclosure.

<Cutting insert>
Hereinafter, the cutting inserts 1 of various embodiments of the present disclosure will be described in detail with reference to the drawings. However, each figure referred to below is shown in a simplified manner only for the main members necessary for explaining the cutting insert 1 of the embodiment for convenience of explanation. Therefore, the cutting insert 1 of the present disclosure may include any component not shown in each of the referenced figures. Further, the dimensions of the members in each drawing do not faithfully represent the dimensions of the actual constituent members, the dimensional ratio of each member, and the like.

As shown in FIG. 1, the cutting insert 1 of the embodiment has an upper surface 9, a lower surface 11 located on the opposite side of the upper surface 9, and a side surface 13 located between the upper surface 9 and the lower surface 11. Further, as shown in FIG. 3, which is a top view, the upper surface 9 includes a corner 3 having a convex curve shape, and a first side 5 and a second side 7 extending from the corner 3, respectively.

The upper surface 9 of the embodiment has a polygonal shape, and in the example shown in FIG. 3, the upper surface 9 has a rhombus shape. Therefore, the upper surface 9 in the example shown in FIG. 3 has four corners and four sides. Further, since the upper surface 9 has a rhombic shape, the side surface 13 is composed of four surface regions. The shape of the upper surface 9 is not limited to the configuration shown in FIG. For example, there is no problem even if the upper surface 9 is not a quadrangle but a pentagon, a hexagon, or an octagon.

In FIG. 3, the corner 3 is one of the four corners of the top surface 9. Further, the first side 5 and the second side 7 are two of the four sides of the upper surface 9.

The upper surface 9 in the embodiment may be generally polygonal, and does not have to be polygonal in a strict sense. That is, the side of the upper surface 9 of the polygonal shape does not have to be strictly a straight line shape, and may be, for example, a convex curve shape or a concave curve shape. Further, the corner of the upper surface 9 of the polygonal shape is not limited to the configuration in which two straight lines intersect, and may be, for example, a shape rounded outward.

As an example shown in FIGS. 3 and 4, the first side 5 and the second side 7 may have a linear shape in a top view. Further, the convex curve shape of the corner 3 may have a constant radius of curvature.

The size of the cutting insert 1 is not particularly limited, but for example, the length of one side of the upper surface 9 may be set to about 3 to 20 mm. Further, the height from the upper surface 9 to the lower surface 11 may be set to about 5 to 20 mm.

The cutting insert 1 may have a cutting edge located at least a part of the ridgeline where the upper surface 9 and the side surface 13 intersect. The cutting edge can cut the work material when cutting the work material. For example, the cutting edge may be located on the upper surface 9 at a corner 3, a part of the first side 5 following the corner 3, and a part of the second side 7 following the corner 3. In the example shown in FIG. 4, the cutting edge is located in the entire corner 3, a part of the area adjacent to the corner 3 on the first side 5, and a part of the area adjacent to the corner 3 on the second side 7. ..

Further, the cutting insert 1 may have a hole 35 that opens on the upper surface 9. The hole 35 may penetrate to the lower surface 11. Further, the hole 35 is not limited to the above-mentioned form, and may be opened to the side surface 13, for example, from one surface region of the side surface 13 to another located on the opposite side of the surface region. It may penetrate over the surface area.

The hole 35 can be used as an insertion hole for a fixative when the cutting insert 1 is mounted on the holder. Examples of fixtures include screws, clamp members, wedges and the like.

As shown in FIGS. 4 and 7, the upper surface 9 in the present disclosure has a first surface 15, a second surface 17, and a third surface 19. The first surface 15 is located along the corner 3. In addition, an inclined surface inclined with respect to each of the first surface 15 and the side surface 13 may be provided between the corner 3 and the first surface 15. The inclined surface may be a flat surface or a curved surface. When the inclined surface is flat, the inclined surface is a so-called champa. Further, when the inclined surface is a curved surface, the inclined surface is a so-called land.

Further, the second surface 17 is separated from the first surface 15 and is located farther from the lower surface 11 than the first surface 15. Further, the third surface 19 is located between the first surface 15 and the second surface 17, and is inclined with respect to each of the first surface 15 and the second surface 17 as shown in FIG. 7. There is.

Further, as in the example shown in FIG. 4, in the top view, the third surface 19 is the side of the first inclined surface 21 located on the side of the first side 5 and the side of the second side 7 with respect to the first inclined surface 21. It has a second inclined surface 23 located at the corner 3, and the first inclined surface 21 is in contact with the corner 3.

Since the first inclined surface 21 is in contact with the corner 3, for example, chips generated from the corner 3 easily come into contact with the first inclined surface 21 during a low-cut cutting process using the entire corner 3, so that chip discharge is stable. do. Further, since the first inclined surface 21 is in contact with the corner 3, the first inclined surface 21 is likely to be located close to the center of the corner 3. Therefore, for example, even at the time of cutting with an extremely low cut using a part of the corner 3, the chips are likely to come into contact with the first inclined surface 21. Therefore, the cutting insert 1 in the embodiment has good chip evacuation property because the behavior of chips can be stabilized even at the time of low cutting.

Further, as in the example shown in FIG. 4, the first inclined surface 21 may be in contact with the first side 5 in the top view. When the first inclined surface 21 is in contact with the first side 5, a predetermined space can be provided between the first inclined surface 21 and the corner 3. Therefore, chips generated from the corner 3 are less likely to be clogged on the first inclined surface 21. Therefore, the cutting insert 1 in the example shown in FIG. 4 has better chip evacuation.

Further, as in the modified example shown in FIG. 5, in the top view, the third surface 19 has a third inclined surface 25 adjacent to the first inclined surface 21 and extending along the first side 5. You may be doing it. Stress tends to concentrate in the vicinity of the intersection where the three surfaces of the side surface 13, the second surface 17, and the first inclined surface 21 intersect. However, in the top view, the third surface 19 has a third inclined surface 25 adjacent to the first inclined surface 21 and extending along the first side 5, so that the third surface 19 is in the vicinity of the intersection. Stress concentration is relaxed. Therefore, the cutting insert 1 in the embodiment has high durability. In the top view, the third inclined surface 25 may be a flat surface or a curved surface.

Further, the upper surface 9 may have a convex curved portion having a radius of curvature different from the radius of curvature of the corner 3 between the corner 3 and the first side 5 and between the corner 3 and the second side 7. .. As shown in FIG. 4, which is a top view, the second inclined surface 23 may be in contact with a convex curve-shaped portion located between the corner 3 and the second side 7.

For example, when cutting is performed by cutting to the position closest to the second side 7 of the corner 3, since the second inclined surface 23 is not located on the corner 3, a predetermined position is provided between the second inclined surface 23 and the corner 3. Space can be provided. Therefore, chips generated from the corner 3 are less likely to be clogged on the second inclined surface 23. Therefore, when the second inclined surface 23 has the above configuration, the chip discharge property is further improved. In the top view, when the second inclined surface 23 is in contact with the convex curve-shaped portion located between the corner 3 and the second side 7, the second inclined surface 23 is in point contact with the corner 3. May be good.

Further, as shown in FIG. 4 which is a top view, the second inclined surface 23 may be separated from the corner 3. When the second inclined surface 23 is separated from the corner 3, the space of the first surface 15 is likely to be secured. Therefore, chips are less likely to be clogged.

Further, in the top view, the second inclined surface 23 may be in contact with the second side 7. For example, when cutting is performed using the second side 7 in addition to the corner 3, the chips are stable and easily come into contact with the second inclined surface 23. Therefore, it is possible to treat chips satisfactorily on the second inclined surface 23.

The first inclined surface 21 and the second inclined surface 23 in the example shown in FIG. 4 are flat surfaces, respectively. The first inclined surface 21 and the second inclined surface 23 may have a convex curved surface shape or a concave curved surface shape, respectively.

Further, as in the example shown in FIG. 4, the first inclined surface 21 and the second inclined surface 23 may intersect. That is, as in the example shown in FIG. 4, the upper surface 3 may have a ridge line 27 between the first inclined surface 21 and the second inclined surface 23. Further, as shown in FIG. 4, the ridge line 27 may be parallel to the bisector M of the corner 3 or may be inclined. In the example shown in FIG. 4, the ridge line 27 is located on the side of the second side of the bisector M of the corner 3, and approaches the bisector M as the distance from the corner 3 increases. ..

In the example shown in FIG. 4, the bisector M of the corner 3 is indicated by a line that bisects the angle formed by the virtual extension line L1 of the first side 5 and the virtual extension line L2 of the second side 7. Has been done.

When the ridge line 27 is inclined with respect to the bisector M when viewed from above, the machined surface of the work material becomes good as described below.

For example, as shown in FIG. 4, when the ridge line 27 is inclined so as to approach the first side 5 as the distance from the corner 3 increases, the end face processing mainly using the portion on the side of the second side 7 in the corner 3 is used. The machined surface of the work material is improved. This is because when the ridge line 27 is inclined as described above, the chips are likely to come into contact with the first inclined surface 21, so that the cutting insert 1 is easily discharged in the feed direction and is difficult to be discharged in the direction of the machined surface. Because.

In the above end face machining, the cutting insert 1 moves in a direction generally along the second side 7 from the second side 7 toward the corner 3. Therefore, the feed direction in the above-mentioned end face machining is generally a direction along the second side 7 and is a direction from the second side 7 toward the corner 3.

Further, when the ridge line 27 is inclined so as to approach the second side 7 as the distance from the corner 3 increases, the machining in the inner diameter processing or the outer diameter processing mainly using the portion on the side of the second side 7 in the corner 3 is used. The processed surface of the material is improved. This is because when the ridge line 27 is inclined as described above, the chips in contact with the second inclined surface 23 are easily discharged in the feed direction of the cutting insert and are difficult to be discharged in the direction of the machined surface. ..

In the above-mentioned inner diameter processing and outer diameter processing, the cutting insert 1 moves in a direction generally orthogonal to the second side 7 and moves from the first side 5 to the second side 7. Therefore, the feed direction in the above-mentioned end face machining is a direction substantially orthogonal to the second side 7 and is a direction from the first side 5 to the second side 7.

Further, the ridge line 27 is a portion where the first inclined surface 21 and the second inclined surface 23 are connected, and does not have to be a strict line. For example, there may be an elongated curved surface connecting these surfaces between the first inclined surface 21 and the second inclined surface 23. That is, if such a curved surface has a substantially linear shape when viewed with the naked eye, this curved surface may be regarded as a ridge line 27.

Further, as in the example shown in FIG. 4, the ridge line 27 may be located on the side of the second side 7 with respect to the angle bisector M of the corner 3 in the top view. When the ridge line 27 is located as described above, the width of the first inclined surface 21 in the direction orthogonal to the bisector M is wide. Therefore, in the end face processing mainly using the portion of the corner 3 on the side of the second side 7, chips are likely to come into contact with the first inclined surface 21.

Further, as in the example shown in FIG. 5, the ridge line 27 may be located on the side of the first side 5 with respect to the angle bisector M of the corner 3 in the top view. When the ridge line 27 is located as described above, the width of the second inclined surface 23 in the direction orthogonal to the bisector M is wide. Therefore, chips tend to come into contact with the second inclined surface 23 in the inner diameter processing or the outer diameter processing mainly using the portion of the corner 3 on the side of the second side 7.

Further, in the top view, the ridge line 27 may intersect the bisector M of the corner 3. When the ridge line 27 is positioned as described above, the ridge line 27 is inclined with respect to the bisector M, and the first inclined surface 21 and the second inclined surface in the direction orthogonal to the bisector M are formed. The width of each of the 23 is widely secured. Therefore, the machined surface is good in any of the end face processing, the inner diameter processing, and the outer diameter processing in which the portion on the side of the second side 7 in the corner 3 is mainly used.

Further, as in the example shown in FIG. 4, the upper surface 9 may have a fourth surface 29 adjacent to the second inclined surface 23 and located along the second side 7. When the upper surface 9 has the fourth surface 29, for example, the machined surface of the work material in the end face pulling process mainly using the portion on the side of the second side 7 in the corner 3 becomes good. This is because the portion of the second surface 17 along the second side 7 is less likely to come into contact with the work material. Therefore, the cutting insert 1 in the example shown in FIG. 4 is less likely to damage the work material even when used for the above-mentioned end face pulling process, and can provide a good machined surface.

In the above-mentioned end face pulling process, the cutting insert 1 moves in a direction generally along the second side 7 from the corner 3 toward the second side 7. Therefore, the feed direction in the above-mentioned end face pulling process is generally a direction along the second side 7 and is a direction from the corner 3 toward the second side 7.

Further, as in the example shown in FIG. 5, the fourth surface 29 may be in contact with the corner 3. When the fourth surface 29 is in contact with the corner 3, the portion of the second surface 17 along the second side 7 is less likely to come into contact with the work material during the pulling process. Therefore, even when the cutting insert 1 in the example shown in FIG. 5 is used for the above-mentioned end face pulling process,
The work material is not easily damaged and a good machined surface can be provided.

Further, as in the example shown in FIG. 5, the second inclined surface 23 may be separated from the second side 7 in the top view. When the second inclined surface 23 is separated from the second side 7 in the top view, a predetermined space can be provided between the second inclined surface 23 and the second side 7. Therefore, chips generated from the second side 7 are less likely to be clogged between the second side 7 and the second inclined surface 23. Therefore, the cutting insert 1 in the example shown in FIG. 5 has good chip evacuation.

Further, in the example shown in FIGS. 12 and 13, the reference plane S is a virtual plane orthogonal to the central axis P passing through the centers of the upper surface and the lower surface. FIG. 12 is a cross-sectional view showing a cross section of C1-C1 in FIG. 4, and is a cross-sectional view orthogonal to the first side 5. In FIG. 12, the angle formed by the first inclined surface 21 and the reference surface S is defined as the first angle θ1. Further, FIG. 13 is a cross-sectional view showing a cross section of C2-C2 in FIG. 4, which is a cross-sectional view orthogonal to the second side 7. In FIG. 13, the angle formed by the second inclined surface 23 and the reference surface S is defined as the second angle θ2. However, FIGS. 12 and 13 do not faithfully represent the positional relationship between the various members and the central axis P.

At this time, the second angle θ2 may be smaller than the first angle θ1. When the second angle θ2 is smaller than the first angle θ1, the resistance generated by the chips coming into contact with the second inclined surface 23 is small. Therefore, the durability of the cutting insert 1 is high.

When the virtual straight line orthogonal to the first side 5 does not pass through the first inclined surface 21 in the top view, it is orthogonal to the virtual extension line L1 of the ridge line 27 in the top view and is the first. The first angle θ1 may be evaluated by the cross section passing through the inclined surface 21.

Examples of the material of the cutting insert 1 include cemented carbide, cermet, ceramics, PCD (polycrystal diamond) and cBN (cubic boron nitride).

Examples of the composition of the cemented carbide include WC (tungsten carbide) -Co, WC-TiC (titanium carbide) -Co and WC-TiC-TaC (tantalum carbide) -Co. Here, WC, TiC and TaC are hard particles, and Co is a bonded phase. Cermet is a sintered composite material in which a metal is composited with a ceramic component. Specifically, examples of the cermet include compounds containing TiC or TiN (titanium nitride) as a main component. The material of the cutting insert 1 is not limited to these.

The cutting insert 1 may be composed of only one member made of the material exemplified above, or may be made of a plurality of members made of the material exemplified above.

For example, as shown in FIG. 1, the cutting insert 1 is composed of a main body portion 31 and a cutting portion 33, and may have a polygonal plate shape as a whole. The main body portion 31 may have a substantially polygonal plate shape, and may have a configuration having a notched portion at a part of the corner. The cutting portion 33 may be joined to the notched portion by using a brazing material or the like. Here, in the example shown in FIG. 1, a corner 3, a part of the first side 5, and a part of the second side 7 are located in the cutting portion 33.

When a material having a relatively high hardness such as PCD and cBN is used as the material of the cutting portion 33 and a cemented carbide, cermet or ceramics is used as the material of the main body portion 31, for example, it is manufactured at low cost. It is a cutting insert 1 that is highly durable against a cutting load while being able to be used. The hardness of the main body portion 31 and the cutting portion 33 may be evaluated by measuring the Vickers hardness of each portion.

Further, the cutting insert 1 may be composed of only the main body portion 31 and the cutting portion 33 described above, but for example, in addition to the portions of the main body portion 31 and the cutting portion 33, a coating covering the surface of these portions. It may have a layer (not shown). The coating layer may cover the entire surface of the substrate composed of the main body portion 31 and the cutting portion 33, or may cover only a part of the surface of the substrate.

Examples of the material of the coating layer include aluminum oxide (alumina), and carbides, nitrides, oxides, carbon oxides, nitrides, carbonitrides, and carbon dioxide oxides of titanium. The coating layer may contain only one of the above materials, or may contain a plurality of the above materials.

Further, the covering layer may be composed of only one layer, or may be a structure in which a plurality of layers are laminated. The material of the coating layer is not limited to these. The coating layer can be located on the substrate, for example by using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method.

<Cutting tool>
Next, the cutting tool 101 of the embodiment will be described with reference to the drawings.

As shown in FIG. 14, the cutting tool 101 of the embodiment has a holder 105 extending from the first end 105a toward the second end 105b. The holder 105 has a pocket 103 (cutting insert pocket) on the side of the first end 105a. The cutting tool 101 includes the above-mentioned cutting insert 1 located in the pocket 103. In the cutting tool 101 of the embodiment, the cutting insert 1 is mounted so that at least a part of the first side, the second side and the corner used as the cutting edge protrudes from the first end 105a of the holder 105. ing.

The holder 105 has an elongated rod shape. One pocket 103 is provided on the side of the first end 105a of the holder 105. The pocket 103 is a portion to which the cutting insert 1 is mounted, and is open to the end surface of the holder 105 on the side of the first end 105a. At this time, when the pocket 103 is also open with respect to the side surface of the holder 105, the cutting insert 1 can be easily attached. The pocket 103 in the example shown in FIG. 14 has a seating surface parallel to the lower surface of the holder 105 and a restraining side surface inclined with respect to the seating surface.

The cutting insert 1 is located in the pocket 103. At this time, the lower surface of the cutting insert 1 may be in direct contact with the pocket 103, or the sheet may be sandwiched between the cutting insert 1 and the pocket 103.

In the example shown in FIG. 14, the cutting insert 1 is attached to the holder 105 by the clamp member 107. That is, the head of the clamp member 107 is pressed against the inner wall of the hole of the cutting insert 1, and the cutting insert 1 is restrained in the pocket 103.

As the holder 105, steel, cast iron, or the like can be used. In particular, it is preferable to use steel having high toughness among these members.

In the embodiment, a cutting tool used for so-called turning is exemplified. Examples of the turning process include inner diameter processing, outer diameter processing, end face processing, and grooving processing. The cutting tool is not limited to the one used for turning. For example, the cutting insert 1 of the above embodiment may be used as a cutting tool used for milling.

<Manufacturing method of machined products>
Next, the manufacturing method of the machined product of the embodiment will be described with reference to the drawings.

The work piece is produced by cutting the work material 201. The method for manufacturing a machined product according to an embodiment includes the following steps. That is,
(1) The process of rotating the work material 201 and
(2) A step of contacting the rotating work material 201 with at least a part of the first side, the second side, and the corner of the cutting tool 101 represented by the above embodiment, which is used as a cutting edge.
(3) The process of separating the cutting tool 101 from the work material 201,
It is equipped with.

More specifically, first, as shown in FIG. 15, the work material 201 is rotated around the shaft O1 and the cutting tool 101 is relatively close to the work material 201. Next, as shown in FIG. 16, at least a part of the first side, the second side, and the corner of the cutting tool 101 used as the cutting edge is brought into contact with the work material 201 to bring the work material 201 into contact with the work material 201. To cut. Then, as shown in FIG. 17, the cutting tool 101 is relatively far from the work material 201.

In the embodiment, the cutting tool 101 is moved in the Y1 direction in a state where the shaft O1 is fixed and the work material 201 is rotated to bring it closer to the work material 201. Further, in FIG. 16, at least a part of the first side, the second side, and the corner of the cutting insert 1 used as the cutting edge is brought into contact with the rotating work material 201 and moved in the X1 direction. As a result, the work material 201 is being cut. Further, in FIG. 17, the cutting tool 101 is moved away in the Y2 direction while the work material 201 is rotated.

In the cutting process in the manufacturing method of the embodiment, in each step, the cutting tool 101 is moved to bring the cutting tool 101 into contact with the work material 201, or the cutting tool 101 is separated from the work material 201. However, of course, it is not limited to such a form.

For example, in the step (1), the work material 201 may be brought closer to the cutting tool 101. Similarly, in the step (3), the work material 201 may be moved away from the cutting tool 101. When cutting is continued, the work material 201 is maintained in a rotated state and used as a cutting edge among the first side, the second side and the corner of the cutting insert 1 at different points of the work material 201. The process of contacting at least a part of the portion to be formed may be repeated.

Typical examples of the material of the work material 201 include carbon steel, alloy steel, stainless steel, cast iron, non-ferrous metal, and the like.

1 ... Cutting insert 3 ... Corner 5 ... 1st side 7 ... 2nd side 9 ... Top surface 11 ... Bottom surface 13 ... Side surface 15 ... First surface 17 ...・ 2nd surface 19 ・ ・ ・ 3rd surface 21 ・ ・ ・ 1st inclined surface 23 ・ ・ ・ 2nd inclined surface 25 ・ ・ ・ 3rd inclined surface 27 ・ ・ ・ Ridge line 29 ・ ・ ・ 4th surface 31 ・ ・・ Main body 33 ・ ・ ・ Cutting part 35 ・ ・ ・ Hole 101 ・ ・ ・ Cutting tool 103 ・ ・ ・ Pocket 105 ・ ・ ・ Holder 107 ・ ・ ・ Clamp member 201 ・ ・ ・ Work material P ・ ・ ・ Central axis θ1・ ・ ・ First angle θ2 ・ ・ ・ Second angle M ・ ・ ・ Bisection line L1 ・ ・ ・ Virtual extension line L2 ・ ・ ・ Virtual extension line S ・ ・ ・ Reference plane

Claims (9)

A corner having a convex curve shape having a constant radius of curvature in the top view, and a top surface having first and second sides of a linear shape in the top view extending from the corner, respectively.
The lower surface located on the opposite side of the upper surface and the lower surface
It has an upper surface and a side surface located between the lower surfaces.
The upper surface is
The first surface located along the corner,
A second surface that is separated from the first surface and is located farther from the lower surface than the first surface.
It has a third surface that is located between the first surface and the second surface and is inclined with respect to each of the first surface and the second surface.
In top view, the third surface is
The first inclined surface located on the side of the first side and
It has a second inclined surface located on the side of the second side with respect to the first inclined surface.
In top view, the first inclined surface is a cutting insert in contact with the corner. The cutting insert according to claim 1, wherein the first inclined surface is in contact with the first side in a top view. The cutting insert according to claim 1 or 2, wherein the second inclined surface is away from the corner in a top view. One of claims 1 to 3, which has a ridgeline between the first inclined surface and the second inclined surface in a top view, and the ridgeline intersects the bisector of the corner. The cutting insert described in. A claim that has a ridgeline between the first inclined surface and the second inclined surface in a top view, and the ridgeline is located on the side of the second side of the corner bisector. The cutting insert according to any one of 1 to 3. The cutting insert according to any one of claims 1 to 5, wherein the upper surface is adjacent to the second inclined surface and has a fourth surface located along the second side. When a virtual plane orthogonal to the central axis passing through the center of the upper surface and the lower surface is used as a reference plane,
The second angle formed by the second inclined surface and the reference surface in the cross section orthogonal to the second side in the top view is the first inclined surface and the said in the cross section orthogonal to the first side in the top view. The cutting insert according to any one of claims 1 to 6, which is smaller than the first angle formed by the reference plane. A holder that extends from the first end toward the second end and has a pocket located on the first end side.
A cutting tool having the cutting insert according to any one of claims 1 to 7, located in the pocket. The process of rotating the work material and
The step of bringing the cutting tool according to claim 8 into contact with the rotating work material, and
A method for manufacturing a machined product, comprising a step of separating the cutting tool from the work material.

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