Cutting tool and method for manufacturing machined product

Abstract

The present invention increases the durability of a holder while ensuring a high detection accuracy of a sensor unit. A unit base is positioned extending from a lower surface to a second side surface, and the unit base has an L-shape in a cross section orthogonal to the longitudinal direction of the holder. A first sensor positioned inside a first recess portion of the unit base abuts on the lower surface. A second sensor positioned inside a second recess portion of the unit base abuts on the second side surface.

Description

[Technical Field]

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

[0002] For example, a cutting tool described in Patent Document 1 is known as a cutting tool used in cutting a workpiece to manufacture a machined product. The cutting tool described in Patent Document 1 is equipped with a sensor unit for detecting a physical quantity (referred to as physical information in Patent Document 1) of a cutting insert (referred to as a cutting blade in Patent Document 1). Examples of this physical quantity include wear, temperature, pressure, and vibration of the cutting insert, and a cutting tool equipped with a temperature sensor is disclosed as an example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-020359 Summary of the Invention

[0004] The cutting tool according to the present disclosure includes a holder, a cutting insert, and a sensor unit. The holder has a rod shape extending from its front end to its rear end, and includes a front end surface located on the front end side, an upper surface extending from the front end surface toward the rear end, a lower surface located opposite the upper surface, a first side surface located between the upper and lower surfaces and extending from the front end surface toward the rear end, a second side surface located opposite the first side surface, and a pocket opening to the front end surface, the upper surface, and the first side surface. The cutting insert is located in the pocket and has a cutting edge. The sensor unit includes a unit base, a first sensor, and a second sensor. The unit base is located from the lower surface to the second side surface, and has a first recess opening toward the lower surface and a second recess opening toward the second side surface, and is L-shaped in a cross section perpendicular to the longitudinal direction of the holder. The first sensor is located within the first recess and abuts against the lower surface to detect a physical quantity of the holder (cutting tool). The second sensor is located in the second recess, abuts against the second side surface, and detects a physical quantity of the holder (cutting tool) in a detection direction perpendicular to the detection direction of the first sensor. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic perspective view of a cutting tool according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic perspective view of the cutting tool shown in FIG. 1, viewed from a different angle. [Figure 3] FIG. 2 is a schematic plan view of the cutting tool shown in FIG. [Figure 4] FIG. 2 is a schematic view of the cutting tool shown in FIG. 1 as viewed from the tip side. [Figure 5] FIG. 2 is a schematic side view of the cutting tool shown in FIG. [Figure 6] 6 is an enlarged schematic view of another side surface of the cutting tool shown in FIG. 5. FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5. [Figure 9] FIG. 6 is a cross-sectional view taken along line IX-IX in FIG. 5. [Figure 10] FIG. 10 is a schematic perspective view of a cutting tool according to another embodiment of the present disclosure. [Figure 11] FIG. 11 is a schematic side view of the cutting tool shown in FIG. [Figure 12] FIG. 10 is a schematic perspective view of a cutting tool according to another embodiment of the present disclosure. [Figure 13] FIG. 13 is a schematic diagram of the cutting tool shown in FIG. 12 as viewed from the tip side. [Figure 14] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. [Figure 15] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. [Figure 16] 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] In the cutting tool described in Patent Document 1, the sensor part is attached to the cutting insert in the vicinity of the cutting edge, and therefore there is a risk that the sensor part may fall off from the cutting insert during cutting of a workpiece.

[0007] To prevent the sensor from falling off, it is possible to incorporate the sensor into the cutting tool holder. If the sensor is a temperature sensor, the sensor is small and there is little risk of the strength of the holder being significantly reduced. However, if the sensor is a pressure sensor or a vibration sensor, the reduction in the strength (rigidity) of the holder due to the incorporation of the sensor cannot be ignored.

[0008] In particular, during cutting, cutting loads are applied to the cutting tool in three directions: principal force, thrust force, and feed force. In order to ensure high detection accuracy of the sensor unit, when detecting physical quantities such as acceleration in three directions corresponding to these three cutting loads, the sensor unit needs to have multiple sensors corresponding to the three directions. If space is provided in the holder to incorporate such a sensor unit, there is a concern that the processing of the holder will become complicated and that the durability of the holder will be reduced.

[0009] According to the present disclosure, it is possible to increase the durability of the holder while ensuring high detection accuracy of the sensor unit.

[0010] Hereinafter, a cutting tool and a method for manufacturing a machined product according to an embodiment 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 embodiment in a simplified form. Therefore, a cutting insert according to an embodiment of the present disclosure may include any components not shown in the drawings referred to. 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] Furthermore, in this disclosure, the following description will be based on an orthogonal coordinate system, XYZ, defined by three mutually orthogonal directions. The X direction refers to the front-to-rear direction, where one side of the X direction is the front side or forward direction, and the other side of the X direction is the rear side or backward direction. The Y direction refers to the left-to-right direction, where one side of the Y direction is the left side or leftward direction, and the other side of the Y direction is the right side or rightward direction. The Z direction refers to the up-down direction, where one side of the Z direction is the upper side or upward direction, and the other side of the Z direction is the lower side or downward direction. The XY direction refers to the two directions, the X direction and the Y direction, the XZ direction refers to the two directions, the X direction and the Z direction, and the YZ direction refers to the two directions, the Y direction and the Z direction. The XYZ direction refers to the three directions, the X direction, the Y direction, and the Z direction.

[0012] In the drawings, "FF" indicates the forward direction, "FR" indicates the rearward direction, "L" indicates the leftward direction, "R" indicates the rightward direction, "U" indicates the upward direction, and "D" indicates the downward direction.

[0013] <Cutting tools> A cutting tool 10 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 9. FIG. 1 is a schematic perspective view of the cutting tool 10 according to an embodiment of the present disclosure. FIG. 2 is a schematic perspective view of the cutting tool shown in FIG. 1 as viewed from another angle. FIG. 3 is a schematic plan view of the cutting tool 10 shown in FIG. 1. FIG. 4 is a schematic view of the cutting tool 10 shown in FIG. 1 as viewed from the tip side. FIG. 5 is a schematic side view of the cutting tool 10 shown in FIG. 1. FIG. 6 is an enlarged side view of the vicinity of the sensor unit as viewed from the opposite side to FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 5.

[0014] As shown in the examples of FIGS. 1 to 3 , a cutting tool 10 according to an embodiment of the present disclosure is a tool used for cutting a workpiece W (see FIG. 10 ). Cutting of the workpiece W includes external diameter machining, internal diameter machining, grooving, cut-off, and the like. The cutting tool 10 may also include a holder 14 attached to a tool rest 12 of a lathe, a cutting insert 16 held by the holder 14, a clamp 18 that fixes the cutting insert 16 to the holder 14, and a clamp screw 20 that attaches the clamp 18 to the holder 14.

[0015] 1 to 5, the holder 14 may be rod-shaped and extend in the X direction from the front end 14a to the rear end 14b. The longitudinal direction of the holder 14 may be the X direction. The holder 14 may have a main body 14m in the shape of a square pillar located closer to the rear end 14b than the clamp 18.

[0016] 1 to 5, the holder 14 may have a leading end surface 22 located on the leading end 14a side and a trailing end surface 24 located on the opposite side of the leading end surface 22. The holder 14 may have an upper surface 26 extending in the X direction from the leading end surface 22 toward the trailing end 14b to the trailing end surface 24. The holder 14 may have a lower surface 28 located on the opposite side of the upper surface 26, and the lower surface 28 may extend in the X direction from the leading end surface 22 toward the trailing end 14b to the trailing end surface 24.

[0017] The holder 14 may have a first side surface 30 located between the upper surface 26 and the lower surface 28, and the first side surface 30 may extend in the X direction from the tip surface 22 toward the rear end 14b to the rear end surface 24. The first side surface 30 of the holder 14 may be connected to the upper surface 26 and the lower surface 28. In the main body portion 14m of the holder 14, the first side surface 30 may be perpendicular to the lower surface 28 and the upper surface 26.

[0018] The holder 14 may have a second side surface 32 located opposite the first side surface 30, and the second side surface 32 may extend in the X direction from the tip surface 22 toward the rear end 14b to the rear end surface 24. The second side surface 32 of the holder 14 may be connected to the upper surface 26 and the lower surface 28. In the main body portion 14m of the holder 14, the second side surface 32 may be perpendicular to the lower surface 28 and the upper surface 26.

[0019] The front end surface 22, the rear end surface 24, the upper surface 26, the lower surface 28, the first side surface 30, and the second side surface 32 of the holder 14 may form the outer surface of the holder 14. The holder 14 may also have a pocket 34 on the side of the front end 14a for holding the cutting insert 16. The pocket 34 may be open to the front end surface 22, the upper surface 26, and the first side surface 30.

[0020] When the cutting tool 10 is attached to the tool rest 12, a lower surface 28 of the main body 14m of the holder 14 is supported by the mounting surface 12a (see FIG. 8) of the tool rest 12. A second side surface 32 of the main body 14m of the holder 14 is supported by the inner wall surface 12b (see FIG. 8) of the tool rest 12. An upper surface 26 of the main body 14m of the holder 14 is pressed by the fixing screw 12c of the tool rest 12 (see FIG. 8).

[0021] Examples of materials for the holder 14 include metals such as stainless steel, carbon steel, cast iron, aluminum alloy, etc. The length of the holder 14 may be set to, for example, 100 mm to 400 mm.

[0022] As shown in the example of FIGS. 1 to 5 , the cutting insert 16 may be positioned in a pocket 34 of the holder 14. The cutting insert 16 may be a replaceable insert known as a throw-away insert. The cutting insert 16 may have a rectangular plate shape, or may have a shape other than a rectangular plate shape, such as a triangular or pentagonal plate shape. The cutting insert 16 may have a first insert surface 36, a second insert surface 38 located opposite the first insert surface 36, and a plurality of insert side surfaces 40 located between the first insert surface 36 and the second insert surface 38.

[0023] The cutting insert 16 may have a cutting edge 42 at the intersection of the first insert surface 36 and the insert side surface 40. The first insert surface 36 may function as a rake surface for chip flow. The insert side surface 40 may function as a clearance surface.

[0024] The cutting insert 16 may have a through hole 44 that opens to the first insert surface 36 and the second insert surface 38. The cutting insert 16 is attached to the pocket 34 by tightening the clamp screw 20 with the tip of the clamp 18 engaged with the through hole 44.

[0025] Examples of the material of the cutting insert 16 include cemented carbide and cermet. Examples of cemented carbide compositions include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. WC-Co is produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering the mixture. WC-TiC-Co is produced by adding titanium carbide (TiC) to WC-Co. WC-TiC-TaC-Co is produced by adding tantalum carbide (TaC) to WC-TiC-Co. Cermets are sintered composite materials in which a ceramic component is combined with a metal. Specific examples of cermets include those primarily composed of titanium compounds such as titanium carbide (TiC) and titanium nitride (TiN).

[0026] A coating may be applied by chemical vapor deposition (CVD) or physical vapor deposition (PVD) to the surface of the cutting insert 16. Examples of the material for the coating include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al2O3).

[0027] As shown in the examples of FIGS. 2 to 7 , the cutting tool 10 may include a sensor unit 46 for detecting physical quantities such as acceleration, vibration, strain, or internal stress of the holder 14 (cutting tool 10). The sensor unit 46 may have a unit base 48 located from the lower surface 28 to the second side surface 32 of the main body 14m of the holder 14. The unit base 48 may be attached to the main body 14m of the holder 14 by adhesive. The unit base 48 may be attached to the main body 14m of the holder 14 by the magnetic force of a built-in magnet. Alternatively, the unit base 48 may be attached to the main body 14m of the holder 14 by a fixing member such as a screw. Examples of materials for the unit base 48 include synthetic resin and metal.

[0028] 4 and 7 , the unit base 48 may be L-shaped in a cross section perpendicular to the X direction, which is the longitudinal direction of the holder 14. In other words, the sensor unit 46 may be L-shaped in a cross section perpendicular to the X direction. The unit base 48 may have a first portion 48a located on the lower surface 28 of the holder 14 and a second portion 48b located on the second side surface 32 of the holder 14. The distance in the X direction from the unit base 48 to the front end surface 22 of the holder 14 may be shorter than the distance in the X direction from the unit base 48 to the rear end surface 24 of the holder 14.

[0029] 4, the entire first portion 48a of the unit base 48 may be located closer to the second side surface 32 of the holder 14 than to the first side surface 30. The entire second portion 48b of the unit base 48 may be located closer to the lower surface 28 of the holder 14 than to the upper surface 26.

[0030] As in the examples shown in FIGS. 6 and 7 , the first portion 48a of the unit base 48 may have a first recess 50 that opens toward the lower surface 28 of the holder 14. The first recess 50 of the unit base 48 may be a hole (depression) with a bottom, or may be a through hole. If the first recess 50 of the unit base 48 is a hole with a bottom, waterproof performance against the first sensor 56 and the like is likely to be improved. The second portion 48b of the unit base 48 may have a second recess 52 that opens toward the second side surface 32 of the holder 14. The second recess 52 of the unit base 48 may be a hole with a bottom, or may be a through hole.

[0031] The unit base 48 may further include another recess in addition to the first recess 50 and the second recess 52. For example, the first portion 48a of the unit base 48 may further include a recess that opens toward the lower surface 28 of the holder 14, separate from the second recess 52. Furthermore, as shown in the example shown in FIGS. 6 and 7 , the second portion 48b of the unit base 48 may include a third recess 54 that opens toward the second side surface 32 of the holder 14. The third recess 54 of the unit base 48 may be a bottomed hole or a through hole. The first recess 50, second recess 52, and third recess 54 of the unit base 48 may be independent of one another or may be continuous. For example, the first recess 50 of the unit base 48 may be independent of the second recess 52 and the third recess 54, and the third recess 54 of the unit base 48 may be continuous with the second recess 52.

[0032] The sensor unit 46 may have a first sensor 56 located in the first recess 50 of the unit base 48. The first sensor 56 may be fixed in the first recess 50 of the unit base 48 with an adhesive or the like. The first sensor 56 may detect one or more physical quantities of the holder 14, such as acceleration, vibration, strain, or internal stress. The detection direction of the first sensor 56 may be the Y direction. In other words, the first sensor 56 may detect physical quantities of the holder 14, such as acceleration, vibration, strain, or internal stress in the Y direction. The first sensor 56 may detect acceleration of the holder 14 corresponding to the feed force, etc. The first sensor 56 may abut against the lower surface 28 of the holder 14. When the first sensor 56 abuts against the lower surface 28 of the holder 14, the accuracy of detecting the above-mentioned physical quantities is improved.

[0033] The sensor unit 46 may have a second sensor 58 located in the second recess 52 of the unit base 48. The second sensor 58 may be fixed in the second recess 52 of the unit base 48 with an adhesive or the like. The position of the second sensor 58 in the X direction may be the same as the position of the first sensor 56 in the X direction. In other words, the position of the center of the second sensor 58 in the X direction may be within a range of ±1 mm with respect to the position of the center of the first sensor 56 in the X direction. The second sensor 58 may abut against the second side surface 32 of the holder 14. When the second sensor 58 abuts against the second side surface 32 of the holder 14, the accuracy of detecting the above-mentioned physical quantity is improved.

[0034] The second sensor 58 may abut against the second side surface 32 of the holder 14. The second sensor 58 may detect one or more physical quantities of the holder 14, such as acceleration, vibration, strain, or internal stress. The second sensor 58 may detect the same physical quantities as the first sensor 56. The detection direction of the second sensor 58 may be the X direction perpendicular to the detection direction of the first sensor 56. In other words, the second sensor 58 may detect physical quantities of the holder 14 in the X direction, such as acceleration, vibration, strain, or internal stress. The second sensor 58 may detect the acceleration of the holder 14 corresponding to the thrust force, etc.

[0035] The cutting tool 10 of the present disclosure is not configured such that sensors such as the first sensor 56 and the second sensor 58 are embedded in the holder 14, but rather is configured such that the sensors are included in a sensor unit 46 that is separate from the holder 14. Therefore, there is no need to perform complex processing to embed a sensor inside the holder 14, and it is easy to utilize an existing holder 14.

[0036] The sensor unit 46 may have a third sensor 60 located in the third recess 54 of the unit base 48. The third sensor 60 may be fixed in the third recess 54 of the unit base 48 with an adhesive or the like. The third sensor 60 may abut against the second side surface 32 of the holder 14. The position of the third sensor 60 in the X direction may be the same as the position of the second sensor 58 in the X direction. In other words, the position of the center of the third sensor 60 in the X direction may be within a range of ±1 mm with respect to the position of the center of the second sensor 58 in the X direction.

[0037] The third sensor 60 may detect one or more physical quantities such as acceleration, vibration, strain, or internal stress of the holder 14. The third sensor 60 may detect the same physical quantities as the first sensor 56 and the second sensor 58. The detection direction of the third sensor 60 may be the Z direction perpendicular to the detection directions of the first sensor 56 and the second sensor 58. In other words, the third sensor 60 may detect physical quantities such as acceleration, vibration, strain, or internal stress of the holder 14 in the Z direction. The third sensor 60 may detect the acceleration of the holder 14 corresponding to the principal component force, etc.

[0038] The first sensor 56, the second sensor 58, and the third sensor 60 may detect physical quantities such as acceleration, vibration, distortion, or internal stress of the holder 14 in the X, Y, and Z directions. The first sensor 56, the second sensor 58, and the third sensor 60 may detect acceleration of the holder 14 corresponding to cutting loads in three directions (principal force, thrust force, and feed force).

[0039] The positions in the X direction of the first sensor 56, the second sensor 58, and the third sensor 60 may be the same. The first sensor 56, the second sensor 58, and the third sensor 60 may be capacitance detection type sensors or piezoresistive type sensors. If the first sensor 56, the second sensor 58, and the third sensor 60 are capacitance detection type sensors, the sensors may be MEMS (Micro Electro Mechanical Systems).

[0040] The detection direction of the first sensor 56 may be changed from the Y direction to the XY direction. The first sensor 56 may detect physical quantities such as acceleration, vibration, strain, or internal stress of the holder 14 in the XY direction. The first sensor 56 may detect acceleration of the holder 14 corresponding to the feed component force and the principal component force. In these cases, either the second sensor 58 or the third sensor 60 may be omitted from the components of the sensor unit 46.

[0041] The detection direction of the second sensor 58 may be changed from the X direction to the XZ direction. The second sensor 58 may detect physical quantities such as acceleration, vibration, distortion, or internal stress of the holder 14 in the XZ directions. The second sensor 58 may detect acceleration of the holder 14 corresponding to the thrust force and the principal force. In this case, the third sensor 60 may be omitted from the components of the sensor unit 46.

[0042] The detection direction of the third sensor 60 may be changed from the Z direction to the XZ direction. The third sensor 60 may detect physical quantities such as acceleration, vibration, strain, or internal stress of the holder 14 in the XZ directions. The third sensor 60 may detect acceleration of the holder 14 corresponding to the principal force and thrust force. In this case, the second sensor 58 may be omitted from the components of the sensor unit 46.

[0043] 2, 5, 6, 8, and 9, the cutting tool 10 may include a wiring member 62 electrically connected to the first sensor 56, the second sensor 58, and the third sensor 60. The wiring member 62 may extend in the X direction from the first sensor 56 side toward the rear end 14b of the holder 14.

[0044] The holder 14 may have a groove 64 extending in the X direction from the side of the first sensor 56 etc. toward the rear end 14b of the holder 14. The groove 64 of the holder 14 may open to the second side surface 32. The groove 64 of the holder 14 may open to the bottom surface 28. The groove 64 of the holder 14 may open to the bottom surface 28 and the second side surface 32.

[0045] As shown in the examples in FIGS. 6 , 8 , and 9 , the wiring member 62 may be positioned in the groove 64 of the holder 14. In other words, the groove 64 of the holder 14 may accommodate the wiring member 62. The wiring member 62 may have a wiring conductor 66 electrically connected to the first sensor 56, the second sensor 58, and the third sensor 60. The wiring conductor 66 may extend in the X direction from the first sensor 56 side toward the rear end 14b of the holder 14. The wiring member 62 may have a cylindrical holding member 68 that holds the wiring conductor 66. The holding member 68 may be positioned in the groove 64 of the holder 14. In other words, the groove 64 of the holder 14 may accommodate the holding member 68. The material of the holding member 68 may be the same as that of the holder 14.

[0046] The wiring member 62 may be electrically connected to an information processing device installed outside the machine tool, etc. The information processing device may be configured by a computer, and may have a memory that stores various control programs, etc., and a CPU (Central Processing Unit) that interprets and executes the control programs.

[0047] The CPU executes the control program, causing the information processing device to perform various functions. In one embodiment, the information processing device may adjust the movement speed of the cutting tool 10 based on the physical quantities of the holder 14 detected by the first sensor 56, the second sensor 58, and the third sensor 60. In another embodiment, the information processing device may adjust the rotation speed of the workpiece W based on the physical quantities of the holder 14 detected by the first sensor 56, the second sensor 58, and the third sensor 60.

[0048] According to the exemplary embodiment of the present disclosure, physical quantities such as acceleration, vibration, strain, or internal stress of the holder 14 in the X, Y, and Z directions can be detected by at least two of the first sensor 56, the second sensor 58, and the third sensor 60. Acceleration of the holder 14 corresponding to cutting loads in three directions (principal force, thrust force, and feed force) can be detected by at least two of the first sensor 56, the second sensor 58, and the third sensor 60. Therefore, according to the exemplary embodiment of the present disclosure, high detection accuracy of the sensor unit 46 can be ensured.

[0049] When the first sensor 56, the second sensor 58, and the third sensor 60 detect physical quantities such as the acceleration of the holder 14 in the X, Y, and Z directions, it is possible to improve the detection accuracy of the sensor unit 46. In particular, when the position of the third sensor 60 in the X direction is the same as the position of the second sensor 58 in the X direction, it is possible to further improve the detection accuracy of the sensor unit 46.

[0050] If the distance in the X direction from the unit base 48 to the front end surface 22 of the holder 14 is shorter than the distance in the X direction from the unit base 48 to the rear end surface 24 of the holder 14, the sensor unit 46 will be located closer to the front end surface 22 of the holder 14 where changes in physical quantities such as acceleration are greater. Therefore, according to the example of the embodiment of the present disclosure, since the sensor unit 46 is closer to the cutting point, it is possible to capture minute changes in physical quantities, thereby improving the detection accuracy of the sensor unit 46.

[0051] According to the embodiment of the present disclosure, the unit base 48 is located in an orthogonal region on the outer surface of the holder 14, from the lower surface 28 of the main body 14m of the holder 14 to the second side surface 32. The unit base 48 is L-shaped in a cross section orthogonal to the X direction, which is the longitudinal direction of the holder 14. Therefore, the unit base 48 can be attached to the outer surface of the holder 14 without having to perform a process such as gouging out the holder 14. As a result, according to the embodiment of the present disclosure, the durability (rigidity) of the holder 14 can be increased.

[0052] Furthermore, according to the embodiment of the present disclosure, since unit base 48 has an L-shape in cross section perpendicular to the X direction, the amount of protrusion of sensor unit 46 from the outer surface of holder 14 can be reduced compared to when a cubic-shaped unit base is attached to the outer surface of holder 14. As a result, according to the embodiment of the present disclosure, sensor unit 46 is less susceptible to the effects of chips, increasing the durability of sensor unit 46 and simplifying attachment of cutting tool 10 to tool post 12.

[0053] Furthermore, according to the example embodiment of the present disclosure, the unit base 48 is attached to the holder 14 from two directions, the lower surface 28 and the second side surface 32 of the holder 14, so the unit base 48 is unlikely to fall off from the holder 14. Furthermore, not only is the unit base 48 unlikely to fall off from the holder 14, but the unit base 48 is also unlikely to become misaligned with respect to the holder 14.

[0054] When the entire first portion 48a of the unit base 48 is located closer to the second side surface 32 than to the first side surface 30 of the holder 14, the sensor unit 46 does not protrude in the Y direction from the first side surface 30 of the holder 14. Therefore, according to the example embodiment of the present disclosure, the sensor unit 46 is less susceptible to the effects of cutting chips, and the durability of the sensor unit 46 can be improved.

[0055] Furthermore, when the entire second portion 48b of the unit base 48 is located closer to the lower surface 28 of the holder 14 than to the upper surface 26 of the holder 14, the sensor unit 46 does not protrude in the Z direction from the upper surface 26 of the holder 14. Therefore, according to the example of the embodiment of the present disclosure, the sensor unit 46 is less susceptible to the effects of cutting chips, and the durability of the sensor unit 46 can be improved.

[0056] According to the embodiment of the present disclosure, the detection directions of the first sensor 56, the second sensor 58, and the third sensor 60 are one or two of the X, Y, and Z directions. In other words, the first sensor 56, the second sensor 58, and the third sensor 60 are one-axis sensors or two-axis sensors. Therefore, compared to using a three-axis sensor whose detection directions are the three directions of the X, Y, and Z directions, the size of each sensor can be made smaller, allowing for a more compact sensor unit 46.

[0057] As described above, the unit base 48 is located from the lower surface 28 to the second side surface 32 of the main body portion 14m of the holder 14, but it may also be configured as follows.

[0058] As shown in the example of FIGS. 10 and 11, the unit base 48 may be located from the lower surface 28 to the tip surface 22 of the holder 14 .

[0059] In this case, the unit base 48 may have a first portion 48a located on the lower surface 28 of the holder 14 and a second portion 48b located on the tip surface 22 of the holder 14. The first portion 48a of the unit base 48 may have a first recess that opens toward the lower surface 28 of the holder 14. The second portion 48b of the unit base 48 may have a second recess that opens toward the tip surface 22 of the holder 14. The second portion of the unit base 48 may have a third recess that opens toward the tip surface 22 of the holder 14. The first sensor located in the first recess of the unit base 48 may abut against the lower surface 28 of the holder 14. The second sensor located in the second recess of the unit base 48 may abut against the tip surface 22 of the holder 14. The third sensor located in the third recess of the unit base 48 may abut against the tip surface 22 of the holder 14.

[0060] 12 and 13, the unit base 48 may be located from the tip surface 22 to the second side surface 32 of the holder 14.

[0061] In this case, the unit base 48 may have a first portion 48a located on the tip surface 22 of the holder 14 and a second portion 48b located on the second side surface 32 of the holder 14. The first portion 48a of the unit base 48 may have a first recess that opens toward the tip surface 22 of the holder 14. The second portion 48b of the unit base 48 may have a second recess that opens toward the second side surface 32 of the holder 14. The second portion of the unit base 48 may have a third recess that opens toward the second side surface 32 of the holder 14. The first sensor located in the first recess of the unit base 48 may abut against the tip surface 22 of the holder 14. The second sensor located in the second recess of the unit base 48 may abut against the second side surface 32 of the holder 14. The third sensor located in the third recess of the unit base 48 may abut against the second side surface 32 of the holder 14.

[0062] In the above two cases, the sensor unit 46 is positioned close to the cutting edge 42 of the cutting insert 16, and the physical quantity of the holder 14 (cutting tool 10) can be detected with high accuracy. On the other hand, the cutting tool 10 of the example shown in Figures 1 to 9 can be positioned farther from the machined surface of the workpiece W than the cutting tool 10 of the example shown in Figures 10 to 13. Therefore, there is less risk that the sensor unit 46 will come into contact with the machined surface of the workpiece W.

[0063] <Method of manufacturing machined products> A method for manufacturing a machined product according to an embodiment of the present disclosure will be described with reference to Figures 14 to 16. Figures 14 to 16 are schematic views for explaining a method for manufacturing a machined product according to an embodiment of the present disclosure.

[0064] As shown in the examples of FIGS. 14 to 16 , 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 the workpiece W around its axis S. The second step is a step of bringing the cutting insert 16 of the cutting tool 10 into contact with the rotating workpiece W to cut the workpiece W. The third step is a step of separating the cutting tool 10 from the cut workpiece W. Examples of materials for the workpiece W include stainless steel, carbon steel, alloy steel, cast iron, and non-ferrous metals. The specific details of the method for manufacturing a machined product according to the embodiment are as follows.

[0065] First, the cutting tool 10 is attached to the tool rest 12, and the workpiece W is attached to the chuck of the lathe. Next, as shown in the example of FIG. 14, the chuck is rotated to rotate the workpiece W around its axis S (first step). Then, as shown in the example of FIG. 15, the cutting tool 10 is moved in the direction of arrow D1 to approach the workpiece W, and the cutting insert 16 is brought into contact with the rotating workpiece W, thereby cutting the workpiece W (second step). This allows a machined surface Wf to be formed on the workpiece W.

[0066] 16, the cutting tool 10 is moved in the direction of arrow D2 to separate the cutting tool 10 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.

[0067] To continue cutting, the cutting insert 16 may be repeatedly brought into contact with different locations on the workpiece W while the workpiece W 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 relatively close to each other, the workpiece W may also be brought close to the cutting tool 10. In this regard, the cutting tool 10 is moved away from the workpiece W in the same manner.

[0068] In one embodiment, (1) the cutting tool is provided with a holder having a rod shape extending from a tip to a rear end, the holder having a tip surface located on the tip side, an upper surface extending from the tip surface toward the rear end, a lower surface located opposite the upper surface, a first side surface located between the upper surface and the lower surface and extending from the tip surface toward the rear end, a second side surface located opposite the first side surface, and a pocket opening to the tip surface, the upper surface, and the first side surface; a cutting insert located in the pocket and having a cutting edge; a unit base located from the lower surface to the second side surface, the unit base having a first recess opening toward the lower surface and a second recess opening toward the second side surface, the unit base being L-shaped in a cross section perpendicular to the longitudinal direction of the holder; and a sensor unit having: a first sensor located in the first recess, abutting the lower surface, and detecting a physical quantity of the holder; and a second sensor located in the second recess, abutting the second side surface, and detecting a physical quantity of the holder in a detection direction perpendicular to the detection direction of the first sensor.

[0069] (2) In the cutting tool of (1), the unit base may have a third recess that opens toward the second side surface, and the sensor unit may further have a third sensor that is located within the third recess, abuts against the second side surface, and detects a physical quantity of the holder in a detection direction perpendicular to the detection directions of the first sensor and the second sensor.

[0070] (3) In the cutting tool of (2), the position of the third sensor in the longitudinal direction may be the same as the position of the second sensor in the longitudinal direction.

[0071] (4) In any of the cutting tools (1) to (3), the holder may further have a rear end surface located opposite the tip surface, and the longitudinal distance from the unit base to the tip surface may be shorter than the longitudinal distance from the unit base to the rear end surface.

[0072] (5) In any of the cutting tools (1) to (4), the unit base may have a first portion located on the lower surface and a second portion located on the second side surface, and the entire first portion may be located closer to the second side surface than to the first side surface.

[0073] (6) In any of the cutting tools (1) to (5), the unit base may have a first portion located on the lower surface and a second portion located on the second side surface, and the entire second portion may be located closer to the lower surface than to the upper surface.

[0074] (7) A method for manufacturing a machined product includes the steps of rotating a workpiece, bringing any one of the cutting tools (1) to (6) into contact with the rotating workpiece to cut the workpiece, and removing the cutting tool from the cut workpiece.

[0075] The invention according to the present disclosure has been described above based on the drawings and embodiments. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art could 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. [Explanation of symbols]

[0076] 10 cutting tools 12 Tool rest 12a Placement surface 12b Inner wall 12c fixing screw 14 Holder 14a Tip 14b rear end 14m main body 16 Cutting inserts 18 Clamp 20 clamp screws 22 Tip surface 24 Rear end surface 26 Top side 28 Bottom side 30 First aspect 32 Second aspect 34 pockets 36 First insert surface 38 Second insert surface 40 Insert side 42 cutting edge 44 through holes 46 Sensor Unit 48 unit base 48a Part 1 48b Part 2 50 First recess 52 Second recess 54 Third recess 56 First Sensor 58 Second Sensor 60 Third Sensor 62 Wiring materials 64 Groove 66 Wiring conductor

Claims

1. It has a rod shape extending from the front end to the rear end, a tip surface located on the tip side; an upper surface extending from the tip surface toward the rear end; a lower surface located opposite the upper surface; a first side surface located between the upper surface and the lower surface and extending from the tip surface toward the rear end; a second side surface located opposite the first side surface; a pocket opening to the tip surface, the top surface, and the first side surface; a holder having a cutting insert located in the pocket and having a cutting edge; a unit base that is positioned from the lower surface to the second side surface, has a first recess that opens toward the lower surface, and a second recess that opens toward the second side surface, and is L-shaped in a cross section perpendicular to the longitudinal direction of the holder; a first sensor located in the first recess, in contact with the lower surface, and configured to detect a physical quantity of the holder; a second sensor located in the second recess, in contact with the second side surface, and configured to detect a physical quantity of the holder in a detection direction perpendicular to the detection direction of the first sensor; A cutting tool comprising: a sensor unit having a

2. the unit base has a third recess that opens toward the second side surface, The sensor unit includes:

2. The cutting tool according to claim 1, further comprising a third sensor located within the third recess, abutting the second side surface, and detecting a physical quantity of the holder in a detection direction perpendicular to the detection directions of the first sensor and the second sensor.

3. The cutting tool of claim 2 , wherein the longitudinal position of the third sensor is the same as the longitudinal position of the second sensor.

4. the holder further has a rear end surface located opposite the front end surface, The cutting tool according to claim 1 , wherein the longitudinal distance from the unit base to the tip end surface is shorter than the longitudinal distance from the unit base to the rear end surface.

5. the unit base has a first portion located on the lower surface and a second portion located on the second side surface, The cutting tool according to claim 1 , wherein the entire first portion is located closer to the second side surface than to the first side surface.

6. 4. The cutting tool according to claim 1, wherein the unit base has a first portion located on the lower surface and a second portion located on the second side surface, and the entire second portion is located closer to the lower surface than to the upper surface.

7. rotating the workpiece; a step of bringing the cutting tool according to any one of claims 1 to 3 into contact with the rotating workpiece to cut the workpiece; and a step of separating the cutting tool from the cut workpiece.

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