Cutting insert, cutting tool, and method for manufacturing cut product

Abstract

The blade comprises an upper surface, a lower surface, a side surface, a cutting edge, and a through hole. The upper surface comprises a first corner in the form of a convex curve, and a first side and a second side extending from the first corner. The first area of ​​the first side surface is concave and recessed toward the axis. The upper surface further comprises a recessed portion located between the second side and the axis and recessed toward the axis. The entire recessed portion is located farther from the first corner than the entire first area in the direction along the axis.

Description

Technical Field

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

[0002] Known cutting tools for cutting workpieces such as metal include those described in Patent Documents 1 to 3. The cutting tools described in Patent Documents 1 and 2 have a tip portion that projects toward the workpiece and is tapered relative to the rest of the tip. The cutting tool described in Patent Document 3 secures the cutting insert to the tool holder using multiple screws.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-190107

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2005-040942

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 2006-035390 Summary of the Invention

[0008] An unrestricted example of a cutting insert in the present disclosure includes an upper surface, a lower surface, a side surface, a cutting edge, and a through hole. The upper surface has a first corner in the shape of a convex curve, and a first side and a second side extending from the first corner. The lower surface is located on the opposite side of the upper surface. The side surface is located between the upper surface and the lower surface. The cutting edge is located at the first corner and the first side. The through hole opens on the upper surface and the lower surface. The side surface includes a first side surface extending from the first side to the lower surface, and a second side surface extending from the second side to the lower surface. An imaginary straight line passing through the front end of the first corner and extending along the long axis of the upper surface when the upper surface is viewed from the front is referred to as an axis. The first side surface includes a first region and a second region. The first region extends from the first side to the lower surface and is concave toward the axis. The second region is located farther from the first corner than the first region and is flat. The upper surface further includes a recessed portion. When the upper surface is viewed from the front, the recessed portion is located between the second side and the axis and is recessed toward the axis. In the direction along the axis, the entire recess is located farther from the first corner than the entire first region. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1It is a perspective view showing a cutting tool in a non-limiting embodiment of the present disclosure.

[0010] Figure 2 It will Figure 1 The area A1 is shown in an enlarged view.

[0011] Figure 3 From another perspective Figure 1 A perspective view of the cutting tool shown.

[0012] Figure 4 It will Figure 3 The enlarged view is obtained by enlarging the area A2 shown.

[0013] Figure 5 It is the dominant observation Figure 1 The upper surface of the cutting tool is shown in FIG.

[0014] Figure 6 It will Figure 5 The area A3 is shown in an enlarged view.

[0015] Figure 7 yes Figure 1 A perspective view of the tool holder in the cutting tool is shown.

[0016] Figure 8 It is a perspective view of a blade showing a non-limiting example.

[0017] Figure 9 It will Figure 8 The enlarged view is obtained by enlarging the area A4 shown.

[0018] Figure 10 From another perspective Figure 8 A perspective view of the blade shown.

[0019] Figure 11 It will Figure 10 The enlarged view is obtained by enlarging the area A5 shown.

[0020] Figure 12 It is the dominant observation Figure 8 The upper surface of the blade is shown in FIG.

[0021] Figure 13 It will Figure 12 The enlarged view is obtained by enlarging the area A6 shown.

[0022] Figure 14 Observed from the direction of B1 Figure 12 The blade is shown in a front view.

[0023] Figure 15 It will Figure 14 The area A7 is shown in an enlarged view.

[0024] Figure 16 Observed from the direction of B2 Figure 12 The blade is shown in side view.

[0025] Figure 17 It will Figure 16 The area A8 is shown in an enlarged view.

[0026] Figure 18 yes Figure 13 An enlarged view of section XVIII-XVIII in the blade is shown.

[0027] Figure 19 yes Figure 12 An enlarged view of section XIX-XIX in the insert is shown.

[0028] Figure 20 This is a schematic diagram showing one step of a method for producing a machined product in a non-limiting example.

[0029] Figure 21 This is a schematic diagram showing one step of a method for producing a machined product in a non-limiting example.

[0030] Figure 22 This is a schematic diagram showing one step of a method for producing a machined product in a non-limiting example. DETAILED DESCRIPTION

[0031] The following drawings describe in detail a cutting insert (hereinafter, also referred to as an insert), a cutting tool, and a method for manufacturing a machined product according to an unrestricted embodiment of the present disclosure. However, in the figures referenced below, for ease of explanation, only the main components required to illustrate the embodiments are simplified. Therefore, the insert and cutting tool may include any components not shown in the figures referenced in this specification. Furthermore, the dimensions of the components in the figures do not accurately represent the dimensions of the actual components or the dimensional ratios of the components.

[0032] (1. Overview of Cutting Tools)

[0033] First, in order to facilitate understanding of the insert according to the non-limiting embodiment of the present disclosure, an example of a cutting tool equipped with the insert will be described. Figures 1 to 7 A brief description is given below. Figure 1 It is a perspective view showing a non-limiting example of the cutting tool 1 . Figure 2 It will Figure 1 The area A1 is shown in an enlarged view. Figure 3 From another perspective Figure 1 A perspective view of the cutting tool 1 is shown. Figure 4 It will Figure 3 The enlarged view is obtained by enlarging the area A2 shown.

[0034] Figure 5 It is the dominant observation Figure 1 FIG. 5 is a diagram showing the upper surface 51 of the insert 5 in the cutting tool 1 .

[0035] Figure 6 It will Figure 5 The area A3 is shown in an enlarged view. Figure 7 yes Figure 1 A perspective view of the tool holder 3 in the cutting tool 1 is shown.

[0036] Figures 1 to 6 The illustrated cutting tool 1 includes a tool holder 3, a blade 5, a first screw 7, and a second screw 9. The cutting tool 1 is, for example, a turning tool. Specific examples of the cutting tool 1 include tools for external diameter machining, tools for internal diameter machining, tools for grooving, and tools for cutting off.

[0037] (Knife Holder)

[0038] like Figures 1 to 7 As shown, the tool holder 3 is, for example, in the shape of a rod extending from the first end 3A toward the second end 3B along the central axis. Hereinafter, the central axis of the tool holder 3 is referred to as the first central axis O1. Generally speaking, the first end 3A is referred to as the front end, and the second end 3B is referred to as the rear end. The portion of the tool holder 3 on the side of the second end 3B ( Figure 1 The portion (shown as a quadrangular prism) in the tool holder is also referred to as a tool holder capable of being held by a machine tool. The first central axis O1 can be determined by defining an imaginary straight line passing through the center of the end surface on the second end 3B side of the tool holder 3 and parallel to the side surfaces of the tool holder. The tool holder 3 also has a tool groove 11, a first threaded hole 13, and a second threaded hole 15.

[0039] The knife groove 11 can be a portion for mounting the blade 5, and is located on the first end 3A side of the tool holder 3. The knife groove 11 in one example can be configured in a manner including the first end 3A, or can be open at the first end 3A. The knife groove 11 can also have a seat surface 17 and a limiting side surface 19 as a surface for the blade 5 to abut. The limiting side surface 19 can be a surface perpendicular to the seat surface 17 or a surface inclined relative to the seat surface 17. The seat surface 17 can extend parallel to the first center axis O1. In addition, the limiting side surface 19 can be inclined relative to the first center axis O1.

[0040] The limiting side surface 19 may include a first limiting side surface 19A close to the first central axis O1 and a second limiting side surface 19B away from the first central axis O1. The sipe 11 may have a receiving space 11A for receiving the front end of the blade 5 at the second end 3B.

[0041] The first threaded hole 13 and the second threaded hole 15 are surfaces for mounting screws for fixing the blade 5 to the tool holder 3. Examples of the screws for fixing the blade 5 to the tool holder 3 include the first screw 7 and the second screw 9.

[0042] The first threaded hole 13 may be opened in the knife groove 11. For example, the first threaded hole 13 may be as follows Figure 7 As shown, the second threaded hole 15 opens at the seat surface 17. In addition, the second threaded hole 15 can be located closer to the second end 3B than the first threaded hole 13. The second threaded hole 15 can open at the knife groove 11 like the first threaded hole 13, or it can be located at a position separated from the knife groove 11. Figure 7 The second threaded hole 15 in the illustrated example may open in the sipe 11 or may be arranged so as to be connected to the first restricting side surface 19A.

[0043] The tool holder 3 can be made of, for example, steel, cast iron, or aluminum alloy. The size of the tool holder 3 can be appropriately adjusted based on the size of the workpiece. The length of the tool holder 3 along the first central axis O1 can be set, for example, to be approximately 50 mm to 200 mm. Furthermore, the width perpendicular to the first central axis O1 can be set, for example, to be approximately 5 mm to 30 mm.

[0044] The blade 5 has a recess 64, and when the second screw 9 is inserted into the second threaded hole 15, the head of the second screw 9, i.e., the second screw head 9A, abuts against the recess 64, which will be described in detail later. Figures 1 to 6 As shown, the blade 5 is fixed to the blade holder 3 using both the first screw 7 and the second screw 9 .

[0045] (Key points of the blade)

[0046] In recent years, there has been a demand for cutting tools capable of performing more complex (and detailed) cutting operations on workpieces. Furthermore, cutting tools are also expected to be capable of processing with higher cutting loads in order to improve machining efficiency. Despite these expectations, there is also the issue of reduced cutting accuracy due to blade vibration during cutting.

[0047] It is difficult to address these multiple expectations simply by changing the blade shape. This is due to the following reasons: (i) a blade with a tapered tip, which is made longer in the longitudinal direction, increases the load on the first threaded hole 13 and the first screw 7 during cutting.

[0048] (ii) Furthermore, if the overall shape of the blade is made thinner, the diameter of the first screw 7 must be reduced. In this case, the restraining force of the first screw 7 is reduced, and the strength of the blade itself may also be reduced. (iii) Generally, the blade has a shape with play (clearance) relative to the tool slot 11 of the tool holder. To ensure cutting accuracy, the blade must be firmly restrained when the blade is installed in the tool slot 11.

[0049] Therefore, the blade 5 of the non-limited embodiment of the present disclosure is generally shaped to have a thinner front end while ensuring a thick center portion, and has a recess 64 for contact with the second screw 9. The position of the front end of the blade 5 in the longitudinal direction and the position of the recess 64 do not overlap each other.

[0050] According to one aspect of the present disclosure, it is possible to realize a cutting insert capable of performing complex cutting while ensuring durability.

[0051] (2. Details of the blade)

[0052] Hereinafter, the blade 5 according to one embodiment will be described in detail with reference to the drawings. Figure 8 It is a perspective view showing a blade 5 of a non-limiting example. Figure 9 It will Figure 8 The enlarged view is obtained by enlarging the area A4 shown. Figure 10 From another perspective Figure 8 The blade 5 is shown in a perspective view. Figure 11 It will Figure 10 The enlarged view is obtained by enlarging the area A5 shown. Figure 12 Is the main view (top view) Figure 8 The upper surface 51 of the blade 5 is shown in a top view. Figure 13 It will Figure 12 The enlarged view is obtained by enlarging the area A6 shown.

[0053] Figure 14 Observed from the direction of B1 Figure 12 The blade 5 is shown in a front view. Figure 15 It will Figure 14 The area A7 is shown in an enlarged view. Figure 16 Observed from the direction of B2 Figure 12 The blade 5 is shown in a side view. Figure 17 It will Figure 16 The area A8 is shown in an enlarged view. Figure 18 yes Figure 13 An enlarged view of the section XVIII-XVIII in the insert 5 is shown. Figure 19 yes Figure 12 An enlarged view of the XIX-XIX section of the blade 5 is shown.

[0054] like Figures 8 to 19 As shown, the blade 5 has an upper surface 51, a lower surface 52 located on the opposite side of the upper surface 51, a side surface 53 located between the upper surface 51 and the lower surface 52, a cutting edge 54, and a through hole 55 opened on the upper surface 51 and the lower surface 52. The blade 5 is not limited to a specific shape, but as an example, Figure 12 As shown, when the blade 5 is viewed from above, the blade 5 may have a partially recessed shape of a substantially square shape (substantially diamond shape) such that both front ends in the longitudinal direction are thinner than other portions.

[0055] In a non-limiting example, the insert 5 may have an upper surface 51 that is point-symmetrical with respect to the center point Q of the through-hole 55 in a plan view, or may be a so-called two-corner insert.

[0056] The upper surface 51 is as follows Figure 12 As shown in FIG. 1 , the first corner 56 is defined as the first corner 56 , and the second corner 59 is defined as the second corner 59 .

[0057] The upper surface 51 may have a first corner 56 in the shape of a convex curve, a first side 57 extending from the first corner 56, and a second side 58 extending from the first corner 56. The first side 57 is the side on the side of the side adjacent to the first corner 56 where the portion capable of functioning as at least the main edge of the cutting edge 54 is located. The second side 58 is the side of the side adjacent to the first corner 56 on the side opposite to the first side 57. The cutting edge 54 may not be located on the second side 58. The upper surface 51 may have a second corner 59 having the same or substantially the same shape as the first corner 56 on the opposite side across the through hole 55, and may have a third side 60 extending from the second corner 59, and a fourth side 61 extending from the second corner 59. The cutting edge 54 on the second corner 59 side is located on the third side 60.

[0058] Here, the portion of the upper surface 51 that is closest to the end in the longitudinal direction is referred to as the front end. When the upper surface 51 is viewed from the front (top view), an imaginary straight line that passes through the front end of the first corner 56 and extends along the longitudinal direction of the upper surface 51 is referred to as the axis L1. Since the upper surface 51 of the blade 5 has a 180° rotationally symmetrical shape, the axis L1 may also be an imaginary straight line that passes through the front end of the first corner 56 and the front end of the second corner 59 when viewed from top. In the case where the through hole 55 is provided at the center of the upper surface 51, the axis L1 may also pass through the center point Q of the through hole 55.

[0059] The axis L1 may also be a line that bisects or roughly bisects the angle of the intersection formed by imaginary extension of the straight first side 57 and the second side 58 near the center of the blade 5. The upper surface 51 of the blade 5 is in a 180° rotationally symmetrical shape, so the above-mentioned relationship is also the same in the relationship between the axis L1 and the third side 60 and the fourth side 61 on the second corner 59 side.

[0060] The lower surface 52 may be a surface located on the opposite side of the upper surface 51 and abuts against the seat surface 17 when the blade 5 is mounted on the tool holder 3. The lower surface 52 may have the same shape as the upper surface 51 or a different shape from the upper surface 51. In one example of the blade 5, the lower surface 52 is the same polygonal shape as the upper surface 51.

[0061] The side surface 53 has a first side surface 531 extending from the first edge 57 to the lower surface 52, a second side surface 532 extending from the second edge 58 to the lower surface 52, a third side surface 533 extending from the third edge 60 to the lower surface 52, and a fourth side surface 534 extending from the fourth edge 61 to the lower surface 52.

[0062] The first side surface 531 may include a first region 62 that is concave toward the axis L1 and a flat second region 63 that is located farther from the first corner 56 than the first region 62. The second side surface 532 may be a flat surface as a whole (see Figure 10 The third side surface 533 may have the same or substantially the same shape as the first side surface 531, that is, it may have areas corresponding to the first area 62 and the second area 63. The fourth side surface 534 may have the same or substantially the same shape as the second side surface 532.

[0063] In this specification, the description of "flat" or "plane" means that it is not a curved surface of a level that can be visually confirmed, or does not have unevenness of a level that can be visually confirmed, and does not require flatness in a strict sense. Therefore, the surface described as "flat" or "plane" can be allowed to have unevenness of an inevitable degree in the manufacture of the blade 5. Specifically, it can have unevenness of, for example, a surface roughness of 50 μm.

[0064] In addition, the meaning of the record of " straight shape " relevant to the edge in this manual refers to straight shape in fact, does not require a straight line in the strict sense (a straight line with a curvature of 0). Therefore, the edge recorded as " straight shape " can be a roughly straight shape, can be a shape with an undulating degree that is inevitable in the manufacture of blade 5, can have concave-convex etc. with the functional degree of the blade 5 in an example that does not damage the present disclosure. Specifically, in the case of a curve having a radius of curvature much larger than the first radius of curvature ~ the third radius of curvature described later, for example, in the case of a very slow curve that the radius of curvature exceeds 100mm, can be regarded as a straight line.

[0065] The cutting edge 54 is located at the first corner 56 and the first side 57, and as an example, is rotated with the workpiece 101 (see Figures 20 to 22 ) to cut the workpiece 101. The cutting edge 54 may be located on the entire first corner 56 or only on a portion of the first corner 56. Furthermore, the cutting edge 54 may be located on the entire first side 57 or only on a portion of the first side 57. The portion of the cutting edge 54 located on the first side 57 can function as the primary cutting edge during cutting. Therefore, the portion of the cutting edge 54 located on the first side 57 can generally be referred to as the primary cutting edge.

[0066] The cutting edge 54 can be located, for example, on a portion of the second side 58. The portion of the cutting edge 54 located on the second side 58 can also function as a wiper edge or a ramping edge, for example. Therefore, the portion of the cutting edge 54 located on the second side 58 can generally be referred to as an auxiliary cutting edge or a secondary cutting edge. The insert 5 can also be configured with cutting edges 54 on the second corner 59, the third side 60, and the fourth side 61.

[0067] The through hole 55 is a location for mounting a fixing member for fixing the blade 5 to the tool holder 3. Figure 1 In the example shown in FIG. 1 , a first screw 7 is inserted as a fixing member. The through hole 55 may have a tapered portion near the opening portion in the upper surface 51. In other words, the through hole 55 may have a portion on the upper surface 51 side where the inner diameter increases as it moves away from the lower surface 52 and closer to the upper surface 51. Alternatively, the first screw head 7A (see FIG. 1 ) may be abutted against the head of the first screw 7 at this portion. Figure 4 ), thereby fixing the blade 5 to the blade holder 3.

[0068] The through hole 55 may be opened at the center of the upper surface 51 and the center of the lower surface 52. In this case, the central axis of the blade 5 (hereinafter referred to as the central axis O2) shown by the imaginary straight line passing through the center of the upper surface 51 and the center of the lower surface 52 may be consistent with the central axis of the through hole 55 (refer to Figure 10 ). The central axis O2 can be the rotational symmetry axis of the blade 5.

[0069] The upper surface 51 may be as follows Figure 12 The top surface 51 is shown with a recess 64 located between the second side 58 and the axis L1 and recessed toward the axis L1 in a plan view.

[0070] In addition, the head of the second screw 9 can abut against the recess 64, and the blade 5 is screwed and fixed to the tool holder 3 by the abutment between the head of the second screw 9 and the recess 64. In addition, the blade 5 can have a plurality of recesses 64. Figure 8 In the example shown in FIG. 5 , the recesses 64 may be located on four sides of the upper surface 51 .

[0071] In the cutting tool 1 of the above example, the insert 5 is mounted and fixed to the tool holder 3 using the cutting edge 54 on the first corner 56 side, and the second screw 9 abuts against the recess 64 located on the fourth side 61 .

[0072] However, the cutting tool 1 is not limited to this example, and the insert 5 may be mounted on the tool holder 3 in such a manner that the second screw 9 abuts against the recess 64 located on the third side 60. Depending on how the cutting tool 1 is used (the shape of the tool holder 3, the direction in which the first corner 56 of the insert 5 protrudes from the tool holder 3, the direction in which the chips flow, etc.), either the recess 64 located on the third side 60 or the recess 64 located on the fourth side 61 may be used.

[0073] When the insert 5 is mounted and fixed to the tool holder 3 using the cutting edge 54 on the second corner 59 side, either the recess 64 located on the first side 57 or the recess 64 located on the second side 58 may be used.

[0074] In this embodiment, the recess 64 located on the first side 57 and the recess 64 located on the second side 58 are described. The recess 64 located on the third side 60 may have the same structure as the recess 64 located on the first side 57, and the recess 64 located on the fourth side 61 may have the same structure as the recess 64 located on the second side 58.

[0075] The entire recess 64 of the insert 5 is located farther from the first corner 56 than the entire first region 62 along the axis L1. The entire recess 64 of the insert 5 is located farther from the second corner 59 than the entire first region 62 along the axis L1.

[0076] The blade 5 is tapered at its tip by the concave first region 62. This facilitates complex cutting operations. Furthermore, the blade 5 is secured to the tool holder 3 by the second screw 9 abutting against the concave portion 64, resulting in a more secure fixation than when the blade 5 is secured to the tool holder 3 using only the first screw 7 inserted through the through hole 55.

[0077] Specifically, in Figure 1In the example shown in FIG. 1 , the lower surface 52 is pressed against the seat surface 17, the third side surface 533 abuts the second limiting side surface 19B, and at least a portion of the fourth side surface 534 abuts the first limiting side surface 19A. Thus, the insert 5 is firmly restrained, and the possibility of vibration of the insert 5 within the sipe 11 during cutting can be reduced.

[0078] Furthermore, as described above, the entire recess 64 of the insert 5 is located farther from the first corner 56 or the second corner 59 than the entire first region 62. Therefore, the wall thickness of the tip portion of the insert 5 can be ensured. As a result, the possibility of insufficient strength at the tip portion of the insert 5 is reduced. Furthermore, when using the cutting edge 54 on the first corner 56 side, the insert 5 is secured to the tool holder 3 using the recess 64 on the second corner 59 side with the second screw 9. Therefore, the second screw 9 does not become an obstacle when machining the workpiece 101.

[0079] As described above, the insert 5 has a small tip angle and sufficient strength. Therefore, by using the cutting tool 1 using the insert 5, it is possible to achieve both complex cutting and high processing efficiency.

[0080] Furthermore, the first side 57 may include a concave first section 65 arranged along the first region 62, and a straight second section 66 arranged along the second region 63. The upper surface 51 may further include a chip breaker wall 67 located between the first section 65 and the axis L1 and moving away from the lower surface 52 as it moves away from the first section 65.

[0081] The recess 64 may have a front end portion 68 closest to the first corner 56 in the direction along the axis L1. The chip-breaking wall surface 67 may have a rear end portion 69 farthest from the first corner 56 in the direction along the axis L1. The rear end portion 69 may be located farther from the first corner 56 than the front end portion 68 in the direction along the axis L1.

[0082] Chips generated in the portion of the cutting edge 54 located on the first side 57 tend to travel in a direction perpendicular to the first side 57. Specifically, chips generated on the first side 57 tend to travel toward the second side 58 and may travel toward the recess 64 located between the second side 58 and the axis L1. When chips travel toward the recess 64 located between the second side 58 and the axis L1, the second screw 9 may be damaged or the chips may become stuck between the recess 64 and the second screw 9. Specifically, when the insert 5 is mounted on the tool holder 3 in a manner such that the second screw 9 abuts the recess 64 of the second side 58, the second screw 9 may be damaged. Alternatively, when the second screw 9 does not abut the recess 64 of the second side 58, chips may remain in the recess 64. If chips remain, they may become trapped between the recess 64 and the second screw 9 when, for example, the corner used is changed.

[0083] On the other hand, the above-described structure can reduce the possibility of chips flowing into the recess 64. This is because when chips generated on the first side 57 move toward the recess 64 located between the second side 58 and the axis L1, the flow direction of the chips is easily changed by the chip breaker wall 67. The chip breaker wall 67 blocks the flow of chips into the recess 64, thereby reducing the above-described possibility.

[0084] like Figure 8 as well as Figure 12 As shown, the first side 57 may have a concave first section 65 arranged along the first region 62, and a straight second section 66 arranged along the second region 63. Figure 13 As shown, the first section 65 may have a straight line first portion 70 connected to the first corner 56 , a convex curve second portion 71 connected to the second section 66 , and a concave curve third portion 72 located between the first portion 70 and the second portion 71 , when viewed from above.

[0085] When the first side 57 includes a straight first portion 70 connected to the first corner 56, the flow direction of the chips generated by the first portion 70 tends to be stable. Therefore, the flow of the chips as a whole tends to be stable. To further stabilize the flow direction of the chips, the length of the first portion 70 may be longer than the other portions constituting the first section 65.

[0086] Furthermore, when the first side 57 includes a third portion 72 having a concave curve shape between the first portion 70 and the second portion 71, the durability of the cutting edge 54 is enhanced. When the cutting edge 54 is concave, the cutting load tends to concentrate near the bottom of the concave shape. However, when the third portion 72, corresponding to the bottom, is concave, this localized concentration of load at the bottom of the concave shape is easily avoided. Therefore, the overall durability of the cutting edge 54 is also enhanced.

[0087] Even when the first side 57 includes the second portion 71 in a convex curve shape connecting to the second section 66, the durability of the cutting edge 54 is high. If the first side 57 includes a concave first section 65 and a straight second section 66, the cutting load may concentrate at the boundary between these sections. However, when the second portion 71, which is the portion of the first section 65 connecting to the second section 66, is in a convex curve shape, the first section 65 and the second section 66 are easily and smoothly connected. Therefore, the cutting load is less likely to concentrate at the boundary between the first section 65 and the second section 66, and the cutting edge 54 as a whole also has high durability.

[0088] As described above, when the first side 57 includes the first portion 70 , the second portion 71 , and the third portion 72 , both the durability of the cutting edge 54 and the chip discharge performance can be improved.

[0089] When viewed from above, the radius of curvature of the first corner 56 of the convex curve shape is set as the first radius of curvature, the radius of curvature of the second portion 71 of the convex curve shape is set as the second radius of curvature, and the radius of curvature of the third portion 72 of the concave curve shape is set as the third radius of curvature. The blade 5 can have a first radius of curvature larger than the second radius of curvature, and a third radius of curvature larger than the first radius of curvature. The first radius of curvature can be set to, for example, about 0.2 to 0.8 mm. The second radius of curvature can be set to, for example, about 0.1 to 0.4 mm. The third radius of curvature can be set to, for example, about 0.5 to 2 mm.

[0090] Compared with the second portion 71, it is easy to apply a larger cutting load to the first corner 56 and the third portion 72. In addition, when the first to third radii of curvature are all large values, the blade 5 becomes large and it is difficult to miniaturize it. When the first and third radii of curvature are larger than the second radius of curvature, high durability can be obtained while miniaturizing the blade 5. Therefore, in the blade 5, it is possible to achieve complex cutting while ensuring durability.

[0091] Furthermore, the third portion 72 is concave, so the chips generated in the third portion 72 are more likely to be torn along the direction of the chips' travel the further they are from the third portion 72. When the chips are torn, their flow may become unstable. However, when the third radius of curvature is larger than the first radius of curvature, the curve of the third portion 72 becomes flatter. Therefore, the chips are less likely to be torn. This improves the durability of the cutting edge 54 and the degree of freedom in the cutting process while also enhancing chip removal.

[0092] like Figure 12As shown, the first section 65 may further include a fourth portion 73, which is a straight line, located between the second portion 71 and the third portion 72. When viewed from above, the inclination angle of the first portion 70 relative to the axis L1 may be smaller than the inclination angle of the second side 58 relative to the axis L1. Furthermore, when viewed from the front of the top surface 51, the inclination angle of the fourth portion 73 relative to the axis L1 may be larger than the inclination angle of the second side 58 relative to the axis L1. Furthermore, when viewed from the front of the top surface 51, the inclination angle of the second section 66 relative to the axis L1 may be the same as the inclination angle of the second side 58 relative to the axis L1.

[0093] According to the above structure, it is easier to ensure a larger area of ​​the tapered tip portion of the blade 5 than when the first section 65 does not have the fourth portion 73. Therefore, complex cutting processing is easier to perform, and processing efficiency is improved.

[0094] As described above, from the viewpoint of further stabilizing the flow direction of the chips, the length of the first portion 70 may be longer than the other portions constituting the first section 65. Therefore, the first portion 70 may be longer than the fourth portion 73.

[0095] (3. Blade material, etc.)

[0096] Examples of materials for the blade 5 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.

[0097] Furthermore, cermets are sintered composite materials formed by combining metal and ceramic components. Specifically, examples of cermets include cermets containing titanium compounds such as titanium carbide (TiC) or titanium nitride (TiN) as their main component.

[0098] The surfaces of the above-mentioned components constituting the blade 5 can be coated with a film using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the composition of the film include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), or aluminum oxide (Al2O3).

[0099] The size of the blade 5 is not particularly limited. For example, the length of one side of the polygonal upper surface 51 can be set to about 10 to 25 mm. In addition, the height from the upper surface 51 to the lower surface 52, in other words, the height along the direction of the second central axis O2 can be set to about 2 to 5 mm.

[0100] The size of the recess 64 is not particularly limited. For example, the width along the first side 57 or the second side 58 when viewing the top surface 51 from the front can be set to approximately 3 to 8 mm. Furthermore, the width in a direction perpendicular to the first side 57 or the second side 58 when viewing the top surface 51 from the front (the depth of the recess 64) can be set to approximately 1 to 3 mm. Furthermore, the width in a direction perpendicular to the first side 57 or the second side 58 when viewing the side surface 53 from the front (the depth of the recess 64) can be set to approximately 0.5 to 1 mm.

[0101] (First screw, second screw)

[0102] The first screw 7 is inserted into the through hole 55 and screwed into the first threaded hole 13. The second screw 9 abuts against the recess 64 and screwed into the second threaded hole 15. As described above, the first screw 7 and the second screw 9 are respectively used to fix the blade 5 to the tool holder 3.

[0103] Here, the first screw 7 can function as a main member for fixing the blade 5 to the tool holder 3. In addition, the second screw 9 can function as a member for suppressing the rotation of the blade 5 based on the first screw 7.

[0104] The recess 64 is open in the side surface 53, and the second screw 9 abuts against the recess 64, so the rotation of the blade 5 based on the first screw 7 is easily suppressed by the second screw 9. In addition, the recess 64 is also open in the upper surface 51, so it is easy to install the second screw 9 and easily make the second screw 9 abut against the recess 64 stably.

[0105] In addition, the recess 64 in the embodiment may also be located at a position separated from the lower surface 52. That is, compared to a case where the recess 64 reaches the lower surface 52, the amount of notches (space volume) such as the recess 64 in the blade 5 can be reduced. Therefore, the reduction in durability caused by providing the notch in the blade 5 is suppressed. Thus, the strength of the blade 5 can be ensured while suppressing the rotation of the blade 5.

[0106] As a member constituting the first screw 7 and the second screw 9 , for example, steel, cast iron, aluminum alloy, or the like can be used.

[0107] Since the through-hole 55 opens on both the upper surface 51 and the lower surface 52, the first screw 7 can be tilted relative to the cutting edge 54. For example, the first screw 7 can be positioned approximately perpendicular to the cutting edge 54. Furthermore, the maximum force applied to the cutting edge 54 during cutting, or the main force component, tends to be applied primarily in a direction perpendicular to the cutting edge 54. Therefore, the maximum force applied to the cutting edge 54 during cutting, or the main force component, is less likely to be directly transmitted to the first screw 7, resulting in increased durability of the first screw 7.

[0108] In this case, the second screw 9 may also be perpendicular to the cutting edge 54. In this case, the main force component described above is less likely to be directly transmitted to the second screw 9, and the durability of the second screw 9 is high.

[0109] The second screw 9 can be inclined relative to the first screw 7 or parallel to the first screw 7. When the second screw 9 is parallel to the first screw 7, the rotation of the blade 5 is further suppressed. The blade 5 easily rotates relative to the first screw 7, but the second screw 9 is perpendicular to this rotation direction, so the second screw 9 can stably receive the rotational movement of the blade 5.

[0110] The second screw 9 can abut against the recess 64 of the blade 5, and on the other hand, away from the side 53. In this case, the side 53 that can be used as the back surface is difficult to be damaged. In addition, the second screw head 9A (refer to Figure 4 ) abuts against the recess 64, while the thread groove of the second screw 9 is difficult to contact with the blade 5. Therefore, the thread groove of the second screw 9 is difficult to be damaged.

[0111] As described above, the blade groove 11 of the blade holder 3 may include the limiting side surface 19. Furthermore, the side surface 53 of the blade 5 may abut against the limiting side surface 19. In this case, the blade 5 can be positioned so as to be sandwiched between the limiting side surface 19 and the second screw 9. When the blade 5 is positioned so as to be sandwiched between the limiting side surface 19 and the second screw 9, positional displacement of the blade 5 is less likely to occur.

[0112] Furthermore, when the limiting side surface 19 is inclined relative to the first central axis O, the back force, which is one of the forces applied to the cutting edge 54 during cutting, is easily received by the limiting side surface 19. Therefore, the load of the back force on the first screw 7 and the second screw 9 is easily reduced. Therefore, the durability of the first screw 7 and the second screw 9 is high. For example, Figure 7 As shown, when the restriction side surface 19 is inclined so as to be separated from the first central axis O as it approaches the first end 3A, the back force is easily received by the restriction side surface 19 .

[0113] The first screw 7 and the second screw 9 can be of different or identical sizes. If the first screw 7 and the second screw 9 are of the same size, for example, even if the first screw 7 and the second screw 9 are installed upside down, there is no problem. This facilitates the manufacture of the cutting tool 1 and the replacement of the insert 5. Furthermore, since the first screw 7 and the second screw 9 can be standardized, manufacturing costs can also be reduced.

[0114] (4. Example of blade structure)

[0115] like Figure 12 As shown, in this embodiment, the structure in which the first side 57 and the cutting edge 54 are located on the left side when the blade 5 is viewed from above is taken as an example for explanation, but it is not limited to this structure. For example, it can also be a structure in which the first side 57 and the cutting edge 54 are located on the right side when the blade 5 is viewed from above. In other words, the blade 5 can also be Figure 12 The shape obtained by reversing the shape shown left to right.

[0116] (5. Method for Manufacturing Machined Product)

[0117] Next, a method for producing a machined product according to an embodiment will be described using the drawings. Figure 20 1 is a schematic diagram showing one step of a method for manufacturing a machined product 103 in an example which is not limited. Figure 21 1 is a schematic diagram showing one step of a method for manufacturing a machined product 103 in an example which is not limited. Figure 22 1 is a schematic diagram showing one step of a method for manufacturing a machined product 103 in an example which is not limited.

[0118] The machined product 103 is manufactured by cutting the workpiece 101. In the embodiment, outer diameter machining is exemplified as the cutting process. The method for manufacturing the machined product 103 in the embodiment includes the following steps. Specifically, it includes:

[0119] (1) A step of rotating the workpiece 101;

[0120] (2) a step of bringing the cutting tool 1 represented by the above-described embodiment into contact with the rotating workpiece 101; and

[0121] (3) A step of separating the cutting tool 1 from the workpiece 101 .

[0122] More specifically, first, if Figure 20 As shown, the workpiece 101 is rotated in the direction D1 around the axis D. In addition, the cutting tool 1 is moved in the direction D2 so that the cutting tool 1 is relatively close to the workpiece 101. Figure 21As shown, the cutting edge 54 of the cutting tool 1 is brought into contact with the workpiece 101 and cuts the workpiece 101 .

[0123] At this time, the outer diameter of the workpiece 101 can be processed by moving the cutting tool 1 in the direction D3. Figure 22 As shown, the cutting tool 1 is moved in the direction D4 so that the cutting tool 1 is relatively away from the workpiece 101 .

[0124] exist Figure 20 In the process, the cutting tool 1 is brought closer while the axis D is fixed and the workpiece 101 is rotated. Figure 21 In the embodiment, the cutting edge 54 of the blade 5 is brought into contact with the rotating workpiece 101 to cut the workpiece 101. Figure 22 In the process, the cutting tool 1 is moved away while the workpiece 101 is being rotated.

[0125] In the cutting process of the manufacturing method of the embodiment, the cutting tool 1 is moved so as to contact the workpiece 101. Furthermore, the cutting tool 1 is moved so as to separate from the workpiece 101. However, the manufacturing method of the embodiment is not limited to this structure.

[0126] For example, in step (1), the workpiece 101 may be brought close to the cutting tool 1. In step (3), the workpiece 101 may be moved away from the cutting tool 1. When the cutting process is continued, the cutting tool 1 is kept rotating and the steps of bringing the blade into contact with different parts of the workpiece 101 are repeated.

[0127] Typical examples of the material of the workpiece 101 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0128] The embodiments of the present disclosure have been described above based on the accompanying drawings and examples. However, the invention of the present disclosure is not limited to the above-mentioned embodiments. That is, the invention of the present disclosure can be variously modified within the scope shown in the present disclosure, and the embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention of the present disclosure. That is, it should be noted that anyone skilled in the art can easily make various modifications or corrections based on the present disclosure. In addition, it should be noted that these modifications or corrections are included in the scope of the present disclosure.

[0129] Description of Reference Numerals

[0130] 1 Cutting tools

[0131] 3 Tool holder

[0132] 5. Blade (cutting blade)

[0133] 7 First screw

[0134] 9 Second screw

[0135] 51 upper surface

[0136] 52 lower surface

[0137] 53 Side

[0138] 531 First side

[0139] 532 Second side

[0140] 54 cutting edges

[0141] 55 through hole

[0142] 56 First Corner

[0143] 57 First Side

[0144] 58 Second Side

[0145] 59 Second Corner

[0146] 60 Third Side

[0147] 61 The Fourth Side

[0148] 62 First Area

[0149] 63 Second Area

[0150] 64 recess

[0151] 65 First Interval

[0152] 66 Second interval

[0153] 67 Chip breaking wall

[0154] 68 front end

[0155] 69 rear end

[0156] 70 Part 1

[0157] 71 Part 2

[0158] 72 Part III

[0159] 73 Part 4

[0160] 101 cutting workpiece

[0161] 103 cutting workpiece

[0162] L1 axis.

Claims

1. A cutting insert, wherein: The cutting insert has: an upper surface having a first corner in a convex curved shape and a first side and a second side extending from the first corner; a lower surface located on an opposite side of the upper surface; a side surface located between the upper surface and the lower surface; a cutting edge located at the first corner and the first side; as well as a through hole opening on the upper surface and the lower surface, The side has: a first side surface extending from the first edge to the lower surface; as well as a second side surface extending from the second edge to the lower surface, When the upper surface is viewed from the front, an imaginary straight line passing through the front end of the first corner and extending along the long axis direction of the upper surface is referred to as an axis. The first side has: a concave first region that is recessed toward the axis; and a flat second region located further away from the first corner than the first region, The first side has: a concave first section arranged along the first region; and a second straight-line section arranged along the second region, The upper surface also has: a recessed portion located between the second side and the axis and recessed toward the axis when viewing the upper surface from the front; and a chip breaking wall surface located between the first section and the axis and moving away from the lower surface as it moves away from the first section, The recess has a front end portion closest to the first corner in a direction along the axis, The chip breaking wall surface has a rear end portion farthest from the first corner in the direction along the axis, In the direction along the axis, the entire recess is located farther from the first corner than the entire first region, and the rear end is located farther from the first corner than the front end.

2. The cutting insert according to claim 1, wherein The first section has the following features when the upper surface is viewed from the front: a first portion having a straight line shape connected to the first corner; a second portion having a convex curve shape connected to the second section; and The third portion has a concave curve shape and is located between the first portion and the second portion.

3. The cutting insert according to claim 2, wherein When observing the upper surface in a front view, the curvature radius of the first corner of the convex curve shape is set as a first curvature radius, the curvature radius of the second portion of the convex curve shape is set as a second curvature radius, and the curvature radius of the third portion of the concave curve shape is set as a third curvature radius. The first radius of curvature is larger than the second radius of curvature, and the third radius of curvature is larger than the first radius of curvature.

4. The cutting insert according to claim 2 or 3, wherein: The first section further includes a fourth portion in a straight line shape located between the second portion and the third portion. When observing the upper surface from the front, The inclination angle of the first portion relative to the axis is smaller than the inclination angle of the second side relative to the axis, The inclination angle of the fourth portion relative to the axis is greater than the inclination angle of the second side relative to the axis, An inclination angle of the second section relative to the axis is the same as an inclination angle of the second side relative to the axis.

5. The cutting insert according to claim 4, wherein The first portion is longer than the fourth portion.

6. A cutting tool, wherein: The cutting tool has: a tool holder in the shape of a rod extending from a first end toward a second end and having a tool groove located at the first end; The cutting insert according to any one of claims 1 to 5, which is located in the cutting groove; a first screw, inserted into the through hole and fixed to the tool holder; as well as A second screw abuts against the recess and is fixed to the tool holder.

7. A method for producing a machined product, wherein: The method for manufacturing the machined product comprises: The process of rotating the workpiece; a step of bringing the cutting tool according to claim 6 into contact with the rotating workpiece; and a step of separating the cutting tool from the workpiece.

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