Cutting tool and method for manufacturing cut workpiece

Abstract

A cutting tool according to one non-limiting aspect of the present disclosure comprises: a first member that extends from a rear end toward a tip along a central axis; a second member that is positioned on the tip side with respect to the first member and extends along the central axis; and screws that fix the first member and the second member. The first member has a protrusion positioned on the tip side, and a first hole extending from the protrusion toward the rear end. The second member has a recess into which the protrusion is fitted, a second hole extending from the recess toward the tip, a third hole extending from the second hole toward the tip, and a second coolant hole extending from the recess to the third hole. The screws are attached to the first hole and the second hole. The inner diameter of the third hole is larger than the inner diameter of the second hole.

Description

Cutting Tool and Method for Manufacturing a Machined Product Cross - Reference to Related Applications

[0001] This application claims the priority of Japanese Patent Application No. 2024 - 162188 filed on September 19, 2024, and the entire disclosure of this prior application is incorporated herein by reference for that purpose.

[0002] The present disclosure relates to a cutting tool used for cutting a workpiece and a method for manufacturing a machined product. Examples of the cutting may include turning and milling. Examples of turning may include internal diameter machining, external diameter machining, grooving, and parting off.

[0003] As a cutting tool used when cutting a workpiece, for example, a cutting tool described in Japanese Utility Model Laid - Open No. 05 - 088823 (Patent Document 1) may be mentioned. The cutting tool described in Patent Document 1 has a pair of split pieces. Among these split pieces, the one located on the tip side is the body, and the one located on the rear end side is the adapter. The adapter is generally also called a chuck or an arbor. A convex portion is provided on one of the body and the adapter, and a concave portion into which the aforementioned convex portion is fitted is provided on the other of the body and the adapter. A screw hole is formed in the cutting tool described in Patent Document 1 in the convex portion and the concave portion, and by attaching a screw to this screw hole, the body is fixed to the adapter.

[0004] A cutting tool according to a non - limiting aspect of the present disclosure has a first member extending from the rear end toward the tip along the central axis, a second member located on the tip side of the first member and extending along the central axis, and a screw for fixing the first member and the second member.

[0005] The first member has a protrusion located on the tip side, a first hole extending from the protrusion toward the rear end and having a first screw groove on its inner circumferential surface, and one or more first coolant holes extending from the protrusion toward the rear end. The second member has a recess located on the rear end side into which the protrusion is fitted, a second hole extending from the recess toward the tip and having a second screw groove on its inner circumferential surface and located coaxially with the first hole, a third hole extending from the second hole toward the tip, and one or more second coolant holes extending from the recess toward the third hole.

[0006] The screws are fitted into the first and second holes. The inner diameter of the third hole is larger than the inner diameter of the second hole.

[0007] This is a perspective view of a cutting tool, not limited to this disclosure. This is a side view of the cutting tool shown in Figure 1. This is a cross-sectional view of section III in the cutting tool shown in Figure 2. This is a plan view of the first member of the cutting tool shown in Figure 1, viewed from the tip side. This is a cross-sectional view of section V in the first member shown in Figure 4. This is a perspective view of the second member of the cutting tool shown in Figure 1. This is a side view of the second member shown in Figure 6. This is a plan view of the second member shown in Figure 6, viewed from the tip side. This is a plan view of the second member shown in Figure 6, viewed from the rear end side. This is a cross-sectional view of section X in the second member shown in Figure 9. This is a perspective view of the second member and screw in the cutting tool shown in Figure 1. This is a side view of the member shown in Figure 11. This is a plan view of the member shown in Figure 11, viewed from the rear end side. This is a cross-sectional view of section XIV in the member shown in Figure 13. This is a perspective view of a cutting tool, not limited to this disclosure. This is a side view of the cutting tool shown in Figure 15. This is a cross-sectional view of section XVII in the cutting tool shown in Figure 16. This is a plan view of the first member of the cutting tool shown in Figure 15, viewed from the rear end side. This is a schematic diagram showing one step in a method for manufacturing a one-sided machined workpiece, not limited to this disclosure. This is a schematic diagram showing one step in a method for manufacturing a one-sided machined workpiece, not limited to this disclosure. This is a schematic diagram showing one step in a method for manufacturing a one-sided machined workpiece, not limited to this disclosure.

[0008] <Cutting Tools> A cutting tool 1, which is not limited to this disclosure, will be described in detail below with reference to the drawings. However, in the drawings referenced below, for the sake of convenience of explanation, only the main components necessary for describing the embodiment are shown in a simplified manner. Therefore, the cutting tool 1 may include any components not shown in the drawings referenced below. Also, 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.

[0009] The cutting tool 1 may extend along the central axis O1 from the rear end 1a to the front end 1b, as shown in the example (not limited to) in Figures 1 to 3. The cutting tool 1 is also rotatable around the central axis O1. Therefore, the central axis O1 may also be referred to as the rotation axis O1. The arrow Y1 in Figure 1 and other figures may indicate the direction of rotation of the central axis O1, or it may indicate the direction of rotation of the cutting tool 1 around the central axis O1.

[0010] The cutting tool 1 may have a first member 3, a second member 5, and a screw 7, as shown in the example (not limited to) in Figures 1 to 14.

[0011] The first member 3 can function as a component attached to a machine tool. The first member 3 may also be called a chuck or arbor. The first member 3 may also be called a connector. The first member 3 may extend along the central axis O1 from the rear end 1a to the front end 1b, as in one example not limited to the one shown in Figure 1. The first member 3 may be rod-shaped.

[0012] The first member 3 may include a rear end 1a. The side of the first member 3 with the rear end 1a may be designed according to the machine tool. For this reason, in Figure 1 and other figures, the rear end 1a is shown by a dashed line for convenience. For example, the rear end 1a may be located further from the front end 1b than the position shown by the dashed line.

[0013] The second member 5 may function as a component that plays a major role in the cutting process of the workpiece. The second member 5 may also be referred to as the main body. The second member 5 may be located closer to the tip 1b than the first member 3. The second member 5 may extend along the central axis O1. The second member 5 may be rod-shaped. The second member 5 may include the tip 1b.

[0014] The screw 7 may be used to fasten the first member 3 and the second member 5, as shown in the example (not limited to) in Figure 3.

[0015] The first member 3 may have a protrusion 9, a first hole 11, and a first coolant hole 13, as shown in the example not limited to the first member 3 and the fifth member 5.

[0016] The protrusion 9 may be located on the side of the tip 1b. The protrusion 9 may be the part of the first member 3 that is closest to the tip 1b.

[0017] The first hole 11 may extend from the protrusion 9 toward the rear end 1a. The first hole 11 may have a first screw groove 15 on its inner circumferential surface. A screw 7 can be attached to the first screw groove 15. The first hole 11 may also open at the top 17 of the protrusion 9.

[0018] The first coolant hole 13 allows coolant to flow through it. The first coolant hole 13 may extend from the protrusion 9 toward the rear end 1a. The first coolant hole 13 may open at the top 17 of the protrusion 9. The first coolant hole 13 may be located further from the central axis O1 than the first hole 11.

[0019] The first coolant hole 13 may be just one, or it may be multiple. In other words, the first coolant hole 13 may be one or more.

[0020] If there are multiple first coolant holes 13, the number of first coolant holes 13 may be 2 to 4. The first member 3 in the example shown in Figure 4, which is not limited to this example, has four first coolant holes 13. If there are multiple first coolant holes 13, the multiple first coolant holes 13 may be positioned such that they are rotationally symmetric with respect to the central axis O1 when the first member 3 is viewed from the tip 1b side.

[0021] The second member 5 may have a recess 19, a second hole 21, a third hole 23, and a second coolant hole 25, as shown in the example not limited to Figures 3 and 10.

[0022] The recess 19 may be located on the side of the rear end 1a. The recess 19 may also be the part into which the protrusion 9 is fitted. When the protrusion 9 is fitted into the recess 19, the top 17 of the protrusion 9 may be located away from the bottom 27 of the recess 19.

[0023] The second hole 21 may extend from the recess 19 toward the tip 1b. The second hole 21 may have a second screw groove 29 on its inner circumferential surface. A screw 7 can be attached to the second screw groove 29. The second hole 21 may also be located coaxially with the first hole 11. The second hole 21 may open at the bottom 27 of the recess 19.

[0024] The third hole 23 may extend from the second hole 21 toward the tip 1b. The third hole 23 may be directly connected to the second hole 21.

[0025] The second coolant hole 25 allows coolant to flow through it. The second coolant hole 25 may extend from the recess 19 to the third hole 23, as shown in the example shown in Figure 10 (not limited to this example). In this case, the third hole 23, which would otherwise be dead space, can be utilized as a coolant passage.

[0026] The second coolant hole 25 may open at the bottom 27 of the recess 19. The second coolant hole 25 may be located further from the central axis O1 than the second hole 21.

[0027] The second coolant hole 25 may be just one, or it may be multiple. In other words, the second coolant hole 25 may be one or more.

[0028] If there are multiple second coolant holes 25, the number of second coolant holes 25 may be 2 to 8. The second member 5 in the example shown in Figure 9, which is not limited to this example, has three second coolant holes 25. If there are multiple second coolant holes 25, the multiple second coolant holes 25 may be positioned such that they are rotationally symmetric with respect to the central axis O1 when the second member 5 is viewed from the rear end 1a side.

[0029] The screw 7 may be mounted in the first hole 11 and the second hole 21, as shown in the example not limited to the one shown in Figure 3. More specifically, the screw 7 may be mounted in the first thread groove 15 in the first hole 11 and the second thread groove 29 in the second hole 21.

[0030] The inner diameter D23 of the third hole 23 may be larger than the inner diameter D21 of the second hole 21, as shown in the example (not limited to) in Figure 10. In this case, it becomes possible to easily form the second coolant hole 25 extending into the third hole 23.

[0031] In the cutting tool described in Patent Document 1, due to the process of forming screw grooves on the inner circumferential surface of the screw hole, holes with smaller inner diameters than the screw hole are provided on the front and rear ends of the screw hole, respectively, where screw grooves are not formed. Screws cannot be attached to these holes, resulting in dead space.

[0032] If the inner diameter D23 of the third hole 23 is smaller than the inner diameter D21 of the second hole 21, a dead space may be created, as in the cutting tool described in Patent Document 1. In such a case, when removing the second member 5 (main body) from the first member 3 (connecting part), the screw 7 cannot enter the dead space. Therefore, it is necessary to ensure sufficient length of the screw holes (first hole 11, second hole 21, and third hole 23) excluding the dead space, which leads to a decrease in the rigidity of the second member 5.

[0033] However, if the inner diameter D23 of the third hole 23 is larger than the inner diameter D21 of the second hole 21, the screw 7 can enter the area that would otherwise be dead space. Therefore, it is possible to avoid making the length of the screw hole excessively long and to improve the rigidity of the second member 5.

[0034] The inner diameter D21 of the second hole 21 and the inner diameter D23 of the third hole 23 are not limited to specific values. For example, the inner diameter D21 of the second hole 21 may be set to 8 to 30 mm. The inner diameter D23 of the third hole 23 may be set to 12 to 32 mm. The second hole 21 and the third hole 23 may each have a circular cross-sectional shape perpendicular to the central axis O1. The inner diameter D21 of the second hole 21 may be evaluated in the region where the second screw groove 29 is provided.

[0035] The second member 5 may further have a fourth hole 31. The fourth hole 31 may extend from the third hole 23 toward the tip 1b. The fourth hole 31 can function as a part into which a tool for operating the screw 7 is inserted. Examples of tools include wrenches and screwdrivers. In the example shown in Figure 3, the screw 7 has a hole 7a that opens on the end face on the tip 1b side. The above-mentioned tool can be attached to this hole 7a. The screw 7 may be turned with the tool attached to the hole 7a.

[0036] The inner diameter D31 of the fourth hole 31 may be smaller than the inner diameter D23 of the third hole 23, as shown in the example (not limited to) in Figure 10. In this case, the wall thickness of the second member 5 between the outer circumference of the second member 5 and the fourth hole 31 is easily secured. Therefore, the strength of the second member 5 is high.

[0037] The inner diameter D31 of the fourth hole 31 may be smaller than the inner diameter D21 of the second hole 21. In this case, the wall thickness of the second member 5 between the outer circumference of the second member 5 and the fourth hole 31 is easily secured. Therefore, the strength of the second member 5 is high.

[0038] As described above, the cutting tool 1 is not limited to the example shown in Figures 1 to 14. For example, the cutting tool 1 may have the configuration shown in Figures 15 to 18. In the example shown in Figures 1 to 14, the inner diameter D23 of the third hole 23 is larger than the inner diameter D31 of the fourth hole 31, whereas in the example shown in Figures 15 to 18, the inner diameter D23 of the third hole 23 is smaller than the inner diameter D31 of the fourth hole 31. In other words, the inner diameter D31 of the fourth hole 31 is larger than the inner diameter D23 of the third hole 23. Note that in the example shown in Figures 15 to 18, some elements, including the cutting insert 41 which will be described later, have been omitted to facilitate visual understanding.

[0039] When the outer diameter of the cutting tool 1 is relatively small, the example shown in Figures 1 to 14 is preferable from the viewpoint of ensuring sufficient length of the screw holes (first hole 11, second hole 21, and third hole 23) while ensuring the rigidity of the second member 5. On the other hand, when the outer diameter of the cutting tool 1 is relatively large, the rigidity of the second member 5 is easily ensured. Therefore, even when the inner diameter D23 of the third hole 23 is smaller than the inner diameter D31 of the fourth hole 31, the rigidity of the second member 5 is easily ensured. In addition, when the inner diameter D23 of the third hole 23 is smaller than the inner diameter D31 of the fourth hole 31, it becomes easier to form the second coolant hole 25.

[0040] The inner diameter D31 of the fourth hole 31 is not limited to a specific value. For example, the inner diameter D31 of the fourth hole 31 may be set to 6 to 20 mm. The fourth hole 31 may have a circular cross-sectional shape perpendicular to the central axis O1.

[0041] The fourth hole 31 may be closed at the tip 1b side by a sealing member 33. For example, the second member 5 may further have a recess 35 that opens at the tip 1b, as shown in the example not limited to the one shown in Figure 10. The fourth hole 31 may open at the bottom 37 of the recess 35. The second member 5 may further have a sealing member 33 that closes the tip 1b side of the fourth hole 31 through the recess 35. Examples of the sealing member 33 include screws.

[0042] The first hole 11, the second hole 21, the third hole 23, and the fourth hole 31 may each extend along the central axis O1, as shown in the example (not limited to) in Figure 3. In this case, the operation of the screw 7 and the attachment and detachment of the second member 5 become easier. Furthermore, because the eccentricity of the cutting tool 1 around the central axis O1 is small, vibrations caused by the above-mentioned eccentricity are easily suppressed when the cutting tool 1 is used as a rotary tool.

[0043] In the direction along the central axis O1, the length of the third hole 23 may be shorter than the length of the second hole 21. Also, in the direction along the central axis O1, the length of the third hole 23 may be shorter than the length of the fourth hole 31. In the direction along the central axis O1, the length of the third hole 23 may be longer than the length of the fourth hole 31 (see Figure 17).

[0044] The inner diameter D13 of the first coolant hole 13 may be smaller than the inner diameter D11 of the first hole 11, as in an example shown in FIG. 5 which is not limited thereto. Also, the inner diameter D25 of the second coolant hole 25 may be smaller than the inner diameter D21 of the second hole 21, as in an example shown in FIG. 10 which is not limited thereto. In these cases, the pressure of the coolant flowing through the first coolant hole 13 and the second coolant hole 25 is less likely to decrease. Also, it is easy to ensure the strength of the screw 7 attached to the first hole 11 and the second hole 21 (see FIG. 3).

[0045] The number of the second coolant holes 25 may be less than the number of the first coolant holes 13 (see FIGS. 4 and 9). Also, the inner diameter D25 of the second coolant hole 25 may be smaller than the inner diameter D13 of the first coolant hole 13 (see FIGS. 5 and 10). In these cases, the pressure of the coolant flowing through the first coolant hole 13 and the second coolant hole 25 is less likely to decrease.

[0046] The inner diameter D11 of the first hole 11, the inner diameter D13 of the first coolant hole 13, and the inner diameter D25 of the second coolant hole 25 are not limited to specific values. For example, the inner diameter D11 of the first hole 11 may be set to 8 to 24 mm. Also, the inner diameter D13 of the first coolant hole 13 may be set to 2 to 5 mm. The inner diameter D25 of the second coolant hole 25 may be set to 1.5 to 3 mm. The first hole 11, the first coolant hole 13, and the second coolant hole 25 may each have a circular cross-sectional shape perpendicular to the central axis O1. The inner diameter D11 of the first hole 11 may be evaluated in the region where the first screw groove 15 is provided.

[0047] The first coolant hole 13 and the second coolant hole 25 may each extend parallel to the central axis O1, as in an example shown in FIG. 3 which is not limited thereto. In this case, the length of the first coolant hole 13 and the second coolant hole 25 as flow paths can be suppressed. Therefore, the pressure loss of the coolant can be reduced. Note that parallel is not limited to strict parallelism and may mean allowing an inclination of about ±5°.

[0048] The second coolant hole 25 may be located closer to the central axis O1 than the first coolant hole 13.

[0049] The pitch of the first screw groove 15 may be the same as or different from the pitch of the second screw groove 29. For example, the pitch of the first screw groove 15 may be greater than the pitch of the second screw groove 29 (see Figures 5 and 10). In this case, the second member 5 can be firmly fastened to the first member 3 by the screw 7.

[0050] The distance W1 between the central axis O1 and the first coolant hole 13 may be greater than the distance W2 between the central axis O1 and the second coolant hole 25, as shown in the example (not limited to) in Figure 3. In other words, the distance from the outer circumference of the cutting tool 1 to the second coolant hole 25 is greater than the distance from the outer circumference of the cutting tool 1 to the first coolant hole 13. In this case, the durability of the cutting tool 1 tends to improve.

[0051] A cutting member, such as a cutting insert 41, is attached to the second member 5, which is located closer to the tip 1b than the first member 3, as will be described later. While the cutting member can cut the workpiece, the second member 5 is more susceptible to a greater cutting load than the first member 3. Here, as shown in the example without limitation in Figures 3 and 10, when the distance W2 between the central axis O1 and the second coolant hole 25 is relatively small, the wall thickness of the second member 5 between the cutting edge and the second coolant hole 25 is more easily ensured. Therefore, the risk of damage to the second member 5 due to the cutting load can be reduced. Also, when the distance W1 between the central axis O1 and the first coolant hole 13 is relatively large, the wall thickness of the second member 5 is more easily ensured. Therefore, the occurrence of chatter vibration is more easily reduced.

[0052] The distance W1 between the central axis O1 and the first coolant hole 13 may be evaluated by the distance between the central axis O1 and the central axis of the first coolant hole 13, as shown in the example (not limited to) in Figure 3. Similarly, the distance W2 between the central axis O1 and the second coolant hole 25 may be evaluated by the distance between the central axis O1 and the central axis of the second coolant hole 25, as shown in the example (not limited to) in Figure 3. If the distance between the central axis O1 and the first coolant hole 13 is not constant, the minimum value may be evaluated as the distance W1. Similarly, if the distance between the central axis O1 and the second coolant hole 25 is not constant, the minimum value may be evaluated as the distance W2.

[0053] The second member 5 may be composed of a holder 39 and a cutting insert 41, as shown in an example not limited to Figure 6. In other words, the second member 5 may have a holder 39 and a cutting insert 41. The holder 39 may be in the shape of a rod extending from the first member 3 toward the tip 1b, as shown in an example not limited to Figure 1.

[0054] The cutting insert 41 may also be simply referred to as the insert 41. The insert 41 may be attached to the tip 1b side of the holder 39, as in the example shown in Figure 6. For example, the insert 41 may be attached to the holder 39 by a fixing member 43. In the example shown in Figure 6, the fixing member 43 is a screw. The holder 39 may have a screw hole 45 for fixing this screw.

[0055] The insert 41 can be used to cut a workpiece in a cutting process. The insert 41 may have a cutting edge 47. The cutting tool 1 can perform cutting by bringing the cutting edge 47 of the insert 41 into contact with the workpiece.

[0056] The insert 41 may be polygonal in shape. Furthermore, there may be one or more inserts 41. If there are multiple inserts 41, the number of inserts 41 may range from 2 to 50.

[0057] If there are multiple inserts 41, the multiple inserts 41 may have the same configuration or may have different configurations. For example, as shown in the example not limited to Figure 6, the insert 41 may consist of a first cutting insert 49 located at the tip 1b and a second cutting insert 51 located on the rear end 1a side of the first cutting insert 49 and having a different shape from the first cutting insert 49.

[0058] The second member 5 is capable of spraying coolant supplied through the first coolant hole 13 and the second coolant hole 25 toward the insert 41. For example, the second member 5 may have a flow path 53 connected to a portion of the second member 5 through which the coolant flows, as shown in the example shown in Figure 6. This flow path 53 may have an outlet 55 that opens toward the insert 41. The coolant may be sprayed toward the insert 41 from this outlet 55.

[0059] Examples of coolants include water-insoluble and water-soluble lubricants. Examples of water-insoluble lubricants include cutting fluids such as oily, inert extreme-pressure, and active extreme-pressure types. Examples of water-soluble lubricants include cutting fluids such as emulsions, solubles, and solutions. The coolant is not limited to a liquid and may also be a gas such as an inert gas. The coolant may be appropriately selected and used depending on the material of the workpiece.

[0060] The first member 3 may further have a fifth hole 57 extending from the first hole 11 toward the rear end 1a, as shown in the example not limited to Figure 5. The fifth hole 57 may open at the rear end 1a. This opening can function as an inlet for coolant to flow into the interior of the first member 3. Note that the opening of the fifth hole 57 is not limited to the example position.

[0061] The first coolant hole 13 may be connected to the fifth hole 57 on the side of the rear end 1a. In this case, coolant supplied from the outside can be flowed through the fifth hole 57 to the first coolant hole 13.

[0062] Examples of materials for the first member 3 include steel and cast iron. Examples of materials for the holder 39 in the second member 5 include aluminum, steel, and cast iron. Examples of materials for the insert 41 include cemented carbide and cermet.

[0063] The holder 39 in the second member 5 may have one or more helical discharge grooves 59 extending from the tip 1b toward the rear end 1a. The discharge grooves 59 can function as parts for discharging chips generated by the cutting edge 47 of the insert 41 to the outside. In the example shown in Figures 1 and 8, the holder 39 has three discharge grooves 59. Multiple inserts 41 may be positioned along each of the multiple discharge grooves 59. Also, multiple inserts 41 may be attached to one of the discharge grooves 59. In the example shown in Figure 1, five inserts 41 are attached to each discharge groove 59. That is, in the example shown in Figure 1, the number of inserts 41 is 15.

[0064] The number of flow paths 53 and outlets 55 in the second member 5 may correspond to the number of inserts 41. In the example shown in Figure 1, which is not limited to this example, the number of flow paths 53 and outlets 55 is 15, corresponding to the number of inserts 41, which is 15.

[0065] The number of second coolant holes 25 may be the same as the number of discharge grooves 59. In the example shown in Figures 1, 8, and 9, the number of second coolant holes 25 is the same as the number of discharge grooves 59. When these numbers are the same, it is possible to efficiently supply coolant to each flow path 53.

[0066] The cutting tool 1 is not limited to a specific size. For example, the length of the second member 5 (holder 39) in the direction along the central axis O1 may be set to about 60 to 150 mm. Also, the width (diameter) of the second member 5 (holder 39) in the direction perpendicular to the central axis O1 may be set to about 20 to 100 mm.

[0067] <Method for Manufacturing a Machined Workpiece> Next, a method for manufacturing a machined workpiece 101 with one surface, not limited to the present disclosure, will be described with reference to the drawings.

[0068] The cut workpiece 101 may be produced by cutting the workpiece 103. The method for manufacturing the cut workpiece 101 may include the following steps: (1) a step of rotating the cutting tool 1, which is representative of the above-described but not limited embodiment; (2) a step of bringing the cutting tool 1 into contact with the workpiece 103; and (3) a step of moving the cutting tool 1 away from the workpiece 103.

[0069] Specifically, first, as shown in the example shown in Figure 19 (not limited), the cutting tool 1 may be rotated around the central axis O1 and brought relatively close to the workpiece 103. Next, as shown in the example shown in Figure 20 (not limited), the second member 5 may be brought into contact with the workpiece 103 to cut the workpiece 103. Then, as shown in the example shown in Figure 21 (not limited), the cutting tool 1 may be moved relatively far away from the workpiece 103. By following these steps, it is possible to obtain a machined workpiece 101 with high surface accuracy.

[0070] In the example shown in Figures 19 to 21, the workpiece 103 is fixed and the cutting tool 1 is moved during each step, but of course, the system is not limited to this configuration.

[0071] For example, in step (1), the workpiece 103 may be brought closer to the cutting tool 1. Alternatively, in step (3), the workpiece 103 may be moved away from the cutting tool 1. If the cutting process is to be continued, the cutting tool 1 may be kept rotating, and the process of bringing the cutting tool 1 into contact with different parts of the workpiece 103 may be repeated.

[0072] Examples of materials for the workpiece 103 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0073] The above exemplifies one aspect of the manufacturing method of a cutting tool 1 and a cut workpiece 101, which are not limited to the embodiments described herein. However, it goes without saying that the present disclosure is not limited to the embodiments described above, and any method can be used as long as it does not deviate from the gist of the present disclosure.

[0074] For example, the manufacturing method of the cutting tool 1 and the workpiece 101 may have the following configuration: [1] The cutting tool has a first member extending from the rear end toward the front end along the central axis, a second member located closer to the front end than the first member and extending along the central axis, and a screw for fixing the first member and the second member, the first member having a protrusion located on the front end side, a first hole extending from the protrusion toward the rear end and having a first screw groove on its inner circumferential surface, and one or more first coolant holes extending from the protrusion toward the rear end, The second member has a recess located on the rear end side into which the protrusion is fitted, a second hole extending from the recess toward the tip and having a second screw groove on its inner circumferential surface and located coaxially with the first hole, a third hole extending from the second hole toward the tip, and one or more second coolant holes extending from the recess toward the third hole, the screw being attached to the first hole and the second hole, the inner diameter of the third hole being larger than the inner diameter of the second hole. [2] The cutting tool of [1] may have a configuration in which the second member further has a fourth hole extending from the third hole toward the tip, the inner diameter of the fourth hole being smaller than the inner diameter of the third hole. [3] The cutting tool of [2] may have a configuration in which the inner diameter of the fourth hole being smaller than the inner diameter of the second hole. [4] The cutting tool described in [1] above may have a configuration in which the second member further has a fourth hole extending from the third hole toward the tip, and the inner diameter of the fourth hole is larger than the inner diameter of the third hole. [5] Any one of the cutting tools described in [2] to [4] above may have a configuration in which the first hole, the second hole, the third hole and the fourth hole each extend along the central axis. [6] Any one of the cutting tools described in [1] to [5] above may have a configuration in which the inner diameter of the first coolant hole is smaller than the inner diameter of the first hole, and the inner diameter of the second coolant hole is smaller than the inner diameter of the second hole. [7] Any one of the cutting tools described in [1] to [6] above may have a configuration in which the number of second coolant holes is less than the number of first coolant holes, and the inner diameter of the second coolant holes is smaller than the inner diameter of the first coolant holes.[8] Any one of the cutting tools described in [1] to [7] above may be configured such that the first coolant hole and the second coolant hole each extend parallel to the central axis. [9] Any one of the cutting tools described in [1] to [8] above may be configured such that the pitch of the first screw groove is greater than the pitch of the second screw groove.

[10] Any one of the cutting tools described in [1] to [9] above may be configured such that the distance between the central axis and the first coolant hole is greater than the distance between the central axis and the second coolant hole.

[11] Any one of the cutting tools described in [1] to

[10] above may be configured such that the second member comprises a rod-shaped holder extending from the first member toward the tip and a cutting insert attached to the tip side of the holder, and the coolant supplied through the first coolant hole and the second coolant hole can be sprayed toward the cutting insert.

[12] A method for manufacturing a machined workpiece may include the steps of rotating one of the cutting tools described in [1] to

[11] above, bringing the cutting tool into contact with a workpiece, and separating the cutting tool from the workpiece.

[0075] 1...Cutting tool 1a...Rear end 1b...Front end 3...First component 5...Second component 7...Screw 7a...Hole 9...Convex part 11...First hole 13...First coolant hole 15...First screw groove 17...Top 19...Concave part 21...Second hole 23...Third hole 25...Second coolant hole 27...Bottom 29...Second screw groove 31...Fourth hole 33...Sealing component 35...Recess 37...Bottom 39...Holder 41...Cutting insert (insert) 43...Fixing component 45...Screw hole 47...Cutting edge 49...First cutting insert 51...Second cutting insert 53...Flow path 55...Outlet 57...Fifth hole 59...Discharge groove 101...Workpiece 103...Work material O1...Center axis Y1...Rotational direction

Claims

1. The device comprises a first member extending from the rear end towards the front end along the central axis, a second member located closer to the front end than the first member and extending along the central axis, and a screw for fixing the first member and the second member, wherein the first member has a protrusion located on the front end side, a first hole extending from the protrusion toward the rear end with a first screw groove on its inner circumferential surface, and one or more first coolant holes extending from the protrusion toward the rear end, the second member has a recess located on the rear end side into which the protrusion is fitted, a second hole extending from the recess toward the front end with a second screw groove on its inner circumferential surface and located coaxially with the first hole, a third hole extending from the second hole toward the front end, and one or more second coolant holes extending from the recess toward the third hole, and the screw is attached to the first hole and the second hole. A cutting tool in which the inner diameter of the third hole is larger than the inner diameter of the second hole.

2. The cutting tool according to claim 1, wherein the second member further has a fourth hole extending from the third hole toward the tip, and the inner diameter of the fourth hole is smaller than the inner diameter of the third hole.

3. The cutting tool according to claim 2, wherein the inner diameter of the fourth hole is smaller than the inner diameter of the second hole.

4. The cutting tool according to claim 1, wherein the second member further has a fourth hole extending from the third hole toward the tip, and the inner diameter of the fourth hole is larger than the inner diameter of the third hole.

5. The cutting tool according to any one of claims 2 to 4, wherein the first hole, the second hole, the third hole, and the fourth hole each extend along the central axis.

6. The cutting tool according to any one of claims 1 to 5, wherein the inner diameter of the first coolant hole is smaller than the inner diameter of the first hole, and the inner diameter of the second coolant hole is smaller than the inner diameter of the second hole.

7. The cutting tool according to any one of claims 1 to 6, wherein the number of second coolant holes is less than the number of first coolant holes, and the inner diameter of the second coolant holes is smaller than the inner diameter of the first coolant holes.

8. The cutting tool according to any one of claims 1 to 7, wherein the first coolant hole and the second coolant hole each extend parallel to the central axis.

9. The cutting tool according to any one of claims 1 to 8, wherein the pitch of the first screw groove is greater than the pitch of the second screw groove.

10. The cutting tool according to any one of claims 1 to 9, wherein the distance between the central axis and the first coolant hole is greater than the distance between the central axis and the second coolant hole.

11. The cutting tool according to any one of claims 1 to 10, wherein the second member comprises a rod-shaped holder extending from the first member toward the tip, and a cutting insert attached to the tip side of the holder, and coolant supplied through the first coolant hole and the second coolant hole can be sprayed toward the cutting insert.

12. A method for manufacturing a machined workpiece, comprising the steps of: rotating a cutting tool according to any one of claims 1 to 11; bringing the cutting tool into contact with a workpiece; and separating the cutting tool from the workpiece.

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