Manufacturing method of cutting tools

Abstract

Improve the quality of cutting tools when manufacturing them. [Solution] The tool blade has a front relief surface at the tip, a pair of side relief surfaces on the side surfaces, a rake face, a cutting edge portion including a cutting edge that is the intersection line of the front relief surface and the rake face, and a base portion located at the base of the cutting edge portion. When a line passing through the cutting edge perpendicular to the rake face is defined as a reference perpendicular line, a line that bisects the inner angle range of the cutting edge portion at a central angle centered on the cutting edge and extends to the outside of the cutting edge portion is defined as a first reference line, a line that bisects a reference angle that is an acute angle between the first reference line and the reference perpendicular line is defined as a second reference line, and a line that is inclined from the reference perpendicular line toward the rake face by an angle that is half the reference angle with the cutting edge as the center is defined as a third reference line, the cutting edge treatment process includes a process of applying an abrasive to the cutting edge edge in an angle direction that is included in either the angle range between the rake face and the second reference line or the angle range between the front relief face and the part of the third reference line that is closer to the front relief face than the center.

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a cutting tool. [Background technology]

[0002] In recent years, the automotive industry has been shifting to EVs, resulting in rapid changes in powertrains, which are the power source. This has led to increased demand for gears, one of the components, to have low noise vibration (NV), be compact, and be low-cost. To meet these demands, gear cutting processes must be highly efficient, highly accurate, and low-cost. One gear cutting process that meets these demands is gear skiving, as described in Patent Document 1, for example.

[0003] In gear skiving, a gear is generated by synchronizing the rotation of a dedicated multi-blade tool with the workpiece, so that the blades of the multi-blade tool mesh with the gear grooves. In other words, the quality of each gear groove depends on the quality of each blade of the multi-blade tool. Therefore, high quality is required for each blade of the multi-blade tool. Furthermore, compared to other gear cutting processes, gear skiving tends to generate larger cutting forces and heat, making the multi-blade tool more susceptible to wear and breakage. In other words, the lifespan of multi-blade tools used in gear skiving tends to be shorter than that of other gear cutting tools. Therefore, gear skiving requires more frequent replacement or re-grinding of multi-blade tools than other gear cutting processes. For this reason, the running costs of gear skiving are higher than those of other gear cutting processes.

[0004] The manufacturing of multi-blade tools for gear skiving includes a shaping process to create the blade shape and an edge treatment process to create the cutting edge. The edge treatment process involves removing burrs from the tool, forming the root of the blade along an involute curve, and adjusting the angle of the cutting edge. Note that burrs are generated during the shaping process.

[0005] Wet blasting is sometimes used for the cutting edge treatment process. Wet blasting polishes an object by spraying a slurry made of abrasives and liquid. More specifically, the cutting edge treatment process using wet blasting is carried out by spraying the slurry from a nozzle positioned opposite the cutting edge. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-39971 Summary of the Invention [Problem to be solved by the invention]

[0007] However, because the root is located farther from the nozzle than the cutting edge, it is more difficult to polish than the cutting edge. In other words, when processing cutting edges using conventional wet blasting, there can be differences in the machining efficiency between the cutting edge and the root. If the cutting edge shape is not as designed, gears that meet the specifications will not be generated.

[0008] Therefore, in the manufacture of cutting tools, a method for improving the quality of cutting tools has been desired. [Means for solving the problem]

[0009] The present disclosure can be realized in the following forms.

[0010] (1) According to one aspect of the present disclosure, there is provided a method for manufacturing a cutting tool, the cutting tool comprising a plurality of tool blades, each of which comprises a front relief surface at a tip end, a pair of side relief surfaces at a side end, a rake face, a cutting edge portion including a cutting edge that is an intersection line between the front relief surface and the rake face, and a base portion disposed at a base of the cutting edge portion, the method for manufacturing the cutting tool comprising a cutting edge treatment step of polishing the tool blades. When viewed along the direction in which the cutting edge extends, a line passing through the cutting edge perpendicular to the rake face is defined as a reference perpendicular line, a line that bisects the inner angle range of the cutting edge at the central angle centered on the cutting edge and that extends to the outer angle range of the cutting edge is defined as a first reference line, a line that bisects the reference angle that is the acute angle formed by the first reference line and the reference perpendicular line is defined as a second reference line, and a line that bisects the reference angle that is half the reference angle from the reference perpendicular line to the rake face side with the cutting edge as the center is defined as a second reference line. When the inclined line is defined as a third reference line, the cutting edge treatment process includes a rough machining process of grinding the tool blade by applying an abrasive toward the cutting edge in a direction parallel to an angle included in one of two first-type angle ranges formed by the angle range between the rake face and the second reference line and the angle range between the front relief face and a portion of the third reference line on the front relief face side with respect to the center, in an outer angle range of the cutting edge portion at a central angle centered on the cutting edge. In this embodiment, the abrasive material discharged onto the multiple tool blades arranged side by side on the outer periphery of the preform is discharged in a direction approximately perpendicular to the rake face. Therefore, burrs protruding from the outer edge of the rake face at an angle close to the angle of the rake face and burrs protruding from the outer edge of the front relief face at an angle close to the angle of the front relief face are easily removed by the discharged abrasive material. In contrast, the direction of the abrasive material discharged in a direction approximately perpendicular to the rake face is at an angle significantly smaller than 90 degrees with respect to the pair of side relief faces. Therefore, the side relief faces, which define the outer shapes of the cutting edge and base, are less likely to be polished by the discharged abrasive material. Therefore, in the rough machining process, only burrs that may occur on the tool blade during the shaping process are efficiently removed. This manufacturing method for cutting tools can prevent excessive polishing of the cutting edge and base, thereby improving the quality of the tool blade. (2) In the manufacturing method of the cutting tool of the above embodiment, the cutting edge treatment step may include a finishing step, after the rough machining step, of polishing the tool blade by applying an abrasive toward the cutting edge in a direction parallel to an angle included in the angle range between the portion of the third reference line and the second reference line. In this embodiment, the cutting edge can be machined into a desired shape. However, the abrasive is ejected at an angle significantly smaller than 90 degrees relative to the pair of side flanks. Therefore, the side flanks that define the outer shape of the base are less likely to be polished by the ejected abrasive. (3) In the manufacturing method of the cutting tool of the above form, the cutting edge treatment step may be performed by blasting using a nozzle that sprays an abrasive, and the finishing step may include a step of: arranging the nozzle in a position and orientation that is realized when, when the cutting tool is viewed along the central axis of the cutting tool, the nozzle facing the central axis is moved parallel to a direction perpendicular to the line from a reference position of the nozzle on a line passing through the central axis; rotating the cutting tool alternately in both circumferential directions around the central axis with the central axis as a rotation axis; and polishing the tool blade while the cutting tool is rotated. In this embodiment, the cutting tool is polished by blasting while rotating, and the degree of polishing varies due to the influence of adjacent tool blades. The manufacturing method for cutting tools changes the way the abrasive hits the tool blade by moving the nozzle. Therefore, the manufacturing method for cutting tools has the potential to polish the tool blade more uniformly than a method in which the abrasive is sprayed from a nozzle at a reference position. The blasting can be wet blasting. (4) In the manufacturing method of the cutting tool of the above aspect, in the finishing process, the nozzle may be arranged within a nozzle arrangement range from the reference position toward each of the positive vertical direction and the negative vertical direction to a position defined by the outermost diameter of the cutting tool. (5) In the method for manufacturing a cutting tool of the above form, the cutting edge treatment step may be performed by blasting using a nozzle that sprays an abrasive, and the finishing step may include a step of arranging the nozzle in a position and orientation that is realized when, when the cutting tool is viewed along the central axis of the cutting tool, the nozzle facing the central axis is moved from a reference position of the nozzle on a straight line passing through the central axis along an arc centered on the central axis while maintaining the orientation of the nozzle, rotating the cutting tool alternately in both circumferential directions around the central axis with the central axis as a rotation axis, and polishing the tool blade while the cutting tool is rotated. In this embodiment, the cutting tool is polished by blasting while rotating, and the degree of polishing varies due to the influence of adjacent tool blades. The manufacturing method for cutting tools changes the way the abrasive hits the tool blade by moving the nozzle. Therefore, the manufacturing method for cutting tools has the potential to polish the tool blade more uniformly than a method in which the abrasive is sprayed from a nozzle at a reference position. The blasting can be wet blasting. (6) In the method for manufacturing a cutting tool according to the above aspect, the tool blade ground in the cutting edge treatment step may include a used cutting tool. By adopting such an embodiment, the method for manufacturing a cutting tool can manufacture a cutting tool at a lower cost than when a new base material is prepared. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing the entire cutting tool. [Figure 2] FIG. 4 is an explanatory diagram showing an enlarged view of a part of the rake face including the radial end portion. [Figure 3] 1 is a flowchart showing a method for manufacturing a cutting tool. [Figure 4] FIG. 4 is an explanatory diagram showing a cross section taken along the line IV-IV in FIG. 2; [Figure 5] 6 is a flowchart showing a method for manufacturing a cutting tool according to a second embodiment. [Figure 6] FIG. 10 is an explanatory view showing a finishing process according to the third embodiment. [Figure 7] FIG. 11 is an explanatory diagram showing an example of a processing change amount due to a finish processing step of the third embodiment. [Figure 8] FIG. 13 is an explanatory view showing a finishing process according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A. First embodiment: A-1. Components of cutting tools: 1 is a perspective view showing the entire cutting tool 10. The cutting tool 10 is a tool for performing gear cutting. Specifically, the cutting tool 10 is a gear skiving cutter.

[0013] In the following description, to facilitate understanding of the technology, the direction parallel to the central axis CL of the cutting tool 10 is defined as the Z axis. When specifying an orientation, a positive direction is designated as "+" and a negative direction is designated as "-", and both positive and negative signs are used to denote the direction. The central axis direction Dcl is defined as the direction along the central axis CL, the circumferential direction Dc is defined as the direction around the central axis CL, and the clockwise direction of the circumferential direction Dc when viewing the cutting tool 10 from the +Z direction is defined as the positive rotation direction Dcp. Furthermore, the radial direction Dr of the central axis CL and the radial direction Drr are defined as the direction of the radial direction Dr away from the central axis CL.

[0014] The cutting tool 10 is cylindrical and is formed by processing a preform by forming a spiral groove on its outer surface. The preform is made of cemented carbide or high-speed steel, the outer shape of which is formed into a substantially solid body of revolution. A substantially solid body of revolution refers to a solid body in which the cross-sectional shape parallel to the central axis CL is substantially constant or substantially regular in the circumferential direction Dc in the portion of the preform where the multiple tool blades 100 are formed. For example, the preform includes a cylindrical member without cutting grooves, a cylindrical member with a key groove in part of the inner circumferential surface, and a used cutting tool 10. A used cutting tool 10 specifically refers to a cutting tool 10 that has become unusable due to wear or damage to the tool blades 100. In other words, the preform may have cutting grooves. The cutting tool 10 includes multiple tool blades 100 and a shank 200.

[0015] The shank 200 supports the multiple tool blades 100. The shank 200 is provided coaxially with the multiple tool blades 100. The shank 200 is a cylindrical portion provided integrally with the end surface of each of the multiple tool blades 100 on the opposite side in the Z-axis direction from the rake face 101.

[0016] The multiple tool blades 100 are arranged in an annular shape. Each of the multiple tool blades 100 protrudes in the radial direction Drr. More specifically, the multiple tool blades 100 are formed in the shape of a helical gear with a ridgeline extending in the central axial direction Dcl. The tool blade 100 has, as its outer surface, a front relief surface 102f at its tip, a pair of side relief surfaces 102s on its side surfaces, and a rake face 101.

[0017] The front clearance surface 102f forms an outer surface facing the radial direction Drr of the tool blade 100. The pair of side clearance surfaces 102s faces the grooves of the multiple tool blades 100 and is a side surface of the tool blade 100 on the circumferential direction Dc side. Each of the pair of side clearance surfaces 102s is connected to the front clearance surface 102f. That is, the pair of side clearance surfaces 102s are connected via the front clearance surface 102f. The rake face 101 forms one end face of the tool blade 100 in the central axis direction Dcl. The rake face 101 forms an end face opposite to the shank 200 in the Z axis direction.

[0018] 2 is an explanatory diagram showing an enlarged view of a portion of the rake face 101 including the end portion in the radial direction Drr. That is, FIG. 2 shows the portion surrounded by the dashed line in FIG. 1. As shown in FIG. 2, the outline of the rake face 101 is made up of one side of each of the pair of side flanks 102s and one side of the front flank 102f. The tool blade 100 further includes a cutting edge portion 110 and a root portion 120 as portions.

[0019] The cutting edge portion 110 includes a cutting edge 103t which is the intersection of the front clearance surface 102f and the rake face 101. More specifically, the cutting edge portion 110 is the portion of the tool blade 100 other than the root portion 120, and is the portion that comes into contact with the workpiece earlier than the root portion 120 during gear cutting.

[0020] The root portion 120 is disposed at the root of the cutting edge portion 110 and includes a portion that follows an involute curve. During gear cutting using the cutting tool 10, the side flank 102s comes into contact with the side surface of the gear groove. The root portion 120 is a portion of the tool blade 100 that is defined by a curved surface that follows an involute curve on the side flank 102s.

[0021] In the tool blade 100, not only the cutting edge 103t but also the intersection line between the side flank 102s and the rake face 101 functions as a cutting edge. When the rake face 101 is viewed along the central axis CL as shown in Figure 2, the cutting edge on the right side of the rake face 101 is called the right cutting edge 103R, and the cutting edge on the left side of the rake face 101 is called the left cutting edge 103L.

[0022] A-2. Manufacturing method of cutting tools: 3 is a flowchart showing a method for manufacturing the cutting tool 10. The manufacturing of the cutting tool 10 begins in step S1 with an operator preparing a base material for the cutting tool 10. In the following explanation, each step will be named with a step number. In the preparation step S1, the operator prepares, for example, a cylindrical base material without cutting grooves.

[0023] In the shape processing step S2 in Fig. 3, an operator uses a grinding machine to grind the base material to form the shapes of the multiple tool blades 100. That is, in the shape processing step S2, the rough shapes of the cutting edge portion 110 and the base portion 120 are formed. As a result of the shape processing step S2, burrs are generated on the tool blades 100, protruding from the cutting edge 103t.

[0024] In the cutting edge treatment step S3 of FIG. 3 , an operator polishes the tool blade 100 by applying an abrasive to the tool blade 100 after the shape machining step S2. Specifically, wet blasting is used to polish the tool blade 100. A wet blasting machine is equipped with a nozzle that discharges a slurry containing an abrasive. In wet blasting, the degree of polishing is changed by changing the orientation of the nozzle relative to the tool blade 100. Furthermore, in wet blasting, the degree of polishing of the tool blade 100 also changes depending on other conditions, such as the slurry discharge pressure, the distance between the nozzle and the tool blade 100, the type of slurry, and the discharge time. Note that these other conditions are determined experimentally. In this specification, the cutting edge treatment step S3 in the first embodiment is also referred to as the rough machining step S3.

[0025] FIG. 4 is an explanatory diagram showing a cross section IV-IV of FIG. 2. FIG. 4 illustrates the cutting edge portion 110 when viewed along the direction in which the cutting edge 103t extends. In FIG. 4, an outer angular range Ro and an inner angular range Ri are defined as ranges included in the central angle with the cutting edge 103t as the center CP. The outer angular range Ro is the angular range included outside the tool blade 100 within the angular range formed by the rake face 101 and the front clearance face 102f. The inner angular range Ri is the angular range included inside the tool blade 100 within the angular range formed by the rake face 101 and the front clearance face 102f. The angular range indicated by the symbol R101 represents the rake angle, and the angular range indicated by the symbol R102f represents the clearance angle.

[0026] In the cutting edge treatment process S3, the nozzle of the wet blasting machine is oriented parallel to an angle included in one of two first-type angular ranges R1. The two first-type angular ranges R1 are composed of a rake face side range R11 and a front flank side range R12. The two first-type angular ranges R1 are non-overlapping angular ranges that each include a reference perpendicular line Lv that is perpendicular to the rake face 101 and passes through the center CP. The rake face side range R11 is the angular range between the rake face 101 and the second reference line L2. The front flank side range R12 is the angular range between the front flank 102f and the straight line portion L3b.

[0027] For the purpose of explaining the rake face side range R11 and the front flank side range R12, a straight line that bisects the inner angle range Ri and extends to the outer angle range Ro is defined as the first reference line L1 (see the upper left portion of FIG. 4). The angle that bisects the inner angle range Ri is represented as "Ri / 2." Furthermore, a straight line that bisects the reference angle Rb, which is the acute angle formed by the first reference line L1 and the reference perpendicular line Lv, is defined as the second reference line L2 (see the upper left portion of FIG. 4). A straight line inclined from the reference perpendicular line Lv toward the rake face 101 by half the reference angle Rb with the cutting edge 103t as the center CP is defined as the third reference line L3 (see the upper center portion of FIG. 4). The portion of the third reference line L3 that is closer to the rake face 101 than the center CP is defined as the straight line segment L3a. The portion of the third reference line L3 on the front flank 102f side with respect to the center CP is defined as a straight line portion L3b. Half the reference angle Rb is represented as "Rb / 2." The rake face side range R11 is the angular range between the second reference line L2 and the rake face 101 (see the upper right part of Figure 4). The front flank side range R12 is the angular range between the third reference line L3 and the front flank 102f (see the lower center part of Figure 4).

[0028] The nozzle of the wet blasting machine is positioned within one of two first-class angle ranges R1 and ejects slurry toward the cutting edge 103t to remove the burr. For example, if the burr extends beyond the cutting edge 103t along the rake face 101 within one of the two first-class angle ranges R1, the nozzle of the wet blasting machine is positioned at an angle included in the front flank side range R12. Alternatively, if the burr extends beyond the cutting edge 103t along the front flank 102f within one of the two first-class angle ranges R1, the nozzle of the wet blasting machine is positioned at an angle included in the rake face side range R11. This configuration makes it easier for the direction of the burr to be perpendicular to the direction of ejection of the slurry. In other words, when the slurry hits the burr, the burr is more easily removed.

[0029] In the coating step S4 of Fig. 3, an operator applies a coating treatment to the cutting tool 10 after the cutting edge treatment step S3 in order to improve wear resistance, anti-weld properties, etc. The coating treatment is, for example, a titanium nitride coating or a diamond-like carbon coating. This completes the manufacture of the cutting tool 10.

[0030] Burrs generated in the shape machining step S2 protrude from the outer edge of the rake face 101 at an angle close to the angle of the rake face 101, and protrude from the outer edge of the front clearance face 102f at an angle close to the angle of the front clearance face 102f. In the manufacturing method of the cutting tool 10 of this embodiment, the abrasive discharged onto the multiple tool edges 100 arranged side by side on the outer periphery of the preform is discharged in a direction approximately perpendicular to the rake face 101 (see R11 and R12 in FIG. 3). Therefore, burrs protruding from the outer edge of the rake face 101 at an angle close to the angle of the rake face 101 and burrs protruding from the outer edge of the front clearance face 102f at an angle close to the angle of the front clearance face 102f are easily removed by the discharged abrasive. In contrast, the jet direction of the abrasive discharged in a direction approximately perpendicular to the rake face 101 is at an angle significantly smaller than 90 degrees with respect to the pair of side clearance faces 102s (see FIGS. 2 and 1). Therefore, the side flanks 102s that define the outer shapes of the cutting edge 110 and the base 120 are less likely to be polished by the discharged abrasive. Therefore, in the rough machining step S3, only burrs that may be generated on the tool blade 100 in the shape machining step S2 are removed. Therefore, in the manufacturing method of the cutting tool 10 of this embodiment, the cutting edge 110 and the base 120 are polished evenly, thereby improving the quality of the tool blade 100.

[0031] Furthermore, when a used cutting tool 10 is used as a base material, the method for manufacturing a cutting tool of this embodiment can manufacture the cutting tool 10 more cheaply than when a new base material is prepared.

[0032] B. Second embodiment: 5 is a flowchart showing a method for manufacturing the cutting tool 10 of the second embodiment. The cutting tool 10 requires grinding of the cutting edge portion 110 and the base portion 120, for example, when the angle of the cutting edge portion 110 corresponding to the inner angle range Ri does not satisfy the required specifications or when the base portion 120 is not formed along an involute curve. In the method for manufacturing the cutting tool 10 of the second embodiment, the cutting edge treatment step S30 includes a finishing step S32 that is performed after the rough machining step S31. In the finishing step S32, the cutting edge portion 110 and the base portion 120 are ground.

[0033] The cutting tool 10 of the second embodiment is the same as the cutting tool 10 of the first embodiment. Furthermore, the preparation step S10, shaping step S20, rough machining step S31, and coating step S40 in the second embodiment shown in Fig. 5 are the same as the preparation step S1, shaping step S2, rough machining step S3, and coating step S4 in the first embodiment shown in Fig. 3. The finishing step S32 will be described below.

[0034] In the finishing process S32 of FIG. 5, the nozzle of the wet blasting machine is oriented parallel to the angle included in the second angle range R2 (see the middle left portion of FIG. 4). The second angle range R2 is the angular range formed by the second reference line L2 and the straight line portion L3b of the third reference line L3 on the side of the front clearance surface 102f with respect to the center CP in the outer angle range Ro. In this embodiment, as shown in FIG. 4, the second angle range R2 includes the first reference line L1 and is an angular range that does not overlap with the two first angle ranges R1 in the outer angle range Ro. By ejecting a slurry containing an abrasive from the nozzle of the wet blasting machine positioned in the second angle range R2 toward the cutting edge 103t, the cutting edge 110 located near the nozzle can be machined into the desired shape. Furthermore, the cutting edge 103t can be curved with a desired curvature, i.e., R. In contrast, the spray direction of the slurry discharged in a direction including the first reference line L1 has an angle significantly smaller than 90 degrees with respect to the pair of side flanks 102s (see FIGS. 4 and 2). In addition, the slurry is rectified by the cutting edge portion 110 located close to the nozzle. Therefore, the side flanks 102s that define the outer shape of the base portion 120 are less likely to be polished by the abrasive material that is discharged. In other words, the finishing process S32 can machine the cutting edge portion 110 into any shape without excessively polishing the base portion 120.

[0035] In this embodiment, the cutting tool 10 from which the burrs have been removed is subjected to a finishing process S32. In the finishing process S32, polishing is performed to form the shapes of the cutting edge 110 and the base 120. Therefore, the manufacturing method for the cutting tool 10 of this embodiment can prevent the cutting tool 10 from being polished excessively, compared to an embodiment in which the removal of burrs and the polishing of the cutting edge 110 and the base 120 are performed simultaneously.

[0036] C. Third embodiment: FIG. 6 is an explanatory diagram showing the finishing process S32 of the third embodiment. FIG. 6 illustrates the cutting tool 10 viewed along the central axis CL and the nozzle position of the wet blasting machine. In the finishing process S32 of the second embodiment, the nozzle of the wet blasting machine is positioned based on a central angle with the cutting edge 103t as the center CP. However, the nozzle of the wet blasting machine may be oriented and positioned in a different manner when polishing the cutting edge 110 and base 120.

[0037] The cutting tool 10 of the third embodiment is the same as the cutting tool 10 of the second embodiment. Furthermore, the manufacturing method of the cutting tool 10 of the third embodiment is the same as the manufacturing method of the cutting tool 10 of the second embodiment, except for the finishing step S32.

[0038] In the finishing process S32 of the third embodiment, the nozzle of the wet blasting machine is positioned and oriented in a direction that is achieved by moving the nozzle, which faces the central axis CL at a reference position Ps on a line Lc perpendicular to the central axis CL, parallel to a vertical direction Dv perpendicular to the central axis CL and the line Lc (right side of FIG. 6). That is, the nozzle of the wet blasting machine is positioned in a direction that is achieved by moving the nozzle in the vertical direction Dv while maintaining its orientation from a position on the line Lc that allows it to face the front clearance surface 102f. In the following description, the nozzle of the wet blasting machine at the reference position Ps will be considered to eject slurry in a direction parallel to the line Lc.

[0039] The nozzle arrangement range Arn, in which the nozzles of the wet blasting machine are arranged, specifically ranges from a reference position Ps to a position defined by the outermost diameter Wd of the cutting tool 10 in both the positive vertical direction +Dv and the negative vertical direction −Dv. FIG. 6 illustrates the first nozzle position P1, which is the furthest in the positive vertical direction +Dv, and the second nozzle position P2, which is the furthest in the negative vertical direction −Dv, in the nozzle arrangement range Arn. That is, when the reference position Ps is 0 and an arbitrary nozzle position along the vertical direction Dv is X, the nozzle arrangement range Arn is expressed by equation (1). The nozzle diameter Wn is the diameter of the circular outlet of the nozzle from which the abrasive is sprayed. -(Wd+Wn) / 2≦X≦(Wd+Wn) / 2 …(1) By adopting such an embodiment, the nozzle of the wet blasting machine is arranged within the nozzle arrangement range Arn, so that the slurry can be applied to the tool blade 100 reliably.

[0040] Furthermore, the finishing process S32 in the third embodiment is performed with the cutting tool 10 rotated. That is, the cutting tool 10 is attached to a rotating machine with the central axis CL as the rotation axis. The cutting tool 10 is rotated alternately in both directions of the circumferential direction Dc, and the tool blade 100 is polished by wet blasting.

[0041] FIG. 7 is an explanatory diagram showing an example of machining change amount in the finishing process S32 of the third embodiment. FIG. 7 illustrates the machining change amount when wet blasting in the finishing process S32 is performed while the cutting tool 10 is rotating in the forward rotation direction Dcp. The machining change amount represents the change in thickness on the left cutting edge 103L side and the change in thickness on the right cutting edge 103R side before and after the finishing process S32, based on a position 1 mm away from the cutting edge 103t toward the center axis CL (see FIG. 2). The conventional results in FIG. 7 are the machining change amount when the nozzle of the wet blasting machine is positioned at the reference position Ps in FIG. 6. The results of the present disclosure in FIG. 7 are the machining change amount when the nozzle of the wet blasting machine is positioned at the reference position Pr in FIG. 6. The arrow De in FIG. 6 indicates the direction in which slurry is discharged from the nozzle of the wet blasting machine at the reference position Pr. As shown by the results of the present disclosure in FIG. 7 , performing wet blasting from a position where the nozzle of the wet blasting machine is moved in the vertical direction Dv may reduce the difference in the amount of change in processing between the left cutting edge 103L and the right cutting edge 103R. This is because the cutting tool 10 is polished by wet blasting while rotating, and the degree of polishing changes due to the influence of adjacent tool edges 100. More specifically, when the rotating tool edge 100 is viewed from the reference position Ps, the portion of the tool edge 100 on the side in the direction of rotation is temporarily hidden by the adjacent tool edge 100. As a result, the portion of the tool edge 100 on the side in the direction of rotation may be difficult to polish.

[0042] However, in the manufacturing method for a cutting tool of this embodiment, the nozzle is moved to change the way the abrasive hits the tool blade 100. Therefore, the manufacturing method for a cutting tool of this embodiment has the potential to grind the tool blade 100 more uniformly than a method in which the abrasive is sprayed from a nozzle at the reference position Ps.

[0043] D. Fourth embodiment: FIG. 8 is an explanatory diagram showing the finishing process S32 of the fourth embodiment. The nozzle arrangement range Brn in the third embodiment is a range in the vertical direction Dv. However, the nozzle arrangement range Brn may be a range in another direction. Specifically, as shown in FIG. 8, the nozzle arrangement range Brn may be a range in the circumferential direction Dc. That is, the nozzle arrangement range Brn may be set so that the shortest distance between the nozzle of the wet blasting machine and the cutting tool 10 is always constant. Even in this embodiment, the nozzle of the wet blasting machine can be arranged at any position Pr between the third nozzle position P3, which is the farthest from the reference position Ps, and the fourth nozzle position P4, and can discharge slurry (see De in FIG. 8).

[0044] By adopting this configuration, the wet blasting conditions are reduced compared to a configuration in which the shortest distance between the nozzle of the wet blasting machine and the cutting tool 10 is changed, making it easier to adjust the degree of grinding of the tool blade 100.

[0045] E. Other Embodiments: E1. Alternative Embodiment 1: (1) In the above embodiment, the cutting tool 10 is a gear skiving cutter. However, the cutting tool 10 may be a hob cutter used for bob cutting or a shaper cutter used for shaping.

[0046] (2) In the first and second embodiments, the cutting edge treatment steps S3 and S30 are performed by wet blasting. However, other processing methods may be used for the cutting edge treatment steps S3 and S30. For example, sandblasting, lapping, or the like may be used for the cutting edge treatment steps S3 and S30.

[0047] (3) In the above embodiment, the wet blasting process may be performed by moving one nozzle, or may be performed by arranging a plurality of nozzles in advance for different purposes.

[0048] (4) In the above embodiment, the rough machining steps S3 and S31 are performed to remove burrs, but may be performed to perform chamfering and honing.

[0049] (5) The manufacturing method for the cutting tool 10 of the present disclosure is directed to the cutting tool 10, but can also be applied to other objects to be machined. For example, the manufacturing method for the cutting tool 10 of the present disclosure can also be applied to the manufacturing of gears. That is, the manufacturing method for the cutting tool 10 of the present disclosure can be applied to deburring, chamfering, honing, and the like, for gears.

[0050] (6) In the above embodiment, other conditions in the wet blasting process, such as the slurry discharge pressure, the distance between the nozzle and the tool blade 100, the type of slurry, and the discharge time, may be set to different conditions in the rough machining steps S3, S31 and the finish machining step S32. For example, the other conditions may be set depending on the state of the cutting tool 10 by measuring the accuracy of the shape of the cutting tool 10 after the rough machining step.

[0051] (7) In the above embodiment, the finishing process S32 of the second embodiment and the finishing process S32 of the third embodiment may be performed in combination. That is, when the nozzle of the wet blasting machine is moved in the vertical direction Dv as in the third embodiment, the nozzle may be positioned so as to face in a direction parallel to an angle included in the second angle range R2 in the second embodiment.

[0052] (8) In the above embodiment, the two first-type angle ranges R1 are defined by ranges based on the rake face side range R11 and the front flank side range R12. However, the two first-type angle ranges R1 may be defined by two non-overlapping ranges that each include the reference perpendicular line Lv. Therefore, for example, the rake face side range R11 may be defined by an angle range between the rake face 101 and a line inclined by Rb / 3 from the second reference line L2 toward the rake face 101 with the cutting edge 103t as the center CP. Furthermore, the front flank side range R12 may be defined by an angle range between the front flank 102f and a line inclined by Rb from the reference perpendicular line Lv toward the rake face 101 with the cutting edge 103t as the center CP.

[0053] (9) The rough machining steps S3 and S31 in the above embodiment and the finish machining step S32 in the second embodiment may be performed with the cutting tool 10 rotating as in the third embodiment.

[0054] (10) In the third embodiment, the nozzle arrangement range Arn is a range from the reference position Ps in both the positive vertical direction +Dv and the negative vertical direction −Dv to a position defined by half the length of the outermost diameter Wd of the cutting tool 10. However, the nozzle arrangement range may be any range that allows the tool blade 100 to be sharpened. For example, the nozzle arrangement range may be a range from the reference position Ps in both the positive vertical direction +Dv and the negative vertical direction −Dv to a position defined by half the length of half the sum of half the length of the outermost diameter Wd of the cutting tool 10 and the nozzle diameter Wn.

[0055] (11) In the rough machining steps S3 and S31 in the above embodiment, the nozzle of the wet blasting machine is positioned in one of two first-class angle ranges R1 depending on whether the burr extends beyond the cutting edge 103t along the rake face 101 or the cutting edge 103t along the front clearance face 102f. However, the nozzle of the wet blasting machine may be positioned in one of the two first-class angle ranges R1 regardless of the state of the burr. For example, the nozzle of the wet blasting machine may be positioned depending on the space available for nozzle placement.

[0056] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above problems or achieve some or all of the above effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0057] E2. Alternative Embodiment 2: In the above embodiment, in the cutting edge treatment step S3, the nozzle of the wet blasting machine is oriented parallel to an angle included in one of the two first-type angle ranges R1, and the rough machining step is performed (see FIG. 4). However, the rough machining step may also be performed using a nozzle oriented parallel to an angle not included in the first-type angle range R1.

[0058] E3. Alternative Embodiment 3: In the third embodiment, the nozzle of the wet blasting machine is positioned and oriented in a direction that is achieved when the nozzle, facing the central axis CL at a reference position Ps of the nozzle on a line Lc perpendicular to the central axis CL, is moved parallel to a vertical direction Dv perpendicular to the central axis CL and the line Lc (see the right part of FIG. 6). However, the nozzle may be positioned in a direction and orientation other than the direction that is achieved when the nozzle is moved parallel to the vertical direction Dv perpendicular to the central axis CL and the line Lc. For example, the nozzle may be positioned on the line Lc. The nozzle may also be positioned in a direction that is not directed toward the central axis CL.

[0059] E4. Alternative Embodiment 4: In the third embodiment, the nozzle arrangement range Arn in which the nozzles of the wet blasting machine are arranged is the range from the reference position Ps in both the positive vertical direction +Dv and the negative vertical direction −Dv to a position defined by the outermost diameter Wd of the cutting tool 10. However, the nozzle arrangement range in which the nozzles of the blasting machine are arranged may be a range defined by other factors such as the dimensions and shape of the cutting tool.

[0060] E5. Alternative Embodiment 5: In the above-described fourth embodiment, the nozzle of the wet blasting machine is positioned and oriented in a position and direction that is achieved when the nozzle, facing the central axis CL, is moved from the reference position Ps of the nozzle on the straight line Lc passing through the central axis CL along an arc centered on the central axis CL while maintaining the orientation of the nozzle. However, the nozzles may be arranged at positions and orientations other than those achieved by moving a nozzle facing the central axis CL from the straight line Lc along an arc centered on the central axis CL while maintaining the nozzle orientation. For example, the nozzles may be arranged on the straight line Lc. The nozzles may also be arranged in an orientation that does not point toward the central axis CL.

[0061] E6. Alternative Embodiment 6: In the above embodiment, the preform includes a used cutting tool 10. However, the preform does not have to include a used cutting tool 10. For example, the preform to be subjected to the rough machining step may be a preform on which no tool blade is formed. [Explanation of symbols]

[0062] Arn,Brn...Nozzle arrangement range, CL...Central axis, CP...Center, Dc...Circumferential direction, Dcl...Central axis direction, Dcp...Correct rotation direction, Dr...Radial direction, Drr...Radial direction, Dv...Vertical direction, P1...1st nozzle position, P2...2nd nozzle position, Pr...Reference position, Ps...Reference position, R101...Rake angle, R102f...Relief angle, R2...2nd angle range, Ri...Inner angle range, Ro...Outer angle range, 10...Cutting Tool for use, 100...tool blade, 101...rake face, 102f...front relief face, 102s...side relief face, 103L...left cutting edge, 103R...right cutting edge, 103t...cutting edge, 110...cutting edge portion, 120...root portion, 200...shank portion, L1~L3...first reference line~third reference line, Lv...reference perpendicular line, R1...first type angle range, R11...rake face side range, R12...front relief side range, Rb...reference angle, Wd...outermost diameter, Wn...diameter

Claims

1. A method for manufacturing a cutting tool, comprising: The cutting tool includes a plurality of tool blades, Each of the plurality of tool blades comprises: The cutting edge has a front relief surface at the tip, a pair of side relief surfaces at the side surfaces, and a rake surface, a cutting edge portion including a cutting edge that is an intersection line between the front relief surface and the rake surface; a base portion disposed at the base of the cutting edge portion, The method for manufacturing the cutting tool includes a cutting edge treatment step of grinding a tool blade, When viewed along the direction in which the cutting edge extends, A line passing through the cutting edge perpendicular to the rake face is defined as a reference perpendicular line, A line that bisects the inner angle range of the cutting edge portion at a central angle centered on the cutting edge and extends to the outer angle range of the cutting edge portion is defined as a first reference line, a line that bisects a reference angle, which is an acute angle formed by the first reference line and the reference perpendicular line, is defined as a second reference line; When a line inclined from the reference perpendicular line to the rake face side by an angle of half the reference angle with the cutting edge as the center is defined as a third reference line, The cutting edge treatment process includes: in an outer angle range of the cutting edge portion at a central angle centered on the cutting edge; a rough machining step of grinding the tool blade by applying an abrasive toward the cutting edge in a direction parallel to an angle included in one of two first type angle ranges constituted by an angle range between the cutting face and the second reference line and an angle range between the front relief face and a portion of the third reference line that is on the front relief face side with respect to the center.

2. A method for manufacturing the cutting tool according to claim 1, The cutting edge treatment step is performed after the rough machining step. a finishing process step of polishing the tool blade by applying an abrasive material toward the cutting edge in a direction parallel to an angle included in an angle range between the portion of the third reference line and the second reference line.

3. A method for manufacturing the cutting tool according to claim 2, The cutting edge treatment step includes: This is done by blasting using a nozzle that sprays abrasives. The finishing process includes: When the cutting tool is viewed along a central axis of the cutting tool, the nozzle is disposed at a position and orientation that is realized when the nozzle facing the central axis is moved parallel to a direction perpendicular to a reference position of the nozzle on a straight line passing through the central axis, from the straight line; rotating the cutting tool alternately in both circumferential directions around the central axis, with the central axis as a rotation axis, and grinding the tool blade while the cutting tool is being rotated.

4. A method for manufacturing the cutting tool according to claim 3, in the finishing process, the nozzle is arranged within a nozzle arrangement range extending from the reference position toward each of the positive vertical direction and the negative vertical direction to a position defined by an outermost diameter of the cutting tool.

5. A method for manufacturing the cutting tool according to claim 2, The cutting edge treatment step includes: This is done by blasting using a nozzle that sprays abrasives. The finishing process includes: When the cutting tool is viewed along a central axis of the cutting tool, the nozzle is arranged at a position and orientation that is realized when the nozzle, facing the central axis, is moved from a reference position of the nozzle on a straight line passing through the central axis along an arc centered on the central axis while maintaining the orientation of the nozzle, from the straight line; rotating the cutting tool alternately in both circumferential directions around the central axis, with the central axis as a rotation axis, and grinding the tool blade while the cutting tool is being rotated.

6. A method for manufacturing the cutting tool according to any one of claims 1 to 5, In the method for manufacturing a cutting tool, the tool blade ground in the cutting edge treatment step is a tool blade of a used cutting tool.

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