Cutting tool and method for manufacturing cut workpiece

Abstract

There is demand for cutting tools having high insert positioning precision. A cutting tool based on one aspect of the present disclosure extends from a leading end toward a rear end and comprises: a holder that has a pocket positioned on the leading end side; an insert that is attached to the pocket; and a plurality of fixing implements that fix the insert to the pocket. The insert has a first surface, a second surface positioned on the reverse side from the first surface, a through-hole that is open on the first surface and the second surface, and a first recess positioned in the first surface. The plurality of fixing implements include a first fixing implement inserted into the through-hole, and a second fixing implement mated with the first recess.

Description

Cutting tool and method for manufacturing machined product

[0001] The present disclosure relates to a cutting tool and a method for manufacturing a machined product.

[0002] Known cutting tools used in cutting a workpiece include those described in Patent Documents 1 to 3. Each of the cutting tools described in Patent Documents 1 to 3 includes an insert, a holder, and a clamper. When the cutting tool includes a clamper, the insert can be pulled toward the restraining surface of the holder by the clamper, thereby improving the positioning accuracy of the insert.

[0003] Japanese Patent Publication No. 2007-144525, International Publication No. 2018 / 172218, Japanese Patent Publication No. 2009-095918

[0004] A cutting tool according to one aspect of the present disclosure is a cutting tool extending from a front end to a rear end along a reference axis, the cutting tool including: a holder having a pocket located on the front end side; an insert attached to the pocket; and a plurality of fasteners for fastening the insert to the pocket. The insert has a first surface, a second surface located opposite the first surface, a through hole opening in the first surface and the second surface, and a first recess located in the first surface. The plurality of fasteners includes a first fastener inserted in the through hole and a second fastener engaged in the first recess.

[0005] 1. A perspective view showing a cutting tool according to a first embodiment. 2. An exploded perspective view showing a cutting tool according to the first embodiment. 3. A plan view of the cutting tool according to the first embodiment, viewed from the front, i.e., from above, from the first surface side. 4. A plan view of the cutting tool according to the first embodiment, viewed from the right side. 5. An enlarged view corresponding to region A1 shown in FIG. 3. 6. An enlarged view corresponding to region A2 shown in FIG. 4, in the VI-VI cross section shown in FIG. 5. 7. A perspective view showing a cutting tool according to a second embodiment. 8. A plan view of the cutting tool according to the second embodiment, viewed from the front, i.e., from above, from the first surface side. 9. An enlarged view corresponding to region A3 shown in FIG. 8. 10. A perspective view showing a cutting tool according to a third embodiment. 11. An exploded perspective view showing a cutting tool according to the third embodiment. 12. A plan view of the cutting tool according to the third embodiment, viewed from the front, i.e., from above, from the first surface side. 13. An enlarged view corresponding to region A4 shown in FIG. 12. 14. An enlarged view corresponding to region A5 shown in FIG. 13, in the XV-XV cross section shown in FIG. 14. 15. A schematic explanatory view showing one step of a method for manufacturing a machined product according to an embodiment. 16. A schematic explanatory view showing one step of a method for manufacturing a machined product according to an embodiment. FIG. 2 is a schematic explanatory view showing one step of a method for manufacturing a machined product according to one embodiment.

[0006] Cutting tools according to non-limiting first to third embodiments of the present disclosure will be described in detail below with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining each embodiment in a simplified form. Therefore, the cutting tool of the present disclosure may include optional components not shown in the drawings. Furthermore, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components, the dimensional ratios of the components, etc.

[0007] In the cutting tools described in Patent Documents 1 and 2, the insert is pulled toward the restraint surface while being pressed toward the seating surface at the same time, which may result in a gap between the insert and the restraint surface. In the cutting tool described in Patent Document 3, the insert is first fixed with a screw, which may result in the insert being attached at an angle. The cutting tool of the present disclosure has high insert positioning accuracy.

[0008] <Cutting Tool> (First Embodiment) As shown in FIGS. 1 to 6 , a cutting tool 1A shown in the first embodiment includes a holder 3, a cutting insert 5, and a plurality of fasteners 7. The cutting insert 5 will be referred to as an insert 5 hereinafter. The cutting tool 1A shown in the first embodiment extends from a first end 3A to a second end 3B along a reference axis O1. The first end 3A may alternatively be referred to as a leading end 3A. The second end 3B may alternatively be referred to as a trailing end 3B. In the cutting tool 1A shown in the first embodiment, the reference axis O1 is the central axis of the cutting tool 1A. Furthermore, as shown in FIG. 1 , there are no particular limitations on the shape of the cutting tool 1A on the side of the first end 3A, but the cutting tool 1A shown in the first embodiment has a rectangular prism shape. Note that the rectangular prism shape does not necessarily have to be a strict rectangular prism shape, and may, for example, have a hole or a groove in part thereof.

[0009] The holder 3 may have a main body 9. As shown in FIG. 1 and other figures, the main body 9 shown in the first embodiment may have a shape that extends from the first end 3A to the second end 3B along the reference axis O1. As shown in FIG. 3, the main body 9 shown in the first embodiment has a columnar shape, more specifically, a quadrangular columnar shape. Note that the shape of the main body 9 is not limited to a quadrangular columnar shape and may be, for example, a cylindrical shape.

[0010] The main body 9 may have an upper surface 11, a lower surface 13, and side surfaces 15. The main body 9 shown in the first embodiment has an upper surface 11, a lower surface 13, and a plurality of side surfaces 15. The lower surface 13 is a surface located opposite the upper surface 11, and the side surfaces 15 are surfaces located between the upper surface 11 and the lower surface 13. There are no particular limitations on the shapes of the upper surface 11, the lower surface 13, and the side surfaces 15, but they may be, for example, rectangular. Note that the rectangular shape does not necessarily have to be a strict rectangular shape, and may have, for example, a hole or a groove in part thereof.

[0011] The main body 9 may have a head 17 located on the first end 3A side and a shank 19 located on the second end 3B side. The head 17 is a portion to which the insert 5 is attached. The shank 19 is a portion to be gripped by a machine tool. In the main body 9 shown in the first embodiment, the head 17 and the shank 19 are integrally formed, but the head 17 and the shank 19 may be formed from separate members. When the head 17 and the shank 19 are formed from separate members, the head 17 may be brazed to the shank 19 with, for example, a brazing material, or one may be fixed to the other with, for example, a screw or the like.

[0012] The shank 19 in the example shown in Figure 1 and elsewhere has a rectangular prism shape. When the main body 9 has such a rectangular prism-shaped shank 19, the central axis of the shank 19 may be regarded as the reference axis O1 of the cutting tool 1A. In the above case, the central axis of the shank 19, which passes through the center of the rear end face of the shank 19 and extends in a direction parallel to the four side faces of the shank 19, may be regarded as the reference axis O1.

[0013] The holder 3 may have a pocket 21 located on the side of the first end 3A. The pocket 21 may be located in the head 17. In the holder 3 shown in the first embodiment, the pocket 21 is a recessed portion where the insert 5 is attached.

[0014] The pocket 21 may have a seating surface 23. In the holder 3 shown in the first embodiment, the seating surface 23 is a surface facing the same direction as the upper surface 11. The pocket 21 may have a restraining surface 25. The restraining surface 25 may be connected to the seating surface 23, or a groove may be provided between the seating surface 23 and the restraining surface 25, as in the example shown in FIG. 2 . The seating surface 23 and the restraining surface 25 are surfaces with which the insert 5 abuts. Note that, when the holder 3 has a seat member 87 described below, an upper surface (first seating surface 89) of the seat member 87 functions as the seating surface 23. When the holder 3 does not have the seat member 87, the seating surface 23 is located in the main body portion 9.

[0015] The pocket 21 shown in the first embodiment has two restraint surfaces 25 facing the first end 3A. The two restraint surfaces 25 may be connected to each other, or a groove may be provided between the restraint surfaces 25, as in the example shown in Figure 2. There is no particular limitation on the number of restraint surfaces 25.

[0016] The holder 3 (main body 9) may have a first insertion opening 27 and a second insertion opening 29. In the cutting tool 1A shown in the first embodiment, the first insertion opening 27 and the second insertion opening 29 are both portions into which the fastener 7 is inserted. The first insertion opening 27 may be connected to a first opening 31 located in the seating surface 23. In the holder 3 shown in the first embodiment, the first insertion opening 27 extends from the first opening 31 toward the lower surface 13. The first insertion opening 27 may extend in a direction perpendicular to the reference axis O1 in a cross section perpendicular to the seating surface 23.

[0017] The second insertion opening 29 may be connected to a second opening 33 located on the top surface 11. As shown in Fig. 2, the second opening 33 may be located closer to the second end 3B than the first opening 31. In the holder 3 shown in the first embodiment, the second insertion opening 29 extends from the second opening 33 toward the bottom surface 13. The second insertion opening 29 may extend in a direction perpendicular to the reference axis O1 in a cross section perpendicular to the top surface 11.

[0018] The insert 5 may have a first surface 35, a second surface 37, and a third surface 39. The second surface 37 may be a surface located opposite the first surface 35, and the third surface 39 may be a surface located between the first surface 35 and the second surface 37. The insert 5 shown in the first embodiment has the first surface 35, the second surface 37, and a plurality of third surfaces 39.

[0019] The insert 5 may have a through hole 51 and a recess 57, which will be described later. The recess 57 is located on the first surface 35. In this embodiment, as shown in FIG. 2 , the recess 57 is located on the upper surface of the insert 5, so the "upper surface" of the insert 5 corresponds to the first surface 35. The lower surface of the insert 5 corresponds to the second surface 37, which is located on the opposite side to the first surface 35.

[0020] In this embodiment, the first surface 35 may have a rake face region 41, and the third surface 39 may have a flank face region 43. There are no particular limitations on the shapes of the first surface 35, the second surface 37, and the third surface 39, but they may be, for example, rectangular.

[0021] For ease of explanation, an axis passing through the center 3P of the holder 3 and perpendicular to the reference axis O1 is defined as the vertical axis O2, and in the direction in which the vertical axis O2 extends, the side on which the first surface 35 is located is defined as the upper side, and the side on which the second surface 37 is located is defined as the lower side. Also, an axis extending in a direction perpendicular to the reference axis O1 and the vertical axis O2 is defined as the left-right axis O3, and when the first surface 35 is viewed from the front, the side on which the insert 5 is located with respect to the reference axis O1 is defined as the right side, and the side opposite to the right side is defined as the left side.

[0022] As in the cutting tool 1A shown in the first embodiment, when the center 5P of the insert 5 is located on the reference axis O1 when viewed from the front of the first surface 35, any one side may be the right side and the other side may be the left side. In the cutting tool 1A shown in the first embodiment, as shown in FIG. 4 , the B1 direction is the upper side, the B2 direction is the lower side, the B3 direction is the right side, and the B4 direction is the left side. In addition, in the cutting tool 1A shown in the first embodiment, a line perpendicular to the first surface 35 and the up-down axis O2 are parallel, and the upper side is synonymous with the side of the first surface 35, and the lower side is synonymous with the side of the second surface 37.

[0023] Note that a front view of the first surface 35 refers to a view of the cutting tool 1A or the like from a direction perpendicular to the first surface 35. If the entire first surface 35 is not flat and the direction perpendicular to the first surface 35 cannot be uniquely determined, the "direction perpendicular to the first surface 35" may be specified based on the plane with the largest area among the first surfaces 35. Similarly, when defining a perpendicular direction or plane or a parallel direction or plane for a surface that is not entirely flat, the plane with the largest area among the surfaces may be used as the reference. Furthermore, the above content is not limited to a front view of the surface, but also applies, for example, to a planar perspective view of the surface.

[0024] The first surface 35 may have corners 45 and sides 47 located at the intersections with the third surface 39. The first surface 35 or the third surface 39 may be expressed as having the corners 45 and sides 47, and the corners 45 and sides 47 may be located on the first surface 35 or the third surface 39. The corners 45 and sides 47 may be connected to each other. The insert 5 shown in the first embodiment has four corners 45 and four sides 47.

[0025] Specifically, the first surface 35 has a first corner 45A closest to the first end 3A, a second corner 45B located closest to the center 3P of the holder 3, and a third corner 45C and a fourth corner 45D adjacent to the first corner 45A. Located closest to the center 3P of the holder 3 means located on the second end 3B side. The third corner 45C and the fourth corner 45D may each be adjacent to the second corner 45B. In FIG. 3 , the third corner 45C is located on the right side, and the fourth corner 45D is located on the left side.

[0026] 5, with respect to a front-rear axis O4 passing through the center 35P of the first surface 35 and the midpoint 45BP of the second corner 45B, the side of the center 35P of the first surface 35 is defined as the front side, and the side of the midpoint 45BP of the second corner 45B is defined as the rear side. Note that because the midpoint 45BP of the second corner 45B is located below the second fastener 7B, FIG. 5 shows the position of the midpoint 45BP of the second corner 45B when viewed through the second fastener 7B.

[0027] In the cutting tool 1A shown in the first embodiment, when the first surface 35 is viewed from the front, the reference axis O1 and the longitudinal axis O4 coincide with each other, so the first end 3A side is synonymous with the front side, and the second end 3B side is synonymous with the rear side. Therefore, hereinafter, when one of these synonymous terms is displayed, it is treated as meaning the other as well. In Figure 3, the B5 direction is the front side, and the B6 direction is the rear side.

[0028] The shapes of the corners 45 and the sides 47 are not particularly limited, but for example, when the first surface 35 is viewed from the front, each corner 45 may be curved and each side 47 may be straight. The straight shape does not have to be a straight shape microscopically, as long as it is a straight shape macroscopically. Furthermore, the curved shape may be, for example, an arc shape with a constant radius of curvature.

[0029] The insert 5 may have a cutting edge 49. The cutting edge 49 may be located on the corner 45 and / or the side 47. The insert 5 shown in the first embodiment has a first corner 45A located on the first end 3A side, and a first side 47A and a second side 47B connected to the first corner 45A. The insert 5 shown in the first embodiment has a first cutting edge 49A located on the first side 47A, a second cutting edge 49B located on the second side 47B, and a corner cutting edge 49Z located on the first corner 45A. The corner cutting edge 49Z may be connected to the first cutting edge 49A and the second cutting edge 49B, respectively.

[0030] The insert 5 may have a through hole 51. In the insert 5 shown in the first embodiment, the through hole 51 penetrates from a first port 53 located in the first surface 35 to a second port 55 located in the second surface 37. In the insert 5 shown in the first embodiment, the first port 53 is located at the center 35P of the first surface 35, and the second port 55 is located at the center 37P of the second surface 37. The central axis of the through hole 51 passes through the center 35P of the first surface 35 and the center 37P of the second surface 37.

[0031] The insert 5 is not limited to the flat-type insert 5 shown in the first embodiment, and may be, for example, a vertical-type insert 5. In the case of the vertical-type insert 5, one of the third surfaces 39 on either the left or right side may have a rake face region 41, and the surface of the third surface 39 located on the first end 3A side may have a flank region 43. In this case, the insert 5 has a cutting edge 49 located on a corner 45 and / or a side 47 located between the surface having the rake face region 41 and the surface having the flank region 43.

[0032] The insert 5 may have a recess 57. As described below, the recess 57 is a portion that comes into contact with the fastener 7. The recess 57 may be spaced apart from the through hole 51. There is no particular limitation on the number of recesses 57, as long as there is at least one recess on either the first surface 35 or the second surface 37. In the insert 5 shown in the first embodiment, the number of recesses 57 on the first surface 35 is four. There is no particular limitation on the shape of the recess 57, and for example, the recess 57 may be a through hole, a blind hole that does not pass through, or a tapered shape that tapers from the first surface 35 to the second surface 37.

[0033] The recess 57 may have a peripheral wall portion 59. The recess 57 shown in the first embodiment is a blind hole, and therefore may have a bottom portion 61 connected to the peripheral wall portion 59. The bottom portion 61 may face upward. There are no particular limitations on the shapes of the peripheral wall portion 59 and the bottom portion 61. For example, the peripheral wall portion 59 may have a curved shape and the bottom portion 61 may have a flat shape. When viewed in cross section as in the example shown in FIG. 6 , the peripheral wall portion 59 may have a first peripheral wall portion 59A located on the front side and a second peripheral wall portion 59B located on the rear side.

[0034] The cutting tool 1A may have a first fixture 7A and a second fixture 7B as the fixture 7. It may also be expressed that the fixture 7 has the first fixture 7A and the second fixture 7B. The first fixture 7A is a fixture 7 for fixing the insert 5 to the main body 9, and the second fixture 7B is a fixture 7 for applying a force to the rear side of the insert 5 to position the insert 5.

[0035] In the cutting tool 1A shown in the first embodiment, the second fixture 7B can apply a force in a direction toward the rear side to the insert 5. More specifically, the second fixture 7B can apply a force to the insert 5 toward the second end 3B corresponding to the rear side in the direction extending along the reference axis O1.

[0036] 6 is an enlarged view of the VI-VI cross section, corresponding to region A2 shown in FIG. 4. The VI-VI cross section is a cross section passing through the center 35P of the first surface 35, the center 37P of the second surface 37, and the center 69P of the clamp 69, which corresponds to the center 7BP of the second fastener 7B. The VI-VI cross section includes the midpoint 45AP of the first corner 45A, the midpoint 45BP of the second corner 45B, and the center 5P of the insert 5, and is also a cross section passing through the central axis of the first fastener 7A, the central axis of the through-hole 51, and the central axis of the second fastener 7B. The VI-VI cross section is parallel to the reference axis O1 and to an imaginary line L1 extending in the direction in which the second fastener 7B applies force to the insert 5.

[0037] In the cutting tool 1A shown in the first embodiment, the first fastener 7A is inserted from above to below into the through-hole 51 and the first insertion opening 27. The second fastener 7B is inserted from above to below into the second insertion opening 29. As shown in Fig. 6 , the first fastener 7A and the second fastener 7B extend perpendicular to the reference axis O1.

[0038] There are no particular limitations on the first fastener 7A and the second fastener 7B, but in the fastener 7 shown in the first embodiment, the first fastener 7A has a first screw 63 and a clamp bolt 65, and the second fastener 7B has a second screw 67 and a clamp 69. The first screw 63 may be hollow inside. The clamp 69 may have a clamp through-hole 71 into which the second screw 67 is inserted. The second screw 67 may be inserted into the clamp through-hole 71 and the second insertion opening 29.

[0039] The first fastener 7A may be composed of, for example, only the first screw 63. Furthermore, the second fastener 7B may be, for example, a member in which the clamp 69 and the second screw 67 are integrally formed. If the first fastener 7A can fix the insert 5 to the main body 9 without inserting it into the through-hole 51 and the first insertion opening 27, the insert 5 does not need to have the through-hole 51, and the main body 9 does not need to have the first insertion opening 27. Furthermore, the main body 9 does not necessarily need to have the second insertion opening 29.

[0040] The upper surface 11 may have an inclined surface 73 that approaches the lower surface 13 from the front side to the rear side. In such a case, for example, by tightening the second screw 67, the clamp 69 moves downward and rearward along the inclined surface 73 with which the clamp 69 abuts. Even if the clamp 69 has a clamp inclined surface 75 that approaches the lower surface 13 from the front side to the rear side, the clamp 69 can similarly move downward and rearward. In the cutting tool 1A shown in the first embodiment, the inclined surface 73 may be located rearward of the second opening 33, and the clamp inclined surface 75 may be located below and rearward of the clamp through-hole 71.

[0041] The clamp 69 may have an arm portion 77. The arm portion 77 extends from the rear side toward the front side. As shown in Fig. 5 , when the first surface 35 is viewed from the front, the arm portion 77 has a width W in the left-right direction that decreases from the rear side toward the front side. In the cutting tool 1A shown in the first embodiment, the arm portion 77 is located forward of the center 71P of the clamp through-hole 71.

[0042] The arm portion 77 may engage with the recess 57. Hereinafter, the recess 57 engaging with the arm portion 77 will be referred to as a first recess 57A to distinguish it from the other recesses 57. The arm portion 77 may have an engaging portion 79. The engaging portion 79 may overlap the first surface 35 when viewed from above. Whether the engaging portion 79 overlaps the first surface 35 when viewed from above may be determined, for example, by whether the objects are aligned in a direction perpendicular to the first surface 35 in a cross section perpendicular to the first surface 35 as shown in FIG. 6 . In the cutting tool 1A shown in the first embodiment, the arm portion 77 has a lower end and a front end. The engaging portion 79 may engage with the first recess 57A or may contact the second peripheral wall portion 59B of the first recess 57A.

[0043] In the cutting tool 1A shown in the first embodiment, tightening the second screw 67 moves the clamp 69 downward and rearward. The clamp 69 applies a force to the insert 5 toward the holder 3, thereby positioning the insert 5. Then, by fixing the positioned insert 5 with the clamp bolt 65, the insert 5 can be fixed in the pocket 21 to an extent that it can be used for cutting.

[0044] When positioning the insert 5, the insert 5 does not actually need to move rearward; even if the insert 5 does not move, it is sufficient that the force applied to the insert 5 by the clamp 69 keeps the insert 5 from moving. Here, the "immovable state" refers to a state in which the insert 5 is fixed to an extent that it will not move due to contact with a human hand, which may occur during normal insert 5 replacement work, for example. Furthermore, when fixed by the first fixing device 7A, the insert 5 may move slightly downward from the positioned position.

[0045] As described above, fixation by the first fixture 7A refers to fixing the insert 5 to the holder 3 to an extent that it can be used for cutting, while fixation by the second fixture 7B merely fixes the insert 5 to its position, and it is not necessary to fix the insert 5 to the holder 3 to an extent that it can be used for cutting. Hereinafter, fixation by the first fixture 7A will be referred to as "fixing," and fixation by the second fixture 7B will be referred to as "positioning."

[0046] As described above, in the cutting tool 1A shown in the first embodiment, the insert 5 can be positioned first by the second fixture 7B, and then fixed by the first fixture 7A. As a result, it is possible to prevent the insert 5 from being attached incorrectly, such as when the insert 5 is fixed to the main body 9 while tilted relative to the seating surface 23, which contributes to reducing the risk of accidents occurring when cutting is performed with the insert 5 improperly attached and improving work efficiency.

[0047] The first recess 57A may be located rearward of the center 5P of the insert 5. The first recess 57A may be located closer to the second end 3B than the center 5P of the insert 5. In such a case, the first recess 57A is relatively closer to the center 3P of the holder 3, so that the force applied to the insert 5 from the second fixture 7B is stabilized, and the positioning accuracy of the insert 5 is improved.

[0048] When the first surface 35 is viewed from the front, the first recess 57A may be located on the imaginary line L2, which is a line connecting the central axis of the through hole 51 corresponding to the center 5P of the insert 5 and the midpoint of the corner 45. In the cutting tool 1A shown in the first embodiment, the imaginary line L2 connecting the center 5P of the insert 5 and the midpoint 45BP of the second corner 45B overlaps with the first recess 57A.

[0049] 5, in the cutting tool 1A according to the first embodiment, the midpoint L2P of the imaginary line segment L2 connecting the center 5P of the insert 5 and the midpoint 45BP of the second corner 45B overlaps with the first recess 57A. In this case, the positioning accuracy of the insert 5 can be improved while minimizing the risk of a decrease in durability of the insert 5.

[0050] When the first surface 35 is viewed from above, the first fastener 7A may be spaced apart from the second fastener 7B. In such a case, the risk of the second fastener 7B interfering with the insertion of the first fastener 7A is reduced, and the insert 5 can be more efficiently fixed by the first fastener 7A. In the cutting tool 1A shown in the first embodiment, at least a portion of the second fastener 7B is located above the first fastener 7A, and when the first surface 35 is viewed from the front, the first fastener 7A is spaced apart from the second fastener 7B. When the first surface 35 is viewed from above, the through hole 51 may be spaced apart from the second fastener 7B.

[0051] The engaging portion 79 may contact the second peripheral wall portion 59B. Alternatively, the engaging portion 79 may be spaced apart from the bottom portion 61. When the engaging portion 79 is spaced apart from the bottom portion 61, it is possible to suppress the generation of frictional force between the engaging portion 79 and the bottom portion 61 when force is applied to the insert 5 from the second fastener 7B, thereby making it possible to more efficiently position the insert 5. In addition, when the engaging portion 79 is spaced apart from the bottom portion 61, it is possible to reduce the risk of the engaging portion 79 receiving an upward force from the insert 5 during cutting, thereby increasing the durability of the second fastener 7B.

[0052] The engagement portion 79 may have a recess 81 that is recessed toward the front end. The recess 81 may be recessed toward the first end 3A. A lower end of the recess 81 may contact the second peripheral wall portion 59B. The bottom 83 of the recess 81 may be located forward of at least a portion of the first recess 57A or closer to the first end 3A. The bottom 83 of the recess 81 may be a dotted area, as shown in FIG. 6 . It may be located above the recess 57. The bottom 83 of the recess 81 may be located above the recess 57.

[0053] When the bottom 83 of the recess 81 is located forward or toward the first end 3A of at least a portion of the first recess 57A, even if the second fixture 7B is tilted slightly clockwise when viewed from the right side of the cutting tool 1A as shown in Figure 6 before positioning the insert 5 using the second fixture 7B, when the second fixture 7B is moved downward and toward the second end 3B, a force can be applied more efficiently rearward from the second fixture 7B to the insert 5.

[0054] The direction of the force applied to the insert 5 from the second fixture 7B and the imaginary line segment L2 connecting the first recess 57A and the corner 45 may be parallel. Here, "parallel" does not necessarily mean strictly parallel; it is considered parallel if the angle θ between the direction of the force applied to the insert 5 by the second fixture 7B and the imaginary line segment L2 connecting the recess 57 and the corner 45 is within the range of -2°≦θ≦+2°. In such a case, the insert 5 is more easily guided by the two third surfaces 39 located near the corner 45 due to the restraining surfaces 25, thereby improving the positioning accuracy of the insert 5. The same applies when the extension direction of the arm portion 77 and the imaginary line segment L2 are parallel.

[0055] In the insert 5 shown in the first embodiment, the clamp 69 pulls in the insert 5 in a direction perpendicular to the band-shaped region 85 formed by the extension of the inclined surface 73, and therefore the longitudinal axis O4 may be perpendicular to the extension direction of the band-shaped region 85, or the imaginary line segment L2 may be perpendicular to the extension direction of the band-shaped region 85. Furthermore, when the first surface 35 is seen through a plane, the second screw 67, the recess 57, and the center 5P of the insert 5 may be aligned in a straight line.

[0056] The holder 3 may have a seat member 87 in addition to the main body portion 9. The seat member 87 may be located between the main body portion 9 and the insert 5. In this case, it is possible to reduce the possibility of damage to the main body portion 9 when the insert 5 is broken.

[0057] The sheet member 87 has a first sheet surface 89, a second sheet surface 91, and a third sheet surface 93. The sheet member 87 shown in the first embodiment has the first sheet surface 89, the second sheet surface 91, and a plurality of third sheet surfaces 93. There are no particular limitations on the shapes of the first sheet surface 89, the second sheet surface 91, and the third sheet surface 93, but they may be, for example, rectangular.

[0058] The first seat surface 89 abuts against the lower surface (second surface 37) of the insert 5. In the example shown in FIG. 1 , the first seat surface 89 faces upward, the same as the upper surface (first surface 35) of the insert 5. The second seat surface 91 may be located on the opposite side of the first seat surface 89. The second seat surface 91 may also abut against the main body portion 9. The second seat surface 91 may face downward, the same as the lower surface (second surface 37) of the insert 5. The pocket 21 may be formed by the main body portion 9 and the seat member 87.

[0059] The third seat surface 93 is a surface connected to the first seat surface 89 and the second seat surface 91. The first seat surface 89 and the second seat surface 91 are positioned as a pair of main surfaces of the sheet member 87, and the third seat surface 93 is positioned as a side surface of the sheet member 87. The sheet member 87 is not limited to a thin plate shape in line with the general concept of a sheet, and may also have a thick plate shape in which the width of the third seat surface 93 in the direction along the up-down axis O2 is large, as shown in a non-limiting example in FIG.

[0060] The seat member 87 may have a seat through-hole 95 penetrating through the first seat surface 89 and the second seat surface 91. In the cutting tool 1A shown in the first embodiment, the seat through-hole 95 penetrates through the center of the first seat surface 89 and the center of the second seat surface 91. The seat through-hole 95 may be aligned with the first insertion opening 27 and the through-hole 51 in the direction in which the reference axis O1 extends.

[0061] In the cutting tool 1A shown in the first embodiment, when the insert 5 is fixed to the holder 3 by the first fastener 7A, first, the seat member 87 is positioned on the main body 9. Specifically, the first screw 63 of the first fastener 7A is inserted into the seat through-hole 95. Next, the insert 5 is positioned on the first seat surface 89. After the insert 5 has been positioned as described above, the clamp bolt 65 of the first fastener 7A is inserted into the through-hole 51 and the seat through-hole 95 (first screw 63), thereby fixing the insert 5 to the holder 3.

[0062] Examples of materials for the main body 9 include steel, cast iron, and aluminum alloy. The size of the main body 9 can be set to the following values, for example: The dimension of the main body 9 in the direction in which the reference axis O1 extends is, for example, 32 to 500 mm. The dimension of the main body 9 in the up-down direction is, for example, 10 to 50 mm. The dimension of the main body 9 in the left-right direction is, for example, 10 to 50 mm.

[0063] Examples of materials for the insert 5 include cemented carbide and cermet. Examples of cemented carbide include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. WC-Co is produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering the mixture. WC-TiC-Co is produced by adding titanium carbide (TiC) to WC-Co. WC-TiC-TaC-Co is produced by adding tantalum carbide (TaC) to WC-TiC-Co. Cermets are sintered composite materials that combine ceramic components with metals. Examples of cermets include those primarily composed of titanium compounds such as titanium carbide (TiC) or titanium nitride (TiN).

[0064] The surface of the insert 5 may be coated with a coating. The coating may have a composition such as titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), or alumina (Al ２ O ３ Examples of the method for forming the coating include chemical vapor deposition (CVD) and physical vapor deposition (PVD).

[0065] The size of the insert 5 can be set to, for example, the following values: The length of one side 47 of the rectangular shape on the upper surface 11 and the lower surface 13 is, for example, 3 to 54 mm. The thickness of the insert 5 from the upper surface 11 to the lower surface 13 is, for example, 2 to 10 mm.

[0066] The insert 5 may be either a positive type or a negative type. In the case where the first surface 35 and the second surface 37 of the insert 5 have the same shape, by providing the recesses 57 on both the first surface 35 and the second surface 37, the above-described positioning of the insert 5 can be utilized even when the first surface 35 and the second surface 37 of the insert 5 are used in a cutting process with the first surface 35 and the second surface 37 of the insert 5 reversed to each other.

[0067] Furthermore, the recess 57 located on the first surface 35 and the recess 57 located on the second surface 37 may be positioned point-symmetrically with respect to the center 5P of the insert 5. In such a case, when the insert 5 is attached to the main body 9 with the first surface 35 and the second surface 37 reversed, the insert 5 can be positioned without changing the position of the second fastener 7B, etc.

[0068] The screw may be made of, for example, SCM 440. The clamp 69 may be made of, for example, SCM 440. The seat member 87 may be made of, for example, cemented carbide.

[0069] Second Embodiment Next, a cutting tool 1B according to a second embodiment of the present disclosure will be described in detail with reference to Figures 7 to 9. The following description will focus on differences from the first embodiment. Therefore, unless otherwise specified, the description of the first embodiment will be used for parts having the same configuration as the first embodiment, and description thereof will be omitted.

[0070] In the insert 5 of the second embodiment, as in the insert 5 of the first embodiment, the recess 57 is located on the upper surface of the insert 5, and therefore the "upper surface" of the insert 5 corresponds to the first surface 35. In addition, the lower surface of the insert 5 corresponds to the second surface 37 located on the opposite side to the first surface 35.

[0071] In the cutting tool 1B shown in the second embodiment, the arm portion 77 includes a first arm portion 77A and a second arm portion 77B. The first arm portion 77A and the second arm portion 77B are split into two at the front side of the arm portion 77. When the first surface 35 is viewed from the front, the first arm portion 77A and the second arm portion 77B are symmetrical with respect to an imaginary line L3 that passes through a branch point 77P of the first arm portion 77A and the second arm portion 77B and the center 69P of the clamp 69. If the position of the branch point cannot be uniquely determined, the imaginary line L3 may be a line that passes through the center 69P of the clamp 69 and is parallel to the direction of the force applied to the insert 5 from the second fixture 7B. As shown in FIG. 8 , the first arm portion 77A may be located on the right side and the second arm portion 77B may be located on the left side of the reference axis O1.

[0072] The first surface 35 may have a first recess 57A and a second recess 57B. The first arm portion 77A engages with the first recess 57A, and the second arm portion 77B engages with the second recess 57B. In this case, since the arm portion 77 engages with multiple recesses 57, the second fastener 7B can apply force to the insert 5 more stably, resulting in higher positioning accuracy of the insert 5.

[0073] Here, the position of the first recess 57A in the second embodiment is different from the position of the first recess 57A in the first embodiment. Specifically, in the cutting tool 1B shown in the second embodiment, the insert 5 has a third corner 45C and a fourth corner 45D adjacent to the first corner 45A, the first recess 57A is located between the center 5P of the insert 5 and the midpoint 45CP of the third corner 45C, and the second recess 57B is located between the center 5P of the insert 5 and the midpoint 45CP of the fourth corner 45D. The first recess 57A and the second recess 57B may each be located on a straight line that is perpendicular to the longitudinal axis O4 and passes through the midpoint of the insert 5.

[0074] When the first surface 35 is viewed from the front, the through hole 51 may be located between the first recess 57A and the second recess 57B. In this case, the first arm portion 77A engaged with the first recess 57A and the second arm portion 77B engaged with the second recess 57B apply a uniform force to the insert 5, thereby improving the positioning accuracy of the insert 5.

[0075] Furthermore, when the first surface 35 is viewed from the front, if the center 51P of the through hole 51 is located on an imaginary line L4 that passes through the center 57AP of the first recess 57A and the center 57BP of the second recess 57B, a more uniform force is applied to the insert 5 from the first arm portion 77A and the second arm portion 77B, thereby further improving the positioning accuracy of the insert 5. In Fig. 9, the imaginary line L4 is perpendicular to the imaginary line L3.

[0076] When the first surface 35 is viewed from the front, the width of each of the first arm portion 77A and the second arm portion 77B in the left-right direction may decrease toward the front.

[0077] Third Embodiment Next, a cutting tool 1C according to a third embodiment of the present disclosure will be described in detail with reference to Figures 10 to 15. The following description will focus on differences from the first embodiment. Therefore, unless otherwise specified, the description of the first embodiment will be used for parts having the same configuration as the first embodiment, and description thereof will be omitted.

[0078] Unlike the insert 5 of the first and second embodiments, the insert 5 of the second embodiment has a recess 57 located on the lower surface of the insert 5. Therefore, in this embodiment, the "lower surface" of the insert 5 corresponds to the first surface 35. Also, the upper surface of the insert 5 corresponds to the second surface 37 located on the opposite side to the first surface 35.

[0079] Therefore, in the direction in which the vertical axis O2 extends, the side on which the second surface 37 is located is referred to as the upper side, and the side on which the first surface 35 is located is referred to as the lower side. In addition, when the first surface 35 is viewed from the front, the side on which the insert 5 is located with respect to the reference axis O1 is referred to as the left side, and the side opposite to the left side is referred to as the right side.

[0080] Furthermore, in the insert 5 of the first and second embodiments, the cutting edge 49 is located at the intersection of the first surface 35 and the third surface 39, but in the insert 5 of this embodiment, the cutting edge 49 is located at the intersection of the second surface 37 and the third surface 39.

[0081] In the cutting tool 1C shown in the third embodiment, the second fixture 7B has a clamp screw 97 and a retracting member 99. The clamp screw 97 may have a first abutment surface 101 facing downward, and the retracting member 99 may have a second abutment surface 103 facing upward and abutting the first abutment surface 101. The retracting member 99 may be an L-shaped member, and is L-shaped in the XV-XV cross section shown in FIG. 15 . The retracting member 99 corresponds to the arm portion 77 in the first embodiment, and may be a member that applies a force to move the insert 5 rearward.

[0082] 15 is an enlarged view of the XV-XV cross section shown in FIG. 14 , corresponding to region A5 shown in FIG. 13 . The XV-XV cross section is a cross section passing through the center 35P of the first surface 35, the center 37P of the second surface 37, and the center 97P of the clamp screw 97, which corresponds to the center 7BP of the second fastener 7B. The XV-XV cross section includes the midpoint 45AP of the first corner 45A, the midpoint 45BP of the second corner 45B, and the center 5P of the insert 5, and also passes through the central axis of the first fastener 7A, the central axis of the second fastener 7B, the central axis of the through-hole 51, and the central axis of the clamp screw 97. The XV-XV cross section is parallel to the reference axis O1 and a straight line extending in the direction in which the second fastener 7B pulls the insert 5.

[0083] In the cutting tool 1C shown in the third embodiment, the retraction member 99 is engaged with the recess 57 (first recess 57A). In the cutting tool 1C shown in the third embodiment, first, the clamp screw 97 is tightened, whereby the clamp screw 97 moves downward, and thereby a downward force is applied from the first abutment surface 101 to the second abutment surface 103.

[0084] The retracting member 99 has a lower front portion (first portion 105) that contacts the main body 9, while a rear portion (second portion 107) that is spaced apart from the main body 9. Therefore, when a downward force is applied from the first abutment surface 101 to the second abutment surface 103 at a location farther away from the center 5P of the insert 5 than the first portion 105, the retracting member 99 rotates clockwise around the first portion 105 as a fulcrum in the cross section shown in Fig. 15. As a result, the retracting member 99 can apply a force to the recess 57 in a direction that moves the insert 5 rearward, thereby positioning the insert 5.

[0085] Since the second surface 37 faces the seat surface 23 of the holder 3, at least a portion of the second fastener 7B that engages with the first recess 57A located on the second surface 37 may be located inside the holder 3. In this case, the risk of chips or the like colliding with the second fastener 7B is reduced, and the durability of the second fastener 7B is increased. In the cutting tool 1C shown in the third embodiment, the entire second fastener 7B is located inside the holder 3.

[0086] The seat member 87 may have a seat hole 109 penetrating through the first seat surface 89 and the second seat surface 91. As shown in FIG. 15 , the seat hole 109 is aligned with the recess 57 in the direction in which the up-down axis O2 extends. The second fastener 7B has a retraction member 99 that passes through the seat hole 109 and engages with the recess 57.

[0087] It should be noted that the cutting tool 1C shown in the third embodiment does not need to have the seat member 87, but if the seat member 87 is provided, there may be a clearance between the retraction member 99 and the seat hole 109. If there is a clearance, a rearward force can be applied to the insert 5 without moving the seat member 87.

[0088] <Method for manufacturing a machined product> Next, a method for manufacturing a machined product according to a non-limiting embodiment will be described in detail. In the example shown in Figures 16 to 18, the cutting tool 1A according to the first embodiment described above is used. For example, there is no problem if the cutting tool 1A according to the second or third embodiment is used.

[0089] A method for manufacturing a machined product according to one embodiment includes the following steps (C1) to (C3).

[0090] (C1) a step of rotating the workpiece 201; (C2) a step of bringing the cutting tool 1A into contact with the rotating workpiece 201; and (C3) a step of moving the cutting tool 1A away from the workpiece 201.

[0091] More specifically, first, as shown in Fig. 16, the workpiece 201 is rotated around the rotation axis O5, and the cutting tool 1A is brought relatively close to the workpiece 201. Next, as shown in Fig. 17, the cutting edge 49 of the cutting tool 1A is brought into contact with the rotating workpiece 201 to cut the workpiece 201. Then, as shown in Fig. 18, the cutting tool 1A is moved relatively away from the workpiece 201.

[0092] In this embodiment, the cutting tool 1A is moved in the Y1 direction while the workpiece 201 is being rotated about the rotation axis O5, thereby bringing it closer to the workpiece 201. In addition, in Fig. 17, the cutting edge 49 of the insert 5 is brought into contact with the rotating workpiece 201 to cut the workpiece 201. In addition, in Fig. 18, the cutting tool 1A is moved in the Y2 direction while the workpiece 201 is being rotated, thereby moving it away from the workpiece 201.

[0093] In the cutting process in the manufacturing method of the embodiment, the cutting tool 1A is moved in each step to bring the cutting tool 1A into contact with the workpiece 201 or to move the cutting tool 1A away from the workpiece 201, but of course, this is not limited to this form.

[0094] For example, in step (C1), the workpiece 201 may be brought closer to the cutting tool 1A. Similarly, in step (C3), the workpiece 201 may be moved away from the cutting tool 1A. To continue the cutting process, the workpiece 201 may be kept rotating, and the step of bringing the cutting edge 49 of the insert 5 into contact with different locations on the workpiece 201 may be repeated.

[0095] The material of the workpiece 201 may be, for example, carbon steel, alloy steel, stainless steel, cast iron, or non-ferrous metal.

[0096] In one embodiment, (1) a cutting tool extending from the tip to the rear end along a reference axis includes a holder having a pocket located on the tip side, an insert attached to the pocket, and a plurality of fasteners for fixing the insert to the pocket, wherein the insert has a first surface, a second surface located opposite the first surface, a through hole opening in the first surface and the second surface, and a first recess located in the first surface, and the plurality of fasteners may include a first fastener inserted into the through hole and a second fastener engaged with the first recess.

[0097] (2) In the cutting tool of (1) above, the first recess may be located closer to the rear end than the center of the insert.

[0098] (3) In the cutting tool of (2) above, the first surface may have a corner located on the rear end side, and when the first surface is viewed from the front, the first recess may be located on an imaginary line segment connecting the center axis of the through hole and the midpoint of the corner.

[0099] (4) In any one of the cutting tools (1) to (3) above, when the first surface is viewed from the front, the first fixture may be positioned away from the second fixture.

[0100] (5) In any of the cutting tools (1) to (4) above, the first recess has a bottom and a peripheral wall connected to the bottom, and the second fixture is in contact with the peripheral wall and spaced from the bottom.

[0101] (6) In any of the cutting tools (1) to (5) above, the second fixture may have an engaging portion that overlaps with the first surface when viewed from above, the engaging portion having a recess that is concave toward the tip, and the bottom of the recess may be located closer to the tip than at least a portion of the first recess.

[0102] (7) In any of the cutting tools (1) to (6) above, the insert may further have a second recess located on the first surface, and the second fixture may have a first arm portion and a second arm portion, the first arm portion engaging with the first recess, and the second arm portion engaging with the second recess.

[0103] (8) In the cutting tool of (7) above, when the first surface is viewed from the front, the through hole may be located between the first recess and the second recess.

[0104] (9) In the cutting tool of (7) or (8) above, when the first surface is viewed from the front, the through hole may be located on an imaginary line passing through the first recess and the second recess.

[0105] (10) In any of the cutting tools (1) to (9) above, the pocket may have a seat surface, the first surface may abut against the seat surface, the holder may have a main body portion and a seat member located on the seat surface, the seat member may have a first seat surface abutting against the second surface, a second seat surface located opposite the first seat surface and abutting against the main body portion, and seat holes penetrating the first seat surface and the second seat surface, and the second fixing device may have an arm portion that passes through the seat hole and engages with the first recess.

[0106] (11) The method may include the steps of rotating a workpiece, bringing any one of the cutting tools (1) to (10) into contact with the rotating workpiece, and removing the cutting tool from the workpiece.

[0107] Furthermore, in the cutting tools 1A according to the first embodiment to 1C according to the third embodiment described above, the insert 5 can be positioned by engaging the arm portion 77 of the second fastener 7B with the recess 57 of the insert 5, but there are no particular limitations on the shape of these engaging portions. For example, the insert 5 may have a convex portion, and the second fastener 7B may have a portion with a shape (such as a concave shape) that can engage with the convex portion, and the insert may be positioned by engaging the convex portion of the insert with the corresponding portion of the second fastener.

[0108] The invention according to the present disclosure has been described above based on the drawings and embodiments. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0109] The above provides examples of embodiments of the present disclosure, but it goes without saying that the present disclosure is not limited to the above-described embodiments and can be any embodiment as long as it does not deviate from the gist of the present disclosure.

[0110] DESCRIPTION OF SYMBOLS 1A to 1C: Cutting tool 3: Main body 3A: First end (front end) 3B: Second end (rear end) 3P: Center of main body 5: Cutting insert (insert) 5P: Center of cutting insert (insert) 7: Fixture 7A: First fixture 7B: Second fixture 7BP: Center of second fixture 9: Main body 11: Upper surface 13: Lower surface 15: Side surface 17: Head 19: Shank 21: Pocket 23: Bearing surface 25: Restraint surface 27: First insertion opening 29: Second insertion opening 31: First opening 33: Second opening 35: First surface 35P: Center of first surface 37: Second surface 37P: Center of second surface 39: Third surface 41: Rake face area 43: Flank face area 45: Corner 45A...First corner 45AP...Midpoint of first corner 45B...Second corner 45BP...Midpoint of second corner 45C...Third corner 45CP...Midpoint of third corner 45D...Fourth corner 45DP...Midpoint of fourth corner 47...Side 47A...First side 47B...Second side 49...Cutting edge 49A...First cutting edge 49B...Second cutting edge 49Z...Corner cutting edge 51...Through hole 51P...Center of through hole 53...First opening 55...Second opening 57...Recess 57A...First recess 57AP...Center of first recess 57B...Second recess 57BP...Center of second recess 59...Circumferential wall portion 59A...First peripheral wall portion 59B...Second peripheral wall portion 61...Bottom portion 63...First screw 65: Clamp bolt 67: Second screw 69: Clamp 69P: Center of clamp 71: Clamp through-hole 71P: Center of clamp through-hole 73: Inclined surface 75: Clamp inclined surface 77: Arm portion 77A: First arm portion 77B: Second arm portion 77P: Branch point of first arm portion and second arm portion 79: Engagement portion 81: Recess 83: Bottom 85: Band-shaped region 87: Seat member 89: First seat surface 91: Second seat surface 93: Third seat surface 95: Seat through-hole 97: Clamp screw97P: Center of clamp screw 99: Retraction member 101: First contact surface 103: Second contact surface 105: First part 107: Second part 109: Seat hole 201: Workpiece O1: Reference axis O2: Up-down axis O3: Left-right axis O4: Front-rear axis O5: Rotation axis L1, L3, L4: Virtual straight line L2: Virtual line segment L2P: Midpoint of virtual line segment W: Width Y1-Y2: Travel direction

Claims

1. A cutting tool extending from a leading end to a trailing end along a reference axis, a holder having a pocket located on the side of the tip; an insert attached to the pocket; a plurality of fasteners for securing the insert to the pocket; The insert is The first page and a second surface located opposite the first surface; a through hole opening in the first surface and the second surface; a first recess located on the first surface; The plurality of fasteners include: a first fixture inserted into the through hole; a second fastener engaged in the first recess.

2. The cutting tool according to claim 1 , wherein the first recess is located closer to the rear end than the center of the insert.

3. the first surface has a corner located on the rear end side, When the first surface is viewed from the front, The cutting tool according to claim 2 , wherein the first recess is located on an imaginary line segment connecting a central axis of the through hole and a midpoint of the corner.

4. When the first surface is viewed from the front, The cutting tool of claim 1 , wherein the first fixture is located remotely from the second fixture.

5. The first recess is The bottom and a peripheral wall portion connected to the bottom portion, The cutting tool according to claim 1 , wherein the second fixture is in contact with the peripheral wall portion and spaced apart from the bottom portion.

6. the second fixing device has an engaging portion that overlaps with the first surface when viewed from above, The engaging portion has a recess that is concave toward the tip end, The cutting tool according to claim 1 , wherein a bottom of the recess is located closer to the tip than at least a portion of the first recess.

7. The insert further includes a second recess located on the first surface; the second fixture has a first arm portion and a second arm portion, the first arm portion engages with the first recess, The cutting tool according to claim 1 , wherein the second arm portion engages with the second recess.

8. When the first surface is viewed from the front, The cutting tool according to claim 7 , wherein the through hole is located between the first recess and the second recess.

9. When the first surface is viewed from the front, The cutting tool according to claim 7 , wherein the through hole is located on an imaginary line passing through the first recess and the second recess.

10. the pocket has a seat; The first surface abuts against the seat surface, The holder is a main body; a seat member positioned on the seat surface, The sheet member is a first seat surface abutting the second surface; a second seat surface located opposite the first seat surface and in contact with the main body portion; a seat hole extending through the first seat surface and the second seat surface; The cutting tool according to claim 1 , wherein the second fastener has an arm portion that passes through the seat hole and engages with the first recess.

11. rotating the workpiece; bringing the cutting tool according to any one of claims 1 to 10 into contact with the rotating workpiece; and removing the cutting tool from the workpiece.