Cutting insert and processing method

Abstract

To provide a cutting insert that can improve a tool life.SOLUTION: A cutting insert includes a rake face, a flank face, and a cutting edge constituted of an edge line between the rake face and the flank face. The cutting edge has a first cutting edge part for corner processing, a second cutting edge part for drawing processing, a third cutting edge part for processing a finished surface, a first connecting / cutting edge part, and a second connecting / cutting edge part. The third cutting edge part is arranged between the first cutting edge part and the second cutting edge part. The first cutting edge part has a curve shape. A curvature radius of the first cutting edge part is 0.1 mm or more and 2.4 mm or less. The second cutting edge part has a linear shape or a curve shape whose curvature radius is 3 mm or more. The third cutting edge part has a linear shape or a curve shape whose curvature radius is 3 mm or more. The first connecting / cutting edge part and the second connecting / cutting edge part respectively have curve shapes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a cutting insert and a machining method. This application claims priority to Japanese Patent Application No. 2022-178143, filed on November 7, 2022. The entire contents of the Japanese patent application are incorporated herein by reference. [Background technology]

[0002] International Publication No. WO 2019 / 087496 (Patent Document 1) discloses a cutting insert having a rake face, a flank face, and a chamfer disposed between the rake face and the flank face. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 087496 Summary of the Invention

[0004] The cutting insert according to one embodiment of the present disclosure includes a rake face, a clearance face, and a cutting edge formed by a ridge between the rake face and the clearance face. The surface involved in cutting is made of at least one of a cBN-based sintered body, a diamond-based sintered body, ceramics, cermet, and cemented carbide. The cutting edge has a first cutting edge portion for corner machining, a second cutting edge portion for drawing, a third cutting edge portion for finishing surface machining, a first connecting cutting edge portion connecting the first cutting edge portion and the third cutting edge portion, and a second connecting cutting edge portion connecting the second cutting edge portion and the third cutting edge portion. The third cutting edge portion is disposed between the first cutting edge portion and the second cutting edge portion. The first cutting edge portion has a curved shape. The radius of curvature of the first cutting edge portion is 0.1 mm or more and 2.4 mm or less. The second cutting edge portion has a straight shape or a curved shape with a radius of curvature of 3 mm or more. The third cutting edge portion has a straight shape or a curved shape with a radius of curvature of 3 mm or more. Each of the first connecting cutting edge portion and the second connecting cutting edge portion has a curved shape. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic perspective view showing the configuration of a cutting insert according to the present embodiment. [Diagram 2] FIG. 2 is a schematic plan view showing the configuration of the cutting tool according to this 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 diagram showing a cross section perpendicular to a tangent line of the first cutting edge portion. [Figure 6] FIG. 6 is a schematic diagram showing a cross section perpendicular to a tangent line of the second cutting edge portion. [Figure 7] FIG. 7 is a schematic diagram showing a cross section perpendicular to a tangent line of the third cutting edge portion. [Figure 8] FIG. 8 is a schematic perspective view showing the first relief region. [Figure 9] FIG. 9 is a schematic perspective view showing the second relief region. [Figure 10] FIG. 10 is a schematic diagram showing the first processing method according to the present embodiment. [Figure 11] FIG. 11 is an enlarged schematic view showing the processed state. [Figure 12] FIG. 12 is a schematic side view showing the side rake angle of the second cutting edge portion. [Figure 13] FIG. 13 is a schematic diagram showing the second processing method according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] [Problem that this disclosure aims to solve] For example, when performing high-efficiency machining of hardened steel, the cutting resistance increases, making it easy for chipping to occur on the cutting edge, making it difficult to improve the tool life of the cutting insert.

[0007] An object of the present disclosure is to provide a cutting insert capable of improving tool life. [Effects of this disclosure] According to the present disclosure, a cutting insert capable of improving tool life can be provided. [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0008] (1) A cutting insert 100 according to one embodiment of the present disclosure includes a rake face 50, a clearance face 30, and a cutting edge 10 formed by a ridge line 20 between the rake face 50 and the clearance face 30. The surface involved in cutting is made of at least one of a cBN-based sintered body, a diamond-based sintered body, ceramics, cermet, and cemented carbide. The cutting edge 10 has a first cutting edge portion 1 for corner machining, a second cutting edge portion 2 for drawing, a third cutting edge portion 3 for finishing surface machining, a first connecting cutting edge portion 11 connecting the first cutting edge portion 1 and the third cutting edge portion 3, and a second connecting cutting edge portion 12 connecting the second cutting edge portion 2 and the third cutting edge portion 3. The third cutting edge portion 3 is disposed between the first cutting edge portion 1 and the second cutting edge portion 2. The first cutting edge portion 1 has a curved shape. The radius of curvature of the first cutting edge portion 1 is 0.1 mm or more and 2.4 mm or less. The second cutting edge portion 2 has a straight shape or a curved shape with a radius of curvature of 3 mm or more. The third cutting edge portion 3 has a straight shape or a curved shape with a radius of curvature of 3 mm or more. Each of the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 has a curved shape.

[0009] (2) According to the cutting insert 100 according to the above (1), the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 may each have a radius of curvature of 0.2 mm or more.

[0010] (3) According to the cutting insert 100 according to (1) or (2) above, the clearance angle of each of the first cutting edge portion 1, the second cutting edge portion 2 and the third cutting edge portion 3 may be equal to or greater than 3° and equal to or less than 20°.

[0011] (4) According to the cutting insert 100 according to any one of (1) to (3) above, the cutting edge 10 may have a fourth cutting edge portion 4 continuing to the first cutting edge portion 1. The first cutting edge portion 1 may be located between the third cutting edge portion 3 and the fourth cutting edge portion 4. The flank surface 30 may have a first flank region 71 and a second flank region 72. The first flank region 71 may continue to the fourth cutting edge portion 4. The second flank region 72 may continue to the first cutting edge portion 1, the second cutting edge portion 2, the third cutting edge portion 3, the first connecting cutting edge portion 11, and the second connecting cutting edge portion 12. The flank angle of the first flank region 71 may be 0°. The flank angle of the second flank region 72 may be 3° or more and 20° or less. When the area of ​​the first escape region 71 is the first area and the area of ​​the second escape region 72 is the second area, the value obtained by dividing the first area by the sum of the first area and the second area may be greater than or equal to 0.05 and less than or equal to 0.95.

[0012] (5) According to the cutting insert 100 according to any one of (1) to (3) above, the cutting edge 10 may have a fourth cutting edge portion 4 connected to the first cutting edge portion 1. The first cutting edge portion 1 may be located between the third cutting edge portion 3 and the fourth cutting edge portion 4. The ridge line 20 may have a first ridge region 81 and a second ridge region 82. The first ridge region 81 may include the fourth cutting edge portion 4. The second ridge region 82 may include the first cutting edge portion 1, the second cutting edge portion 2, the third cutting edge portion 3, the first connecting cutting edge portion 11, and the second connecting cutting edge portion 12. The clearance angle of the first ridge region 81 may be 0°. The clearance angle of the second ridge region 82 may be 3° or more and 20° or less. When the length of the first ridge region 81 is the first length and the length of the second ridge region 82 is the second length, the value obtained by dividing the first length by the sum of the first length and the second length may be greater than 0.05 and less than or equal to 0.95.

[0013] (6) According to the cutting insert 100 according to any one of (1) to (3) above, the cutting edge 10 may have a fourth cutting edge portion 4 connected to the first cutting edge portion 1. The first cutting edge portion 1 may be located between the third cutting edge portion 3 and the fourth cutting edge portion 4. The first cutting edge portion 1 may be composed of a first region 1a and a second region 1b connected to the first region 1a. The cutting edge 10 may be composed of a first cutting portion 91 and a second cutting portion 92. The first cutting portion 91 may be composed of the first region 1a, the second cutting edge portion 2, the third cutting edge portion 3, the first connecting cutting edge portion 11, and the second connecting cutting edge portion 12. The second cutting portion 92 may be composed of the second region 1b and the fourth cutting edge portion 4 connected to the second region 1b.

[0014] (7) A machining method according to one embodiment of the present disclosure is a machining method using the cutting insert 100 described in any one of (1) to (6) above. In a drawing process in which a workpiece is machined using the second cutting edge portion 2, a side rake angle of the second cutting edge portion 2 may be greater than or equal to -20° and less than or equal to 10°.

[0015] (8) A processing method according to one embodiment of the present disclosure is a processing method using the cutting insert 100 described in any one of (1) to (6) above. In the pushing process, the side cutting edge angle of the first cutting edge portion 1 may be 30° or more and less than 70°. In the pulling process, the side cutting edge angle of the second cutting edge portion 2 may be 70° or more and less than 89°. [Details of the embodiment of the present disclosure] A specific example of a cutting insert according to an embodiment of the present disclosure will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated.

[0016] FIG. 1 is a perspective schematic diagram showing the configuration of the cutting insert 100 according to this embodiment. As shown in FIG. 1, the cutting insert 100 according to this embodiment has a blade member 6 and a base metal 7. The blade member 6 is attached to the base metal 7. The blade member 6 is involved in cutting. The planar shape of the base metal 7 is not particularly limited, but is, for example, a rhombus. The blade member 6 is joined to an acute corner portion of the base metal 7. The base metal 7 is made of, for example, cemented carbide or cermet. The cutting insert 100 according to this embodiment is formed by joining the blade member 6 to an acute corner portion of the base metal 7, but the entire cutting insert 100 may be formed of the blade member 6.

[0017] The present disclosure is also applicable to cutting inserts 100 having polygonal shapes other than a diamond shape. Since the cutting edge shape is common, only a diamond-shaped cutting insert 100 is illustrated. A counterbore 8 is formed by partially recessing a part of the upper surface at an acute corner of the base metal 7. The blade member 6 is joined to the base metal 7 at the counterbore 8 by a joining means such as brazing.

[0018] The blade member 6 is composed of a cBN-based sintered body, a diamond-based sintered body, ceramics, cermet, or cemented carbide. The cBN-based sintered body is a sintered body containing cBN (cubic boron nitride) at a volume ratio of 10% to 99.9%. The diamond-based sintered body is a sintered body containing diamond at a volume ratio of 10% to 99.9%. The ceramic is not particularly limited, but for example, ceramics such as alumina (Al2O3), silicon nitride (Si3N4), and titanium carbide (TiC) can be preferably used. The cermet is not particularly limited, but for example, nitride-based cermet and carbide-based cermet can be preferably used.

[0019] The cutting insert 100 according to this embodiment has a rake face 50, a clearance face 30, a cutting edge 10, and a bottom surface 60. The cutting edge 10 is formed by a ridge line 20 between the rake face 50 and the clearance face 30. The ridge line 20 has the cutting edge 10, a first ridge line portion 21, and a second ridge line portion 22. The cutting edge 10 is a part of the ridge line 20. The cutting edge 10 has a first cutting edge portion 1 for corner machining, a second cutting edge portion 2 for drawing, a third cutting edge portion 3 for finishing surface machining, a first connecting cutting edge portion 11, a second connecting cutting edge portion 12, and a fourth cutting edge portion 4.

[0020] The first connecting cutting edge portion 11 connects the first cutting edge portion 1 and the third cutting edge portion 3. The first connecting cutting edge portion 11 is located between the first cutting edge portion 1 and the third cutting edge portion 3. The second connecting cutting edge portion 12 connects the second cutting edge portion 2 and the third cutting edge portion 3. The second connecting cutting edge portion 12 is located between the second cutting edge portion 2 and the third cutting edge portion 3. The third cutting edge portion 3 is disposed between the first cutting edge portion 1 and the second cutting edge portion 2. The third cutting edge portion 3 connects the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12. The fourth cutting edge portion 4 is connected to the first cutting edge portion 1. The first cutting edge portion 1 is located between the third cutting edge portion 3 and the fourth cutting edge portion 4.

[0021] Fig. 2 is a schematic plan view showing the configuration of a cutting tool according to this embodiment. The schematic plan view shown in Fig. 2 shows a state seen along a straight line perpendicular to the rake face 50. The viewpoint is at a position opposite to the rake face 50. The line of sight D is a direction from the rake face 50 toward the bottom surface 60.

[0022] As shown in FIG. 2, the first cutting edge portion 1 has a curved shape. The first cutting edge portion 1 is curved so as to be convex outward. The first cutting edge portion 1 is a corner cutting edge portion. When viewed along a straight line perpendicular to the rake face 50, the curvature radius of the first cutting edge portion 1 is 0.1 mm or more and 2.4 mm or less. The curvature radius of the first cutting edge portion 1 is not particularly limited, and may be 0.2 mm or more and 2.2 mm or less, 0.4 mm or more and 2.0 mm or less, or 0.6 mm or more and 1.8 mm or less.

[0023] 2, when viewed along a straight line perpendicular to the rake face 50, the second cutting edge portion 2 has a straight shape or a curved shape with a radius of curvature of 3 mm or more. When the second cutting edge portion 2 has a curved shape, the radius of curvature of the second cutting edge portion 2 may be 5 mm or more, 10 mm or more, 30 mm or more, or 50 mm or more. The radius of curvature of the second cutting edge portion 2 may be 150 mm or less, 130 mm or less, or 100 mm or less.

[0024] 2, when viewed along a straight line perpendicular to the rake face 50, the third cutting edge portion 3 has a straight shape or a curved shape with a radius of curvature of 3 mm or more. When the third cutting edge portion 3 has a curved shape, the radius of curvature of the third cutting edge portion 3 may be 5 mm or more, 10 mm or more, 20 mm or more, or 40 mm or more. The radius of curvature of the third cutting edge portion 3 may be 80 mm or less, 70 mm or less, or 60 mm or less.

[0025] The length of the second cutting edge portion 2 may be greater than the length of the third cutting edge portion 3. The length of the second cutting edge portion 2 may be 1.5 times or more, or may be 2 times or more, the length of the third cutting edge portion 3. The length of the second cutting edge portion 2 may be 10 times or less, or may be 5 times or less, the length of the third cutting edge portion 3. In addition, when the cutting edge portion is curved, the length of the cutting edge portion refers to the length when the curve is made into a straight line.

[0026] Each of the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 is curved, for example, so as to be convex outward. When viewed along a straight line perpendicular to the rake face 50, each of the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 has a radius of curvature of, for example, 0.2 mm or more. Each of the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 may have a radius of curvature of 0.3 mm or more, or 0.5 mm or more. Each of the first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 may have a radius of curvature less than 3 mm, or less than 2 mm. It is preferable that the first connecting cutting edge portion 11 and each of the adjacent first cutting edge portion 1 and third cutting edge portion 3 have different radii of curvature. It is preferable that the second connecting cutting edge portion 12 and each of the adjacent second cutting edge portion 2 and third cutting edge portion 3 have different radii of curvature. The first connecting cutting edge portion 11 and the second connecting cutting edge portion 12 are not structurally and functionally involved in cutting.

[0027] As shown in FIG. 2, each of the first ridge portion 21 and the second ridge portion 22 has a straight line shape. The first ridge portion 21 is continuous with the fourth cutting edge portion 4. The second ridge portion 22 is continuous with the second cutting edge portion 2. The length of the first ridge portion 21 may be greater than the length of the second ridge portion 22. The length of the first ridge portion 21 may be greater than the length of the fourth cutting edge portion 4. The length of the second ridge portion 22 may be greater than the length of the second cutting edge portion 2. Each of the first ridge portion 21 and the second ridge portion 22 is formed by a base metal 7. The cutting edge 10 is formed by a blade member 6.

[0028] The rake face 50 has a first rake face portion 51 and a second rake face portion 52. The first rake face portion 51 is formed of a blade member 6. The second rake face portion 52 is formed of a base metal 7. A through hole 5 is formed in the second rake face portion 52. The cutting edge 10 may be formed at two places on a diagonal line of a rhombus. The shape of the cutting edge 10 may be two-fold symmetric with respect to an axis line passing through the through hole 5. The angle formed by the straight line along the first ridge portion 21 and the straight line along the second ridge portion 22 (the apex angle θ8 of the first cutting edge portion 1) is, for example, 30° or more and 90° or less. The apex angle θ8 of the first cutting edge portion 1 may be, for example, 35°, 55°, 60°, 70°, or 80°.

[0029] 3 is an enlarged schematic diagram of region III in FIG. 1. As shown in FIG. 3, the flank 30 has a first flank portion 31, a second flank portion 32, a third flank portion 33, a fourth flank portion 34, a fifth flank portion 35, a sixth flank portion 36, a seventh flank portion 37, and a side portion 40. The first flank portion 31 is continuous with the first cutting edge portion 1. The second flank portion 32 is continuous with the second cutting edge portion 2. The third flank portion 33 is continuous with the third cutting edge portion 3.

[0030] The fourth flank portion 34 is connected to the fourth cutting edge portion 4. The fifth flank portion 35 is connected to the first connecting cutting edge portion 11. The sixth flank portion 36 is connected to the second connecting cutting edge portion 12. The seventh flank portion 37 is connected to each of the first flank portion 31 and the fourth flank portion 34. The first flank portion 31, the second flank portion 32, the third flank portion 33, the fourth flank portion 34, the fifth flank portion 35, the sixth flank portion 36, and the seventh flank portion 37 are configured by the blade member 6.

[0031] The side surface portion 40 has a first side surface region 41, a second side surface region 42, a third side surface region 43, a fourth side surface region 44, a fifth side surface region 45, a sixth side surface region 46, and a seventh side surface region 47. The first side surface region 41 is continuous with each of the first clearance surface portion 31 and the bottom surface 60. The second side surface region 42 is continuous with each of the second clearance surface portion 32, the second ridge portion 22, and the bottom surface 60. The third side surface region 43 is continuous with each of the third clearance surface portion 33 and the bottom surface 60.

[0032] The fourth side surface region 44 is continuous with the seventh flank portion 37. The fifth side surface region 45 is continuous with each of the fifth flank portion 35 and the bottom surface 60. The sixth side surface region 46 is continuous with each of the sixth flank portion 36 and the bottom surface 60. The seventh side surface region 47 is continuous with each of the fourth flank portion 34, the first ridge portion 21 and the bottom surface 60. The side surface portion 40 is formed of a base metal 7.

[0033] As shown in FIG. 3, the cutting edge 10 is composed of a first cutting portion 91 and a second cutting portion 92. The first cutting portion 91 is composed of a first region 1a of the first cutting edge portion 1, a second cutting edge portion 2, a third cutting edge portion 3, a first connecting cutting edge portion 11, and a second connecting cutting edge portion 12. The second cutting portion 92 is composed of a second region 1b of the first cutting edge portion 1 and a fourth cutting edge portion 4. The first cutting edge portion 1 is composed of a first region 1a and a second region 1b. The first region 1a is connected to the second region 1b. The first ridge portion 21 and the second ridge portion 22 do not constitute the cutting edge 10.

[0034] Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 2. As shown in Fig. 4, through hole 5 penetrates base metal 7. Through hole 5 opens to each of rake face 50 and bottom face 60. Seventh side region 47 is inclined perpendicularly to rake face 50. Fourth side region 44 is inclined relative to seventh side region 47. The inclination angle (fourth angle θ4) of fourth side region 44 relative to seventh side region 47 is, for example, 3° or more and 20° or less.

[0035] Fig. 5 is a schematic diagram showing a cross section perpendicular to a tangent line of the first cutting edge portion 1. As shown in Fig. 5, the first flank portion 31 is inclined inward with respect to a plane perpendicular to the rake face 50. The clearance angle (first angle θ1) of the first cutting edge portion 1 is the inclination angle of the first flank portion 31 with respect to the plane perpendicular to the rake face 50. The first angle θ1 may be, for example, 3° or more and 20° or less, 5° or more and 18° or less, or 7° or more and 15° or less.

[0036] Fig. 6 is a schematic diagram showing a cross section perpendicular to a tangent line of the second cutting edge portion 2. As shown in Fig. 6, the second flank portion 32 is inclined inward with respect to a plane perpendicular to the rake face 50. The clearance angle (second angle θ2) of the second cutting edge portion 2 is the inclination angle of the second flank portion 32 with respect to the plane perpendicular to the rake face 50. The second angle θ2 may be, for example, 3° or more and 20° or less, 5° or more and 18° or less, or 7° or more and 15° or less.

[0037] Fig. 7 is a schematic diagram showing a cross section perpendicular to a tangent line of the third cutting edge portion 3. As shown in Fig. 7, the third flank portion 33 is inclined inward with respect to a plane perpendicular to the rake face 50. The clearance angle (third angle θ3) of the third cutting edge portion 3 is the inclination angle of the third flank portion 33 with respect to the plane perpendicular to the rake face 50. The third angle θ3 may be, for example, 3° or more and 20° or less, 5° or more and 18° or less, or 7° or more and 15° or less.

[0038] FIG. 8 is a perspective schematic diagram showing the first clearance region 71. As shown in FIG. 8, the clearance face 30 has the first clearance region 71 and the second clearance region 72. The first clearance region 71 is composed of the fourth clearance face portion 34 and the seventh side region 47. The hatched region in FIG. 8 corresponds to the first clearance region 71. The clearance angle of the first clearance region 71 is 0°. In other words, the first clearance region 71 is perpendicular to the rake face 50. The clearance angle of the first clearance region 71 is the inclination angle of the first clearance region 71 with respect to a plane perpendicular to the rake face 50.

[0039] The ridge 20 has a first ridge region 81 and a second ridge region 82. The first ridge region 81 is composed of the fourth cutting edge portion 4 and the first ridge portion 21. In the case of the shape of the cutting insert 100 shown in FIG. 8, the length of the first ridge region 81 is the length from one corner of the cutting insert 100 to the end of the fourth cutting edge portion 4. The first ridge region 81 is continuous with the first relief region 71. The relief angle of the first ridge region 81 is 0°. The relief angle of the first ridge region 81 is the inclination angle of the first relief region 71 in a cross section perpendicular to the tangent of the first ridge region 81.

[0040] FIG. 9 is a perspective schematic diagram showing the second relief region 72. As shown in FIG. 9, the second relief region 72 is constituted by the region other than the first relief region 71 on the relief face 30. The second relief region 72 is constituted by the first relief face portion 31, the second relief face portion 32, the third relief face portion 33, the fifth relief face portion 35, the sixth relief face portion 36, the seventh relief face portion 37, the first side face region 41, the second side face region 42, the third side face region 43, the fourth side face region 44, the fifth side face region 45, and the sixth side face region 46. The hatched region in FIG. 9 corresponds to the second relief region 72. The relief angle of the second relief region 72 is 3° or more and 20° or less. The relief angle of the second relief region 72 is the inclination angle of the second relief region 72 with respect to a plane perpendicular to the rake face 50. The clearance angle of the second clearance region 72 corresponds to a fourth angle θ4 (see FIG. 4).

[0041] The second ridge region 82 is composed of the first cutting edge portion 1, the second cutting edge portion 2, the third cutting edge portion 3, the first connecting cutting edge portion 11, the second connecting cutting edge portion 12, and the second ridge portion 22. In the case of the shape of the cutting insert 100 shown in FIG. 9, the length of the second ridge region 82 is the length from another corner portion of the cutting insert 100 to the end portion of the first cutting edge portion 1. The second ridge region 82 is continuous with the second relief region 72. The relief angle of the second ridge region 82 is 3° or more and 20° or less. The relief angle of the second ridge region 82 is the inclination angle of the second relief region 72 in a cross section perpendicular to the tangent of the second ridge region 82.

[0042] When the area (surface area) of the first relief region 71 is the first area and the area (surface area) of the second relief region 72 is the second area, the value obtained by dividing the first area by the sum of the first area and the second area is, for example, 0.05 to 0.95. The value obtained by dividing the first area by the sum of the first area and the second area may be 0.1 to 0.9, or 0.2 to 0.8.

[0043] When the length of the first ridge region 81 is the first length and the length of the second ridge region 82 is the second length, the value obtained by dividing the first length by the sum of the first length and the second length is, for example, greater than 0.05 and equal to or less than 0.95. The value obtained by dividing the first length by the sum of the first length and the second length may be equal to or greater than 0.1 and equal to or less than 0.9, or may be equal to or greater than 0.2 and equal to or less than 0.8.

[0044] Next, a machining method according to the present embodiment will be described. In the machining method according to the present embodiment, a workpiece is machined using the cutting insert 100 according to the present embodiment.

[0045] FIG. 10 is a schematic diagram showing a first processing method according to the present embodiment. As shown in FIG. 10, the cutting insert 100 is attached to the holder 150 using a pressing member 160. The pressing member 160 has a main body portion 162 and an insertion portion 161. The insertion portion 161 is inserted into the through hole 5 of the cutting insert 100. The main body portion 162 has an attachment hole 163. A fastening screw 170 is inserted into the attachment hole 163. As a result, the pressing member 160 is fixed to the holder 150. The pressing member 160 pulls the cutting insert 100 toward the holder 150, thereby fixing the cutting insert 100 to the holder 150.

[0046] The cutting insert 100 according to this embodiment is capable of outer diameter machining. The workpiece 200 has an outer peripheral surface 201. The pressing process is a process performed while moving the cutting insert 100 in a first feed direction A1. The first feed direction A1 is a direction from the holder 150 toward the cutting insert 100. In the pressing process, the workpiece 200 is machined using the first cutting edge portion 1. The drawing process is a process performed while moving the cutting insert 100 in a second feed direction A2. The second feed direction A2 is a direction from the cutting insert 100 toward the holder 150. In the drawing process, the workpiece 200 is machined using the second cutting edge portion 2. Each of the first feed direction A1 and the second feed direction A2 is parallel to the rotation axis X of the workpiece 200. The workpiece 200 rotates in a rotation direction R around the rotation axis X.

[0047] FIG. 11 is an enlarged schematic diagram showing a machining state. The enlarged schematic diagram shown in FIG. 11 shows a state seen along a straight line perpendicular to the rake face 50. The cutting edge 10 cuts into the workpiece 200 with a cutting depth H. In the pushing process, the side cutting edge angle of the first cutting edge portion 1 is a fifth angle θ5. The fifth angle θ5 is an angle formed by a tangent to the first cutting edge portion 1 at a contact point between the outer peripheral surface 201 of the workpiece 200 and the first cutting edge portion 1, and a straight line perpendicular to the rotation axis X of the workpiece 200. The fifth angle θ5 is, for example, 30° or more and less than 70°. The fifth angle θ5 may be 35° or more and less than 65°, or 40° or more and less than 60°.

[0048] As shown in FIG. 11, the side cutting edge angle of the second cutting edge portion 2 in the drawing process is a sixth angle θ6. The sixth angle θ6 is an angle between a tangent to the second cutting edge portion 2 at a contact point between the outer peripheral surface 201 of the workpiece 200 and the second cutting edge portion 2 and a straight line perpendicular to the rotation axis X of the workpiece 200. The sixth angle θ6 is, for example, 70° or more and less than 89°. The sixth angle θ6 may be 73° or more and less than 86°, or 76° or more and less than 83°. The sixth angle θ6 may be greater than the fifth angle θ5.

[0049] Fig. 12 is a schematic side view showing the side rake angle of the second cutting edge portion 2. The schematic side view shown in Fig. 12 shows a state seen along a straight line perpendicular to the rotation axis X of the workpiece 200.

[0050] In the pull process for machining the workpiece 200 using the second cutting edge portion 2, the cutting insert 100 is fed in the second feed direction A2 along a direction parallel to the rotation axis X of the workpiece 200. As shown in FIG. 12, the side rake angle θ7 of the second cutting edge portion 2 is an inclination angle of the second cutting edge portion 2 with respect to a straight line C parallel to the rotation axis X of the workpiece 200, as viewed in a direction perpendicular to the rotation axis X of the workpiece 200. The side rake angle of the second cutting edge portion 2 is a seventh angle θ7. The seventh angle θ7 may be, for example, -20° or more and 10° or less. The seventh angle θ7 may be -15° or more and 8° or less, or -10° or more and 5° or less. In addition, when the cutting edge 10 advances beyond the rake face 50 during cutting, the side rake angle is a positive angle. Conversely, when the cutting edge 10 lags behind the rake face 50 during cutting, the side rake angle is a negative angle.

[0051] FIG. 13 is a schematic diagram showing a second machining method according to the present embodiment. As shown in FIG. 13, in the second machining method according to the present embodiment, end face machining and outer diameter machining may be performed. The workpiece 200 has an outer peripheral surface 201 and an end surface 202. The outer peripheral surface 201 is parallel to the rotation axis X of the workpiece 200. The end surface 202 is perpendicular to the rotation axis X of the workpiece 200. The pushing and corner machining are performed while moving the cutting insert 100 in the third feed direction B1. In the pushing and corner machining, the workpiece 200 is machined using the first cutting edge portion 1. The drawing is performed while moving the cutting insert 100 in the fourth feed direction B2. In the drawing, the workpiece 200 is machined using the second cutting edge portion 2. The third feed direction B1 is perpendicular to the rotation axis X of the workpiece 200. The fourth feed direction B2 is parallel to the rotation axis X of the workpiece 200.

[0052] Next, the effects of the cutting insert 100 and the machining method according to this embodiment will be described.

[0053] According to the cutting insert 100 of this embodiment, the cutting edge 10 has a first cutting edge portion 1 for corner machining, a second cutting edge portion 2 for drawing, a third cutting edge portion 3 for finishing surface machining, a first connecting cutting edge portion 11 connecting the first cutting edge portion 1 and the third cutting edge portion 3, and a second connecting cutting edge portion 12 connecting the second cutting edge portion 2 and the third cutting edge portion 3. The third cutting edge portion 3 is disposed between the first cutting edge portion 1 and the second cutting edge portion 2. The first cutting edge portion 1 has a curved shape. The radius of curvature of the first cutting edge portion 1 is 0.1 mm or more and 2.4 mm or less.

[0054] The cutting insert 100 according to this embodiment has a first cutting edge portion 1 for corner machining, so that it can perform corner machining and copy machining. Furthermore, the cutting insert 100 according to this embodiment has a second cutting edge portion 2 for drawing machining, so that it can perform drawing machining.

[0055] By increasing the side cutting edge angle θ6 of the second cutting edge portion 2, the feed force during drawing can be reduced. Therefore, damage to the cutting edge 10 can be suppressed. As a result, the tool life can be improved. Furthermore, the cutting insert 100 can be prevented from being pulled out of the holder 150 during drawing.

[0056] Furthermore, since the cutting insert 100 according to this embodiment has the third cutting edge portion 3 for finishing the surface, the roughness of the finished surface can be significantly improved. Therefore, a stable and good surface roughness can be obtained even in high-efficiency machining. Note that high-efficiency machining refers to a process in which the volume of the workpiece 200 that can be removed per unit time is, for example, 10 cm 3 This refers to processing that requires more than 1 / min.

[0057] According to the cutting insert 100 of this embodiment, the clearance angle of each of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3 may be 3° or more and 20° or less. By making the clearance angle of each of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3 a positive angle, the cutting resistance in the thrust force direction can be reduced. Therefore, the dimensional accuracy can be stably improved.

[0058] According to the cutting insert 100 according to this embodiment, the clearance face 30 may have a first clearance region 71 and a second clearance region 72. The clearance angle of the first clearance region 71 may be 0°. The clearance angle of the second clearance region 72 may be 3° or more and 20° or less. When the area of ​​the first clearance region 71 is a first area and the area of ​​the second clearance region 72 is a second area, the value obtained by dividing the first area by the second area may be 0.2 or more and 1 or less.

[0059] The first relief region 71 and the second relief region 72 are portions that come into contact with the holder 150. Compared with the second relief region 72, the first relief region 71 has a larger contact area with the holder 150. When the area of ​​the cutting insert 100 that comes into contact with the holder 150 becomes larger, the restraining performance between the holder 150 and the cutting insert 100 becomes higher. As a result, the cutting insert 100 becomes less likely to be pulled out from the holder 150. By setting the value obtained by dividing the first area by the second area to be 0.2 or more and 1 or less, the cutting insert 100 can be further prevented from being pulled out from the holder 150.

[0060] According to the cutting insert 100 according to the present embodiment, the ridge 20 may have a first ridge region 81 and a second ridge region 82. The clearance angle of the first ridge region 81 may be 0°. The clearance angle of the second ridge region 82 may be 3° or more and 20° or less. When the length of the first ridge region 81 is the first length and the length of the second ridge region 82 is the second length, the value obtained by dividing the first length by the second length may be greater than 0.5 and less than or equal to 1. This makes it possible to further suppress the cutting insert 100 from being pulled out of the holder 150, while suppressing chattering and waviness in high-efficiency machining of hardened steel.

[0061] According to the processing method of this embodiment, in the drawing process in which the workpiece 200 is processed using the second cutting edge portion 2, the side rake angle θ7 of the second cutting edge portion 2 may be -20° or more and 10° or less. This can reduce the load on the second cutting edge portion 2. As a result, it is possible to suppress damage to the second cutting edge portion 2. Therefore, the life of the cutting insert 100 can be further extended.

[0062] According to the processing method of this embodiment, the side cutting edge angle θ5 of the first cutting edge portion 1 may be 30° or more and less than 70° in the pushing process. The side cutting edge angle θ6 of the second cutting edge portion 2 may be 70° or more and less than 89° in the pulling process. This reduces the load on the first cutting edge portion 1 and the second cutting edge portion 2. As a result, damage to the first cutting edge portion 1 and the second cutting edge portion 2 can be suppressed. Therefore, the life of the cutting insert 100 can be further extended. EXAMPLES

[0063] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0064] Cutting inserts 100 (samples S1 to S32) having shapes shown in Tables 1 and 2 were produced and evaluated under the following conditions. The cutting inserts 100 of samples S1 to S32 each have a blade member 6 and a base metal 7 (see FIG. 1). In the cutting inserts 100 of samples S1 to S32, the material of the blade member 6 was a cBN-based sintered body.

[0065] In Tables 1 and 2, the first cutting edge, the second cutting edge, the third cutting edge, the first connecting portion, and the second connecting portion correspond to the first cutting edge portion 1, the second cutting edge portion 2, the third cutting edge portion 3, the first connecting cutting edge portion 11, and the second connecting cutting edge portion 12, respectively. The clearance angles are the clearance angles of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3. The seventh angle θ7 is the side rake angle of the second cutting edge portion 2 (see FIG. 12). The fifth angle θ5 is the side cutting edge angle of the first cutting edge portion 1 (see FIG. 11). The sixth angle θ6 is the side cutting edge angle of the second cutting edge portion 2 (see FIG. 11).

[0066] The cutting inserts 100 of Samples S1 to S22 and Samples S26 to S32 are examples. In the cutting inserts 100 of Samples S1 to S22 and Samples S26 to S32, the radius of curvature of the first cutting edge portion 1 was 0.1 mm or more and 2.4 mm or less. The second cutting edge portion 2 was linear or curved with a radius of curvature of 3 mm or more. The third cutting edge portion 3 was linear or curved with a radius of curvature of 3 mm or more.

[0067] The cutting inserts 100 of Samples S23 to S25 are comparative examples. In the cutting insert 100 of Sample S23, the radius of curvature of the first cutting edge portion 1 was 0.09 mm. In the cutting insert 100 of Sample S24, the second cutting edge portion 2 was curved with a radius of curvature of 2 mm. In the cutting insert 100 of Sample S25, the third cutting edge portion 3 was curved with a radius of curvature of 2 mm.

[0068] With the cutting insert 100 attached to the holder 150, the following workpiece 200 was machined under the following cutting conditions. The cutting time (tool life) was evaluated when the cutting edge 10 of the cutting insert 100 was chipped or when the ten-point average roughness Rz of the machined surface exceeded 12.5 μm, whichever was shorter. (Cutting Geometry) Cutting edge inclination angle = -5°, front relief angle = 5°, side relief angle = 5°, front cutting edge angle = 5° (work material) High-hardness steel SUJ2 (HRC62), diameter = 85 mm, length = 200 mm (Cutting conditions) Cutting speed: V = 200 m / min, Feed rate: f = 0.5 mm / revolution, Depth of cut: ap = 0.2 mm, Wet (Processing form) External machining (pushing and drawing) The results are summarized in Tables 1 and 2.

[0069] [Table 1]

[0070] As shown in Table 1, it was confirmed that the cutting inserts 100 of Samples S1 to S22 had longer tool life than the cutting inserts 100 of Samples S23 to S25.

[0071] In the cutting inserts 100 of Samples S8 and S19, the clearance angles of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3 are 3° and 2°, respectively. As shown in Table 1, it was confirmed that the cutting inserts 100 have a long tool life when the clearance angles of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3 are 3° or more.

[0072] In the cutting inserts 100 of Samples S9 and S20, the clearance angles of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3 are 20° and 21°, respectively. As shown in Table 1, it was confirmed that the cutting inserts 100 have a long tool life when the clearance angles of the first cutting edge portion 1, the second cutting edge portion 2, and the third cutting edge portion 3 are 20° or less.

[0073] In the cutting inserts 100 of samples S10 and S21, the side rake angles (seventh angle θ7) of the second cutting edge portion 2 are 10° and 11°, respectively. As shown in Table 1, it was confirmed that the cutting inserts 100 have a long tool life when the seventh angle θ7 is 10° or less.

[0074] In the cutting inserts 100 of Samples S11 and S22, the side rake angles (seventh angle θ7) of the second cutting edge portion 2 are -20° and -21°, respectively. As shown in Table 1, it was confirmed that the cutting inserts 100 have a long tool life when the seventh angle θ7 is -20° or more.

[0075] In the cutting inserts 100 of samples S12 and S13, the side cutting edge angle (fifth angle θ5) of the first cutting edge portion 1 is 30° and 70°, respectively. As shown in Table 1, it was confirmed that the cutting inserts 100 have a long tool life when the fifth angle θ5 is 30° or more and 70° or less.

[0076] In the cutting inserts 100 of samples S14 and S15, the side cutting edge angle (sixth angle θ6) of the second cutting edge portion 2 is 70° and 89°, respectively. As shown in Table 1, it was confirmed that the cutting inserts 100 have a long tool life when the sixth angle θ6 is 70° or more and 89° or less.

[0077] In the cutting inserts 100 of samples S26 to S32, the first clearance region 71 has a clearance angle of 0°. The second clearance region 72 has a clearance angle of 3° or more and 20° or less. The area of ​​the first clearance region 71 is a first area SN. The area of ​​the second clearance region 72 is a second area SP. The value obtained by dividing the first area SN by the sum of the first area SN and the second area SP is 0.05 or more and 0.95 or less. The first ridge region 81 has a clearance angle of 0°. The second ridge region 82 has a clearance angle of 3° or more and 20° or less. The length of the first ridge region 81 is a first length LN. The length of the second ridge region 82 is a second length LP. The value obtained by dividing the first length LN by the sum of the first length LN and the second length LP is 0.05 or more and 0.95 or less.

[0078] [Table 2]

[0079] In the cutting inserts 100 of Samples S27 and S28, the clearance angles of the second relief region 72 are 3° and 20°, respectively. As shown in Table 2, it was confirmed that the cutting inserts 100 have a long tool life when the clearance angle of the second relief region 72 is 3° or more and 20° or less.

[0080] As shown in Table 2, it was confirmed that the cutting insert 100 has a long tool life when the value obtained by dividing the first area SN by the sum of the first area SN and the second area SP is 0.05 or more and 0.95 or less.

[0081] As shown in Table 2, it was confirmed that the cutting insert 100 has a long tool life when the value obtained by dividing the first length LN by the sum of the first length LN and the second length LP is 0.05 or more and 0.95 or less.

[0082] The embodiments and examples 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]

[0083] 1 first cutting edge portion, 1a first region, 1b second region, 2 second cutting edge portion, 3 third cutting edge portion, 4 fourth cutting edge portion, 5 through hole, 6 blade member, 7 base metal, 8 countersink portion, 10 cutting edge, 11 first connecting cutting edge portion, 12 second connecting cutting edge portion, 20 ridge line, 21 first ridge line portion, 22 second ridge line portion, 30 flank surface, 31 first flank surface portion, 32 second flank surface portion, 33 third flank surface portion, 34 fourth flank surface portion, 35 fifth flank surface portion, 36 sixth flank surface portion, 37 seventh flank surface portion, 40 side surface portion, 41 first side surface region, 42 second side surface region, 43 third side surface region, 44 fourth side surface region, 45 fifth side surface region, 46 sixth side surface region, 47 seventh side surface region, 50 rake surface, 51 first rake surface portion, 52 Second rake face portion, 60 bottom surface, 71 first relief region, 72 second relief region, 81 first ridge region, 82 second ridge region, 91 first cutting processing portion, 92 second cutting processing portion, 100 cutting insert, 150 holder, 160 pressing member, 161 insertion portion, 162 main body portion, 163 mounting hole, 170 fastening screw, 200 workpiece, 201 outer peripheral surface, 202 end surface, A1 first feed direction, A2 second feed direction, B1 third feed direction, B2 fourth feed direction, C straight line, D line of sight, LN first length, LP second length, R rotation direction, SN first area, SP second area, X rotation axis, θ1 first angle, θ2 second angle, θ3 third angle, θ4 fourth angle, θ5 fifth angle, θ6 sixth angle, θ7 side rake angle, θ8 Vertical angle.

Claims

1. The surface involved in cutting is made of at least one of a cBN-based sintered body, a diamond-based sintered body, a ceramic, a cermet, and a cemented carbide; A cutting insert including a rake face, a flank face, and a cutting edge formed by a ridge line between the rake face and the flank face, The cutting edge is A first cutting edge portion for corner machining; A second cutting edge portion for drawing; A third cutting edge portion for finishing surface processing; a first connecting cutting edge portion connecting the first cutting edge portion and the third cutting edge portion; A second connecting cutting edge portion connecting the second cutting edge portion and the third cutting edge portion, The third cutting edge portion is disposed between the first cutting edge portion and the second cutting edge portion, The first cutting edge portion has a curved shape, The radius of curvature of the first cutting edge portion is 0.1 mm or more and 2.4 mm or less, The second cutting edge portion has a straight line shape or a curved shape with a curvature radius of 3 mm or more, The third cutting edge portion has a straight line shape or a curved shape with a curvature radius of 3 mm or more, Each of the first connecting cutting edge portion and the second connecting cutting edge portion has a curved shape, The cutting edge has a fourth cutting edge portion connected to the first cutting edge portion, The first cutting edge portion is located between the third cutting edge portion and the fourth cutting edge portion, The relief surface has a first relief region and a second relief region, The first relief region is continuous with the fourth cutting edge portion, The second relief region is continuous with the first cutting edge portion, the second cutting edge portion, the third cutting edge portion, the first connecting cutting edge portion, and the second connecting cutting edge portion, The clearance angle of the first clearance region is 0°; The clearance angle of the second clearance region is equal to or greater than 3° and equal to or less than 20°, When an area of ​​the first relief region is a first area and an area of ​​the second relief region is a second area, a value obtained by dividing the first area by a sum of the first area and the second area is 0.05 or more and 0.95 or less.

2. The surface involved in cutting is made of at least one of a cBN-based sintered body, a diamond-based sintered body, a ceramic, a cermet, and a cemented carbide; A cutting insert including a rake face, a flank face, and a cutting edge formed by a ridge line between the rake face and the flank face, The cutting edge is A first cutting edge portion for corner machining; A second cutting edge portion for drawing; A third cutting edge portion for finishing surface processing; a first connecting cutting edge portion connecting the first cutting edge portion and the third cutting edge portion; A second connecting cutting edge portion connecting the second cutting edge portion and the third cutting edge portion, The third cutting edge portion is disposed between the first cutting edge portion and the second cutting edge portion, The first cutting edge portion has a curved shape, The radius of curvature of the first cutting edge portion is 0.1 mm or more and 2.4 mm or less, The second cutting edge portion has a straight line shape or a curved shape with a curvature radius of 3 mm or more, The third cutting edge portion has a straight line shape or a curved shape with a curvature radius of 3 mm or more, Each of the first connecting cutting edge portion and the second connecting cutting edge portion has a curved shape, The cutting edge has a fourth cutting edge portion connected to the first cutting edge portion, The first cutting edge portion is located between the third cutting edge portion and the fourth cutting edge portion, The ridge line has a first ridge line region and a second ridge line region, The first ridge region includes the fourth cutting edge portion, The second ridge region includes the first cutting edge portion, the second cutting edge portion, the third cutting edge portion, the first connecting cutting edge portion, and the second connecting cutting edge portion, The clearance angle of the first ridge region is 0°; a clearance angle of the second ridge region is equal to or greater than 3° and equal to or less than 20°; When a length of the first ridge region is a first length and a length of the second ridge region is a second length, a value obtained by dividing the first length by a sum of the first length and the second length is greater than 0.05 and not greater than 0.

95.

3. The surface involved in cutting is made of at least one of a cBN-based sintered body, a diamond-based sintered body, a ceramic, a cermet, and a cemented carbide; A cutting insert including a rake face, a flank face, and a cutting edge formed by a ridge line between the rake face and the flank face, The cutting edge is A first cutting edge portion for corner machining; A second cutting edge portion for drawing; A third cutting edge portion for finishing surface processing; a first connecting cutting edge portion connecting the first cutting edge portion and the third cutting edge portion; A second connecting cutting edge portion connecting the second cutting edge portion and the third cutting edge portion, The third cutting edge portion is disposed between the first cutting edge portion and the second cutting edge portion, The first cutting edge portion has a curved shape, The radius of curvature of the first cutting edge portion is 0.1 mm or more and 2.4 mm or less, The second cutting edge portion has a straight line shape or a curved shape with a curvature radius of 3 mm or more, The third cutting edge portion has a straight line shape or a curved shape with a curvature radius of 3 mm or more, Each of the first connecting cutting edge portion and the second connecting cutting edge portion has a curved shape, The cutting edge has a fourth cutting edge portion connected to the first cutting edge portion, The first cutting edge portion is located between the third cutting edge portion and the fourth cutting edge portion, The first cutting edge portion includes a first region and a second region connected to the first region, The cutting edge includes a first cutting portion and a second cutting portion, The first cutting processing portion includes the first region, the second cutting edge portion, the third cutting edge portion, the first connecting cutting edge portion, and the second connecting cutting edge portion, The second cutting portion comprises the second region and the fourth cutting edge portion connected to the second region.

4. The cutting insert according to claim 1 , wherein each of the first connecting cutting edge portion and the second connecting cutting edge portion has a radius of curvature of 0.2 mm or more.

5. The cutting insert according to claim 1 , wherein each of the first cutting edge portion, the second cutting edge portion and the third cutting edge portion has a clearance angle of 3° or more and 20° or less.

Images