Cutting insert, rotary tool, and method for manufacturing machined product

Abstract

The present invention increases the durability of a base portion to set a cutting condition with a large feeding amount. A first end face of the base portion comprises, when seen from the tip-end side in a direction along a rotational axis: a first region positioned rearwardly in a rotational direction and radially outside with respect to a second rear face of a cutting portion; and a second region positioned rearwardly in the rotational direction with respect to a second front face of the cutting portion and radially inside of the first region. When a virtual plane including the second rear face is a reference surface, the first region includes a first portion in which the width of a region sandwiched between the reference surface and a first rear face of the base portion gradually increases radially outward, and the second region includes a second portion in which the width of a region sandwiched between the reference surface and the first rear face gradually increases radially inward.

Description

[Technical Field]

[0001] The present disclosure relates to a cutting insert used in milling a workpiece, a rotary tool, and a method for manufacturing a machined product. [Background technology]

[0002] For example, rotary tools described in Patent Documents 1 to 3 are known as rotary tools used for milling workpieces made of metal or the like. Each of the rotary tools described in Patent Documents 1 to 3 has a holder and a cutting insert held by the holder. The cutting insert in the rotary tool described in Patent Document 3 has a base portion called a cartridge in Patent Document 3 and a cutting portion called a cutting tip in Patent Document 3. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-284010 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-023632 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-011612 Summary of the Invention

[0004] A cutting insert according to the present disclosure is a cutting insert for use in a rotary tool rotatable around a rotation axis, and includes a base portion and a cutting portion. The base portion has a first rearward surface located rearward in the direction of rotation of the rotary tool, a first forward surface located radially outward and facing forward in the direction of rotation, and a first end surface located toward the tip end along the rotation axis and connected to the first rearward surface and the first forward surface. The cutting portion has a flat second rearward surface joined to the first forward surface, a flat second forward surface located opposite the second rearward surface, a second end surface located toward the tip end and connected to the second rearward surface and the second forward surface, and a cutting edge located at an intersection of the second forward surface and the second end surface. When viewed from the tip end side, the first end surface has a first region located rearward of the second rearward surface in the direction of rotation and radially outward, and a second region located rearward of the second forward surface in the direction of rotation and radially inward of the first region. When an imaginary plane including the second rear surface is defined as a reference plane, the first region has a first portion where the width of a region sandwiched between the reference plane and the first rear surface gradually increases radially outward, and the second region has a second portion where the width of a region sandwiched between the reference plane and the first rear surface gradually increases radially inward. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic perspective view of a rotary tool according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic view of the rotary tool shown in FIG. 1 as viewed from its tip end side. [Figure 3] FIG. 2 is a schematic side view of the rotary tool shown in FIG. 1. [Figure 4] FIG. 3 is an enlarged view of part IV in FIG. 2. [Figure 5] FIG. 1 is a schematic perspective view of a cutting insert according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic plan view of the cutting insert shown in FIG. 5. [Figure 7] FIG. 6 is a schematic plan view of the cutting insert shown in FIG. 5. [Figure 8] FIG. 6 is a schematic plan view of the cutting insert shown in FIG. 5. [Figure 9] FIG. 9 is a schematic enlarged view of a part of the cutting insert shown in FIG. 8. [Figure 10] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. [Figure 11] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. [Figure 12] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006] Hereinafter, a cutting insert, a cutting tool, and a method for manufacturing a machined product according to embodiments of the present disclosure will be described in detail with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the components necessary for explaining the embodiments in a simplified form. Therefore, the cutting insert and the rotary tool according to embodiments of the present disclosure may include any components not shown in the drawings referred to. Furthermore, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components and the dimensional ratios of each member.

[0007] In this disclosure, the rotation axis refers to the rotation axis (rotation axis center) of the rotary tool. The radially outer side refers to the direction or side away from the rotation axis in the radial direction, and is synonymous with the outer circumferential side. The radially inner side refers to the direction or side approaching the rotation axis in the radial direction. The radial direction refers to the direction perpendicular to the rotation axis. The perpendicular direction is not limited to being strictly perpendicular, but means that an error of about ±5 degrees is allowed. The parallel direction is not limited to being strictly parallel, but means that an error of about ±5 degrees is allowed. Furthermore, in this disclosure, for convenience, the positional relationship of each part of the cutting insert is defined based on the state in which the cutting insert is held (fixed) in the pocket of the holder.

[0008] <Rotary tools> A rotary tool 10 according to an embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is a schematic perspective view of the rotary tool 10 according to an embodiment of the present disclosure. Fig. 2 is a schematic view of the rotary tool 10 shown in Fig. 1 as seen from its tip end side. Fig. 3 is a schematic side view of the rotary tool shown in Fig. 1. Fig. 4 is an enlarged view of part IV in Fig. 2.

[0009] 1 to 3 , a rotary tool 10 according to an embodiment of the present disclosure is a tool used for milling a workpiece W (see FIG. 10 ) and is rotatable around a rotation axis S. The rotary tool 10 may have a holder 12 attached to a spindle of a processing machine such as a milling machine, and a plurality of cutting inserts 14 held by the holder 12. The holder 12 and the cutting inserts 14 are used in the rotary tool 10.

[0010] The holder 12 may have a cylindrical shape extending from the front end 12a to the rear end 12b along the rotation axis S. Examples of materials for the holder 12 include metals such as stainless steel, carbon steel, cast iron, and aluminum alloys. A plurality of pockets 16 may be provided at intervals in the circumferential direction on the outer circumferential surface of the holder 12. The plurality of pockets 16 may be arranged at equal intervals in the circumferential direction, or may be arranged at uneven intervals in the circumferential direction. The plurality of pockets 16 may be located on the front end 12a side of the holder 12. The number of pockets 16 may be one.

[0011] As shown in the example shown in FIGS. 3 and 4 , the pocket 16 may be open on a side of a tip end PDa in the direction PD parallel to the rotation axis S. The pocket 16 may be open on a radially outer side RDe. The pocket 16 may have a bottom surface 16a located on a radially inner side RDi, and a first inner side surface 16b and a second inner side surface 16c rising from both sides of the bottom surface 16a toward the radially outer side RDo. The first inner side surface 16b of each pocket 16 may be located forward in the rotation direction T, in other words, on the side of the rotation direction T. The second inner side surface 16c of each pocket 16 may be located rearward in the rotation direction T, in other words, on the opposite side of the rotation direction T. The second inner side surface 16c of each pocket 16 may have a curved shape (convex shape) protruding forward in the rotation direction T. In other words, the second inner side surface 16c of each pocket 16 may have a convex portion 16d protruding forward in the rotation direction T.

[0012] 1 to 3, a cutting insert 14 may be positioned in each pocket 16 of the holder 12. The cutting insert 14 may be positioned only in one or more selected pockets 16 of the holder 12. The cutting insert 14 may also be fixed to the pocket 16 of the holder 12 by a fixing screw 18. The cutting insert 14 may also be fixed to the pocket 16 of the holder 12 by a clamping member.

[0013] The rotary tool 10 may have an adjustment mechanism 20 for adjusting the position of the cutting insert 14 relative to the pocket 16 of the holder 12. The adjustment mechanism 20 may be located adjacent to the cutting insert 14 in the pocket 16 of the holder 12. The adjustment mechanism 20 may be fixed to the pocket 16 of the holder 12 by a set screw 22.

[0014] <Cutting insert> The configuration of the cutting insert 14 according to the embodiment of the present disclosure will be described with reference to Figures 5 to 8. Figure 5 is a schematic perspective view of the cutting insert 14 according to the embodiment of the present disclosure. Figures 6 to 8 are schematic plan views of the cutting insert 14 shown in Figure 5. Figure 6 is a plan view (side view) seen in a direction from the radially outer side RDe toward the rotation axis S. Figure 7 is a plan view of the cutting insert 14 shown in Figure 5 seen from the front in the rotation direction T. Figure 8 is a plan view (front view) of the cutting insert 14 shown in Figure 5 seen from the tip side along the rotation axis S.

[0015] 5 to 8 , the cutting insert 14 according to the embodiment of the present disclosure may have a base portion 24 for attachment to the pocket 16 of the holder 12. The base portion 24 may have a recess that opens toward the radially outward side RDe and toward the side of the tip PDa in the direction PD parallel to the rotation axis S. The base portion 24 may have a main wall portion 24a that can abut against the bottom surface 16a of the pocket 16 of the holder 12.

[0016] The base portion 24 may have a first outer wall portion 24b facing the first inner surface 16b of the pocket 16 of the holder 12. The first outer wall portion 24b of the base portion 24 may extend radially outward RDe from the main wall portion 24a. The base portion 24 may have a second outer wall portion 24c that can abut against the second inner surface 16c of the pocket 16 of the holder 12. The second outer wall portion 24c of the base portion 24 may extend radially outward from the main wall portion 24a. The second outer wall portion 24c of the base portion 24 may be located rearward in the rotational direction T with respect to the first outer wall portion 24b. In addition, the base portion 24 may have a rising wall portion 24d that rises from the second outer wall portion 24c to the first outer wall portion 24b on the side of a rear end PDb in the direction PD parallel to the rotation axis S.

[0017] The main wall portion 24a, the first outer wall portion 24b, the second outer wall portion 24c, and the rising wall 24d are each a component of the outer edge surface of the base portion 24, and each have a thickness.

[0018] The base portion 24 may have a through hole 26 for inserting the fixing screw 22. The through hole 26 may be open toward the radially inner side RDi and the radially outer side RDe. The opening of the through hole 26 toward the radially inner side RDi may be located on the wall surface of the main wall portion 24a. In addition, the first outer wall portion 24b of the base portion 24 may have a notch 28 for avoiding interference with the fixing screw 22.

[0019] 8 , the base portion 24 may have a first rear surface 30 located rearward in the rotational direction T, and most of the first rear surface 30 may be formed by the outer surface of the second outer wall portion 24c of the base portion 24. The first rear surface 30 of the base portion 24 may extend from the front end PDa side to the rear end PDb side in the direction PD parallel to the rotation axis S. The direction PD parallel to the rotation axis S is an example of a direction along the rotation axis S.

[0020] The base portion 24 may be provided with a recess 32 that is open forward in the rotational direction T and radially outward RDe. The recess 32 may be located on the radially outward RDe of the base portion 24, on the side of the tip PDa in the direction PD parallel to the rotation axis S. The bottom surface of the recess 32 may be a first front surface 34A that faces forward in the rotational direction T. In other words, the base portion 24 may have the first front surface 34A that faces forward in the rotational direction T. The first front surface 34A of the base portion 24 may be located on the radially outward RDe of the base portion 24, on the side of the tip PDa in the direction PD parallel to the rotation axis S.

[0021] The base portion 24 may have a first end surface 36 located on the side of the tip PDa in the direction PD parallel to the rotation axis S. The first end surface 36 may be formed by end surfaces of the main wall portion 24a, the first outer wall portion 24b, and the second outer wall portion 24c on the side of the tip PDa in the direction PD parallel to the rotation axis S. The first end surface 36 of the base portion 24 may be connected to the first rear surface 30 and the first front surface 34A.

[0022] Examples of materials for the base portion 24 include stainless steel, carbon steel, and tool steel.

[0023] The cutting insert 14 may have a cutting portion 38 that contacts the workpiece W to perform cutting. The cutting portion 38 may be joined to a first front surface 34A, which is the bottom surface of the recess 32 of the base portion 24, by a joining material such as a brazing material. The recess 32 may have a lateral wall surface 34B located radially inward RDi from the first front surface 34A, and the cutting portion 38 may be joined to the lateral wall surface 34B in addition to the first front surface 34A. Alternatively, the recess 32 may have a rear wall surface 34C located toward a rear end PDb from the first front surface 34A in the direction PD parallel to the rotation axis S, and the cutting portion 38 may be joined to the rear wall surface 34C in addition to the first front surface 34A and the lateral wall surface 34B. The cutting portion 38 may have a generally polygonal plate shape, such as a generally triangular plate shape.

[0024] As in the example shown in Figures 5 to 8, the cutting portion 38 may have a flat second rearward surface 40 joined to the first forward surface 34A of the base portion 24. The second rearward surface 40 of the cutting portion 38 may face rearward in the direction of rotation T. In other words, the second rearward surface 40 of the cutting portion 38 may be located rearward in the direction of rotation T of the cutting portion 38. The cutting portion 38 may also have a flat second forward surface 42 located opposite the second rearward surface 40. The second forward surface 42 of the cutting portion 38 may face forward in the direction of rotation T. In other words, the second forward surface 42 of the cutting portion 38 may be located forward in the direction of rotation T of the cutting portion 38.

[0025] The cutting portion 38 may have a second end surface 44 located on the side of the tip end PDa in the direction PD parallel to the rotation axis S. The second end surface 44 of the cutting portion 38 may be connected to the second rear surface 40 and the second forward surface 42. The cutting portion 38 may also have an outer surface 46 located on the radially outer side RDe. The outer surface 46 of the cutting portion 38 may be connected to the second rear surface 40 and the second forward surface 42.

[0026] The cutting portion 38 may have a bottom cutting edge 48 as a first cutting edge located at the intersection of the second forward surface 42 and the second end surface 44. The cutting portion 38 may have a peripheral cutting edge 50 as a second cutting edge located at the intersection of the second forward surface 42 and the outer surface 46. The bottom cutting edge 48 and the peripheral cutting edge 50 may be connected via a corner portion 52. The corner portion 52 of the cutting portion 38 may function as a corner edge.

[0027] Examples of materials for the cutting portion 38 include hard materials such as cBN (Cubic Boron Nitride) and PCD (Polycrystalline Diamond). The surface of the cutting portion 38 may be coated with a film using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of materials for the film include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al2O3).

[0028] As in the examples shown in FIGS. 5 to 8 , the base portion 24 may be provided with a chip pocket 54 for discharging chips. The recess 32 may be located within the chip pocket 54. The chip pocket 54 may be located forward of the cutting portion 38 in the rotational direction T. The base portion 24 may also be provided with an injection hole 56 for injecting coolant (cooling medium) toward the cutting portion 38. The number of injection holes 56 may be one or more. The injection hole 56 may be connected to a coolant supply source via a coolant passage provided inside the holder 12.

[0029] Another configuration of the cutting insert 14 according to the embodiment of the present disclosure will be described with reference to Figures 6, 8, and 9. Figure 9 is a schematic enlarged view of a portion of the cutting insert 14 shown in Figure 8.

[0030] As shown in the examples in FIGS. 8 and 9, the first end surface 36 of the base portion 24 may have a first region F1. When viewed from the side of the tip end PDa in the direction PD parallel to the rotation axis S (see FIG. 1), the first region F1 may include a portion located rearward in the rotation direction T with respect to the second rear surface 40 of the cutting portion 38, and may be located radially outward RDe of the base portion 24. When viewed from the side of the tip end PDa in the direction PD parallel to the rotation axis S, the first end surface 36 of the base portion 24 may have a second region F2 located rearward in the rotation direction T with respect to the second front surface 42 of the cutting portion 38 and radially inward RDi of the first region F1. In the example shown in FIG. 9, the first region F1 and the second region F2 of the first end surface 36 of the base portion 24 are marked with different dots.

[0031] When an imaginary plane including the second rear surface 40 of the cutting portion 38 is defined as a reference plane VP, the first region F1 of the first end surface 36 of the base portion 24 may have a first portion F1p that is rearward of the second rear surface 40 of the cutting portion 38 in the rotational direction T and in which the width of the region sandwiched between the reference plane VP and the first rear surface 30 gradually increases toward the radially outer side RDe. The second region F2 of the first end surface 36 of the base portion 24 may have a second portion F2p that is rearward of the second rear surface 40 of the cutting portion 38 in the rotational direction T and in which the width of the region sandwiched between the reference plane VP and the first rear surface 30 gradually increases toward the radially inner side RDi. The width of the region sandwiched between the reference plane VP and the first rear surface 30 is the width in a direction perpendicular to the reference plane VP.

[0032] The first region F1 may have a portion other than the first portion F1p. For example, the first region F1 may have a portion with a constant width in addition to the first portion F1p whose width gradually increases toward the radially outer side RDe. The portion with a constant width may be located radially inward RDi relative to the first portion F1p, or may be located radially outward RDe.

[0033] The second region F2 may have a portion other than the second portion F2p. For example, the second region F2 may have a portion with a constant width in addition to the second portion F2p whose width gradually increases toward the radially outer side RDe. The portion with a constant width may be located radially inward RDi with respect to the second portion F2p, or may be located radially outward RDe. For example, as shown in FIG. 9, when the portion with a constant width is located radially inward RDi with respect to the second portion F2p, the thickness of the portion of the holder 12 that supports the cutting insert 14 is likely to be ensured.

[0034] The maximum width L1max of the region in the first region F1 of the first end face 36 of the base portion 24 between the reference plane VP and the first rear surface 30 may be smaller than the maximum width L2max of the region in the second region F2 between the reference plane VP and the first rear surface 30. Furthermore, the minimum width L1min of the region in the first region F1 of the first end face 36 of the base portion 24 may be larger than the minimum width L2min of the region in the second region F2 between the reference plane VP and the first rear surface 30.

[0035] As in the examples shown in Figures 6, 8, and 9, the first end surface 36 of the base portion 24 may have a groove 58 extending in a direction along the rotation axis S. The groove 58 of the base portion 24 may extend in a direction PD parallel to the rotation axis S. The groove 58 of the base portion 24 may have a curved shape (concave shape) recessed forward in the rotation direction T. In other words, the first end surface 36 of the base portion 24 may have the groove 58 as a recessed portion recessed forward in the rotation direction T. The groove 58 of the base portion 24 may be engageable with the protrusion 16d of the pocket 16 of the holder 12.

[0036] The groove 58 of the base portion 24 may have a bottom 58b located most forward in the rotational direction T. The bottom 58b of the groove 58 of the base portion 24 may be located radially inward RDi of the cutting portion 38. An edge 58e of the radially outer RDe of the groove 58 of the base portion 24 may coincide with the edge 30e of the radially outer RDe of the first rear surface 30. The groove 58 of the base portion 24 may be spaced apart from the edge 30i of the radially inner RDi of the first rear surface 30.

[0037] 9, when the first region F1 of the first end face 36 of the base portion 24 has the first portion F1p, it is possible to ensure a sufficient thickness on the radially outer side RDe (outer periphery side) of the base portion 24. Therefore, even if a large cutting load is applied to the outer periphery side of the base portion 24, the base portion 24 is less likely to break. This increases the durability of the base portion 24, making it possible to set cutting conditions at high rotational speeds.

[0038] As shown in FIGS. 8 and 9 , when the first region F1 of the first end surface 36 of the base portion 24 has the first portion F1p, the durability of the base portion 24 against cutting loads is enhanced. Furthermore, when the second region F2 of the first end surface 36 of the base portion 24 has the second portion F2p, the presence of the second portion F2p reduces scattering of the cutting insert 14 due to centrifugal force, even at high rotational speeds. When the base portion 24 has both the first portion F1p and the second portion F2p, the first rear surface 30 of the base portion 24 has a concave shape recessed forward in the rotational direction T. This ensures durability of the portion of the holder 12 located rearward of the cutting insert 14 in the rotational direction and the base portion 24, while increasing the number of pockets 16 in which the cutting insert 14 can be attached. This allows for more efficient machining.

[0039] Furthermore, since the first rear surface 30 of the base portion 24 has a concave shape recessed forward in the rotational direction T, the cutting insert 14 is less likely to shift position relative to the holder 12, thereby improving the machining accuracy of the cutting insert 14.

[0040] As described above, the first region F1 is a portion of the first end face 36 that is located rearward of the second rear surface 40 in the rotational direction T, and the second region F2 is a portion of the first end face 36 that is adjacent to the first region F1 on the radially inner side RDi. In particular, in the example shown in Fig. 9, the first region F1 is a portion of the first end face 36 that is located radially outward RDi from the bottom 58b of the groove 58, and the second region F2 is a portion of the first end face 36 that is located radially inward RDi from the bottom 58b of the groove 58. In other words, the bottom 58b of the groove 58 is located at the boundary between the first region F1 and the second region F2.

[0041] 8 and 9, the maximum width L1max of the first portion F1p in the first region F1 of the first end face 36 of the base portion 24 is set to be smaller than the maximum width L2max of the second portion F2p in the second region F2. In this case, it is possible to ensure a sufficient thickness for the portion of the holder 12 that supports the cutting insert 14 on the outer circumferential side (radially outward RDe). This makes the holder 12 less susceptible to breakage, and the durability of the holder 12 can be further improved.

[0042] 8 and 9, the minimum width L1min of the first portion F1p in the first region F1 of the first end face 36 of the base portion 24 is greater than the minimum width L2min of the second portion F2p in the second region F2. In this case, the thickness of the portion of the base portion 24 that supports the cutting portion 38 on the outer periphery side can be ensured to be sufficient. The thickness of the holder 12 on the outer periphery side can be ensured to be sufficient. This makes the holder 12 less susceptible to breakage, and the durability of the holder 12 can be further improved.

[0043] 6, 8, and 9, when the groove 58 of the base portion 24 has a curved shape (concave shape) recessed forward in the rotation direction T, the cutting load is less likely to concentrate on specific locations on the first rear surface 30 of the base portion 24 and the first inner surface 16b, which is the seating surface of the holder 12. This makes the cutting insert 14 and the holder 12 less likely to be damaged, and the durability of the cutting insert 14 and the holder 12 can be further improved.

[0044] 8 and 9, when the bottom 58b of the groove 58 of the base portion 24 is located radially inward RDi of the cutting portion 38, a cutting load is less likely to be applied to the portion of the base portion 24 corresponding to the bottom 58b, which is a thinner portion of the base portion 24. This makes the cutting insert 14 even less likely to be damaged, and the durability of the cutting insert 14 can be further improved.

[0045] As shown in the examples of Figures 6, 8, and 9, when the groove 58 of the base portion 24 extends in the direction PD parallel to the rotation axis S, the cutting insert 14 is less likely to be misaligned with respect to the holder 12, and the machining accuracy of the cutting insert 14 can be further improved.

[0046] 8 and 9, when the edge 58e of the radially outer side RDe of the groove 58 of the base portion 24 coincides with the edge 30e of the radially outer side RDe of the first rear surface 30, the thickness of the base portion can be sufficiently secured on the outer circumferential side (radially outer side RDe). This makes the cutting insert 14 even more resistant to breakage, and the durability of the cutting insert 14 can be further improved.

[0047] 8 and 9, when the groove 58 of the base portion 24 is spaced apart from the edge portion 30i of the radially inner side RDi of the first rear surface 30, it is possible to prevent the thickness of the portion of the holder 12 that supports the cutting insert 14 on the radially inner side RDi from becoming excessively small. This makes the holder 12 less susceptible to breakage, and the durability of the holder 12 can be further improved.

[0048] As shown in the examples of Figures 8 and 9, the width W2 of the second portion F2p in the radial direction may be larger than the width W1 of the first portion F1p in the radial direction. In this case, the inclination of the second portion F2p with respect to the reference plane VP is made gentle, and it is easy to ensure a large maximum width L2max of the second portion F2p. Because the inclination of the second portion F2p with respect to the reference plane VP is gentle, the cutting load transmitted from the cutting insert 14 to the holder 12 is less likely to be directed toward the radially outer side RDe, and the cutting insert 14 is stably held. Furthermore, because the maximum width L2max of the second portion F2p is made large, it is less likely that the cutting insert 14 will fly off due to centrifugal force.

[0049] <Method of manufacturing machined parts> The method for manufacturing a machined product according to the embodiment will be described with reference to Fig. 10 to Fig. 12. Fig. 10 to Fig. 12 are schematic diagrams for explaining the method for manufacturing a machined product according to the embodiment.

[0050] As shown in the examples of FIGS. 10 to 12 , the method for manufacturing a machined product according to an embodiment of the present disclosure is a method for manufacturing a machined product M, which is a workpiece W that has been machined, and includes a first step, a second step, and a third step. The first step is a step of rotating a rotary tool 10. The second step is a step of bringing the rotating rotary tool 10 into contact with the workpiece W. The third step is a step of separating the rotary tool 10 from the workpiece W. Examples of materials for the workpiece W include aluminum alloy, stainless steel, carbon steel, alloy steel, cast iron, and non-ferrous metal. Specific details of the method for manufacturing a machined product according to this embodiment are as follows.

[0051] 10 and 11, the rotary tool 10 is rotated in the rotation direction T and moved in the direction of the arrow FD to approach the workpiece W. Then, the cutting insert 14 of the rotating rotary tool 10 is moved in the direction of the arrow FD while being brought into contact with the workpiece W. As a result, the rotary tool 10 performs cutting (milling) on ​​the workpiece W, and as in the example shown in FIG. 12, a machined surface Wf is formed on the workpiece.

[0052] 12, the rotary tool 10 is then moved in the direction of arrow FD to separate it from the workpiece W. This completes the cutting of the workpiece W, and a machined product M can be produced, which is the machined workpiece W. Because the rotary tool 10 has excellent cutting ability for the reasons described above, it is possible to produce a machined product M with excellent machining accuracy.

[0053] To continue cutting, the rotary tool 10 is rotated and the cutting insert 14 of the rotary tool 10 is repeatedly brought into contact with different locations on the workpiece W. In this embodiment, the rotary tool 10 is brought close to the workpiece W, but since it is sufficient that the rotary tool 10 and the workpiece W are relatively close to each other, the workpiece W may also be brought close to the rotary tool 10. In this regard, the rotary tool 10 is moved away from the workpiece W in the same manner.

[0054] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art would easily be able to make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure. [Explanation of symbols]

[0055] 10 Rotary tools 12 Holder 14 Cutting insert 16 pockets 16a Bottom 16b 1st inner surface 16c 2nd inner surface 16d convex part 18 Fixing screws 20 Adjustment mechanism 22 Fixing screw 24 Base 24a Main wall 24b 1st outer wall part 24c 2nd outer wall section 24d Rising wall 26 Through hole 28 Notch 30 1st rear surface 30e Radial outer edge 30i Radial inner edge 32 recess 34A 1st front surface 34B Side wall 34C Rear wall 36 1st end face 38 Cutting part 40 2nd rear surface 42 2nd front surface 44 Second end face 46 External surface 48 Bottom blade (cutting blade) 50 Peripheral blade (peripheral blade) 52 Corner 54 Chip pocket 56 Injection hole 58 Groove 58b bottom 58e Radial outer edge F1 1st area F1p part 1 F2 2nd area F2p 2nd part

Claims

1. A cutting insert for use in a rotary tool that can rotate around a rotation axis, a first rear surface located rearward in a rotation direction of the rotary tool; a first front surface located radially outward and facing forward in the rotation direction; a first end surface located on a tip side in a direction along the rotation axis and connected to the first rear surface and the first front surface; a base portion having a second planar rear surface joined to the first forward surface; a second planar front surface opposite the second rear surface; and a second end surface located on the tip side and connected to the second rear surface and the second front surface; a cutting edge located at an intersection of the second forward surface and the second end surface; a cutting portion having When viewed from the tip end side, the first end surface has a first region located rearward in the rotational direction relative to the second rear surface and radially outward; a second region located rearward of the second front surface in the rotational direction and radially inward of the first region, When a virtual plane including the second rear surface is used as a reference plane, the first region has a first portion in which the width of a region sandwiched between the reference surface and the first rear surface gradually increases toward the radially outer side, the second region has a second portion in which the width of a region sandwiched between the reference surface and the first rear surface gradually increases toward the radially inner side, a maximum value of a width of a region in the first region sandwiched between the reference surface and the first rear surface being smaller than a maximum value of a width of a region in the second region sandwiched between the reference surface and the first rear surface.

2. 2. The cutting insert according to claim 1, wherein a minimum value of a width of a region sandwiched between the reference surface and the first rear surface in the first region is larger than a minimum value of a width of a region sandwiched between the reference surface and the first rear surface in the second region.

3. A cutting insert for use in a rotary tool that can rotate around a rotation axis, a first rear surface located rearward in a rotation direction of the rotary tool; a first front surface located radially outward and facing forward in the rotation direction; a first end surface located on a tip side in a direction along the rotation axis and connected to the first rear surface and the first front surface; a base portion having a second planar rear surface joined to the first forward surface; a second planar front surface opposite the second rear surface; and a second end surface located on the tip side and connected to the second rear surface and the second front surface; a cutting edge located at an intersection of the second forward surface and the second end surface; a cutting portion having When viewed from the tip end side, the first end surface has a first region located rearward in the rotational direction relative to the second rear surface and radially outward; a second region located rearward of the second front surface in the rotational direction and radially inward of the first region, When a virtual plane including the second rear surface is used as a reference plane, the first region has a first portion in which the width of a region sandwiched between the reference surface and the first rear surface gradually increases toward the radially outer side, the second region has a second portion in which the width of a region sandwiched between the reference surface and the first rear surface gradually increases toward the radially inner side, a minimum value of a width of a region sandwiched between the reference surface and the first rear surface in the first region is greater than a minimum value of a width of a region sandwiched between the reference surface and the first rear surface in the second region.

4. the first rear surface has a groove extending in a direction along the rotation axis, The cutting insert according to claim 1 or 3, wherein the groove has a curved shape recessed forward in the rotation direction.

5. the groove has a bottom located most forward in the rotational direction, The cutting insert according to claim 4 , wherein the bottom portion is located radially inward of the cutting portion.

6. The cutting insert according to claim 4 , wherein the groove extends in a direction parallel to the rotation axis.

7. The cutting insert according to claim 4 , wherein a radially outer edge of the groove coincides with a radially outer edge of the first rearward surface.

8. The cutting insert according to claim 4 , wherein the groove is spaced from a radially inner edge of the first rearward surface.

9. a holder used in a rotary tool rotatable around a rotation axis, the holder having a cylindrical shape extending from a front end to a rear end along the rotation axis and having a pocket located on the front end side; A rotary tool comprising: a cutting insert according to claim 1 or 3 located in the pocket.

10. rotating the rotary tool according to claim 9; bringing the rotating rotary tool into contact with a workpiece; and a step of separating the rotary tool from the workpiece.

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