Cutting tool and method for manufacturing machined product

Abstract

The present invention ensures that, when replacing a cutting insert, chips are less likely to become trapped between the cutting insert and the seat surface of a pocket. The pocket includes: the seat surface; a first restraining surface that faces a first main side surface of the cutting insert; a second restraining surface that faces a second main side surface of the cutting insert; and a recessed surface portion that is positioned between the first restraining surface and the second restraining surface, and faces a corner side surface of the cutting insert. A coolant flow path includes a first opening portion that opens to the recessed surface portion.

Description

Cutting tool and method for manufacturing machined product

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

[0002] Examples of cutting tools include rotary tools and turning tools. Rotary tools include milling tools. Milling tools are used for milling processes such as face milling and end milling. Turning tools include external diameter machining tools, internal diameter machining tools, grooving tools, and cut-off tools.

[0003] Known cutting tools include those described in Patent Documents 1 to 3. Each of the cutting tools described in Patent Documents 1 to 3 includes a holder having a pocket and a cutting insert positioned in the pocket. A coolant flow path is provided inside the holder to supply coolant (cooling fluid) to the cutting insert.

[0004] In the cutting tools described in Patent Documents 1 to 3, the coolant is mainly used to cool the cutting insert, and therefore the coolant is sprayed toward the cutting edge or rake face of the cutting insert, where heat is likely to be generated during cutting.

[0005] Japanese Patent Application Laid-Open No. 2014-046446 Japanese Patent Application Laid-Open No. 2020-069584 Special Publication No. 2021-517072

[0006] A cutting tool according to one aspect of the present disclosure includes a holder extending from a front end to a rear end and having a pocket located on the front end side, and a cutting insert located in the pocket. The cutting insert has a polygonal upper surface, a polygonal lower surface located opposite the upper surface and usable as a seating surface, multiple side surfaces connected to the upper and lower surfaces, and a cutting edge located at an intersection of the upper surface and the side surfaces. The upper surface has multiple corners and multiple sides. The multiple side surfaces have multiple corner side surfaces extending from the corners toward the lower surface and multiple major side surfaces extending from the sides toward the lower surface. The multiple major side surfaces have a first major side surface and a second major side surface. The pocket has a seating surface facing the lower surface, a first constraint surface facing the first major side surface, a second constraint surface facing the second major side surface, and a concave portion located between the first constraint surface and the second constraint surface, away from the cutting insert, and facing one of the multiple corner side surfaces. The holder further has a coolant passage extending from the rear end side toward the pocket, The coolant passage has one or more first openings that open into the concave portion.

[0007] A method for manufacturing a machined product according to one aspect of the present disclosure includes the steps of rotating a cutting tool, bringing the rotating cutting tool into contact with a workpiece, and removing the cutting tool from the workpiece.

[0008] 8 is a schematic perspective view of a cutting tool according to an example of the present disclosure, as viewed from the side; FIG. 9 is a schematic perspective view of a cutting tool according to an example of the present disclosure, as viewed from the tip side; FIG. 10 is a schematic front view of a cutting tool according to an example of the present disclosure, as viewed from the tip side; FIG. 11 is a schematic perspective view of a holder according to an example of the present disclosure, as viewed from the tip side; FIG. 12 is an enlarged view of section V in FIG. 4; FIG. 13 is a schematic front view of a holder according to an example of the present disclosure, as viewed from the tip side; FIG. 14 is an enlarged view of section VII in FIG. 6; FIG. 15 is a schematic side view of a holder according to an example of the present disclosure, as viewed from the side; FIG. 16 is an enlarged view of section IX in FIG. 8; FIG. 17 is a schematic perspective view of a cutting insert according to an example of the present disclosure; FIG. 18 is a schematic view of a cutting insert according to an example of the present disclosure, as viewed from the top side; FIG. 19 is a schematic view illustrating a method for manufacturing a machined product according to an example of the present disclosure; FIG. 19 is a schematic view illustrating a method for manufacturing a machined product according to an example of the present disclosure;

[0009] If chips generated during cutting work get into the pockets, they may get caught between the seating surface of the pocket and the cutting insert when replacing the cutting insert, potentially reducing the accuracy of the cutting insert's installation in the holder. Therefore, a process is required to remove the chips that have gotten into the pockets when replacing the cutting insert. However, manually removing chips that have gotten into the pockets is cumbersome. Furthermore, automating the chip removal process is not easy. Automating the chip removal process requires image processing to identify the chips, but because the pockets are wet with coolant, this is difficult to do.

[0010] 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 simplified components necessary for explaining the embodiments. Therefore, the cutting tool of the example 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.

[0011] In this disclosure, the rotation direction refers to the rotation direction of the cutting tool. The term "orthogonal" does not necessarily mean strictly orthogonal, but rather means that an error of about ±5 degrees is permitted. The term "parallel" does not necessarily mean strictly parallel, but rather means that an error of about ±5 degrees is permitted.

[0012] <Cutting tool 10> A cutting tool 10 according to an example of the present disclosure will be described with reference to Figures 1 to 11. Figure 1 is a schematic perspective view of the cutting tool 10 according to an example of the present disclosure, as viewed from the side. Figure 2 is a schematic perspective view of the cutting tool 10 according to an example of the present disclosure, as viewed from the tip end. Figure 3 is a schematic front view of the cutting tool 10 according to an example of the present disclosure, as viewed from the tip end. Figure 4 is a schematic perspective view of the holder 12 according to an example of the present disclosure, as viewed from the tip end. Figure 5 is an enlarged view of the V portion in Figure 4.

[0013] Fig. 6 is a schematic front view of the holder 12 according to an example of the present disclosure, as viewed from the tip side. Fig. 7 is an enlarged view of part VII in Fig. 6. Fig. 8 is a schematic side view of the holder 12 according to an example of the present disclosure, as viewed from the side. Fig. 9 is an enlarged view of part IX in Fig. 8. Fig. 10 is a schematic perspective view of the cutting insert 18 according to an example of the present disclosure. Fig. 11 is a schematic view of the cutting insert 18 according to an example of the present disclosure, as viewed from the top side.

[0014] As shown in the examples of FIGS. 1 to 3 , a cutting tool 10 according to an embodiment of the present disclosure is used for cutting a workpiece W (see FIG. 12 ), particularly for milling such as face milling or end milling. The cutting tool 10 is a rotary tool such as a milling tool that is rotatable about a rotation axis RD. The cutting tool 10 may include a holder 12 that is attached to a spindle of a processing machine such as a milling machine. The holder 12 may have a cylindrical shape extending from a front end 12 a to a rear end 12 b along the rotation axis RD. Examples of materials for the holder 12 include metals such as stainless steel, carbon steel, cast iron, and aluminum alloys.

[0015] As in the examples shown in FIGS. 4 to 9 , the holder 12 may have a plurality of notches 14 located at intervals in the circumferential direction on its outer peripheral surface. The plurality of notches 14 may be located at equal intervals in the circumferential direction, or may be located at unequal intervals in the circumferential direction. The number of notches 14 may be one. The holder 12 may also have a recessed pocket 16 located on the wall surface of the notch 14 on the side facing the rotation direction T. In other words, the holder 12 may have a plurality of pockets 16 located at intervals in the circumferential direction on its outer peripheral surface. The plurality of pockets 16 may be located at equal intervals in the circumferential direction, or may be located at unequal intervals in the circumferential direction. The number of pockets 16 may be one.

[0016] 1 to 3, the cutting tool 10 may include a cutting insert 18 positioned in a pocket 16 of the holder 12. The cutting insert 18 may be positioned only in one or more selected pockets 16 of the holder 12. The cutting insert 18 may also be fixed to the pocket 16 of the holder 12 by a mounting screw B. The cutting insert 18 may also be fixed to the pocket 16 of the holder 12 by a clamping member.

[0017] 10 and 11 , the cutting insert 18 may have a rectangular upper surface 20 and a rectangular lower surface 22 located opposite the upper surface 20. The upper surface 20 and the lower surface 22 may each have a polygonal shape other than a rectangular shape, such as a triangular shape. The term "tetragonal shape" is not limited to a rectangular shape in the strict sense, but includes a shape that can be visually recognized as a rectangular shape overall. The term "polygonal shape" is not limited to a polygonal shape in the strict sense, but includes a shape that can be visually recognized as a polygonal shape overall.

[0018] 11 , the upper surface 20 and the lower surface 22 may each have a rotationally symmetric shape at a certain angle about the central axis 18c of the cutting insert 18. The upper surface 20 and the lower surface 22 may also have a shape that is inversion symmetric on the front and back. In other words, the cutting insert 18 may have a shape that is rotationally symmetric at a certain angle about the central axis 18c of the cutting insert 18, or may have a shape that is inversion symmetric on the front and back.

[0019] 10 and 11 , the cutting insert 18 may have a plurality of side surfaces 24 located between the upper surface 20 and the lower surface 22. The plurality of side surfaces 24 may be connected to the upper surface 20 and the lower surface 22. The plurality of side surfaces 24 may function as clearance surfaces and may be parallel to the central axis 18c of the cutting insert 18. The cutting insert 18 may be a so-called negative type cutting insert having a clearance angle of 0 degrees.

[0020] The cutting insert 18 may have a through hole 26 that penetrates from the upper surface 20 to the lower surface 22. The through hole 26 may be a hole for inserting a mounting screw B (see FIG. 1 ). One opening of the through hole 26 may be located in the center of the upper surface 20, and the other opening of the through hole 26 may be located in the center of the lower surface 22. The central axis of the through hole 26 may coincide with the central axis 18c of the cutting insert 18.

[0021] 10 and 11 , the cutting insert 18 may have an upper cutting edge 28 located at the intersection of the upper surface 20 and the side surface 24, and a lower cutting edge 30 located at the intersection of the lower surface 22 and the side surface 24. In other words, the cutting insert 18 may be a double-sided insert having an upper cutting edge 28 and a lower cutting edge 30. The upper cutting edge 28 may be located at the entire intersection of the upper surface 20 and the side surface 24, or may be located at a portion of the intersection. The lower cutting edge 30 may be located at the entire intersection of the lower surface 22 and the side surface 24, or may be located at a portion of the intersection.

[0022] The upper surface 20 and the lower surface 22 can each be used as a seating surface. When cutting is performed using the upper cutting edge 28, the lower surface 22 may be used as a seating surface for attaching to the pocket 16 of the holder 12. When cutting is performed using the lower cutting edge 30, the upper surface 20 may be used as a seating surface. When cutting is performed using the lower cutting edge 30, in other words, when the upper surface 20 is used as a seating surface, the terms "upper" and "lower" may be understood interchangeably in the following description.

[0023] When the lower surface 22 is used as a seating surface, the upper surface 20 may function as a rake surface, and when the upper surface 20 is used as a seating surface, the lower surface 22 may function as a rake surface.

[0024] As shown in the examples of Figures 10 and 11, the upper surface 20 may have a plurality of corner portions 32 and a plurality of side portions 34. The side portions 34 may be located between adjacent corner portions 32. The side portions 34 may have a linear shape in a top view. Furthermore, the plurality of side surfaces 24 may have a plurality of corner side surfaces 36 extending from the corner portions 32 toward the lower surface 22 and a plurality of main side surfaces 38 extending from the side portions 34 toward the lower surface 22. The plurality of main side surfaces 38 may have a first main side surface 38a and a second main side surface 38b. The first main side surface 38a and the second main side surface 38b may be adjacent to each other with one corner side surface 36 interposed therebetween.

[0025] When the upper surface 20 and the lower surface 22 have shapes that are inverted symmetrical to each other, the lower surface 22 may have portions that correspond to the corners 32 and sides 34 of the upper surface 20. The configurations of the portions that correspond to the corners 32 and sides 34 of the lower surface 22 may be the same as the configurations of the corners 32 and sides 34 of the upper surface 20, except that their positional relationship in the up-down direction is reversed.

[0026] Examples of the material of the cutting insert 18 include cemented carbide and cermet. Examples of cemented carbide compositions include WC-Co, which is produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering the mixture; WC-TiC-Co, which is produced by adding titanium carbide (TiC) to WC-Co; and WC-TiC-TaC-Co, which is produced by adding tantalum carbide (TaC) to WC-TiC-Co. Cermet is a sintered composite material in which a ceramic component is combined with a metal, and specific examples include sintered composite materials whose main component is a titanium compound such as titanium carbide (TiC) or titanium nitride (TiN).

[0027] The surface of the cutting insert 18 may be coated with a film by chemical vapor deposition (CVD) or physical vapor deposition (PVD). The film may have a composition of titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), or alumina (Al ２ O ３ ) etc.

[0028] 2 and 4 to 10 , the pocket 16 of the holder 12 may have a seating surface 40 that faces the lower surface 22 that is used as the seating surface of the cutting insert 18. Note that, in the case where the upper surface 20 is used as the seating surface, the seating surface 40 faces the upper surface 20. The seating surface 40 may have a flat abutting portion 40a that abuts against the lower surface 22 of the cutting insert 18, and a curved portion 40b that is positioned around the abutting portion 40a and curved concavely. Furthermore, the pocket 16 of the holder 12 may have a screw hole 42 for threading in the mounting screw B. The screw hole 42 may open in the center of the abutting portion 40a of the seating surface 40.

[0029] As shown in the example in Figures 4 to 7, the pocket 16 of the holder 12 may have a first restraint surface 44 facing the first major side surface 38a of the cutting insert 18. The first restraint surface 44 may have a flat abutment portion 44a that abuts against the first major side surface 38a of the cutting insert 18, and recessed portions 44b located above (the opening side of the pocket 16) and below (the side opposite the opening side of the pocket 16) the abutment portion 44a. The recessed portions 44b in the example shown in Figures 4 to 7 are concavely curved and may also be referred to as recesses. The abutment portion 44a of the first restraint surface 44 may be perpendicular to the abutment portion 40a of the seating surface 40.

[0030] The pocket 16 of the holder 12 may have a second restraint surface 46 facing the second major side surface 38b of the cutting insert 18. The second restraint surface 46 may have a flat abutment portion 46a that abuts against the second major side surface 38b of the cutting insert 18. The second restraint surface 46 may have recessed portions 46b located above (the opening side of the pocket 16) and below (the side opposite the opening side of the pocket 16) the abutment portion 46a. The recessed portions 46b in the examples shown in FIGS. 4 to 7 are concavely curved and may also be referred to as recesses. The abutment portion 46a of the second restraint surface 46 may be perpendicular to the abutment portion 46a of the seating surface 40. The abutment portion 46a of the second restraint surface 46 may intersect the abutment portion 44a of the first restraint surface 44.

[0031] The pocket 16 of the holder 12 may have a concave portion 48 located between the first restraining surface 44 and the second restraining surface 46 and facing one of the plurality of corner side surfaces 36 of the cutting insert 18. The concave portion 48 may be spaced from the cutting insert 18.

[0032] 1 , the holder 12 may have a coolant passage 50 located therein for supplying coolant (cooling fluid) to the cutting insert 18. The coolant passage 50 may extend from the rear end 12b of the holder 12 toward the pocket 16. When cleaning the pocket 16 of the holder 12, a cleaning liquid may be allowed to flow through the coolant passage 50 instead of coolant. When cleaning the pocket 16 of the holder 12, coolant may be allowed to flow through the coolant passage 50 as a cleaning liquid.

[0033] Examples of coolants include water-insoluble oils and water-soluble oils. Examples of water-insoluble oils include cutting oils such as oil-based, inactive extreme pressure, and active extreme pressure. Examples of water-soluble oils include cutting oils such as emulsions, solubles, and solutions. The coolant is not limited to a liquid, but may also be a gas such as an inert gas.

[0034] The coolant passage 50 may have one or more first openings 52 that open into the concave portion 48 of the pocket 16. The coolant passage 50 in the examples shown in FIGS. 4 to 7 has multiple first openings 52. The multiple first openings 52 of the coolant passage 50 may be located closer to the seating surface 40 of the pocket 16 than to the top surface 20 of the cutting insert 18. In other words, the distance between the multiple first openings 52 and the seating surface 40 may be smaller than the distance between the top surface 20 and the seating surface 40. The multiple first openings 52 of the coolant passage 50 may open toward the corner side surface 36 of the cutting insert 18. The multiple first openings 52 of the coolant passage 50 may open toward the seating surface 40 of the pocket 16.

[0035] 1 , 2 , 4 , and 5 , the coolant passage 50 may have one or more second openings 54 located away from the pocket 16 in the cutout 14. The second openings 54 of the coolant passage 50 may be located on the wall surface opposite the side facing the direction of rotation T of the cutout 14. The second openings 54 of the coolant passage 50 may open toward the top surface 20 of the cutting insert 18. The second openings 54 of the coolant passage 50 may be located forward of the cutting insert 18 in the direction of rotation T. The opening area of ​​the second openings 54 of the coolant passage 50 may be larger than the opening area of ​​the first openings 52.

[0036] 4 to 9 , the coolant passage 50 may have a plurality of third openings 56 that open to the seating surface 40 of the pocket 16. The third openings 56 of the coolant passage 50 may open to the curved portion 40b of the seating surface 40 of the pocket 16. The third openings 56 of the coolant passage 50 may open to the abutting portion 40a of the seating surface 40.

[0037] The third opening 56 may overlap the cutting insert 18 when the upper surface 20 is viewed from the front. In this case, the third opening 56 of the coolant passage 50 may be blocked by the lower surface 22 of the cutting insert 18.

[0038] The third opening 56 of the coolant flow path 50 is not limited to the above configuration. For example, the third opening 56 may open toward the first constraining surface 44 and the second constraining surface 46. In such a case, cleaning of the first constraining surface 44 and the second constraining surface 46 becomes easier when replacing the cutting insert 18, and the mounting accuracy of the cutting insert 18 becomes easier to improve.

[0039] The coolant passage 50 may have one or more fourth openings 58 that open to the first restraint surface 44 of the pocket 16. The coolant passage 50 in the examples shown in Figures 4 to 7 has multiple fourth openings 58. The multiple fourth openings 58 of the coolant passage 50 may open to the recessed portion 44b of the first restraint surface 44 of the pocket 16. The multiple fourth openings 58 of the coolant passage 50 may open toward the seat surface 40 of the pocket 16.

[0040] The plurality of fourth openings 58 of the coolant passage 50 may open to the abutment portion 44 a of the first restraint surface 44 of the pocket 16. The plurality of fourth openings 58 of the coolant passage 50 may overlap the cutting insert 18 when the first restraint surface 44 is viewed from the front. In this case, the plurality of fourth openings 58 may be blocked by the first major side surface 38 a of the cutting insert 18.

[0041] The coolant passage 50 may have one or more fifth openings 60 that open to the second restraint surface 46 of the pocket 16. The coolant passage 50 in the examples shown in Figures 4 to 7 has multiple fifth openings 60. The multiple fifth openings 60 of the coolant passage 50 may open to the recessed portion 46b of the second restraint surface 46 of the pocket 16. The multiple fifth openings 60 of the coolant passage 50 may open toward the seat surface 40 of the pocket 16.

[0042] The plurality of fifth openings 60 of the coolant passage 50 may open to the abutment portion 46 a of the second restraint surface 46 of the pocket 16. The plurality of fifth openings 60 of the coolant passage 50 may overlap the cutting insert 18 when the second restraint surface 46 is viewed from the front. In this case, the plurality of fifth openings 60 may be blocked by the second major side surface 38 b of the cutting insert 18.

[0043] 4 to 7 , in the cutting tool 10 according to the example of the present disclosure, the coolant flow passage 50 of the holder 12 has one or more first openings 52 that open into the concave portion 48 of the pocket 16. Therefore, during cleaning of the pocket 16 of the holder 12, cleaning liquid is sprayed from the first openings 52 of the coolant flow passage 50, thereby removing chips adhering to the pocket 16.

[0044] In particular, when the plurality of first openings 52 of the coolant flow passage 50 are open toward the seating surface 40 of the pocket 16, the cleaning liquid is sprayed from the plurality of first openings 52 of the coolant flow passage 50 toward the seating surface 40 of the pocket 16 while cleaning the pocket 16 of the holder 12. This allows chips adhering to the pocket 16 to be sufficiently removed.

[0045] Therefore, according to the cutting tool 10 of the example disclosed herein, when replacing the cutting insert 18, it is possible to prevent chips from getting caught between the seat surface 40 of the pocket 16 and the cutting insert 18. As a result, it is possible to ensure sufficient mounting accuracy of the cutting insert 18 to the holder 12, and to improve the processing accuracy of cutting the workpiece W (see FIG. 12 ).

[0046] When the plurality of first openings 52 of the coolant flow passage 50 are positioned closer to the seating surface 40 of the pocket 16 than the surface (upper surface 20) opposite the seating surface (lower surface 22) of the cutting insert 18, coolant is ejected from the plurality of first openings 52 of the coolant flow passage 50 toward the cutting insert 18 during cutting of the workpiece W. This cools the cutting insert 18 and increases the durability of the cutting insert 18. Furthermore, ejecting coolant from the first openings 52 makes it more difficult for chips to enter the concave surface 48 during cutting.

[0047] When the multiple first openings 52 of the coolant flow passage 50 are open toward the corner side surface 36 of the cutting insert 18, coolant is sprayed from the multiple first openings 52 of the coolant flow passage 50 toward the corner side surface 36 of the cutting insert 18 during cutting of the workpiece W. This makes it possible to cool the corner side surface 36 side of the cutting insert 18 during cutting of the workpiece W, thereby increasing the durability of the cutting insert 18. Furthermore, by spraying coolant from the first openings 52 toward the corner side surface 36, the coolant acts as a barrier at the concave surface 48, making it difficult for chips to enter the concave surface 48 during cutting.

[0048] 1, 2, 4, and 5, when the coolant flow passage 50 has the second opening 54 that opens toward the upper surface 20, coolant is sprayed from the second opening 54 of the coolant flow passage 50 toward the upper surface 20 of the cutting insert 18 during cutting of the workpiece W. This allows the cutting insert 18 to be cooled during cutting of the workpiece W, thereby increasing the durability of the cutting insert 18.

[0049] In particular, when the opening area of ​​the second opening 54 of the coolant flow passage 50 is larger than the opening area of ​​the first opening 52, a sufficient flow rate of coolant is sprayed from the second opening 54 of the coolant flow passage 50 toward the cutting insert 18 during cutting of the workpiece W. This allows the cutting insert 18 to be sufficiently cooled during cutting of the workpiece W, further increasing the durability of the cutting insert 18.

[0050] 4 to 9 , when the coolant flow passage 50 has one or more third openings 56 that open to the seating surface 40 of the pocket 16, coolant is ejected from the third openings 56 of the coolant flow passage 50 toward the cutting insert 18 during cutting of the workpiece W. This cools the cutting insert 18 and increases the durability of the cutting insert 18. In addition, chips are less likely to get into the curved portion 40b of the seating surface.

[0051] When the third opening 56 overlaps with the cutting insert 18 when the upper surface 20 is viewed from the front, cleaning liquid is sprayed from the third opening 56 of the coolant flow path 50 while cleaning the pocket 16 of the holder 12. This makes it possible to remove chips adhering to the seat surface 40 of the pocket 16 of the holder 12. Furthermore, when the third opening 56 opens toward the first constraint surface 44 and the second constraint surface 46, cleaning of the first constraint surface 44 and the second constraint surface 46 becomes easier when replacing the cutting insert 18, and the mounting accuracy of the cutting insert 18 becomes easier to improve.

[0052] In the above, when the third opening 56 of the coolant flow path 50 is blocked by the seating surface of the cutting insert 18, the coolant can be used efficiently. When cleaning the pocket 16 of the holder 12 when replacing the cutting insert 18, cleaning liquid is sprayed from the third opening 56, making it possible to remove chips adhering to the seating surface 40 of the pocket 16 of the holder 12. In addition, during cutting, the outflow of cleaning liquid from the third opening 56 is suppressed, making it possible to increase the amount and flow rate of coolant sprayed from the first opening 52 and / or the second opening 54.

[0053] 4 to 7 , when the coolant flow passage 50 has one or more fourth openings 58 that open to the first constraint surface 44 of the pocket 16, coolant is ejected from the fourth openings 58 of the coolant flow passage 50 toward the cutting insert 18 during cutting of the workpiece W. This cools the cutting insert 18, making it possible to increase the durability of the cutting insert 18.

[0054] When the fourth openings 58 overlap the cutting insert 18 when the first restraint surface 44 is viewed from the front, cleaning fluid is sprayed from the plurality of fourth openings 58 of the coolant flow path 50 during cleaning of the pocket 16 of the holder 12. This makes it possible to remove chips adhering to the seat surface 40 of the pocket 16 of the holder 12.

[0055] In the above, when the fourth opening 58 of the coolant flow path 50 is blocked by the first main side surface 38a of the cutting insert 18, the coolant can be used efficiently. When cleaning the pocket 16 of the holder 12 when replacing the cutting insert 18, cleaning liquid is sprayed from the fourth opening 58, making it possible to remove chips adhering to the seat surface 40 of the pocket 16 of the holder 12. In addition, during cutting, the outflow of cleaning liquid from the fourth opening 58 is suppressed, making it possible to increase the amount and flow rate of coolant sprayed from the first opening 52 and / or the second opening 54.

[0056] In particular, when the fourth opening 58 of the coolant flow path 50 is open toward the seating surface 40 of the pocket 16, the cleaning liquid is sprayed from the fourth opening 58 of the coolant flow path 50 toward the seating surface 40 of the pocket 16 during cleaning of the pocket 16 of the holder 12. This allows chips adhering to the seating surface 40 of the pocket 16 of the holder 12 to be sufficiently removed.

[0057] 4 to 7 , when the coolant flow passage 50 has one or more fifth openings 60 that open to the second constraint surface 46 of the pocket 16, coolant is ejected from the fifth openings 60 of the coolant flow passage 50 toward the cutting insert 18 during cutting of the workpiece W. This cools the cutting insert 18, making it possible to increase the durability of the cutting insert 18.

[0058] When the fifth openings 60 overlap the cutting insert 18 when the second restraint surface 46 is viewed from the front, cleaning fluid is sprayed from the plurality of fifth openings 60 of the coolant flow path 50 during cleaning of the pocket 16 of the holder 12. This makes it possible to remove chips adhering to the seat surface 40 of the pocket 16 of the holder 12.

[0059] In the above, when the fifth opening 60 of the coolant flow path 50 is blocked by the second main side surface 38b of the cutting insert 18, the coolant can be used efficiently. When cleaning the pocket 16 of the holder 12 when replacing the cutting insert 18, cleaning liquid is sprayed from the fifth opening 60, making it possible to remove chips adhering to the seat surface 40 of the pocket 16 of the holder 12. In addition, during cutting, the outflow of cleaning liquid from the fifth opening 60 is suppressed, making it possible to increase the amount and flow rate of coolant sprayed from the first opening 52 and / or the second opening 54.

[0060] In particular, when the fifth opening 60 of the coolant flow path 50 is open toward the seating surface 40 of the pocket 16, the cleaning liquid is sprayed from the fifth opening 60 of the coolant flow path 50 toward the seating surface 40 of the pocket 16 during cleaning of the pocket 16 of the holder 12. This allows chips adhering to the seating surface 40 of the pocket 16 of the holder 12 to be sufficiently removed.

[0061] <Method of manufacturing machined product> A method of manufacturing a machined product according to an example of the present disclosure will be described with reference to Fig. 12 to Fig. 14. Fig. 12 to Fig. 14 are schematic diagrams illustrating a method of manufacturing a machined product according to an example of the present disclosure.

[0062] As shown in the examples of FIGS. 12 to 14 , the manufacturing method of a machined product according to 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 cutting tool 10. The second step is a step of bringing the rotating cutting tool 10 into contact with the workpiece W. The third step is a step of separating the cutting tool 10 from the workpiece W. Examples of materials for the workpiece W include aluminum alloys, stainless steel, carbon steel, alloy steel, cast iron, and non-ferrous metals. Specific details of the manufacturing method of a machined product according to the embodiment of the present disclosure are as follows.

[0063] 12 and 13 , the cutting tool 10 is rotated in the rotation direction T and moved in the direction of the arrow FD to approach the workpiece W (first step). Then, the cutting insert 18 of the rotating cutting tool 10 is moved in the direction of the arrow FD while being brought into contact with the workpiece W (second step). As a result, the cutting tool 10 performs a milling process, which is one type of cutting process, on the workpiece W, and a machined surface Wf is formed on the workpiece W as in the example shown in FIG.

[0064] 14, the cutting tool 10 is further moved in the direction of the arrow FD to separate it from the workpiece W (third step). This completes the cutting of the workpiece W, and a machined product M can be produced, which is the machined workpiece W. Because the cutting tool 10 has excellent cutting ability for the reasons described above, it is possible to produce a machined product M with excellent machining precision.

[0065] To continue the milling process, the cutting insert 18 of the cutting tool 10 may be repeatedly brought into contact with different locations on the workpiece W while the cutting tool 10 is being rotated. In the embodiment of the present disclosure, the cutting tool 10 is brought close to the workpiece W, but since it is sufficient that the cutting tool 10 and the workpiece W are brought relatively close to each other, for example, the workpiece W may be brought close to the cutting tool 10. In this regard, the same process is carried out when the cutting tool 10 is moved away from the workpiece W.

[0066] As in the examples shown in Figures 1 to 11, the technical concept applied to the cutting tool 10 used for milling the workpiece W may also be applied to a cutting tool used for turning the workpiece W.

[0067] In one embodiment, (1) a cutting tool includes a holder extending from a front end to a rear end and having a pocket located on the front end side, and a cutting insert located in the pocket. The cutting insert has a polygonal upper surface, a polygonal lower surface located opposite the upper surface and usable as a seating surface, a plurality of side surfaces connected to the upper surface and the lower surface, and a cutting edge located at an intersection of the upper surface and the side surfaces. The upper surface has a plurality of corners and a plurality of sides. The side surfaces have a plurality of corner side surfaces extending from the corners toward the lower surface and a plurality of major side surfaces extending from the sides toward the lower surface. The plurality of major side surfaces include a first major side surface and a second major side surface. The pocket has a seating surface facing the lower surface, a first constraint surface facing the first major side surface, a second constraint surface facing the second major side surface, and a concave portion located between the first constraint surface and the second constraint surface, away from the cutting insert, and facing one of the corner side surfaces. The holder further includes a coolant passage extending from the rear end toward the pocket, the coolant passage having one or more first openings opening into the recessed portion.

[0068] (2) In the cutting tool of (1), the first opening may be located closer to the seating surface than the upper surface.

[0069] (3) In the cutting tool of (1) or (2), the coolant passage may further have one or more second openings located away from the pocket and opening toward the upper surface.

[0070] (4) In the cutting tool of (3), the second opening may have a larger opening area than the first opening.

[0071] (5) In the cutting tool according to any one of (1) to (4), the first opening may open toward the corner side surface.

[0072] (6) In the cutting tool according to any one of (1) to (5), the first opening may be open toward the seating surface.

[0073] (7) In the cutting tool according to any one of (1) to (6), the coolant passage may further include one or more third openings that open to the seating surface.

[0074] (8) In the cutting tool of (7) above, the third opening may overlap the cutting insert when the upper surface is viewed from the front.

[0075] (9) In the cutting tool according to any one of (1) to (8), the coolant flow path may further include one or more fourth openings that open to the first restraint surface.

[0076] (10) In the cutting tool of (9), the fourth opening overlaps with the cutting insert when the first constraint surface is viewed from the front.

[0077] (11) In the cutting tool of (9) or (10), the fourth opening may be open toward the seating surface.

[0078] (12) In the cutting tool according to any one of (1) to (11), the coolant flow path may further include one or more fifth openings that open to the second constraint surface.

[0079] (13) In the cutting tool of (12), the fifth opening overlaps with the cutting insert when the second constraint surface is viewed from the front.

[0080] (14) In the cutting tool of (12) or (13), the fifth opening may be open toward the seating surface.

[0081] (15) A method for manufacturing a machined product includes the steps of rotating a cutting tool according to any one of (1) to (14), bringing the rotating cutting tool into contact with a workpiece, and removing the cutting tool from the workpiece.

[0082] The invention according to the present disclosure has been described above based on the drawings and embodiments. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the disclosed technical means are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0083] REFERENCE SIGNS LIST 10 Cutting tool 12 Holder 12a Tip 12b Rear end 14 Notch 16 Pocket 18 Cutting insert 18c Central axis 20 Upper surface 22 Lower surface 24 Side surface 26 Through hole 28 Upper cutting edge 30 Lower cutting edge 32 Corner portion 34 Side portion 36 Corner side surface 38 Main side surface 38a First main side surface 38b Second main side surface 40 Bearing surface 40a Abutment portion 40b Curved portion 42 Screw hole 44 First restraint surface 44a Abutment portion 44b Recessed portion 46 Second restraint surface 46a Abutment portion 46b Recessed portion 48 Concave portion 50 Coolant flow path 52 First opening 54 Second opening 56 Third opening 58 Fourth opening 60 Fifth opening

Claims

1. a holder extending from a front end to a rear end and having a pocket located on the front end side; a cutting insert located in the pocket, The cutting insert comprises: A polygonal top surface; a polygonal lower surface located opposite the upper surface and usable as a seating surface; a plurality of side surfaces connected to the upper surface and the lower surface; a cutting edge located at an intersection of the top surface and the side surface, the upper surface has a plurality of corners and a plurality of sides, The aspects include: a plurality of corner side surfaces extending from the corner portion toward the lower surface; a plurality of major side surfaces extending from the side portions toward the lower surface; the plurality of major sides include a first major side and a second major side; The pocket is a seat surface facing the lower surface; a first constraint surface opposite the first major side surface; a second restraining surface opposite the second major side surface; a concave portion located between the first constraint surface and the second constraint surface, spaced from the cutting insert, and facing one of the plurality of corner side surfaces; the holder further includes a coolant flow passage extending from the rear end toward the pocket, The coolant passage has one or more first openings that open into the concave surface portion.

2. The cutting tool according to claim 1 , wherein the first opening is located closer to the seating surface than to the upper surface.

3. The cutting tool of claim 1 , wherein the coolant passage further comprises one or more second openings located away from the pocket and opening toward the top surface.

4. The cutting tool according to claim 3 , wherein an opening area of ​​the second opening is larger than an opening area of ​​the first opening.

5. The cutting tool according to claim 1 , wherein the first opening is open toward the corner side surface.

6. The cutting tool according to claim 1 , wherein the first opening is open toward the seating surface.

7. The cutting tool according to claim 1 , wherein the coolant passage further includes one or more third openings that open into the seating surface.

8. The cutting tool according to claim 7 , wherein the third opening overlaps the cutting insert when the upper surface is viewed from the front.

9. The cutting tool according to claim 1 , wherein the coolant passage further includes one or more fourth openings that open into the first restraint surface.

10. The cutting tool according to claim 9 , wherein the fourth opening overlaps the cutting insert when the first constraint surface is viewed from the front.

11. The cutting tool according to claim 9 , wherein the fourth opening is open toward the seating surface.

12. The cutting tool according to claim 1 , wherein the coolant passage further includes one or more fifth openings that open into the second restraint surface.

13. The cutting tool according to claim 12 , wherein the fifth opening overlaps the cutting insert when the second constraint surface is viewed from the front.

14. The cutting tool according to claim 12 , wherein the fifth opening is open toward the seating surface.

15. rotating the cutting tool according to any one of claims 1 to 14; bringing the rotating cutting tool into contact with a workpiece; and removing the cutting tool from the workpiece.