Cutting tools for milling and turning

Abstract

The milling cutting tool has a cutting insert and a body. The cutting insert is attached to the body. The body is rotatable around a rotation axis. The cutting insert includes a base member and a cutting member joined to the base member. The cutting member has a main cutting edge portion. The cutting insert has a mounting surface attached to the body and an upper surface opposite to the mounting surface. When viewed in a direction perpendicular to the upper surface, an angle between a reference line perpendicular to the rotation axis and a joint between the base member and the cutting member is 5° or more and 20° or less. When viewed in a direction perpendicular to the upper surface, an angle between the reference line and the main cutting edge portion is 5° or more and 20° or less.

Description

[Technical field]

[0001] The present disclosure relates to milling and turning cutting tools. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 8-141822 (Patent Document 1) discloses a throw-away insert for a milling cutter having a base metal made of a cemented carbide alloy and a cutting edge made of a sintered cubic boron nitride body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-141822 Summary of the Invention

[0004] The milling cutting tool according to the present disclosure includes a cutting insert and a body. The cutting insert is attached to the body. The body is rotatable around a rotation axis. The cutting insert includes a base member and a cutting member joined to the base member. The cutting member has a major cutting edge portion. The cutting insert has a mounting surface attached to the body and an upper surface opposite to the mounting surface. When viewed in a direction perpendicular to the upper surface, an angle between a reference line perpendicular to the rotation axis and a joint between the base member and the cutting member is 5° or more and 20° or less. When viewed in a direction perpendicular to the upper surface, an angle between the reference line and the major cutting edge portion is 5° or more and 20° or less. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic perspective view showing the configuration of a cutting insert according to a first embodiment. [Diagram 2] FIG. 2 is a schematic plan view showing the configuration of the cutting insert according to the first embodiment. [Diagram 3] FIG. 3 is an enlarged schematic view of region III in FIG. [Figure 4]FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a schematic side view illustrating the configuration of the cutting tool for milling according to this embodiment. [Figure 8] FIG. 8 is a schematic side view illustrating the configuration of the cutting tool for turning according to this embodiment. [Figure 9] FIG. 9 is a schematic plan view showing the configuration of a first modified example of the cutting insert according to the first embodiment. [Figure 10] FIG. 10 is a schematic plan view showing the configuration of a second modified example of the cutting insert according to the first embodiment. [Figure 11] FIG. 11 is a schematic side view showing a state in which a workpiece is cut using the cutting tool for milling. [Figure 12] FIG. 12 is a schematic plan view showing the configuration of the cutting insert according to the second embodiment. [Figure 13] FIG. 13 is a schematic diagram illustrating the direction in which the joint portion extends. [Figure 14] FIG. 14 is a schematic plan view showing the configuration of the cutting insert according to the third embodiment. [Figure 15] FIG. 15 is a schematic cross-sectional view taken along line XV-XV in FIG. [Figure 16] FIG. 16 is a schematic cross-sectional view taken along line XVI-XVI in FIG. [Figure 17] FIG. 17 is a schematic plan view showing the configuration of a cutting insert according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] [Description of the embodiments of the present disclosure] First, an embodiment of the present disclosure (also referred to as the present embodiment) will be described.

[0007] (1) A milling cutting tool according to the present disclosure includes a cutting insert and a body. The cutting insert is attached to the body. The body is rotatable around a rotation axis. The cutting insert includes a base member and a cutting member joined to the base member. The cutting member has a major cutting edge portion. The cutting insert has a mounting surface attached to the body and an upper surface opposite to the mounting surface. When viewed in a direction perpendicular to the upper surface, an angle between a reference line perpendicular to the rotation axis and a joint between the base member and the cutting member is 5° or more and 20° or less. When viewed in a direction perpendicular to the upper surface, an angle between the reference line and the major cutting edge portion is 5° or more and 20° or less.

[0008] (2) In the cutting tool for milling according to the above (1), the cutting member may be made of cubic boron nitride.

[0009] (3) In the cutting tool for turning according to the above (1) or (2), the joint may be linear when viewed in a direction perpendicular to the upper surface.

[0010] (4) In the cutting tool for turning according to the above (1) or (2), the joint may be curved when viewed in a direction perpendicular to the upper surface.

[0011] (5) A cutting tool for turning according to the present disclosure includes a cutting insert and a holder. The cutting insert is attached to the holder. The holder includes a shank extending along a central axis. The cutting insert includes a base member and a cutting member joined to the base member. The cutting member has a major cutting edge portion. The cutting insert has a mounting surface attached to the holder and an upper surface opposite to the mounting surface. When viewed in a direction perpendicular to the upper surface, an angle formed between a reference line perpendicular to the central axis and a joint between the base member and the cutting member is 5° or more and 20° or less. When viewed in a direction perpendicular to the upper surface, an angle formed between the reference line and the major cutting edge portion is 5° or more and 20° or less.

[0012] (6) In the cutting tool for turning according to the above (5), the cutting member may be made of cubic boron nitride.

[0013] (7) In the cutting tool for turning according to (5) or (6) above, the joint may be linear when viewed in a direction perpendicular to the upper surface.

[0014] (8) In the cutting tool for turning according to (5) or (6) above, the joint may be curved when viewed in a direction perpendicular to the upper surface. [Details of the embodiment of the present disclosure] Specific examples of the embodiments of the present disclosure will be described below with reference to the drawings, in which the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0015] (First embodiment) Fig. 1 is a schematic perspective view showing the configuration of the cutting insert according to the first embodiment Fig. 2 is a schematic plan view showing the configuration of the cutting insert according to the first embodiment.

[0016] As shown in Fig. 1 and Fig. 2, the cutting insert 1 according to the first embodiment has a base member 30 and a cutting member 7. The base member 30 is formed of, for example, a cemented carbide alloy. The cutting member 7 is formed of, for example, cubic boron nitride. The cutting member 7 is joined to the base member 30. A joint 4 between the cutting member 7 and the base member 30 is formed of, for example, a brazing material such as silver brazing.

[0017] The cutting member 7 has a rake face 40, a flank face 50, and a cutting edge 60. The flank face 50 is continuous with the rake face 40. The ridge between the rake face 40 and the flank face 50 forms the cutting edge 60. The cutting edge 60 has a major cutting edge portion 61, a minor cutting edge portion 62, and a corner cutting edge portion 63. The major cutting edge portion 61 is continuous with each of the minor cutting edge portion 62 and the corner cutting edge portion 63. The major cutting edge portion 61 is located between the minor cutting edge portion 62 and the corner cutting edge portion 63.

[0018] The rake face 40 has a first rake face portion 41, a second rake face portion 42, and a third rake face portion 43. The flank face 50 has a first flank face portion 51, a second flank face portion 52, and a third flank face portion 53. The ridgeline between the first rake face portion 41 and the first flank face portion 51 forms a major cutting edge portion 61. The ridgeline between the second rake face portion 42 and the second flank face portion 52 forms a minor cutting edge portion 62. The ridgeline between the third rake face portion 43 and the third flank face portion 53 forms a corner cutting edge portion 63.

[0019] As shown in FIG. 2, the first scooping surface portion 41 has a first region 41a and a second region 41b. The first region 41a is continuous with the second region 41b. The second scooping surface portion 42 has a third region 42a and a fourth region 42b. The third region 42a is continuous with the fourth region 42b. The third scooping surface portion 43 has a fifth region 43a and a sixth region 43b. The fifth region 43a is continuous with the sixth region 43b.

[0020] 1 and 2, the base member 30 has an upper surface 35, a mounting surface 36, and an outer peripheral surface 37. The mounting surface 36 is a surface that is attached to a body 90 (see FIG. 7) or a holder 70 (see FIG. 8), which will be described later. The mounting surface 36 is opposite the upper surface 35. The base member 30 is provided with a through hole 2. The through hole 2 opens to both the upper surface 35 and the mounting surface 36. The outer peripheral surface 37 is continuous with both the upper surface 35 and the mounting surface 36.

[0021] 1, a notch 3 is provided in the base member 30. The notch 3 is provided in a part of the boundary between an outer circumferential surface 37 and an upper surface 35. The cutting member 7 is disposed in the notch 3. The cutting member 7 is joined to the base member 30 at the notch 3.

[0022] The outer peripheral surface 37 has a first outer peripheral region 31, a second outer peripheral region 32, a third outer peripheral region 33, and a fourth outer peripheral region 34. The first outer peripheral region 31 is disposed between the first clearance surface portion 51 and the mounting surface 36. The second outer peripheral region 32 is disposed between the second clearance surface portion 52 and the mounting surface 36. The third outer peripheral region 33 is disposed between the third clearance surface portion 53 and the mounting surface 36. The fourth outer peripheral region 34 is continuous with each of the upper surface 35 and the mounting surface 36. The first outer peripheral region 31 is disposed between the second outer peripheral region 32 and the third outer peripheral region 33.

[0023] Fig. 3 is an enlarged schematic view of region III in Fig. 2. In Fig. 3, the outer peripheral surface 37 of the base member 30 is omitted.

[0024] As shown in FIG. 3, the major cutting edge portion 61 is linear when viewed in a direction perpendicular to the upper surface 35. Similarly, the minor cutting edge portion 62 is linear when viewed in a direction perpendicular to the upper surface 35. When viewed in a direction perpendicular to the upper surface 35, the angle between the reference line E and the major cutting edge portion 61 is defined as a first angle θ1. The first angle θ1 is measured at an intersection (first intersection P1) between a tangent to the major cutting edge portion 61 and a tangent to the minor cutting edge portion 62. In measuring the first angle θ1, the reference line E is set to pass through the first intersection P1. The first angle θ1 is 5° or more and 20° or less. The first angle θ1 may be 7° or more, or 9° or more. The first angle θ1 may be 18° or less, or 16° or less.

[0025] The reference line E is a line parallel to the feed direction C of the cutting tool. Specifically, in the case of the turning cutting tool 101, the reference line E is a line perpendicular to the rotation axis B of the body 90 when viewed in a direction perpendicular to the top surface 35 (see FIG. 7). In the case of the turning cutting tool 102, the reference line E is a line perpendicular to the central axis D of the shank 71 when viewed in a direction perpendicular to the top surface 35 (see FIG. 8).

[0026] As shown in FIG. 3, the joint 4 between the base member 30 and the cutting member 7 is linear when viewed in a direction perpendicular to the upper surface 35. The angle between the reference line E and the joint 4 is set as a second angle θ2. The second angle θ2 is measured at an intersection (second intersection P2) between a tangent to the corner cutting edge portion 63 at an end of the corner cutting edge portion 63 opposite to the main cutting edge portion 61 and a tangent to the joint 4. In the case of the turning cutting tool 101, in measuring the second angle θ2, the reference line E is set by translating the reference line E set in measuring the first angle θ1 along the rotation axis B so that the reference line E and the second intersection P2 overlap when viewed in a direction perpendicular to the upper surface 35. Similarly, in the case of the turning cutting tool 102, in measuring the second angle θ2, the reference line E is set by translating the reference line E set in measuring the first angle θ1 along the central axis D so that the reference line E and the second intersection point P2 overlap when viewed in a direction perpendicular to the upper surface 35. The second angle θ2 is 5° or more and 20° or less. The second angle θ2 may be 7° or more, or 9° or more. The second angle θ2 may be 18° or less, or 16° or less.

[0027] 3, when viewed in a direction perpendicular to the top surface 35, the minor cutting edge portion 62 may be parallel to the reference line E. In this embodiment, the first angle θ1 is the same as the second angle θ2. When viewed in a direction perpendicular to the top surface 35, the corner cutting edge portion 63 may be curved.

[0028] Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 2. The cross section shown in Fig. 4 is perpendicular to the main cutting edge portion 61 and perpendicular to the upper surface 35.

[0029] As shown in Fig. 4, the upper surface 35 is parallel to the mounting surface 36. The second region 41b of the first scooping surface portion 41 extends along the upper surface 35. The first region 41a of the first scooping surface portion 41 is inclined with respect to each of the second region 41b and the first flank surface portion 51. The first flank surface portion 51 is disposed along the first outer peripheral region 31. The first outer peripheral region 31 is continuous with the mounting surface 36.

[0030] In the cross section shown in FIG. 4, the angle between the upper surface 35 and the first outer peripheral region 31 is a third angle θ3. The third angle θ3 is greater than 90°. The angle between the first region 41a of the first scooping surface portion 41 and the first clearance surface portion 51 is greater than 90°. From another perspective, the clearance angle of the first clearance surface portion 51 may be negative. In the cross section shown in FIG. 4, the angle between the mounting surface 36 and the first outer peripheral region 31 is a fourth angle θ4. The fourth angle θ4 is less than 90°.

[0031] Fig. 5 is a schematic cross-sectional view taken along line VV in Fig. 2. The cross section shown in Fig. 5 is perpendicular to the minor cutting edge portion 62 and perpendicular to the upper surface 35.

[0032] 5, the fourth region 42b of the second scooping surface portion 42 extends along the upper surface 35. The third region 42a of the second scooping surface portion 42 is inclined with respect to each of the fourth region 42b and the second flank surface portion 52. The second flank surface portion 52 is disposed along the second outer peripheral region 32. The second outer peripheral region 32 is continuous with the mounting surface 36.

[0033] In the cross section shown in FIG. 5, the angle between the upper surface 35 and the second outer peripheral region 32 is a fifth angle θ5. The fifth angle θ5 may be smaller than the third angle θ3. The fifth angle θ5 is, for example, 90°. The angle between the third region 42a of the second scooping surface portion 42 and the second clearance surface portion 52 may be, for example, 90°. From another perspective, the clearance angle of the second clearance surface portion 52 may be 0°. In the cross section shown in FIG. 5, the angle between the mounting surface 36 and the second outer peripheral region 32 is a sixth angle θ6. The sixth angle θ6 may be larger than the fourth angle θ4. The sixth angle θ6 is, for example, 90°.

[0034] Fig. 6 is a schematic cross-sectional view taken along line VI-VI in Fig. 2. The cross section shown in Fig. 6 is parallel to the minor cutting edge portion 62, intersects with the fourth outer peripheral region 34, and is perpendicular to the upper surface 35.

[0035] 6, the fourth outer peripheral region 34 has a fifth outer peripheral region 5 and a sixth outer peripheral region 6. The sixth outer peripheral region 6 is opposite to the fifth outer peripheral region 5. The through hole 2 is located between the fifth outer peripheral region 5 and the sixth outer peripheral region 6. The fifth outer peripheral region 5 is connected to both the upper surface 35 and the mounting surface 36. Similarly, the sixth outer peripheral region 6 is connected to both the upper surface 35 and the mounting surface 36.

[0036] In the cross section shown in FIG. 6, the fifth outer peripheral region 5 is inclined with respect to each of the upper surface 35 and the mounting surface 36. The angle between the upper surface 35 and the fifth outer peripheral region 5 is a seventh angle θ7. The seventh angle θ7 is smaller than 90°. In the cross section shown in FIG. 6, the angle between the mounting surface 36 and the fifth outer peripheral region 5 is an eighth angle θ8. The eighth angle θ8 is larger than the seventh angle θ7. The eighth angle θ8 is larger than 90°.

[0037] In the cross section shown in FIG. 6, the sixth outer peripheral region 6 is inclined with respect to each of the upper surface 35 and the mounting surface 36. The angle formed between the upper surface 35 and the sixth outer peripheral region 6 is a ninth angle θ9. The ninth angle θ9 is greater than 90°. In the cross section shown in FIG. 6, the angle formed between the mounting surface 36 and the sixth outer peripheral region 6 is a tenth angle θ10. The tenth angle θ10 is less than the ninth angle θ9. The tenth angle θ10 is less than 90°.

[0038] Next, the configuration of the milling cutting tool 101 according to this embodiment will be described. FIG. 7 is a side schematic view for explaining the configuration of a cutting tool 101 for turning according to this embodiment. As shown in FIG. 7, the cutting tool 101 for turning has a body 90, a cutting insert 1, and a fastening screw 93. The body 90 is rotatable around a rotation axis B. The body 90 is attached to a machine tool (not shown) via an arbor (not shown). An insert mounting groove 92 is provided on an outer periphery 91 of the body 90. The cutting insert 1 is disposed in the insert mounting groove 92. The cutting insert 1 is attached to the body 90 using the fastening screw 93. The fastening screw 93 is inserted into the through hole 2 of the cutting insert 1. The cutting tool 101 for turning is, for example, a milling tool.

[0039] 7, the milling cutting tool 101 is disposed facing the workpiece 80. The milling cutting tool 101 is movable along a feed direction C while rotating around a rotation axis B. The milling cutting tool 101 may have the cutting insert 1 according to the first embodiment, or may have the cutting insert 1 according to another embodiment described later.

[0040] Fig. 8 is a schematic side view illustrating the configuration of a turning cutting tool 102 according to this embodiment. As shown in Fig. 8, the turning cutting tool 102 according to this embodiment has a holder 70, a cutting insert 1, and a fastening screw 93. The cutting insert 1 is attached to the holder 70. The holder 70 has a shank 71 and an insert holding member 72.

[0041] The shank 71 is attached to a machine tool (not shown). The shank 71 extends along a central axis D. The insert holding member 72 is connected to the shank 71. The insert holding member 72 is provided with an insert mounting groove 73. The insert mounting groove 73 is provided at a position away from the central axis D in the feed direction C. The cutting insert 1 is placed in the insert mounting groove 73. The cutting insert 1 is attached to the insert holding member 72 using a fastening screw 93. The fastening screw 93 is inserted into the through hole 2 of the cutting insert 1.

[0042] The workpiece 80 rotates around an axis F. As shown in FIG. 8, the turning cutting tool 102 is disposed so that the central axis D of the shank 71 is perpendicular to the axis F. The turning cutting tool 102 is movable along a feed direction C. The turning cutting tool 102 may have the cutting insert 1 according to the first embodiment, or may have the cutting insert 1 according to other embodiments described later.

[0043] 9 is a schematic plan view showing the configuration of a first modified example of the cutting insert 1 according to the first embodiment. The region shown in FIG. 9 corresponds to the region shown in FIG.

[0044] As shown in FIG. 9, the angle between the reference line E and the main cutting edge portion 61 when viewed in a direction perpendicular to the upper surface 35 is defined as a first angle θ1. The first angle θ1 is 5° or more and 20° or less. The angle between the reference line E and the joint portion 4 when viewed in a direction perpendicular to the upper surface 35 is defined as a second angle θ2. The second angle θ2 may be greater than the first angle θ1. In this case, the corner cutting edge portion 63 can be extended upward. Therefore, the cutting insert of the first modified example is suitable for corner cutting.

[0045] The value obtained by subtracting the first angle θ1 from the second angle θ2 may be equal to or greater than 1°, or may be equal to or greater than 2°. The value obtained by subtracting the first angle θ1 from the second angle θ2 may be equal to or less than 5°, or may be equal to or less than 4°.

[0046] 10 is a schematic plan view showing the configuration of a second modified example of the cutting insert 1 according to the first embodiment. The region shown in FIG.

[0047] As shown in FIG. 10, the second angle θ2 may be smaller than the first angle θ1. In this case, the volume of the cutting member 7, which is relatively expensive, can be reduced. The first angle θ1 is 5° or more and 20° or less. The value obtained by subtracting the second angle θ2 from the first angle θ1 may be 1° or more, or may be 2° or more. The value obtained by subtracting the second angle θ2 from the first angle θ1 may be 5° or less, or may be 4° or less.

[0048] Next, a method for cutting the workpiece 80 using the cutting tool 101 for milling will be described. Fig. 11 is a side schematic view showing a state in which the workpiece 80 is cut using the cutting tool 101 for milling. The workpiece 80 is, for example, high-hardness steel. The Rockwell hardness of the workpiece 80 is, for example, 50HRC or more and 70HRC or less.

[0049] As shown in FIG. 7 and FIG. 11, the turning cutting tool 101 moves along the feed direction C while rotating around the rotation axis B. In the direction along the rotation axis B, the distance from the minor cutting edge 60 to the surface of the workpiece 80 corresponds to the axial cutting depth H. The turning cutting tool 101 moves along the feed direction C while rotating around the rotation axis B. As a result, the main cutting edge portion 61 and the minor cutting edge portion 62 of the cutting insert 1 cut the workpiece 80. The main cutting edge portion 61 is a blade that mainly cuts the workpiece 80. The minor cutting edge portion 62 is, for example, a wiper blade that performs finishing. In addition to the main cutting edge portion 61 and the minor cutting edge portion 62, the corner cutting edge portion 63 may be used to cut the workpiece 80.

[0050] In the above description, the material of the base member 30 is described as being cemented carbide, but the material of the base member 30 is not limited to cemented carbide. The base member 30 may be made of high-speed tool steel, ceramic, or the like. Similarly, the material of the cutting member 7 is not limited to cubic boron nitride. The cutting member 7 may be made of polycrystalline diamond, single crystal diamond, or the like.

[0051] Second embodiment Next, the configuration of the cutting insert 1 according to the second embodiment will be described. The cutting insert 1 according to the second embodiment differs from the cutting insert 1 according to the first embodiment mainly in that the shape of the joint portion 4 is curved, and other configurations are substantially the same as those of the cutting insert 1 according to the first embodiment. Below, the configurations different from the cutting insert 1 according to the first embodiment will be mainly described.

[0052] Fig. 12 is a schematic plan view showing the configuration of the cutting insert 1 according to the second embodiment. As shown in Fig. 12, the joint 4 may be curved when viewed in a direction perpendicular to the upper surface 35. Specifically, the joint 4 has a wave shape.

[0053] 13 is a schematic diagram illustrating the extension direction of the joint portion 4. When viewed in a direction perpendicular to the upper surface 35, the X-axis is parallel to the extension direction of the minor cutting edge portion 62, and the Y-axis is perpendicular to the extension direction of the minor cutting edge portion 62.

[0054] As shown in FIG. 13, the joint 4 has a first end A1 and a second end A2 when viewed in a direction perpendicular to the upper surface 35. The second end A2 is located opposite to the first end A1. The joint 4 is approximated by a regression line G. The regression line G is obtained using the least squares method. Specifically, the regression line G is obtained so that the sum of the squares of the distance between the position of the joint 4 in the Y direction and the regression line G is minimized. In a direction parallel to the X direction, the distance between the second end A2 and the first end A1 is divided into 100 parts. The regression line G is obtained using data of 101 points divided into 100 parts. When the joint 4 is curved when viewed in a direction perpendicular to the upper surface 35, the angle (second angle θ2) between the joint 4 and the reference line E is the angle between the regression line G and the reference line E.

[0055] Third embodiment Next, the configuration of the cutting insert 1 according to the third embodiment will be described. The cutting insert 1 according to the third embodiment differs from the cutting insert 1 according to the first embodiment mainly in that the clearance angle of the first clearance surface portion 51 is positive, and other configurations are substantially the same as those of the cutting insert 1 according to the first embodiment. Below, the configurations different from those of the cutting insert 1 according to the first embodiment will be mainly described.

[0056] Fig. 14 is a schematic plan view showing the configuration of the cutting insert 1 according to the third embodiment. As shown in Fig. 14, the cutting edge 60 of the cutting insert 1 according to the third embodiment has a major cutting edge portion 61, a minor cutting edge portion 62, and a corner cutting edge portion 63. The major cutting edge portion 61 is continuous with each of the minor cutting edge portion 62 and the corner cutting edge portion 63. The major cutting edge portion 61 is located between the minor cutting edge portion 62 and the corner cutting edge portion 63.

[0057] Fig. 15 is a schematic cross-sectional view taken along line XV-XV in Fig. 14. The cross section shown in Fig. 15 is perpendicular to the main cutting edge portion 61 and also perpendicular to the upper surface 35.

[0058] 15, the upper surface 35 is parallel to the mounting surface 36. The second region 41b of the first scooping surface portion 41 extends along the upper surface 35. The first region 41a of the first scooping surface portion 41 is inclined with respect to each of the second region 41b and the first flank surface portion 51. The first flank surface portion 51 is disposed along the first outer peripheral region 31. The first outer peripheral region 31 is continuous with the mounting surface 36.

[0059] In the cross section shown in FIG. 15, the angle between the upper surface 35 and the first outer peripheral region 31 is a third angle θ3. The third angle θ3 is smaller than 90°. The angle between the first region 41a of the first scooping surface portion 41 and the first clearance surface portion 51 is smaller than 90°. From another perspective, the clearance angle of the first clearance surface portion 51 is positive. In the cross section shown in FIG. 15, the angle between the mounting surface 36 and the first outer peripheral region 31 is a fourth angle θ4. The fourth angle θ4 is larger than 90°.

[0060] Fig. 16 is a schematic cross-sectional view taken along line XVI-XVI in Fig. 14. The cross section shown in Fig. 16 is perpendicular to the minor cutting edge portion 62 and perpendicular to the upper surface 35.

[0061] 16, the fourth region 42b of the second scooping surface portion 42 extends along the upper surface 35. The third region 42a of the second scooping surface portion 42 is inclined with respect to each of the fourth region 42b and the second flank surface portion 52. The second flank surface portion 52 is disposed along the second outer peripheral region 32. The second outer peripheral region 32 is continuous with the mounting surface 36.

[0062] In the cross section shown in FIG. 16, the angle between the upper surface 35 and the second outer peripheral region 32 is a fifth angle θ5. The fifth angle θ5 is smaller than 90°. The angle between the third region 42a of the second scooping surface portion 42 and the second clearance surface portion 52 is smaller than 90°. From another perspective, the clearance angle of the second clearance surface portion 52 may be positive. In the cross section shown in FIG. 16, the angle between the mounting surface 36 and the second outer peripheral region 32 is a sixth angle θ6. The sixth angle θ6 is larger than 90°.

[0063] (Fourth embodiment) Next, the configuration of the cutting insert 1 according to the fourth embodiment will be described. The cutting insert 1 according to the fourth embodiment differs from the cutting insert 1 according to the first embodiment mainly in that it has three cutting members 7, and other configurations are substantially the same as those of the cutting insert 1 according to the first embodiment. Below, the configurations different from those of the cutting insert 1 according to the first embodiment will be mainly described.

[0064] Fig. 17 is a schematic plan view showing the configuration of the cutting insert 1 according to the fourth embodiment. As shown in Fig. 17, the cutting insert 1 according to the fourth embodiment has one base member 30 and three cutting members 7. Each of the three cutting members 7 is joined to the base member 30. Each of the three cutting members 7 is formed of, for example, cubic boron nitride. The joints 4 between each of the three cutting members 7 and the base member 30 are formed of, for example, a brazing material such as silver brazing.

[0065] Each of the three cutting members 7 has a cutting edge 60. The cutting edge 60 has a major cutting edge portion 61, a minor cutting edge portion 62, and a corner cutting edge portion 63. The major cutting edge portion 61 is continuous with each of the minor cutting edge portion 62 and the corner cutting edge portion 63. The major cutting edge portion 61 is located between the minor cutting edge portion 62 and the corner cutting edge portion 63. As shown in FIG. 17, the shape of the cutting insert 1 according to the fourth embodiment may be three-fold symmetric with respect to the direction in which the through hole 2 extends. In other words, the shape of the cutting insert 1 after rotating 120° around the axis in the direction in which the through hole 2 extends is the same as the shape of the cutting insert 1 before the rotation.

[0066] Next, the effects of the turning cutting tool 101 and the turning cutting tool 102 according to this embodiment will be described.

[0067] According to the milling cutting tool 101 of this embodiment, the angle between the reference line E perpendicular to the rotation axis B and the joint 4 between the base member 30 and the cutting member 7 is 5° or more and 20° or less when viewed in a direction perpendicular to the upper surface 35. This increases the length of the joint 4 formed by, for example, a brazing material. Therefore, the cutting member 7 can be firmly joined to the base member 30. Therefore, in a highly efficient milling process in which the feed rate per cutting edge 60 is increased, the possibility that the cutting member 7 will fall off the base member 30 can be reduced.

[0068] When viewed in a direction perpendicular to the upper surface 35, the angle between the reference line E and the main cutting edge portion 61 is 5° or more and 20° or less. As a result, the length of contact of the main cutting edge 60 with the workpiece 80 is longer than when the angle between the reference line E and the main cutting edge portion 61 is greater than 20°. Therefore, the load per unit length on the main cutting edge 60 can be reduced. As a result, the feed rate per cutting edge 60 can be increased. Therefore, high-efficiency milling can be performed on high-hardness steel.

[0069] According to the milling cutting tool 101 of this embodiment, the joint 4 may be curved when viewed in a direction perpendicular to the upper surface 35. This allows the length of the joint 4 to be greater than when the joint 4 is linear. Therefore, the cutting member 7 can be firmly joined to the base member 30.

[0070] According to the cutting tool 102 for turning according to this embodiment, the angle between the reference line E perpendicular to the central axis D of the shank 71 and the joint 4 between the base member 30 and the cutting member 7 is 5° or more and 20° or less when viewed in a direction perpendicular to the upper surface 35. This increases the length of the joint 4 formed by, for example, a brazing material. Therefore, the cutting member 7 can be firmly joined to the base member 30. Therefore, in a highly efficient turning process in which the feed rate per cutting edge 60 is increased, the possibility that the cutting member 7 will fall off the base member 30 can be reduced.

[0071] When viewed in a direction perpendicular to the top surface 35, the angle between the reference line E and the main cutting edge portion 61 is 5° or more and 20° or less. As a result, the length of contact of the main cutting edge 60 with the workpiece 80 is longer than when the angle between the reference line E and the main cutting edge portion 61 is greater than 20°. Therefore, the load per unit length on the main cutting edge 60 can be reduced. As a result, the feed rate per cutting edge 60 can be increased. Therefore, high-efficiency turning can be performed on high-hardness steel.

[0072] According to the turning cutting tool 102 of this embodiment, the joint 4 may be curved when viewed in a direction perpendicular to the upper surface 35. This allows the length of the joint 4 to be greater than when the joint 4 is linear. Therefore, the cutting member 7 can be firmly joined to the base member 30.

[0073] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not by the embodiments described above, and is intended to include the equivalent meanings of the claims and all modifications within the scope of the claims. [Explanation of symbols]

[0074] 1 cutting insert, 2 through hole, 3 notch, 4 joint, 5 fifth outer peripheral region, 6 sixth outer peripheral region, 7 cutting member, 30 base member, 31 first outer peripheral region, 32 second outer peripheral region, 33 third outer peripheral region, 34 fourth outer peripheral region, 35 upper surface, 36 mounting surface, 37 outer peripheral surface, 40 rake face, 41 first rake face portion, 41a first region, 41b second region, 42 second rake face portion, 42a third region, 42b fourth region, 43 third rake face portion, 43a fifth region, 43b sixth region, 50 flank face, 51 first flank face portion, 52 second flank face portion, 53 third flank face portion, 60 cutting edge, 61 main cutting edge portion, 62 minor cutting edge portion, 63 corner cutting edge portion, 70 holder, 71 shank, 72 Insert retaining member, 73, 92 insert mounting groove, 80 workpiece, 90 body, 91 outer periphery, 93 fastening screw, 101 turning cutting tool, 102 turning cutting tool, A1 first end, A2 second end, B rotation axis, C feed direction, D central axis, E reference line, F axis line, G regression line, H axial cutting amount, P1 first intersection, P2 second intersection.

Claims

1. Cutting inserts and The cutting insert is attached to a body that is rotatable around a rotation axis, The cutting insert includes a base member and a cutting member joined to the base member, The cutting member has a main cutting edge portion, The cutting insert has a mounting surface that is attached to the body and an upper surface opposite to the mounting surface, When viewed in a direction perpendicular to the upper surface, the angle between the reference line perpendicular to the rotation axis and the joint between the base member and the cutting member is 5° or more and 20° or less. When viewed in a direction perpendicular to the upper surface, the angle between the reference line and the main cutting edge portion is 5° or more and 20° or less. The cutting member is a milling cutting tool having a secondary cutting edge portion that is connected to the main cutting edge portion and is parallel to the reference line when viewed in a direction perpendicular to the upper surface.

2. The cutting tool for milling according to claim 1, wherein the cutting member is formed of cubic boron nitride.

3. The milling cutting tool according to claim 1 or claim 2, wherein the joint is straight when viewed in a direction perpendicular to the upper surface.

4. The milling cutting tool according to claim 1 or claim 2, wherein the joint is curved when viewed in a direction perpendicular to the upper surface.

5. Cutting inserts and The holder to which the cutting insert is attached comprises, The holder includes a shank extending along the central axis, The cutting insert includes a base member and a cutting member joined to the base member, The cutting member has a main cutting edge portion, The cutting insert has a mounting surface that is attached to the holder and an upper surface opposite to the mounting surface, When viewed in a direction perpendicular to the upper surface, the angle between the reference line perpendicular to the central axis and the joint between the base member and the cutting member is 5° or more and 20° or less. When viewed in a direction perpendicular to the upper surface, the angle between the reference line and the main cutting edge portion is 5° or more and 20° or less. The cutting member is a turning cutting tool having a secondary cutting edge portion that is connected to the main cutting edge portion and is parallel to the reference line when viewed in a direction perpendicular to the upper surface.

6. The cutting tool for turning according to claim 5, wherein the cutting member is formed of cubic boron nitride.

7. The turning cutting tool according to claim 5 or claim 6, wherein the joint is straight when viewed in a direction perpendicular to the upper surface.

8. The turning cutting tool according to claim 5 or claim 6, wherein the joint is curved when viewed in a direction perpendicular to the upper surface.

Images