Method for manufacturing cutting inserts, cutting tools, and cut workpieces
The cutting insert design with convex curved corners and geometrically configured land surfaces addresses the trade-off between surface accuracy and durability, achieving enhanced machining performance and durability through optimized cutting edge sharpness and chip flow control.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KYOCERA CORP
- Filing Date
- 2023-08-14
- Publication Date
- 2026-06-04
AI Technical Summary
Existing cutting inserts face a trade-off between improved surface accuracy of machined surfaces and durability, with linear land surfaces enhancing cutting performance but increasing chipping, while convex curved land surfaces improve durability but reduce surface accuracy.
A cutting insert design featuring a top surface with convex curved corners, linear side portions, and land surfaces with specific geometric configurations, including linear and convex curved sections, to enhance both cutting edge strength and durability.
The design achieves improved surface accuracy and durability of machined surfaces by optimizing cutting edge sharpness and chip flow management, reducing chipping and enhancing machining performance.
Smart Images
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Figure 0007870344000002 
Figure 0007870344000003
Abstract
Description
Technical Field
[0004] , , , , , ,
[0001] The present disclosure relates to a cutting insert used for cutting a workpiece, a cutting tool, and a method for manufacturing a machined product.
Background Art
[0002] As a cutting insert used when cutting a workpiece made of metal or the like, for example, the cutting inserts described in Patent Documents 1 and 2 are known. The cutting inserts described in Patent Documents 1 and 2 include a land surface (referred to as the first rake face in Patent Document 1 and as a land in Patent Document 2) located along the outer edge of their upper surface, and a rake face located along the land surface. By providing the cutting insert with a land surface, the edge strength of the cutting edge is increased, and the durability of the cutting insert is improved. Therefore, when performing a cutting process in which a large cutting load is applied to the cutting edge, such as rough machining, a cutting insert having a land surface is actively used. In the cutting inserts described in Patent Documents 1 and 2, the shape of the land surface in a cross section orthogonal to the outer edge of their upper surface (hereinafter, appropriately referred to as the cross-sectional shape of the land surface) is a straight line shape, but there are cases where the cross-sectional shape of the land surface is a convex curve shape.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Summary of the Invention
[0004] The cutting insert according to this disclosure comprises a top surface, a bottom surface located opposite the top surface, a side surface located between the top surface and the bottom surface, and a cutting edge located at the intersection of the top surface and the side surface. A virtual axis passing through the center of the top surface and the center of the bottom surface is defined as the insert's central axis, and a virtual plane located between the top surface and the bottom surface and perpendicular to the insert's central axis is defined as the reference plane. The top surface has an outer edge having a convex curved corner portion and a linear side portion extending from the corner portion, a land surface located along the outer edge, and a linear rake face located along the land surface and, in a cross section perpendicular to the outer edge, becoming linear as it moves away from the land surface and approaching the reference plane. The land surface has a first land surface located along the corner portion and a second land surface located along the side portion. The first land surface has a linear first straight portion in a cross section perpendicular to the corner portion. The entire second land surface has a convex curved shape in a cross section perpendicular to the side portion.
[0005] The cutting tool according to this disclosure comprises a holder and a cutting insert according to this disclosure. The holder is rod-shaped, extending from a first end to a second end, and has a pocket located on the side of the first end. The cutting insert is located within the pocket. [Brief explanation of the drawing]
[0006] [Figure 1] This is a schematic perspective view of a cutting insert according to an embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic top view of the cutting insert shown. [Figure 3] This is an enlarged view of part III in Figure 2. [Figure 4] The IVA in Figure 4 is a schematic cross-sectional view along the IVA-IVA line in Figure 3. The IVB in Figure 4 is an enlarged view of section F1 of the IVA in Figure 4. [Figure 5] VA in Figure 5 is a schematic cross-sectional view along the VA-VA line in Figure 3. VB in Figure 5 is an enlarged view of section F2 of VA in Figure 5. [Figure 6]VIA in Figure 6 is a schematic cross-sectional view along the VIA-VIA line in Figure 3. VIB in Figure 6 is an enlarged view of section F3 of VIA in Figure 6. [Figure 7] VIIA in Figure 7 is a schematic cross-sectional view along the VIIA-VIIA line in Figure 3. VIIB in Figure 7 is an enlarged view of section F4 of VIIA in Figure 7. [Figure 8] VIIIA in Figure 8 is a schematic cross-sectional view along the line VIIIA-VIIIA in Figure 3. VIIIB in Figure 8 is an enlarged view of section F5 of VIIIA in Figure 8. [Figure 9] This is a schematic perspective view of a cutting tool according to an embodiment of the present disclosure. [Figure 10] This is a schematic diagram illustrating a method for manufacturing a machined workpiece according to an embodiment of the present disclosure. [Figure 11] This is a schematic diagram illustrating a method for manufacturing a machined workpiece according to an embodiment of the present disclosure. [Figure 12] This is a schematic diagram illustrating a method for manufacturing a machined workpiece according to an embodiment of the present disclosure. [Modes for carrying out the invention]
[0007] When the cross-sectional shape of the land surface is linear, sharpening the cutting edge improves its cutting performance and thus the surface accuracy of the machined surface of the workpiece. However, this also makes the cutting edge more prone to chipping, raising concerns about a decrease in the durability of the cutting insert. Conversely, when the cross-sectional shape of the land surface is convex and curved, chipping is less likely to occur on the cutting edge, improving the durability of the cutting insert. However, this also makes it more difficult to improve the cutting edge's cutting performance, raising concerns about a decrease in the surface accuracy of the machined surface of the workpiece. In recent years, there has been a demand for achieving both improved surface accuracy of the machined surface of the workpiece and improved durability of the cutting insert.
[0008] According to this disclosure, it is possible to achieve both improved surface accuracy of the machined surface of the workpiece and improved durability of the cutting insert.
[0009] Hereinafter, the cutting insert, cutting tool, and method for manufacturing a machined workpiece according to the embodiments of this disclosure will be described in detail with reference to the drawings. However, for the sake of clarity, the drawings referenced below show only the components necessary for describing the embodiments in a simplified manner. Therefore, the cutting insert and cutting tool according to the embodiments of this disclosure may include any components not shown in the drawings referenced. Furthermore, the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component.
[0010] In this disclosure, "orthogonal" does not mean strictly orthogonal, but rather allows for an error of approximately ±5 degrees. "Parallel" does not mean strictly parallel, but rather allows for an error of approximately ±5 degrees.
[0011] <Cutting inserts> A cutting insert 10 according to an embodiment of the present disclosure will be described with reference to Figures 1 to 8. Figure 1 is a schematic perspective view of a cutting insert 10 according to an embodiment of the present disclosure. Figure 2 is a schematic top view of the cutting insert 10 shown in Figure 1. Figure 3 is an enlarged view of part III in Figure 2. IVA in Figure 4 is a schematic cross-sectional view along the IVA-IVA line in Figure 3. IVB in Figure 4 is an enlarged view of part F1 of IVA in Figure 4. VA in Figure 5 is a schematic cross-sectional view along the VA-VA line in Figure 3. VB in Figure 5 is an enlarged view of part F2 of VA in Figure 5. VIA in Figure 6 is a schematic cross-sectional view along the VIA-VIA line in Figure 3. VIB in Figure 6 is an enlarged view of part F3 of VIA in Figure 6. VIIA in Figure 7 is a schematic cross-sectional view along the VIIA-VIIA line in Figure 3. VIIB in Figure 7 is an enlarged view of part F4 of VIIA in Figure 7. VIIIA in Figure 8 is a schematic cross-sectional view along the line VIIIA-VIIIA in Figure 3. VIIIB in Figure 8 is an enlarged view of section F5 of VIIIA in Figure 8.
[0012] As shown in the examples of FIGS. 1 and 2, the cutting insert 10 may be an exchangeable insert used for machining a workpiece W (see FIG. 10). The cutting insert 10 may include an upper surface 12 and a lower surface 14 located on the opposite side of the upper surface 12. The upper surface 12 and the lower surface 14 may each be square-shaped. In other words, the cutting insert 10 may be square plate-shaped. The upper surface 12 and the lower surface 14 may each be a polygon other than a square shape, such as a triangular shape or a pentagonal shape, for example. In other words, the cutting insert 10 may be a multi-sided plate shape other than a square plate shape, such as a triangular plate shape or a square plate shape, for example. The term "polygon" is not limited to the strict meaning of a polygon shape.
[0013] As shown in the examples of FIGS. 1 and 2, the upper surface 12 and the lower surface 14 may each be a shape that is rotationally symmetric at regular angles about an insert central axis CS. In other words, the cutting insert 10 may be a shape that is rotationally symmetric at regular angles about the insert central axis CS. The insert central axis CS refers to a virtual axis passing through the center of the upper surface 12 and the center of the lower surface 14.
[0014] The cutting insert 10 may include a plurality of side surfaces 16 located between the upper surface 12 and the lower surface 14. Each of the plurality of side surfaces 16 may be connected to the upper surface 12 and the lower surface 14. The side surface 16 may have a function as a relief surface.
[0015] The cutting insert 10 may include a mounting hole 18 that penetrates from the upper surface 12 to the lower surface 14. One opening of the mounting hole 18 may be located at the central portion of the upper surface 12, and the other opening of the mounting hole 18 may be located at the central portion of the lower surface 14. The central axis of the mounting hole 18 may coincide with the insert central axis CS.
[0016] The cutting insert 10 may include a cutting edge E located at the intersection of the upper surface 12 and the side surface 16. The cutting edge E may be located over the entire intersection of the upper surface 12 and the side surface 16, or may be located at a part of the intersection.
[0017] As shown in the examples of FIGS. 1 and 2, the upper surface 12 may have an outer edge 12p that is the contour of the upper surface 12. The outer edge 12p of the upper surface 12 may have a first corner 20 as a corner portion and a second corner 22 as another corner portion. The first corner 20 and the second corner 22 may be alternately located at the outer edge 12p of the upper surface 12. The first corner 20 and the second corner 22 may each have a convex curve shape that protrudes outward in a top view. The top view means that the upper surface 12 is synonymous with a front view. The outer direction means the direction away from the insert central axis CS.
[0018] As shown in the examples of FIGS. 1 and 2, the outer edge 12p of the upper surface 12 may have two side portions 24 extending from each first corner 20. Each side portion 24 may be connected to the second corner 22. Each side portion 24 may have a linear shape in a top view. Having a linear shape in a top view means that in a top view, it is not limited to a strictly linear shape and includes a slightly curved shape.
[0019] As shown in the examples of FIGS. 1 to 3, the upper surface 12 may have a land surface 26 located along the outer edge 12p. Note that the above-mentioned "located along" refers to a state where two target regions extend in the same direction. Therefore, the two target regions may be separated from each other or in contact with each other.
[0020] For example, the land surface 26 being located along the outer edge 12p means that the land surface 26 extends in accordance with the shape of the outer edge 12p. At this time, the land surface 26 may be connected to the outer edge 12p, or the land surface 26 may be slightly separated from the outer edge 12p.
[0021] Since the cutting edge E is located at the outer edge 12p, the land surface 26 may be located along the cutting edge E. The land surface 26 may have a function of enhancing the edge strength of the cutting edge E. A part of the land surface 26 may have a function as a rake face. The land surface 26 may be connected to the cutting edge E.
[0022] As shown in the examples in Figures 1 to 5, the upper surface 12 may have a main rake face 28 located inside the land surface 26 and along the land surface 26. The main rake face 28 may primarily function as a rake face. The main rake face 28 may be connected to the land surface 26. The main rake face 28 may be a straight line inclined with respect to a reference plane BF in a cross section perpendicular to the outer edge 12p of the upper surface 12, such that it approaches the reference plane BF as it moves away from the land surface 26. The reference plane BF is a virtual plane located between the upper surface 12 and the lower surface 14 and perpendicular to the insert central axis CS. In Figures 4 (IVB), 5 (VB), 6 (IVB), 7 (VIIB), and 8 (VIIIB), the main rake face 28 is shown in bold and is a straight line in each cross-sectional view.
[0023] As shown in the examples in Figures 1 to 3, the upper surface 12 may have a connecting surface 30 located inside the main rake face 28 and along the main rake face 28. The connecting surface 30 may function as a rake face. The connecting surface 30 may be connected to the main rake face 28. In a cross section perpendicular to the outer edge 12p of the upper surface 12, the connecting surface 30 may have a shape that is recessed toward the reference plane BF.
[0024] As shown in the examples in Figures 1 to 3, the upper surface 12 may have a rising surface 32 located inside the connecting surface 30 and along the connecting surface 30. The rising surface 32 may have the function of curling the chips to improve chip evacuation. The rising surface 32 may be connected to the connecting surface 30. In a cross section perpendicular to the outer edge 12p of the upper surface 12, the rising surface 32 may be inclined with respect to the reference surface BF such that it moves away from the connecting surface 30 and away from the reference surface BF.
[0025] As shown in the examples in Figures 1 and 2, the upper surface 12 may have an upper end surface (boss surface) 34 surrounding one of the openings of the mounting hole 18. The upper end surface 34 may be perpendicular to the insert central axis CS. The upper end surface 34 may be connected to the rising surface 32 inside of the rising surface 32.
[0026] As shown in the example in Figure 2, the land surface 26 and the upper end surface 34 may each be symmetrical with respect to the insert centerline CL. The main rake face 28, connecting surface 30, and rising surface 32 may each be arranged symmetrically with respect to the insert centerline CL. The insert centerline CL is an imaginary line passing through the vertices of the two first corners 20 and the insert axis CS in a top view.
[0027] As shown in the examples in Figures 1 and 2, the cutting edge E may have a first cutting edge Ea located at the first corner 20 and a second cutting edge Eb located at the edge 24. The first cutting edge Ea may be located over the entire first corner 20, or in part of the first corner 20. The second cutting edge Eb may be located over the entire edge 24, or in part of the edge 24.
[0028] As shown in the examples in Figures 3, VIA of Figure 4, VA of Figure 5, VIA of Figure 6, VIIA of Figure 7, and VIIIA of Figure 8, the land surface 26 may have a first land surface 36 located along the first corner 20 and a second land surface 38 located along the edge 24. The land surface 26 may also have a third land surface 40 located between the first land surface 36 and the second land surface 38 and along the edge 24. The boundary between the first land surface 36 and the third land surface 40 is shown in VA and VB of Figure 5.
[0029] As shown in the examples in Figures 3, 4 (IVA), 4 (IVB), 5 (VA), and 5 (VB), the first land surface 36 may have a linear first straight section 36s in a cross section perpendicular to the first corner 20 (a cross section perpendicular to the outer edge 12p of the top surface 12). The first straight section 36s of the first land surface 36 may be inclined with respect to the reference surface BF in a cross section perpendicular to the first corner 20, such that it approaches the reference surface BF as it moves away from the first corner 20. The first land surface 36 may also have a circular arc section 36c in a cross section perpendicular to the first corner 20. The first circular arc section 36c of the first land surface 36 may be connected to the side surface 16. In Figures 4 (IVB) and 5 (VB), the first straight section 36s of the first land surface 36 is highlighted using a thick line.
[0030] In a cross section perpendicular to the first corner 20, the inclination angle θ1 of the first straight portion 36s of the first land surface 36 with respect to a virtual plane VF perpendicular to the insert central axis CS may be smaller than the inclination angle α1 of the main rake face 28. Also, the width T1 of the first land surface 36 in the direction perpendicular to the first corner 20 may increase as it approaches the edge portion 24 in a top view. The length M1 of the first straight portion 36s of the first land surface 36 in a cross section perpendicular to the first corner 20 may also increase as it approaches the edge portion 24. Since the reference plane BF is perpendicular to the insert central axis CS, the virtual plane VF is parallel to the reference plane BF. Therefore, for example, the inclination angle θ1 may be replaced with the inclination angle of the first straight portion 36s with respect to the reference plane BF.
[0031] As shown in the examples in Figure 3, Figure 7 VIIA, Figure 7 VIIB, Figure 8 VIIIA, and Figure 8 VIIIB, the entire second land surface 38 may have a convex curve shape that protrudes upward in a cross section perpendicular to the edge portion 24 (a cross section perpendicular to the outer edge 12p of the upper surface 12). The second land surface 38 may have a second circular arc portion 38c which is an arc shape in a cross section perpendicular to the edge portion 24. The second circular arc portion 38c of the second land surface 38 may be connected to the side surface 16.
[0032] The width T2 of the second land surface 38 in the direction perpendicular to the edge portion 24 may increase as it moves away from the first corner 20 in a top view. The second arc portion 38c of the second land surface 38 may be connected to the side surface 16. The radius of curvature R1 of the first arc portion 36c of the first land surface 36 and the radius of curvature R2 of the second arc portion 38c of the second land surface 38 may be the same. Two radii of curvature R1 and R2 being the same means that, taking into account manufacturing tolerances, etc., the difference between the two radii of curvature R1 and R2 is within ±5% of the average value of the two radii of curvature R1 and R2.
[0033] As shown in the examples in Figures 3, 5 VA, 5 VB, 6 VIA, and 6 VIB, the third land surface 40 may have a second linear portion 40s that is linear in shape in a cross section perpendicular to the edge portion 24 (a cross section perpendicular to the outer edge 12p of the top surface 12). The second linear portion 40s of the third land surface 40 may be inclined with respect to the reference surface BF such that it approaches the reference surface BF as it moves away from the edge portion 24 in a cross section perpendicular to the edge portion 24. The third land surface 40 may also have a third circular arc portion 40c that is arc-shaped in a cross section perpendicular to the edge portion 24. The third circular arc portion 40c of the third land surface 40 may be connected to the side surface 16. In Figures 5 VB and 6 VIB, the second linear portion 40s of the third land surface 40 is shown in bold.
[0034] In a cross-section perpendicular to the edge portion 24, the inclination angle θ2 of the second straight portion 40s of the third land surface 40 with respect to a virtual plane VF perpendicular to the insert central axis CS may be smaller than the inclination angle α2 of the main rake face 28. The width T3 of the third land surface 40 in the direction perpendicular to the edge portion 24 may be constant in a top view. The length M2 of the second straight portion 40s of the third land surface 40 in a cross-section perpendicular to the edge portion 24 may be constant. As mentioned above, the virtual plane VF is parallel to the reference plane BF. Therefore, for example, the inclination angle θ2 may be replaced with the inclination angle of the second straight portion 40s with respect to the reference plane BF.
[0035] The radius of curvature R1 of the first arc portion 36c of the first land surface 36, the radius of curvature R2 of the second arc portion 38c of the second land surface 38, and the radius of curvature R3 of the third arc portion 40c of the third land surface 40 may be the same. The three radii of curvature R1, R2, and R3 being the same means that, taking into account manufacturing tolerances, the maximum difference between the three radii of curvature R1, R2, and R3 is within ±5% of the average value of the three radii of curvature R1, R2, and R3.
[0036] As shown in the examples in Figures 1 and 2, the material of the cutting insert 10 can be, for example, cemented carbide and cermet. Examples of cemented carbide compositions include WC-Co, which is produced by sintering tungsten carbide (WC) with cobalt (Co) powder; WC-TiC-Co, which is produced by adding titanium carbide (TiC) to WC-Co; and WC-TiC-TaC-Co, which is produced by adding tantalum carbide (TaC) to WC-TiC-Co. Cermet is a sintered composite material that combines a ceramic component with a metal, and specifically, examples include sintered composite materials mainly composed of titanium compounds such as titanium carbide (TiC) and titanium nitride (TiN).
[0037] The surface of the cutting insert 10 may be coated with a film using chemical vapor deposition (CVD) or physical vapor deposition (PVD). Examples of film compositions include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al2O3).
[0038] In an example of the embodiment of this disclosure, the first land surface 36 is located along the first corner 20, which is located near the machined surface of the workpiece W. The first land surface 36 has a linear first straight portion 36s in a cross section perpendicular to the first corner 20. Therefore, in an example of the embodiment of this disclosure, the first cutting edge Ea of the cutting edge E can be made sharper, improving the cutting performance of the cutting edge E and thus improving the surface accuracy of the workpiece W.
[0039] In an example of the embodiment of this disclosure, the second land surface 38 is located along the edge portion 24 that plays a major role in cutting the workpiece W, away from the machined surface of the workpiece W. The entire second land surface 38 has a convex curve shape in a cross section perpendicular to the edge portion 24. Therefore, according to an example of the embodiment of this disclosure, chipping of the cutting edge E is less likely to occur, and the durability of the cutting insert 10 can be improved.
[0040] In other words, according to the embodiment of this disclosure, it is possible to achieve both improved surface accuracy of the workpiece W and improved durability of the cutting insert 10.
[0041] If the first straight portion 36s of the first land surface 36 approaches the reference surface BF as it moves away from the first corner 20 in a cross section perpendicular to the first corner 20, the first cutting edge Ea can be made sharper, the cutting performance of the cutting edge E can be improved, and the surface accuracy of the workpiece W can be further improved.
[0042] In a cross-section perpendicular to the first corner 20, if the inclination angle θ1 of the first straight portion 36s of the first land surface 36 is smaller than the inclination angle α1 of the main rake face 28, the cutting edge strength of the cutting edge E, in particular the cutting edge strength of the first cutting edge Ea, can be sufficiently increased while securing space for chip flow and controlling the flow of chips.
[0043] When the radius of curvature R1 of the first arc portion 36c of the first land surface 36 and the radius of curvature R2 of the second arc portion 38c of the second land surface 38 are the same, variations in the cutting edge E's sharpness are reduced, and the surface accuracy of the workpiece W is further improved. In particular, when the radius of curvature R1 of the first arc portion 36c of the first land surface 36, the radius of curvature R2 of the second arc portion 38c of the second land surface 38, and the radius of curvature R3 of the third arc portion 40c of the third land surface 40 are the same, variations in the cutting edge E's sharpness can be sufficiently reduced, and the surface accuracy of the workpiece W can be further improved.
[0044] When the width T1 in the direction perpendicular to the first corner 20 of the first land surface 36 increases as it approaches the edge 24, the portion of the first cutting edge Ea that is further away from the second cutting edge Eb can be made sharper, thereby improving the cutting performance of the cutting edge E and further improving the surface accuracy of the workpiece W. In particular, when the length M1 of the first straight portion 36s of the first land surface 36 in the cross section perpendicular to the first corner 20 increases as it approaches the edge 24, the portion of the first cutting edge Ea that is further away from the second cutting edge Eb can be made even sharper, further improving the surface accuracy of the workpiece W.
[0045] When the width T2 in the direction perpendicular to the edge portion 24 of the second land surface 38 increases as it moves away from the first corner 20, the cutting edge strength of the cutting edge E can be increased in the region of the second land surface 38 that is further away from the first land surface 36. As a result, even in cutting operations with a large depth of cut (cutting operations with a large amount of material removed), chipping of the cutting edge E becomes less likely, and the durability of the cutting insert 10 can be further improved.
[0046] When the third land surface 40 has a linear second linear portion 40s in a cross-section perpendicular to the edge portion 24, a significant decrease in the cutting performance of the cutting edge E can be avoided even under the first machining conditions using the first cutting edge Ea and the second cutting edge Eb, compared to the case where the entire portion of the land surface 26 along the edge portion 24 is the second land surface 38. As a result, the surface accuracy of the workpiece W can be improved even under the first machining conditions.
[0047] When the width T3 in the direction perpendicular to the edge portion 24 of the third land surface 40 is constant, in a second machining condition in which the first land surface 36 and the third land surface 40 contribute to chip flow control and the second land surface 38 does not contribute to chip flow control, the chip flow direction is aligned on the third land surface 40. As a result, in the second machining condition, the chip flow on the third land surface 40 becomes dominant, making it less likely for chips to clog the land surface 26 and improving chip discharge.
[0048] <Cutting tools> A cutting tool 42 according to an embodiment of the present disclosure will be described with reference to Figure 9. Figure 9 is a schematic perspective view of a cutting tool 42 according to an embodiment of the present disclosure.
[0049] As shown in Figure 9, the cutting tool 42 according to the embodiment of this disclosure may be a tool used for turning, a type of cutting process. Examples of turning processes include outer diameter machining, grooving, and parting. The cutting tool 42 according to the embodiment of this disclosure may include a rod-shaped holder 44. The holder 44 may extend from its first end (front) 44a to its second end (rear) 44b. The holder 44 is made of a metal material such as steel. The holder 44 may have a pocket 46 located on the side of the first end 44a. The holder 44 may have a screw hole opening in the pocket 46.
[0050] The cutting tool 42 may include a cutting insert 10 located in a pocket 46 of the holder 44. The cutting insert 10 is attached to the pocket 46 of the holder 44 by inserting a clamp screw 48 through a mounting hole 18 of the cutting insert 10 and screwing it into a threaded hole in the holder 44 and tightening it.
[0051] In this disclosure, a cutting tool 42 used for turning, a type of cutting process, is given as an example; however, a cutting tool used for milling, another type of cutting process, may also include a cutting insert 10 as a component.
[0052] <Method for manufacturing machined parts> A method for manufacturing a machined workpiece according to an embodiment of this disclosure will be described with reference to Figures 10 to 12. Figures 10 to 12 are schematic diagrams illustrating a method for manufacturing a machined workpiece according to an embodiment of this disclosure.
[0053] As shown in the examples in Figures 10 to 12, the method for manufacturing a machined workpiece according to the embodiment of this disclosure is a method for manufacturing a machined workpiece M, which is a machined workpiece W, and comprises a first step, a second step, and a third step. The first step is to rotate the workpiece W around its axis S. The second step is to bring the cutting insert 10 of the cutting tool 42 into contact with the rotating workpiece W and cut the workpiece W. The third step is to remove the cutting tool 42 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 workpiece according to the embodiment are as follows.
[0054] First, the cutting tool 42 is attached to the tool post of the lathe, and the workpiece W is mounted in the chuck of the lathe. Next, as shown in the example in Figure 10, the chuck is rotated to rotate the workpiece W around its axis S (first step). Then, as shown in the example in Figure 11, the cutting tool 42 is moved in the direction of arrow D1 to bring it closer to the workpiece W, and the cutting insert 10 of the cutting tool 42 comes 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.
[0055] Subsequently, as shown in the example in Figure 12, the cutting tool 42 is moved in the direction of arrow D2, thereby separating the cutting tool 42 from the workpiece W (third step). This completes the cutting of the workpiece W, and a machined workpiece M, which is the machined workpiece W, can be manufactured. Because the cutting insert 10 of the cutting tool 42 has excellent cutting ability for the reasons mentioned above, a machined workpiece M with excellent machining accuracy can be manufactured.
[0056] To continue the cutting process, the cutting tool 42's cutting insert 10 can be repeatedly brought into contact with different parts of the workpiece W while the workpiece W is being rotated. In this embodiment of the disclosure, the cutting tool 42 is brought close to the workpiece W, but it is sufficient for the cutting tool 42 and the workpiece W to be relatively close, so the workpiece W may also be brought close to the cutting tool 42. The same procedure is followed when moving the cutting tool 42 away from the workpiece W.
[0057] In one embodiment, (1) the cutting unit comprises an upper surface, a lower surface located opposite the upper surface, a side surface located between the upper surface and the lower surface, and a cutting edge located at the intersection of the upper surface and the side surface. When a virtual axis passing through the center of the upper surface and the center of the lower surface is defined as the insert central axis, and a virtual plane located between the upper surface and the lower surface and perpendicular to the insert central axis is defined as the reference plane, the upper surface has an outer edge having a convex curved corner portion and a straight edge portion extending from the corner portion, a land surface located along the outer edge, and a main rake face located along the land surface and having a straight shape in a cross section perpendicular to the outer edge, such that it approaches the reference plane as it moves away from the land surface. The land surface has a first land surface located along the corner portion and a second land surface located along the edge portion. The first land surface has a first straight portion that is straight in a cross section perpendicular to the corner portion. The entire second land surface has a convex curve shape in a cross section perpendicular to the edge portion.
[0058] (2) In the cutting insert of (1), the width of the first straight portion in the direction perpendicular to the corner portion may be such that, in a cross section perpendicular to the corner portion, it approaches the reference plane as it moves away from the corner portion.
[0059] (3) In the cutting insert of (2) above, the inclination angle of the first straight portion with respect to a virtual plane perpendicular to the central axis of the insert in a cross section perpendicular to the corner portion may be smaller than the inclination angle of the main rake face.
[0060] (4) In any of the cutting inserts described in (1) to (3) above, the first land surface may further have a first arc portion connected to the side surface and having an arc shape in a cross section perpendicular to the corner portion. The second land surface may have a second arc portion connected to the side surface and having an arc shape in a cross section perpendicular to the edge portion. The radius of curvature of the first arc portion and the radius of curvature of the second arc portion may be the same.
[0061] (5) In any of the cutting inserts described in (1) to (4) above, the width of the first land surface in the direction perpendicular to the corner portion may increase as it approaches the edge portion.
[0062] (6) In the cutting insert of (5) above, the length of the first straight portion in the cross section perpendicular to the corner portion may increase as it approaches the side portion.
[0063] (7) In any of the cutting inserts described in (1) to (6) above, the width of the second land surface in the direction perpendicular to the edge portion may increase as it moves away from the corner portion.
[0064] (8) In any of the cutting inserts described in (1) to (7), the land surface may further have a third land surface located between the first land surface and the second land surface along the edge. The third land surface may have a second straight portion that is linear in shape in a cross section perpendicular to the edge.
[0065] (9) In the cutting insert of (8) above, the width in the direction perpendicular to the edge portion on the third land surface may be constant.
[0066] (10) The cutting tool comprises a holder having a rod shape extending from a first end to a second end and a pocket located on the side of the first end, and any of the cutting inserts (1) to (9) located within the pocket.
[0067] (11) The process includes the steps of rotating the workpiece, bringing the cutting tool (10) into contact with the rotating workpiece, and removing the cutting tool from the workpiece.
[0068] The inventions described in this disclosure have been explained based on the drawings and embodiments. However, the inventions described in this disclosure are not limited to the embodiments described above. That is, the inventions described in this disclosure can be modified in various ways within the scope shown in this disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the inventions described in this disclosure. In other words, it should be noted that it is easy for those skilled in the art to make various modifications or alterations based on this disclosure. Furthermore, it should be noted that these modifications or alterations are included in the scope of this disclosure. [Explanation of Symbols]
[0069] 10 cutting inserts 12 Top side 12p outer edge 14 Bottom side 16 Side view 18 mounting holes 20. First corner (corner section) 22. Second Corner (Other Corner Sections) 24 side 26 Land surface 28 Main scooping surface 30 connection surface 32. Rising surface 34 Upper end surface 36. First Round 36s 1st straight section 36c First arc section 38 Second Round 38c Second arc section 40 Third Round 40s 2nd straight section 40c Third arc section 42 Cutting tools 44 holder 46 pockets 48 clamp screws E Cutting edge Ea First Cutting Edge Eb Second cutting edge
Claims
1. Top surface and, The lower surface located on the opposite side of the upper surface, A side surface located between the upper surface and the lower surface, It comprises a cutting edge located at the intersection of the upper surface and the side surface, When a virtual axis passing through the center of the upper surface and the center of the lower surface is defined as the insert central axis, and a virtual plane located between the upper surface and the lower surface and perpendicular to the insert central axis is defined as the reference plane, The aforementioned upper surface is, An outer edge having a convex curved corner portion, and a straight edge portion extending from the corner portion and sharing the endpoint of the corner portion, A land surface located along the aforementioned outer edge, It has a principal rake face located along the land surface and having a linear shape in a cross section perpendicular to the outer edge such that it approaches the reference plane as it moves away from the land surface, The aforementioned land surface is A first land surface located along the aforementioned corner portion, A second land surface located along the aforementioned edge, A third land surface is located between the first land surface and the second land surface along the edge portion, The first land surface has a first straight section that is linear in shape in a cross-section perpendicular to the corner portion, The entire second land surface has a convex curve shape in a cross section perpendicular to the edge portion. The third land surface has a second straight section that is linear in shape in a cross-section perpendicular to the edge portion, The first straight section, in a cross-section perpendicular to the corner, approaches the reference plane as it moves away from the corner. A cutting insert in which, in a cross section perpendicular to the corner portion, the inclination angle of the first straight portion with respect to a virtual plane perpendicular to the central axis of the insert is smaller than the inclination angle of the main rake face.
2. The first land surface is connected to the side surface and further has a first arc portion which is arc-shaped in a cross section perpendicular to the corner portion, The second land surface is connected to the side surface and has a second arc portion which is arc-shaped in cross-section perpendicular to the edge portion. The cutting insert according to claim 1, wherein the radius of curvature of the first arc portion and the radius of curvature of the second arc portion are the same.
3. The cutting insert according to claim 1, wherein the width of the first land surface in the direction perpendicular to the corner portion increases as it approaches the edge portion.
4. The cutting insert according to claim 3, wherein the length of the first straight section in the cross-section perpendicular to the corner portion increases as it approaches the side portion.
5. The cutting insert according to claim 1, wherein the width of the second land surface in the direction perpendicular to the edge portion increases as it moves away from the corner portion.
6. The cutting insert according to claim 1, wherein the width in the direction perpendicular to the edge portion on the third land surface is constant.
7. A holder having a rod shape extending from a first end to a second end, with a pocket located on the side of the first end, A cutting tool comprising a cutting insert located within the aforementioned pocket, as described in any one of claims 1 to 6.
8. The process of rotating the workpiece, A step of bringing the cutting tool described in claim 7 into contact with the rotating workpiece, A method for manufacturing a machined workpiece, comprising the step of separating the cutting tool from the workpiece.