Methods for machining dovetail grooves, machine tools, and tool bits

Abstract

The present invention provides a method for machining dovetail grooves, a machine tool, and a tool bit capable of suitably cutting the groove bottom of the dovetail groove. [Solution] The method for machining a dovetail groove comprises the steps of: inserting a tool bit into a roughly machined dovetail groove; cutting a portion of the groove bottom of the dovetail groove by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove; changing the position of the tool bit in the width direction of the dovetail groove; and, after the position of the tool bit has been changed in the width direction of the dovetail groove, cutting another portion of the groove bottom by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove. The tool bit has a cutting edge whose width increases from the root to the tip edge. The dovetail groove has an opening width through which the tip edge can pass.

Description

Technical Field

[0006] , , , ,

[0007] , ,

[0001] The present invention relates to a method for machining an ant groove, a machine tool, and a tool bit.

Background Art

[0002] Techniques for forming ant grooves are known.

[0003] As a related technique, Patent Document 1 discloses an ant groove machining apparatus. The ant groove machining apparatus described in Patent Document 1 includes a cutter having a blade surface provided on a conical surface. The cutter is fed forward, then fed in the left - right direction, and then fed backward.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a method for machining an ant groove, a machine tool, and a tool bit capable of suitably cutting the groove bottom of the ant groove.

Means for Solving the Problems

[0006] Embodiments of the present invention relate to the following method for machining an ant groove, a machine tool, and a tool bit. <0000s34>

[0007] (1) A step of causing a tool bit to enter an ant groove in a rough - machined state, and A step of cutting a part of the groove bottom of the ant groove by moving the tool bit along the extending direction of the ant groove in a state where the tool bit has entered the ant groove, and A step of changing the position of the tool bit in the width direction of the ant groove, and After the position of the tool bit is changed in the width direction of the dovetail groove, the tool bit is moved along the extending direction of the dovetail groove while it is inside the dovetail groove, thereby cutting another part of the groove bottom. Prepare, The tool bit has a blade portion whose width increases from the base to the tip edge, The dovetail groove has an opening width through which the tip edge can pass. Method for machining dovetail grooves. (2) The tip edge of the blade portion has a plurality of apex portions that are in contact with the bottom of the groove, The multiple vertices form multiple grooves at the bottom of the groove along the extending direction of the dovetail groove. The method for machining the dovetail groove described in (1) above. (3) The tip edge of the blade portion has one apex that contacts the bottom of the groove, The aforementioned top portion forms a plurality of grooves at the bottom of the groove, along the extending direction of the dovetail groove. The method for machining the dovetail groove described in (1) above. (4) Cutting of the groove bottom is performed with the tool bit mounted on a spindle that is rotatable around the first axis via a tool holder. A method for machining a dovetail groove as described in any one of (1) to (3) above. (5) The groove opening of the dovetail groove has a constant width along the extending direction of the dovetail groove, The groove opening having a certain width is used as an opening for the tool bit to approach. A method for machining a dovetail groove as described in any one of (1) to (4) above. (6) When the direction from the groove opening of the dovetail groove toward the groove bottom is defined as the first direction, the dovetail groove has a closed shape when viewed in the first direction. A method for machining a dovetail groove as described in any one of (1) to (4) above. (7) The step of cutting a portion of the bottom of the dovetail groove includes rotating the cutting blade along the extending direction of the dovetail groove while the cutting blade is in contact with the bottom of the groove. The method for machining the dovetail groove described in (6) above. (8) The step of inserting the tool bit into the dovetail groove in the rough-machined state includes inserting the tool bit into the dovetail groove with the cutting edge width direction of the cutting edge portion perpendicular or inclined with respect to the width direction of the dovetail groove, After the tool bit enters the dovetail groove, and before performing the step of cutting a portion of the groove bottom of the dovetail groove, the tool bit is rotated around the first axis so that the width direction of the cutting edge is substantially parallel to the width direction of the dovetail groove. The method for machining the dovetail groove described in (4) above. (9) The tool bit has a shaft that supports the cutting edge, The distance between one end of the tip edge in the blade width direction and the central axis of the shaft, when viewed in the blade thickness direction, is greater than the distance between the other end of the tip edge in the blade width direction and the central axis, when viewed in the blade thickness direction. A method for machining a dovetail groove as described in any one of (1) to (7) above. (10) A first machining cycle is defined as a cycle including the steps of moving the blade along the extending direction of the dovetail groove with the tip edge in contact with the bottom of the groove, and changing the position of the blade in the width direction of the dovetail groove; the direction in which the blade moves along the extending direction of the dovetail groove in the first machining cycle is defined as the first movement direction, and the direction opposite to the first movement direction is defined as the second movement direction; a second machining cycle is defined as a cycle including the steps of moving the blade in the second movement direction with the tip edge in contact with the bottom of the groove, and changing the position of the blade in the width direction of the dovetail groove; and each of the first machining cycle and the second machining cycle is executed multiple times. A method for machining a dovetail groove as described in any one of (1) to (9) above. (11) A step of forming the dovetail groove in the rough state using a roughing tool held on the spindle, A step of using a tool changing device to replace the roughing tool held on the spindle with the tool holder to which the tool bit is attached. further comprising After executing the step of replacing the rough machining tool held by the spindle with the tool holder to which the tool bit is attached, a step of causing the tool bit to enter the chamfer groove in the rough machining state is executed. The method for machining a chamfer groove according to (4) above. (12) The blade part has a one-sided tapered shape in which the blade width expands from the root part toward the tip edge part, The tip edge part of the blade part has a waveform shape having a plurality of peaks and a plurality of valleys. The method for machining a chamfer groove according to (1) above. (13) A machining head that holds a tool holder to which a tool bit having a blade part whose blade width expands from the root part toward the tip edge part is attached, A work support device that supports a work, A moving device that relatively moves the machining head with respect to the work support device, A control device that controls the moving device comprising The control device A process of causing the tool bit to enter a chamfer groove in a rough machining state formed in the work, A process of cutting a part of the groove bottom of the chamfer groove by moving the tool bit along the extending direction of the chamfer groove while the tool bit has entered the chamfer groove, A process of changing the position of the tool bit in the width direction of the chamfer groove, After the position of the tool bit is changed in the width direction of the chamfer groove, a process of cutting another part of the groove bottom by moving the tool bit along the extending direction of the chamfer groove while the tool bit has entered the chamfer groove is executable Machine tool. (14) A blade part whose blade width expands from the root part toward the tip edge part, A shaft that supports the blade part comprising The tip edge part of the blade part has a plurality of peaks that contact the groove bottom of the chamfer groove. Tool bit (15) When viewed in the cutting edge thickness direction, the distance between one end in the cutting edge width direction of the tip edge portion and the central axis of the shaft is greater than the distance between the other end in the cutting edge width direction of the tip edge portion and the central axis when viewed in the cutting edge thickness direction The tool bit according to (14) above

Effect of the Invention

[0008] According to the present invention, it is possible to provide a method for machining an anti-drill groove, a machine tool, and a tool bit that can suitably cut the groove bottom of the anti-drill groove

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic perspective view schematically showing an example of a workpiece [Figure 2] FIG. 2 is a schematic cross-sectional view schematically showing an example of a workpiece [Figure 3] FIG. 3 is a schematic cross-sectional view schematically showing the entering process [Figure 4] FIG. 4 is a schematic cross-sectional view schematically showing the entering process [Figure 5] FIG. 5 is a schematic perspective view schematically showing a state where a part of the groove bottom of the anti-drill groove is machined [Figure 6] FIG. 6 is a schematic perspective view schematically showing a state where a part of the groove bottom of the anti-drill groove is machined [Figure 7] FIG. 7 is a schematic perspective view schematically showing a state where the outside region of the groove bottom of the anti-drill groove is machined [Figure 8] FIG. 8 is a schematic cross-sectional view schematically showing a state where the position of the tool bit is changed in the width direction of the anti-drill groove [Figure 9] FIG. 9 is a schematic cross-sectional view schematically showing a state where the position of the tool bit is changed in the width direction of the anti-drill groove [Figure 10] FIG. 10 is a schematic perspective view schematically showing a state where another part of the groove bottom of the anti-drill groove is machined after the position of the tool bit is changed in the width direction of the anti-drill groove [Figure 11] Figure 11 is a schematic front view illustrating an example of a tool bit. [Figure 12] Figure 12 is a magnified view of a portion of Figure 11. [Figure 13] Figure 13 is a schematic plan view illustrating how multiple grooves are formed at the bottom of the groove, along the direction of extension of the dovetail groove. [Figure 14] Figure 14 schematically shows how a tool bit is attached to a spindle via a tool holder. [Figure 15] Figure 15 is a schematic perspective view illustrating another example of the workpiece. [Figure 16] Figure 16 is a schematic front view illustrating the tool bit in the first modified example. [Figure 17] Figure 17 is a schematic front view illustrating the tool bit in the second modified example. [Figure 18] Figure 18 is a schematic front view illustrating the tool bit in the third modified example. [Figure 19] Figure 19 is a schematic perspective view of the tool bit from a diagonal downward angle. [Figure 20] Figure 20 is a schematic side view illustrating a portion of the tool bit. [Figure 21] Figure 21 is a schematic bottom view illustrating an example of a tool bit. [Figure 22] Figure 22 is a schematic cross-sectional view illustrating the entry process. [Figure 23] Figure 23 is a schematic perspective view illustrating the entry process. [Figure 24] Figure 24 is a schematic perspective view illustrating how the orientation of the cutting edge of the tool bit changes after the entry process is performed. [Figure 25] Figure 25 is a schematic cross-sectional view illustrating how the position of the tool bit changes in the width direction of the dovetail groove. [Figure 26] Figure 26 is a schematic cross-sectional view illustrating the state after the first processing cycle has been performed three times. [Figure 27] Figure 27 is a schematic perspective view illustrating how the orientation of the cutting edge changes around the first axis. [Figure 28] Figure 28 is a schematic perspective view illustrating how the inside region of the groove bottom of a dovetail groove is machined. [Figure 29] Figure 29 is a schematic cross-sectional view illustrating the state after the second processing cycle has been performed twice. [Figure 30] Figure 30 is a schematic cross-sectional view illustrating how the seal ring is positioned in the dovetail groove. [Figure 31] Figure 31 is a schematic cross-sectional view illustrating an example of a lid with a dovetail groove. [Figure 32] Figure 32 is a schematic cross-sectional view illustrating an example of a rough machining process. [Figure 33] Figure 33 is a schematic cross-sectional view illustrating another example of the rough machining process. [Figure 34] Figure 34 is a flowchart showing an example of a method for machining a dovetail groove in the first embodiment. [Figure 35] Figure 35 is a flowchart showing another example of the method for machining the dovetail groove in the first embodiment. [Figure 36] Figure 36 is a schematic perspective view illustrating a machine tool in the second embodiment. [Figure 37] Figure 37 is a schematic front view illustrating the tool change process in action. [Figure 38] Figure 38 is a schematic diagram illustrating how a control device can control multiple devices. [Figure 39] Figure 39 is a schematic front view illustrating a portion of the machine tool in the second embodiment. [Figure 40] Figure 40 is a schematic front view illustrating a portion of the machine tool in the second embodiment. [Figure 41] Figure 41 is a schematic front view illustrating a portion of a machine tool in the second embodiment. [Modes for carrying out the invention]

[0010] The following description of the embodiment will explain the method for machining the dovetail groove, the machine tool 1, and the tool bit 8 with reference to the drawings. In the following description of the embodiment, parts and components having the same function will be denoted by the same reference numerals, and repeated explanations of parts and components denoted by the same reference numerals will be omitted.

[0011] (First embodiment) The machining method for a dovetail groove in the first embodiment will be described with reference to Figures 1 to 35. Figure 1 is a schematic perspective view showing an example of a workpiece 9. Figure 2 is a schematic cross-sectional view showing an example of a workpiece 9. Figures 3 and 4 are schematic cross-sectional views showing the entry process. Figures 5 and 6 are schematic perspective views showing a portion of the groove bottom 91 of the dovetail groove 90 being machined. Figure 7 is a schematic perspective view showing the outside region of the groove bottom 91 of the dovetail groove 90 being machined. Figures 8 and 9 are schematic cross-sectional views showing the position of the tool bit 8 being changed in the width direction of the dovetail groove 90. Figure 10 is a schematic perspective view showing another portion of the groove bottom 91 of the dovetail groove 90 being machined after the position of the tool bit 8 has been changed in the width direction of the dovetail groove 90. Figure 11 is a schematic front view showing an example of a tool bit 8. Figure 12 is an enlarged view of a portion of Figure 11. Figure 13 is a schematic plan view illustrating how multiple grooves 91v are formed in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. Figure 14 is a schematic diagram illustrating how the tool bit 8 is attached to the spindle 21 via the tool holder HD. Figure 15 is a schematic perspective view illustrating another example of the workpiece 9. Figure 16 is a schematic front view illustrating the tool bit 8 in the first modified example. Figure 17 is a schematic front view illustrating the tool bit 8 in the second modified example. Figure 18 is a schematic front view illustrating the tool bit 8 in the third modified example. Figure 19 is a schematic perspective view of the tool bit 8 viewed from diagonally below. Figure 20 is a schematic side view illustrating a part of the tool bit 8. Figure 21 is a schematic bottom view illustrating an example of the tool bit 8. Figure 22 is a schematic cross-sectional view illustrating the entry process. Figure 23 is a schematic perspective view illustrating the entry process. Figure 24 is a schematic perspective view illustrating how the orientation of the cutting edge of the tool bit 8 changes after the entry process is performed. Figure 25 is a schematic cross-sectional view illustrating how the position of the tool bit 8 changes in the width direction of the dovetail groove 90. Figure 26 is a schematic cross-sectional view illustrating the state after the first machining cycle has been performed three times. Figure 27 is a schematic perspective view illustrating how the orientation of the cutting edge 81 changes around the first axis AX1.Figure 28 is a schematic perspective view illustrating the machining of the inside region of the groove bottom 91 of the dovetail groove 90. Figure 29 is a schematic cross-sectional view illustrating the state after the second machining cycle has been performed twice. Figure 30 is a schematic cross-sectional view illustrating the placement of the seal ring SR in the dovetail groove 90. Figure 31 is a schematic cross-sectional view illustrating an example in which the dovetail groove 90 is formed on the lid 9b. Figure 32 is a schematic cross-sectional view illustrating an example of a rough machining process. Figure 33 is a schematic cross-sectional view illustrating another example of a rough machining process. Figure 34 is a flowchart illustrating an example of a method for machining a dovetail groove in the first embodiment. Figure 35 is a flowchart illustrating another example of a method for machining a dovetail groove in the first embodiment.

[0012] Figure 1 shows a workpiece 9 with a roughly machined dovetail groove 90 formed on it. In the example shown in Figure 1, no approach hole with a diameter larger than the opening width W1 of the dovetail groove 90 is formed. In this case, it is difficult to bring the cutting edge of the tool bit into the area indicated by the dashed arrow AR1 in Figure 2. Therefore, in the method for machining the dovetail groove in the first embodiment, a tool bit 8 having a cutting edge 81 (see Figure 11) whose cutting edge width increases from the root portion 82 to the tip edge portion 83 is used, and as illustrated in Figure 3, the dovetail groove 90 has an opening width W1 through which the tip edge portion 83 of the cutting edge 81 can pass.

[0013] As illustrated in Figures 3 and 4, in the first step ST1, the tool bit 8 is inserted into the rough-machined dovetail groove 90. The first step ST1 is an insertion step. In the example shown in Figures 3 and 4, the insertion step (first step ST1) includes inserting the tool bit 8 into the dovetail groove 90 from outside the dovetail groove 90 of the workpiece 9 through the groove opening OP of the dovetail groove 90.

[0014] As illustrated in Figures 5 to 10, in the second step ST2, the groove bottom 91 of the dovetail groove 90 is cut by the tool bit 8. The second step ST2 is a machining process. Figures 5 to 10 show an example in which the groove bottom 91 of the dovetail groove 90 formed in the workpiece 9 is finished using the tool bit 8.

[0015] As illustrated in Figures 5 to 10, the machining process includes: (1) a step of cutting a portion of the groove bottom 91 of the dovetail groove 90 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is entered into the dovetail groove 90 (see Figures 5 and 6); (2) a step of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90 (see Figures 8 and 9); and (3) a step of cutting another portion of the groove bottom 91 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is entered into the dovetail groove 90 after the position of the tool bit 8 has been changed in the width direction MR2 of the dovetail groove 90 (see Figure 10).

[0016] In the method for machining the dovetail groove in the first embodiment, the groove bottom 91 of the dovetail groove 90 is suitably cut.

[0017] The dovetail groove machining method in the first embodiment includes a step of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90. Therefore, the groove bottom 91 of the dovetail groove 90 can be suitably cut using a tip edge 83 that has a width smaller than the width of the groove bottom 91 of the dovetail groove 90. Also, as illustrated in Figure 11, the tool bit 8 has a blade portion 81 whose blade width increases from the root portion 82 to the tip edge 83. When the blade portion 81 has a flared shape, one end 831 of the tip edge 83 of the blade portion 81 in the blade width direction can be easily brought into contact with the deeper part of the dovetail groove 90 in the width direction (see dashed arrow AR1 in Figure 2). Furthermore, when the width of the tip edge 83 is large, the number of times the position of the tool bit 8 needs to be changed in the width direction MR2 of the dovetail groove 90 is reduced.

[0018] In addition, since the dovetail groove 90 has an opening width W1 through which the tip edge 83 of the blade portion 81 can pass, it is not necessary to provide an approach hole in the workpiece 9 with a diameter larger than the opening width W1 of the dovetail groove 90 (see Figure 1).

[0019] (Optional additional configuration) Next, with reference to Figures 1 to 35, optional additional configurations that can be adopted in the dovetail groove machining method of the first embodiment will be described.

[0020] (Top 84) In the example shown in Figure 12, the tip edge 83 of the blade portion 81 has at least one apex 84 that contacts the groove bottom 91 of the dovetail groove 90. As illustrated in Figure 13, at least one apex 84 may form a plurality of grooves 91v (e.g., a plurality of micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. In Figure 13, the plurality of grooves 91v are indicated by dashed lines. The grooves 91v may be grooves that can be directly seen by the user, or they may be grooves that cannot be confirmed without using a microscope.

[0021] In the example shown in Figure 12, the tip edge 83 of the blade portion 81 has a plurality of vertices 84 that contact the groove bottom 91 of the dovetail groove 90. More specifically, the tip edge 83 of the blade portion 81 has a plurality of vertices 84 that contact the groove bottom 91 of the dovetail groove 90 along the blade width direction.

[0022] In this case, multiple tops 84 form multiple grooves 91v (e.g., multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. More specifically, as the multiple tops 84 move along the extending direction MR1 of the dovetail groove 90, multiple grooves 91v (e.g., multiple micro-grooves) are formed in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90.

[0023] Alternatively, the tip edge 83 of the blade portion 81 may have only one apex 84 that contacts the groove bottom 91 of the dovetail groove 90. In this case, the single apex 84 forms multiple grooves 91v (e.g., multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. More specifically, the single apex 84 moves along the extending direction MR1 of the dovetail groove 90, then the single apex 84 is repositioned in the width direction MR2 of the dovetail groove 90, and then the single apex 84 moves along the extending direction MR1 of the dovetail groove 90, thereby forming multiple grooves 91v (e.g., multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90.

[0024] In the example shown in Figure 12, the tip edge 83 of the blade portion 81 has a plurality of peaks 84 and a plurality of valleys 85 that are recessed toward the base portion 82. Each of the plurality of peaks 84 may be made up of a curved edge. Each of the plurality of valleys 85 may be made up of a curved edge. The tip edge 83 of the blade portion 81 may have a wave-shaped SH having a plurality of peaks 84 and a plurality of valleys 85.

[0025] As illustrated in Figure 12, the width W4 of each peak 84 may be smaller than the width W5 of each valley 85. In the direction of the blade thickness, the line segment 86 connecting the peak 84 and the valley 85 may be inclined with respect to the central axis AT1 of the shaft 87 that supports the blade portion 81. In the example shown in Figure 12, the tip edge 83 has three peaks 84. Alternatively, the tip edge 83 may have four or more peaks 84.

[0026] (Spindle 21) As illustrated in Figure 14, the cutting process (second step ST2) may be performed with the tool bit 8 mounted on a spindle 21 that is rotatable around the first axis AX1 via a tool holder HD. In other words, cutting of the groove bottom 91 may be performed with the tool bit 8 mounted on a spindle 21 that is rotatable around the first axis AX1 via a tool holder HD. In this case, as illustrated in Figure 6, the orientation of the cutting edge 81 can be changed while moving the tool bit 8 along the curved portion 90c of the dovetail groove 90. As illustrated in Figure 14, with the tool bit 8 mounted on the spindle 21 via a tool holder HD, the first axis AX1 may be substantially coaxial with the central axis AT1 of the tool bit 8.

[0027] As illustrated in Figure 6, consider a case where the dovetail groove 90 has a curved portion 90c that extends along the curve. In this case, the cutting process (more specifically, cutting the groove bottom 91) includes changing the orientation of the cutting edge 81 while moving the tool bit 8 along the curve by rotating the spindle 21 in accordance with the change in the tangential direction of the curve. More specifically, the cutting process (more specifically, cutting the groove bottom 91) includes substantially maintaining the angle between the cutting edge width direction of the cutting edge 81 and the tangential direction of the curve at a predetermined angle (e.g., 90 degrees) while moving the tool bit 8 along the curve.

[0028] Since the tool bit 8 is a non-rotating cutting tool, it does not rotate when it moves along the straight portion 90s of the dovetail groove 90 (see Figure 5). On the other hand, when the tool bit 8 moves along the curved portion 90c of the dovetail groove 90, it is preferable that the orientation of the cutting edge 81 is changed while the tool bit 8 moves along the curved portion 90c (see Figure 6).

[0029] (Groove opening OP) In the example shown in Figure 6, the groove opening OP of the dovetail groove 90 has a constant width Wc along the extending direction MR1 of the dovetail groove 90. Furthermore, the groove opening OP with a constant width Wc itself is used as the approach opening OP1 for the tool bit 8 (see Figure 3).

[0030] As illustrated in Figure 3, in this specification, the direction from the groove opening OP of the dovetail groove 90 toward the groove bottom 91 of the dovetail groove 90 is defined as the first direction DR1. In the example shown in Figure 3, the first direction DR1 is perpendicular to the plane along the groove opening OP and toward the groove bottom 91.

[0031] As illustrated in Figure 1, the dovetail groove 90 may have a closed shape when viewed in the first direction DR1. In the dovetail groove machining method of the first embodiment, even when the dovetail groove 90 has a closed shape, the tool bit 8 can be suitably inserted into the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0032] As illustrated in Figure 1, the dovetail groove 90 may have a substantially rectangular shape when viewed in the first direction DR1. In other words, the closed shape described above may be substantially rectangular. As illustrated in Figure 1, the substantially rectangular shape may be a rounded rectangular shape. Alternatively, as illustrated in Figure 15, the dovetail groove 90 may have a substantially circular shape when viewed in the first direction DR1. In other words, the closed shape described above may be substantially circular.

[0033] As illustrated in Figure 7, if the dovetail groove 90 has a closed shape (for example, a roughly rectangular or roughly circular shape, etc.) when viewed in the first direction DR1, the above-described machining process (for example, the process of cutting a portion of the groove bottom 91 of the dovetail groove 90) may include rotating the blade portion 81 along the extending direction MR1 of the dovetail groove 90 while the blade portion 81 is in contact with the groove bottom 91. More specifically, the above-described machining process (for example, the process of cutting a portion of the groove bottom 91 of the dovetail groove 90) may include rotating the blade portion 81 at least once around the region 92 surrounded by the dovetail groove 90 while the blade portion 81 is in contact with the groove bottom 91. As illustrated in Figure 6, rotating the blade portion 81 may include changing the orientation of the blade portion 81 while moving the tool bit 8 along the curved portion 90c of the dovetail groove 90.

[0034] (blade part 81) In the example shown in Figure 11, when viewed from the tip 8d of the tool bit 8 toward the base 8p of the tool bit 8, the center of the tip edge 83 of the cutting edge 81 is offset from the center of the root 82 of the cutting edge 81. Also, when viewed in the direction of the cutting edge thickness, the half-line LN extending from the center of the root 82 through the center of the tip edge 83 is inclined with respect to the direction from the base of the tool bit 8 toward the tip of the tool bit 8 (more specifically, when viewed in the direction of the cutting edge thickness, the half-line LN is inclined with respect to the central axis AT1 of the shaft 87). In this case, as illustrated in Figure 8, one end 831 of the tip edge 83 in the cutting edge width direction can easily approach the depth in the width direction of the dovetail groove 90. Also, the amount of lateral protrusion of the other end 832 of the tip edge 83 in the cutting edge width direction is reduced. Therefore, it is easier to enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90. In this specification, the second direction DR2 is defined as the direction parallel to the width direction of the blade portion 81 and extending from one end 831 in the width direction of the tip edge portion 83 to the other end 832 in the width direction of the tip edge portion 83. In this specification, the third direction DR3 is defined as the blade thickness direction (more specifically, the direction perpendicular to the width direction of the blade and opposite to the direction in which the blade portion 81 moves during cutting).

[0035] In the example shown in Figure 11, the blade portion 81 has a flared shape where the blade width increases towards the cutting edge when viewed in the third direction DR3. As illustrated in Figure 11, the blade portion 81 may have a flared shape on one side where the blade width increases from the root portion 82 towards the tip edge portion 83 when viewed in the third direction DR3 (more specifically, a flared shape on one side where the blade width increases towards the cutting edge). When the blade portion 81 has a flared shape on one side, the tip edge portion 83 is easily inserted into the dovetail groove 90 through the groove opening OP of the dovetail groove 90. Alternatively, as illustrated in Figure 16, the blade portion 81 may have a flared shape on both sides where the blade width increases from the root portion 82 towards the tip edge portion 83 when viewed in the third direction DR3 (more specifically, a flared shape on both sides where the blade width increases towards the cutting edge).

[0036] In the examples shown in Figures 12 and 16, the tip edge 83 of the blade portion 81 has a corrugated shape SH having a plurality of peaks 84 and a plurality of valleys 85. Alternatively, as illustrated in Figures 17 and 18, the tip edge of the blade portion 81 may be straight.

[0037] As illustrated in Figure 19, the tip edge 83 of the blade portion 81 may have a plurality of grooves 83v extending in the third direction DR3. In the example shown in Figure 19, the tip edge 83 of the blade portion 81 has a plurality of vertices 84 extending in the third direction DR3 and a plurality of valleys 85 extending in the third direction DR3, and each of the plurality of valleys 85 extending in the third direction DR3 constitutes a groove 83v extending in the third direction DR3. In addition, each of the plurality of vertices 84 extending in the third direction DR3 constitutes a ridge 83r extending in the third direction DR3.

[0038] (Shaft 87) In the examples shown in Figures 11, 16, 17, and 18, the tool bit 8 has a shaft 87 that supports the cutting edge 81.

[0039] In the examples shown in Figures 11 and 17, the center of the tip edge 83 of the blade portion 81 is located away from the central axis AT1 of the shaft 87 when viewed in the blade thickness direction (more specifically, in the third direction DR3). In this case, as illustrated in Figure 8, one end 831 of the tip edge 83 in the blade width direction can easily approach the depth of the dovetail groove 90 in the width direction. Also, the amount of protrusion of the other end 832 of the tip edge 83 of the blade portion 81 from the central axis AT1 of the shaft 87 is small, making it easier for the tip edge 83 to enter the dovetail groove 90 through the groove opening OP.

[0040] In this specification, the distance between one end 831 of the tip edge 83 of the blade portion 81 and the central axis AT1 of the shaft 87, viewed in the blade thickness direction (more specifically, in the third direction DR3), is defined as the first distance L1 (see Figure 11), and the distance between the other end 832 of the tip edge 83 of the blade portion 81 and the central axis AT1 of the shaft 87, viewed in the blade width direction, is defined as the second distance. In the example shown in Figure 11, the first distance L1 is greater than the second distance (in the example shown in Figure 11, the second distance is zero, but the second distance does not have to be zero). When the first distance L1 is large, one end 831 of the tip edge 83 can easily approach the depth of the dovetail groove 90 in the width direction. Also, when the second distance is small, the tip edge 83 can easily enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0041] In the examples shown in Figures 11 and 17, the entire tip edge 83 of the blade portion 81 is positioned on one side of the central axis AT1 of the shaft 87, when viewed in the blade thickness direction (more specifically, in the third direction DR3). Alternatively, a large portion of the tip edge 83 of the blade portion 81 (for example, more than 3 / 4 of the total volume of the tip edge 83 of the blade portion 81) may be positioned on one side of the central axis AT1 of the shaft 87, when viewed in the blade thickness direction (more specifically, in the third direction DR3). By positioning the entire or a large portion of the tip edge 83 of the blade portion 81 on one side of the central axis AT1 of the shaft 87, the tip edge 83 is made more likely to enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0042] As illustrated in Figure 20, when viewed in the width direction of the blade portion 81 (more specifically, in the second direction DR2), most of the tip edge portion 83 of the blade portion 81 (for example, 3 / 4 or more of the total volume of the tip edge portion 83 of the blade portion 81) may be positioned on one side of the central axis AT1 of the shaft 87. Alternatively, when viewed in the width direction of the blade portion 81 (more specifically, in the second direction DR2), the entire blade portion 81 may be positioned on one side of the central axis AT1 of the shaft 87.

[0043] As illustrated in Figure 20, the ridge portion 83r of the tip edge portion 83 may be inclined to approach the base portion 82 of the blade portion 81 as it moves toward the third direction DR3 (more specifically, perpendicular to the blade width direction and in the opposite direction to the direction in which the blade portion 81 moves during cutting).

[0044] As illustrated in Figure 21, the entire tip edge 83 may be located inside the outer edge 87e of the shaft 87 when viewed in the direction along the central axis AT1 of the shaft 87. Alternatively, when viewed in the direction along the central axis AT1 of the shaft 87, one end 831 of the tip edge 83 in the cutting width direction may be located outside the outer edge 87e of the shaft 87, and the other end 832 of the tip edge 83 in the cutting width direction may be located inside the outer edge 87e of the shaft 87.

[0045] As illustrated in Figure 21, the entire tip edge 83 may be located within two quadrants (or one quadrant) centered on the central axis AT1 when viewed along the central axis AT1 of the shaft 87. Alternatively, the majority of the tip edge 83 (for example, more than 3 / 4 of the total volume of the tip edge 83 of the blade portion 81) may be located within two quadrants (or one quadrant) centered on the central axis AT1 when viewed along the central axis AT1 of the shaft 87.

[0046] (Entry process) In the example shown in Figure 22, the entry step (first step ST1) is performed with the blade width direction (more specifically, the second direction DR2) of the blade portion 81 positioned substantially parallel to the width direction of the dovetail groove 90. More specifically, the entry step (first step ST1) includes inserting the tool bit 8 into the dovetail groove 90 through the groove opening OP of the dovetail groove 90 with the blade width direction (more specifically, the second direction DR2) of the blade portion 81 positioned substantially parallel to the width direction of the dovetail groove 90. In the example shown in Figure 22, the width W2 of the tip edge 83 (more specifically, the width of the tip edge 83 in the direction along the second direction DR2, and more specifically, the distance between one end 831 of the tip edge 83 in the blade width direction and the other end 832 of the tip edge 83 in the blade width direction) is smaller than the opening width W1 of the dovetail groove 90 (more specifically, the constant width Wc of the groove opening OP). Because the width W2 of the tip edge 83 of the blade portion 81 is smaller than the opening width W1 of the dovetail groove 90, the tip edge 83 can easily enter the dovetail groove 90. Furthermore, even if the blade portion 81 has a flared shape, the entire tip edge 83 of the blade portion 81 can easily enter the dovetail groove 90.

[0047] Alternatively, the entry step (first step ST1) may include inserting the tool bit 8 into the dovetail groove 90 through the groove opening OP of the dovetail groove 90 with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) perpendicular or inclined with respect to the width direction of the dovetail groove 90 (see dashed arrow AR2 in Figure 23). In this case, after the tool bit 8 has entered the dovetail groove 90, before performing the step of cutting a portion of the groove bottom 91 of the dovetail groove 90, the tool bit 8 is rotated around the first axis AX1 so that the blade width direction of the blade portion 81 (more specifically, the second direction DR2) is substantially parallel to the width direction of the dovetail groove 90 (see dashed arrow AR3 in Figure 24).

[0048] In the examples shown in Figures 22 and 23, the entry step (first step ST1) includes inserting the tip edge 83 of the blade 81 into the dovetail groove 90, such that the entire blade 81 is positioned inside both side edges of the groove opening OP when viewed in the first direction DR1. The entry step (first step ST1) may also include inserting the tool bit 8 into the dovetail groove 90 by moving the tool bit 8 in a direction substantially parallel to the first direction DR1.

[0049] (Processing process) In this specification, a first machining cycle is defined as a cycle that includes the steps of moving the blade portion 81 along the extending direction MR1 of the dovetail groove 90 while the tip edge 83 of the blade portion 81 is in contact with the groove bottom 91 of the dovetail groove 90, and changing the position of the blade portion 81 in the width direction MR2 of the dovetail groove 90.

[0050] As illustrated in Figures 1 and 15, we assume that the dovetail groove 90 has a closed shape (for example, a roughly rectangular shape, a roughly circular shape, etc.). More specifically, we assume that the dovetail groove 90 has a closed loop shape. In this case, the step of moving the cutting edge 81 along the extending direction MR1 of the dovetail groove 90 in the first machining cycle may include rotating the cutting edge 81 along the extending direction MR1 of the dovetail groove 90 (more specifically, the cutting edge 81 making at least one rotation around the region 92 surrounded by the dovetail groove 90).

[0051] As shown by the dashed arrow AR4 in Figure 25, the step of changing the position of the blade portion 81 in the width direction MR2 of the dovetail groove 90 may include performing the following steps in this order: (1) moving the blade portion 81 away from the groove bottom 91, (2) moving the blade portion 81 in the blade width direction (more specifically, in the second direction DR2 or the direction opposite to the second direction DR2), and (3) bringing the blade portion 81 into contact with the groove bottom 91.

[0052] The machining process (second step ST2) may include repeatedly executing the first machining cycle described above. For example, the machining process (second step ST2) may include shifting the blade portion 81 in the blade width direction by a predetermined distance each time the blade portion 81 completes one rotation along the dovetail groove 90 while in contact with the groove bottom 91.

[0053] The processing step (second step ST2) may include repeating the above-described first processing cycle two or more times, three or more times, four or more times, or five or more times.

[0054] Figure 26 shows the state after the first processing cycle described above has been performed three times.

[0055] The machining process (second step ST2) may include a step of changing the orientation of the cutting edge 81 around the first axis AX1 after the first machining cycle has been performed two or more times. More specifically, the machining process (second step ST2) may include a step of changing the orientation of the cutting edge 81 around the first axis AX1 by a predetermined angle (for example, 180 degrees) after the first machining cycle has been performed two or more times. Figure 27 shows the process of changing the orientation of the cutting edge 81 in progress.

[0056] The step of changing the orientation of the blade portion 81 (more specifically, the step of changing the orientation of the blade portion 81 by a predetermined angle (e.g., 180 degrees)) is preferably performed when the entire tool bit 8 is located outside the dovetail groove 90. In this case, the machining step (second step ST2) may include performing, in this order: (1) after the first machining cycle has been performed two or more times, moving the entire tool bit 8 outside the dovetail groove 90; (2) changing the orientation of the blade portion 81 around the first axis AX1 (more specifically, changing the orientation of the blade portion 81 around the first axis AX1 by a predetermined angle (e.g., 180 degrees)); and (3) re-entering the tool bit 8 into the dovetail groove 90.

[0057] Alternatively, if the size of the dovetail groove 90 is sufficiently large, the step of changing the orientation of the blade portion 81 (more specifically, the step of changing the orientation of the blade portion 81 by a predetermined angle (e.g., 180 degrees)) may be performed while the tool bit 8 is entered into the dovetail groove 90.

[0058] In the example shown in Figure 27, if the tool bit 8 retracts from the top of the first side wall 99-1 of the workpiece 9 outside the dovetail groove 90, and then the tool bit 8 re-enters the dovetail groove 90 at the top of the second side wall 99-2 opposite the first side wall 99-1, the step of changing the orientation of the cutting edge 81 around the first axis AX1 may be omitted. In other words, the step of changing the orientation of the cutting edge 81 (more specifically, the step of changing the orientation of the cutting edge 81 by a predetermined angle) is not essential.

[0059] In this specification, in the first machining cycle, the direction in which the cutting edge 81 moves along the extending direction MR1 of the dovetail groove 90 is defined as the first movement direction MD1 (see Figure 10), and the direction opposite to the first movement direction MD1 is defined as the second movement direction MD2 (see Figure 28). Furthermore, in this specification, a cycle including the steps of moving the cutting edge 81 in the second movement direction MD2 while the tip edge 83 of the cutting edge 81 is in contact with the groove bottom 91 of the dovetail groove 90, and changing the position of the cutting edge 81 in the width direction MR2 of the dovetail groove 90 is defined as the second machining cycle.

[0060] As illustrated in Figures 1 and 15, we assume that the dovetail groove 90 has a closed shape (for example, a roughly rectangular shape, a roughly circular shape, etc.). More specifically, we assume that the dovetail groove 90 has a closed loop shape. In this case, as illustrated in Figure 28, the step of moving the cutting edge 81 in the second movement direction MD2 of the second machining cycle may include rotating the cutting edge 81 along the extending direction of the dovetail groove 90 (more specifically, the cutting edge 81 making at least one rotation around the region 92 surrounded by the dovetail groove 90).

[0061] The machining process (second step ST2) may include repeatedly executing the second machining cycle described above. For example, the machining process (second step ST2) may include shifting the blade portion 81 in the blade width direction by a predetermined distance each time the blade portion 81 completes one rotation along the dovetail groove 90 in the second movement direction MD2 while in contact with the groove bottom 91.

[0062] The machining process (second step ST2) may include a step of changing the orientation of the blade portion 81 (more specifically, a step of changing the orientation of the blade portion 81 by a predetermined angle (e.g., 180 degrees) around the first axis AX1), followed by repeatedly executing the second machining cycle described above. The machining process (second step ST2) may also include repeatedly executing the second machining cycle described above two or more times, three or more times, four or more times, or five or more times.

[0063] Figure 29 shows the state after the second processing cycle described above has been performed twice.

[0064] It is preferable that the machining process (second step ST2) is performed such that substantially the entire groove bottom 91 of the dovetail groove 90 is cut by the tip edge 83 of the cutting edge 81. More specifically, it is preferable that the first machining cycle described above is performed multiple times, and the second machining cycle described above is performed multiple times, so that substantially the entire groove bottom 91 of the dovetail groove 90 is cut by the tip edge 83 of the cutting edge 81. In the examples shown in Figures 7 and 10, performing the first machining cycle multiple times includes cutting one side of the groove bottom 91 of the dovetail groove 90 (e.g., the outside region of the groove bottom 91) by the tip edge 83 of the cutting edge 81. In the example shown in Figure 28, performing the second machining cycle multiple times includes cutting the other side of the groove bottom 91 of the dovetail groove 90 (e.g., the inside region of the groove bottom 91) by the tip edge 83 of the cutting edge 81.

[0065] (Seal Ring SR) As illustrated in Figure 30, the dovetail groove 90 may also be a seal ring receiving groove 90a. In the first embodiment, the groove bottom 91 of the dovetail groove 90 is cut by the tip edge 83 of the cutting edge 81 (more specifically, the groove bottom 91 of the dovetail groove 90 is finished by the tool bit 8). Thus, a smooth surface suitable for sealing by the seal ring SR is obtained.

[0066] (Work 9) The workpiece 9 may be a case 9a (see Figure 1) or a fluid flange. In the example shown in Figure 1, the dovetail groove 90 (more specifically, the seal ring receiving groove 90a) is formed in the case 9a. As illustrated in Figure 2, the dovetail groove 90 may be formed on the top surface 99s of the side wall 99 of the case 9a.

[0067] Alternatively, as illustrated in Figure 31, the workpiece 9 may be a lid 9b. In this case, the dovetail groove 90 (more specifically, the seal ring receiving groove 90a) is formed in the lid 9b. As illustrated in Figure 31, the dovetail groove 90 (more specifically, the seal ring receiving groove 90a) may be formed on the back surface 98s of the lid 9b.

[0068] In the example shown in Figure 8, the workpiece 9 has multiple surfaces that define the dovetail groove 90. More specifically, the workpiece 9 has a first surface 97a that defines the first side of the dovetail groove 90, a second surface 97b that defines the second side of the dovetail groove 90, and a third surface 97c that defines the groove bottom 91 of the dovetail groove 90. Cutting the groove bottom 91 is equivalent to cutting the third surface 97c.

[0069] The dovetail groove 90 is defined by the first surface 97a, the second surface 97b, and the third surface 97c. In the example shown in Figure 3, the second surface 97b is positioned inward of the first surface 97a. More specifically, the second surface 97b is the inner circumferential surface of the dovetail groove 90, and the first surface 97a is the outer circumferential surface of the dovetail groove 90.

[0070] The angle between the first surface 97a and the third surface 97c is, for example, less than 80 degrees or less than 70 degrees. The angle between the second surface 97b and the third surface 97c is, for example, less than 80 degrees or less than 70 degrees. A radius may be formed between the first surface 97a and the third surface 97c. A radius may be formed between the second surface 97b and the third surface 97c.

[0071] (Rough processing process) The method for machining the dovetail groove in the first embodiment may include a rough machining step. The rough machining step is performed before the entry step (first step ST1).

[0072] More specifically, the method for machining the dovetail groove in the first embodiment (more specifically, the rough machining step) includes forming a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90 using at least one cutting tool.

[0073] In the example shown in Figure 32, the method for machining the dovetail groove in the first embodiment (more specifically, the rough machining step) includes using a milling tool T1 to form a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90.

[0074] Alternatively, the method for machining the dovetail groove in the first embodiment (more specifically, the rough machining step) may include forming a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90 using at least one non-rotating tool (e.g., the tool bit 8 described above, or another tool bit T2 for rough machining), as illustrated in Figure 33.

[0075] The rough machining process for rough machining the dovetail groove is not limited to the examples shown in Figures 32 and 33. The rough machining process for rough machining the dovetail groove can be carried out using any known method.

[0076] The machining method for the dovetail groove 90 in the first embodiment may include (1) a step of forming a rough-machined dovetail groove 90 using a rough-machining tool T (e.g., a milling tool T1) held on the spindle 21, and a step of replacing the rough-machining tool T (e.g., a milling tool T1) held on the spindle 21 with a tool holder HD to which a tool bit 8 is attached, using a tool changer 6 (see Figure 37). The step of forming a rough-machined dovetail groove 90 may include forming a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90 using a rough-machining tool T (e.g., a milling tool T1) held on the spindle 21. The step of forming a rough-machined dovetail groove 90 may also include forming a rough-machined groove bottom 91. After the step of replacing the rough-machining tool T held on the spindle 21 with a tool holder HD to which a tool bit 8 is attached, the above-described entry step (first step ST1) may be performed.

[0077] When the roughing tool T (for example, a milling tool T1) and the tool bit 8 are exchanged using a tool changer 6, both roughing and finishing of the dovetail groove can be efficiently performed using a single machine tool 1.

[0078] Referring to Figure 35, an example of a method for machining a dovetail groove in the first embodiment will be described. In the example shown in Figure 35, the method for machining a dovetail groove comprises (1) a step of forming a roughly machined dovetail groove 90 using a roughing tool T (e.g., a milling tool T1) (see Figure 32 or Figure 33), and (2) a step of replacing the roughing tool T (e.g., a milling tool T1) held on the spindle 21 with a tool bit 8 (more specifically, a tool holder HD to which the tool bit 8 is attached). After the replacement step, the entry step (first step ST1) and the machining step (second step ST2) described above are performed.

[0079] The machining process described above (second step ST2) includes machining one side of the groove bottom 91 of the dovetail groove 90 (for example, one of the outside region and the inside region of the groove bottom 91) with the tool bit 8. Machining one side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include performing the first machining cycle described above multiple times. More specifically, machining one side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include rotating the tool bit 8 in a first movement direction MD1 along the extending direction MR1 of the dovetail groove 90 while the tip edge 83 of the tool bit 8 is in contact with the groove bottom 91, and shifting the tool bit 8 by a predetermined distance in the groove width direction with each rotation.

[0080] In the example shown in Figure 35, the method for machining the dovetail groove includes machining one side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8, then retracting the tool bit 8 outside the dovetail groove 90, and rotating the spindle 21 around the first axis AX1 by a predetermined angle (e.g., 180 degrees) while the tool bit 8 is retracted outside the dovetail groove 90. This rotation changes the orientation of the cutting edge 81 by a predetermined angle (e.g., 180 degrees) around the first axis AX1.

[0081] In the example shown in Figure 35, the method for machining the dovetail groove includes changing the orientation of the cutting edge 81 by a predetermined angle (for example, 180 degrees) around the first axis AX1, and then re-entering the tool bit 8 into the dovetail groove 90. However, if the tool bit 8 retracts from the top of the first side wall 99-1 of the workpiece 9 outside the dovetail groove 90 (see Figure 27), and then re-enters the dovetail groove 90 at the top of the second side wall 99-2 opposite the first side wall 99-1, the step of changing the orientation of the cutting edge 81 around the first axis AX1 may be omitted.

[0082] In the example shown in Figure 35, the method for machining the dovetail groove includes, after the tool bit 8 re-enters the dovetail groove 90, machining the other side of the groove bottom 91 of the dovetail groove 90 (for example, the other of the outside and inside regions of the groove bottom 91) with the tool bit 8. Machining the other side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include performing the above-described second machining cycle multiple times. More specifically, machining the other side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include rotating the tool bit 8 in a second movement direction MD2 opposite to the first movement direction MD1 along the extending direction of the dovetail groove 90, with the tip edge 83 of the tool bit 8 in contact with the groove bottom 91, and shifting the tool bit 8 by a predetermined distance in the groove width direction with each rotation.

[0083] In the example shown in Figure 35, the method for machining the dovetail groove includes machining the other side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8, and then retracting the tool bit 8 out of the dovetail groove 90.

[0084] (Second embodiment) The machine tool 1 in the second embodiment will be described with reference to Figures 1 to 41. Figure 36 is a schematic perspective view showing the machine tool 1 in the second embodiment. Figure 37 is a schematic front view showing the tool change process M2 being executed. Figure 38 is a schematic diagram showing how the control device 5 can control multiple control target devices. Figures 39 to 41 are schematic front views showing a part of the machine tool 1 in the second embodiment.

[0085] The second embodiment will primarily describe the differences from the first embodiment. On the other hand, the second embodiment will omit repetitive explanations of matters already described in the first embodiment. Therefore, it goes without saying that even if not explicitly explained in the second embodiment, matters already described in the first embodiment can be applied to the second embodiment. Furthermore, matters described in the second embodiment can also be adopted in the first embodiment.

[0086] As illustrated in Figure 36, the machine tool 1 in the second embodiment comprises a machining head 2, a workpiece support device 3, a moving device 4, and a control device 5.

[0087] The machining head 2 holds a tool holder HD to which the tool bit 8 is attached. As illustrated in Figures 11, 16, 17, and 18, the tool bit 8 has a cutting edge 81 whose cutting edge width increases from the root 82 to the tip edge 83.

[0088] The workpiece support device 3 supports the workpiece 9.

[0089] The moving device 4 moves the machining head 2 relative to the workpiece support device 3.

[0090] The control device 5 controls the moving device 4. The control device 5 can perform machining operations M3 (see, for example, Figures 3 to 6).

[0091] The machining process M3 includes (1) process M3-1 (see Figures 3 and 4) of inserting the tool bit 8 into the rough-machined dovetail groove 90 formed in the workpiece 9; (2) process M3-2 (see, for example, Figures 5 and 6) of moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is inside the dovetail groove 90, thereby cutting a portion of the groove bottom 91 of the dovetail groove 90; (3) process M3-3 (see, for example, Figures 8 and 9) of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90; and (4) process M3-4 (see, for example, Figure 10) of moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is inside the dovetail groove 90, thereby cutting another portion of the groove bottom 91.

[0092] In the second embodiment, the machine tool 1 can suitably cut the groove bottom 91 of the dovetail groove 90 using the tool bit 8.

[0093] In the second embodiment, the control device 5 can perform the process of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90, so that the groove bottom 91 of the dovetail groove 90 can be suitably cut using the tip edge 83 which has a width smaller than the width of the groove bottom 91 of the dovetail groove 90. Also, as illustrated in Figure 8, the tool bit 8 has a blade portion 81 whose blade width increases from the root portion 82 to the tip edge 83. When the blade portion 81 has a flared shape, one end 831 of the tip edge 83 of the blade portion 81 in the blade width direction can be easily brought into contact with the depth of the dovetail groove 90 in the width direction. Also, when the width of the tip edge 83 is large, the number of times the position of the tool bit 8 needs to be changed in the width direction MR2 of the dovetail groove 90 is reduced.

[0094] (Optional additional configuration) Next, with reference to Figures 1 to 41, we will describe optional additional configurations that can be adopted in the machine tool 1 in the second embodiment.

[0095] (Processing head 2) As illustrated in Figure 14, the machining head 2 comprises a spindle 21 and a support 23 that rotatably supports the spindle 21 around a first axis AX1. The spindle 21 is capable of holding a tool holder HD to which a tool bit 8 is attached.

[0096] The machine tool 1 (more specifically, the machining head 2) includes a rotary drive device 11 that rotates the spindle 21 around the first axis AX1. The rotary drive device 11 may include a motor 11m that rotates the spindle 21 around the first axis AX1.

[0097] In the example shown in Figure 36, machine tool 1 is a vertical machining center. Alternatively, machine tool 1 may be a horizontal machining center or a multi-tasking machine.

[0098] (Work support device 3) In the example shown in Figure 36, the workpiece support device 3 comprises a table 31 for supporting the workpiece 9. The workpiece support device 3 may also comprise a table rotation device 35 for rotating the table 31, and / or a tilting device for tilting the table 31. Alternatively, or additionally, the workpiece support device 3 may comprise a chuck for gripping the workpiece 9.

[0099] (Mobile device 4) The moving device 4 moves the machining head 2 relative to the workpiece support device 3. The moving device 4 moves the machining head 2. Alternatively, or additionally, the moving device 4 may move the table 31 (or the chuck that grips the workpiece 9) that supports the workpiece 9.

[0100] The moving device 4 may include a first moving device 41 that moves the machining head 2 in a direction along the Z-axis perpendicular to the horizontal plane. The first moving device 41 may include, for example, a Z-axis motor that moves the machining head 2 in a direction along the Z-axis.

[0101] The moving device 4 may include a second moving device 42 that moves the machining head 2 in a direction along the X-axis parallel to the horizontal plane. The second moving device 42 may include, for example, an X-axis motor that moves the machining head 2 in a direction along the X-axis.

[0102] The moving device 4 may include a third moving device 43 that moves the machining head 2 in a direction along the Y-axis parallel to the horizontal plane. The third moving device 43 may include, for example, a Y-axis motor that moves the machining head 2 in a direction along the Y-axis. In the example shown in Figure 36, the Y-axis is perpendicular to both the X-axis and the Z-axis.

[0103] In the example shown in Figure 36, the moving device 4 is capable of moving the machining head 2 in three dimensions. Alternatively, the moving device 4 may be a device that moves the machining head 2 in two dimensions or one dimension. Alternatively, or additionally, the moving device 4 may be capable of moving the table 31 in one dimension, two dimensions, or three dimensions.

[0104] (Tool changer 6) The machine tool 1 may be equipped with a tool changer 6. As illustrated in Figure 37, the tool changer 6 can replace a roughing tool T (e.g., a milling tool T1) held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) with a tool holder HD to which a tool bit 8 is attached. The tool changer 6 can also replace the tool holder HD held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) with another tool holder to which another tool is attached.

[0105] The tool changing device 6 may include a tool changing arm 61, an arm rotating device 63 for rotating the tool changing arm 61, and an arm moving device 65 for moving the tool changing arm 61 linearly. The arm rotating device 63 rotates the tool changing arm 61 around the second axis AX2. The arm moving device 65 moves the tool changing arm 61 in a direction parallel to the second axis AX2.

[0106] (Control device 5) The control device 5 controls the moving devices 4 (for example, the first moving device 41, the second moving device 42, and / or the third moving device 43). Additionally, the control device 5 may control the rotary drive device 11. Additionally, the control device 5 may control the tool changer 6 and / or the table rotation device 35.

[0107] An example of the control device 5 will be described with reference to Figure 38. In the example shown in Figure 38, the control device 5 comprises an arithmetic unit 50, a memory 52, and a communication circuit 54. The control device 5 may also include an input device 56 and / or a display 57. In the example shown in Figure 38, the arithmetic unit 50, the memory 52, the communication circuit 54, the input device 56, and the display 57 are connected to each other via a bus 58.

[0108] The memory 52 is a storage medium readable by the arithmetic unit 50. The memory 52 may be, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, or flash memory, or it may be a magnetic disk or other type of memory.

[0109] Memory 52 stores the processing program PM and various data. Memory 52 may be distributed across multiple locations. Memory 52 may include cloud storage accessible via a network.

[0110] The arithmetic unit 50 includes at least one hardware processor 50a (e.g., at least one CPU). The control unit 5 (more specifically, the arithmetic unit 50) generates a plurality of control commands by executing a machining program PM stored in the memory 52. ​​In this specification, the execution of the machining program PM by the control unit 5 (more specifically, the arithmetic unit 50) includes the execution of the machining program PM by the control unit 5 (more specifically, the arithmetic unit 50) via an arithmetic program. In other words, the machining program PM may be processed (in other words, interpreted) by the control unit 5 by executing an arithmetic program.

[0111] In the example shown in Figure 38, the input device 56 includes a touch panel 56a on the display 57. In other words, the display 57 is a display with a touch panel. Note that the input device 56 is not limited to the touch panel 56a on the display 57. For example, the input device 56 may include a button 56b, a switch, a lever, a pointing device such as a mouse, and / or a keyboard.

[0112] The communication circuit 54 transmits multiple control commands generated by the execution of the machining program PM to multiple controlled devices (for example, the moving device 4 and the rotary drive device 11).

[0113] The control device 5 is capable of executing machining process M3. Machining process M3 is, for example, a finishing process. In the example shown in Figure 40, machining process M3 includes transmitting a number of control commands SB to at least the moving device 4 so that the groove bottom 91 of the dovetail groove 90 is cut by the tool bit 8. More specifically, machining process M3 includes (1) process M3-1 (see Figures 3 and 4) to move the tool bit 8 into the dovetail groove 90 through the groove opening OP of the dovetail groove 90 in a rough state, (2) process M3-2 (see Figures 5 and 6) to cut a portion of the groove bottom 91 of the dovetail groove 90 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is inside the dovetail groove 90, and (3) in the width direction MR2 of the dovetail groove 90. The process includes transmitting at least a number of control commands SB to the moving device 4 so that the following are performed in this order: (4) after the position of the tool bit 8 has been changed in the width direction MR2 of the dovetail groove 90, the tool bit 8 is moved along the extending direction MR1 of the dovetail groove 90, thereby cutting another part of the groove bottom 91 (see Figure 10).

[0114] As illustrated in Figure 22, the process M3-1 for inserting the tool bit 8 into the dovetail groove 90 may include transmitting a plurality of control commands SB (e.g., a first group of control commands) to the moving device 4 so that the tool bit 8 enters the dovetail groove 90 with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) positioned substantially parallel to the width direction of the dovetail groove 90. In this case, the moving device 4, which receives a plurality of control commands SB (e.g., a first group of control commands) from the control device 5, moves the machining head 2 relative to the workpiece support device 3 so that the tool bit 8 enters the dovetail groove 90 with the blade width direction of the blade portion 81 positioned substantially parallel to the width direction of the dovetail groove 90.

[0115] Alternatively, as illustrated in Figure 23, the process M3-1 for inserting the tool bit 8 into the dovetail groove 90 may include transmitting a plurality of control commands SB to the moving device 4 so that the tool bit 8 enters the dovetail groove 90 with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) perpendicular or inclined with respect to the width direction of the dovetail groove 90. In this case, after the tool bit 8 enters the dovetail groove 90, the control device 5 performs a process to rotate the tool bit 8 around the first axis AX1 so that the blade width direction of the blade portion 81 (more specifically, the second direction DR2) is substantially parallel to the width direction of the dovetail groove 90 (see dashed arrow AR3 in Figure 24).

[0116] The process M3-2 (see Figure 6) for cutting a portion of the groove bottom 91 of the dovetail groove 90 may include sending a plurality of control commands SB to the moving device 4 and the rotary drive device 11 so that the orientation of the cutting edge 81 is changed as the tool bit 8 moves along the curved portion 90c (see Figure 6) of the dovetail groove 90 while the cutting edge 81 is in contact with the groove bottom 91. In this case, the moving device 4 and the rotary drive device 11, which receive the plurality of control commands SB from the control device 5, may rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees).

[0117] The process M3-2 (see Figure 7) for cutting a portion of the groove bottom 91 of the dovetail groove 90 may include transmitting a plurality of control commands SB to the moving device 4 and the rotary drive device 11 such that the cutting edge 81 rotates at least once around the region 92 surrounded by the dovetail groove 90 while the cutting edge 81 is in contact with the groove bottom 91. In this case, the moving device 4 and the rotary drive device 11, which receive the plurality of control commands SB from the control device 5, may rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 such that the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees) while the cutting edge 81 rotates at least once around the region 92 surrounded by the dovetail groove 90.

[0118] The process M3-3 (see Figures 8 and 9) for changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90 may include sending a plurality of control commands SB to the moving device 4 so that the tool bit 8 moves in the width direction MR2 of the dovetail groove 90. In this case, the moving device 4, which receives the plurality of control commands SB from the control device 5, moves the machining head 2 relative to the workpiece support device 3 so that the position of the tool bit 8 is changed in the width direction MR2 of the dovetail groove 90.

[0119] The process M3-4 (see Figure 10) for cutting the remaining portion of the groove bottom 91 of the dovetail groove 90 may include sending a plurality of control commands SB to the moving device 4 and the rotary drive device 11 so that, after the process M3-3 for changing the position of the tool bit 8 is performed, the cutting edge 81 makes contact with the groove bottom 91 and the cutting edge 81 makes at least one rotation around the region 92 surrounded by the dovetail groove 90. In this case, the moving device 4 and the rotary drive device 11, which receive the plurality of control commands SB from the control device 5, may rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that the cutting edge 81 makes at least one rotation around the region 92 surrounded by the dovetail groove 90 while substantially maintaining the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 at a predetermined angle (e.g., 90 degrees).

[0120] The machining process M3 may include sending a plurality of control commands SB (e.g., a second group of control commands) to the moving device 4 and the rotary drive device 11 so that the first machining cycle described above is executed multiple times. The first machining cycle may be performed while the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees).

[0121] The machining process M3 may include sending a plurality of control commands SB (e.g., a third group of control commands) to the moving device 4 and the rotary drive device 11 so that the orientation of the cutting edge 81 is changed by a predetermined angle (e.g., 180 degrees) around the first axis AX1 after the first machining cycle described above has been performed multiple times. More specifically, the machining process M3 may include sending a plurality of control commands SB (e.g., a third group of control commands) to the moving device 4 and the rotary drive device 11 so that the following are performed in this order after the first machining cycle described above has been performed multiple times: retracting the tool bit 8 out of the dovetail groove 90, rotating the tool bit 8 by a predetermined angle (e.g., 180 degrees) around the first axis AX1 so that the orientation of the cutting edge 81 is changed by a predetermined angle (e.g., 180 degrees), and re-entering the tool bit 8 into the dovetail groove 90.

[0122] The machining process M3 may include transmitting a plurality of control commands SB (e.g., a fourth group of control commands) to the moving device 4 and the rotary drive device 11 so that the second machining cycle described above is executed multiple times. The second machining cycle may be performed while the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees).

[0123] The machining process M3 may include transmitting a plurality of control commands SB to the moving device 4 and the rotary drive device 11 such that the first machining cycle described above is performed multiple times, thereafter the orientation of the cutting edge 81 is changed around the first axis AX1, and thereafter the second machining cycle described above is performed multiple times. Each of the first and second machining cycles may be performed while the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees). The first machining cycle may include cutting one of the outside and inside regions of the groove bottom 91 of the dovetail groove 90 with the tip edge 83 of the cutting edge 81, and the second machining cycle may include cutting the other of the outside and inside regions of the groove bottom 91 of the dovetail groove 90 with the tip edge 83 of the cutting edge 81.

[0124] The control device 5 may be capable of performing a rough machining process M1. In the example shown in Figure 41, the rough machining process M1 includes transmitting a plurality of control commands SC (e.g., a fifth group of control commands) to the moving device 4 and the rotary drive device 11 so that a rough machining tool T (e.g., a milling tool T1) forms a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90. More specifically, the rough machining process M1 includes (1) transmitting a plurality of control commands SC (e.g., a fifth group of control commands) to the moving device 4 and the rotary drive device 11 so that a milling tool T1 rotating around a first axis AX1 forms a first surface 97a defining the first side of the dovetail groove 90 (see Figure 32) and a second surface 97b defining the second side of the dovetail groove 90 (see Figure 32).

[0125] The moving device 4 and the rotary drive device 11, which receive multiple control commands SC (for example, control commands of the fifth group), rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90 are formed.

[0126] The control device 5 may be capable of performing a tool change operation M2. In the example shown in Figure 37, the tool change operation M2 includes sending a plurality of control commands SD (e.g., a sixth group of control commands) to the transfer device 4 and the tool changer 6 so that a roughing tool T (e.g., a milling tool T1) held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) is replaced with a tool holder HD to which a tool bit 8 is attached.

[0127] The moving device 4 and the tool changing device 6, which receive multiple control commands SD (for example, control commands of the sixth group), replace the roughing tool T (for example, a milling tool T1) held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) with a tool holder HD to which a tool bit 8 is attached.

[0128] After the tool change process M2 is executed, the control device 5 executes the machining process M3 described above.

[0129] (Toolbit 8) In the examples shown in Figures 11 and 16, the tool bit 8 comprises (1) a cutting edge 81 whose cutting width increases from the base 82 to the tip edge 83, and (2) a shaft 87 that supports the cutting edge 81.

[0130] In the examples shown in Figures 12 and 16, the tip edge 83 of the blade portion 81 has a plurality of apex portions 84 that are in contact with the groove bottom 91 of the dovetail groove 90.

[0131] Since the tool bit 8 has already been described in the first embodiment, a repeated explanation of the tool bit 8 will be omitted.

[0132] The present invention is not limited to the embodiments or modifications described above, and it is clear that each embodiment or modification can be appropriately modified or changed within the scope of the technical concept of the present invention. Furthermore, the various technologies used in each embodiment or modification can be applied to other embodiments or other modifications, as long as no technical inconsistencies arise. In addition, any optional additional configurations in each embodiment or modification can be omitted as appropriate. [Explanation of Symbols]

[0133] 1...Machine tool, 2...Machining head, 3...Workpiece support device, 4...Moving device, 5...Control device, 6...Tool changer, 8...Tool bit, 8d...Tip, 8p...Base, 9...Workpiece, 9a...Case, 9b...Lid, 11...Rotary drive device, 11m...Motor, 21...Spindle, 23...Support, 31...Table, 35...Table rotation device, 41...First moving device, 42...Second moving device, 43...Third moving device, 50...Calculation unit, 50a...Hardware processor, 52...Memory, 54...Communication circuit, 56...Input device, 56a...Touch Panel, 56b...button, 57...display, 58...bus, 61...tool change arm, 63...arm rotation device, 65...arm movement device, 81...blade part, 82...root part, 83...tip edge part, 83r...ridge part, 83v...groove part, 84...top part, 85...valley part, 86...line segment, 87...shaft, 87e...outer edge, 90...dovetail groove, 90a...seal ring receiving groove, 90c...curved part, 90s...straight part, 91...groove bottom, 91v...groove, 92...area surrounded by dovetail groove, 97a...first surface, 97b...second surface, 97c...third surface, 98s...back side, 99 ...side wall, 99-1...first side wall, 99-2...second side wall, 99s...top surface, 831...one end, 832...other end, AT1...central axis, AX1...first axis, AX2...second axis, DR1...first direction, DR2...second direction, DR3...third direction, HD...tool holder, L1...first distance, LN...half-line, M1...rough machining process, M2...tool change process, M3...machining process, M3-1...process of inserting the tool bit into the dovetail groove, M3-2...process of cutting a part of the groove bottom of the dovetail groove, M3-3...process of changing the position of the tool bit 8 in the width direction of the dovetail groove, M 3-4…Process for cutting another part of the groove bottom, MD1…First movement direction, MD2…Second movement direction, MR1…Extension direction of the dovetail groove, MR2…Width direction of the dovetail groove, OP…Groove opening, OP1…Approach opening, PM…Machining program, RG1…One side of the groove bottom of the dovetail groove, RG2…The other side of the groove bottom of the dovetail groove, SB, SC, SD…Control command, SH…Wave shape, SR…Seal ring, ST1…First step, ST2…Second step, T…Roughing tool, T1…Milling tool, T2…Tool bit, W1…Opening width, Wc…Constant width

Claims

1. The process involves inserting the tool bit into the roughly machined dovetail groove, The process of cutting a portion of the groove bottom of the dovetail groove by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove, A step of changing the position of the tool bit in the width direction of the dovetail groove, After the position of the tool bit is changed in the width direction of the dovetail groove, the tool bit is moved along the extending direction of the dovetail groove while it is inside the dovetail groove, thereby cutting another part of the groove bottom. Prepare, The tool bit has a blade portion whose width increases from the base to the tip edge, The dovetail groove has an opening width through which the tip edge can pass. Method for machining dovetail grooves.

2. The tip edge of the blade portion has a plurality of apex portions that are in contact with the bottom of the groove, The multiple vertices form multiple grooves at the bottom of the groove along the extending direction of the dovetail groove. The method for machining a dovetail groove according to claim 1.

3. The tip edge of the blade portion has a single apex that contacts the bottom of the groove, The aforementioned top portion forms a plurality of grooves at the bottom of the groove, along the extending direction of the dovetail groove. The method for machining a dovetail groove according to claim 1.

4. The cutting of the groove bottom is performed with the tool bit mounted on a spindle rotatable around a first axis via a tool holder. A method for machining a dovetail groove according to any one of claims 1 to 3.

5. The groove opening of the dovetail groove has a constant width along the extending direction of the dovetail groove. The groove opening having a certain width is used as an opening for the tool bit to approach. A method for machining a dovetail groove according to any one of claims 1 to 3.

6. When the direction from the groove opening of the dovetail groove toward the groove bottom is defined as the first direction, the dovetail groove has a closed shape when viewed in the first direction, The aforementioned dovetail groove is a seal ring receiving groove. A method for machining a dovetail groove according to any one of claims 1 to 3.

7. The step of cutting a portion of the groove bottom of the dovetail groove includes rotating the cutting blade along the extending direction of the dovetail groove while the cutting blade is in contact with the groove bottom. The method for machining a dovetail groove according to claim 6.

8. The step of inserting the tool bit into the dovetail groove in the rough-machined state includes inserting the tool bit into the dovetail groove with the cutting edge width direction of the cutting edge portion perpendicular or inclined with respect to the width direction of the dovetail groove, After the tool bit enters the dovetail groove, and before performing the step of cutting a portion of the groove bottom of the dovetail groove, the tool bit is rotated around the first axis so that the width direction of the cutting edge is substantially parallel to the width direction of the dovetail groove. The method for machining a dovetail groove according to claim 4.

9. The tool bit has a shaft that supports the cutting edge, The distance between one end of the tip edge in the blade width direction and the central axis of the shaft, when viewed in the blade thickness direction, is greater than the distance between the other end of the tip edge in the blade width direction and the central axis, when viewed in the blade thickness direction. A method for machining a dovetail groove according to any one of claims 1 to 3.

10. A first machining cycle is defined as a cycle that includes the steps of moving the blade along the extending direction of the dovetail groove while the tip edge is in contact with the bottom of the groove, and changing the position of the blade in the width direction of the dovetail groove. The direction in which the blade moves along the extending direction of the dovetail groove in the first machining cycle is defined as the first movement direction, and the direction opposite to the first movement direction is defined as the second movement direction. A second machining cycle is defined as a cycle that includes the steps of moving the blade in the second movement direction while the tip edge is in contact with the bottom of the groove, and changing the position of the blade in the width direction of the dovetail groove. Each of the first and second machining cycles is executed multiple times. A method for machining a dovetail groove according to any one of claims 1 to 3.

11. A step of forming the dovetail groove in the rough state using a roughing tool held on the spindle, A step of using a tool changing device to replace the roughing tool held on the spindle with the tool holder to which the tool bit is attached. Furthermore, After performing the step of replacing the roughing tool held on the spindle with the tool holder to which the tool bit is attached, the step of inserting the tool bit into the dovetail groove in the roughed state is performed. The method for machining a dovetail groove according to claim 4.

12. The blade portion has a shape that widens on one side, with the blade width increasing from the base to the tip edge. The tip edge of the blade portion has a wave-like shape with a plurality of peaks and a plurality of valleys. The method for machining a dovetail groove according to claim 1.

13. A machining head that holds a tool holder to which a tool bit having a blade section that widens from the base to the tip edge is attached, A workpiece support device that supports the workpiece, A moving device for moving the machining head relative to the workpiece support device, A control device for controlling the aforementioned mobile device and Equipped with, The control device is The process of inserting the tool bit into the rough-machined dovetail groove formed in the workpiece, With the tool bit inserted into the dovetail groove, the tool bit is moved along the direction of extension of the dovetail groove to cut a portion of the groove bottom of the dovetail groove, A process to change the position of the tool bit in the width direction of the dovetail groove, After the position of the tool bit is changed in the width direction of the dovetail groove, the tool bit is moved along the extending direction of the dovetail groove while it is inside the groove, thereby cutting another part of the groove bottom. It is possible to execute Machine tools.

14. When a third direction is defined as a direction perpendicular to the blade width direction and opposite to the direction in which the blade moves during cutting, the blade has a blade width that increases from the root to the tip edge when viewed in the third direction, The shaft supporting the blade portion Equipped with, The tip edge of the blade portion has a plurality of apex portions that are in contact with the bottom of the dovetail groove along the width direction of the blade. Tool bits.

15. A blade portion having a blade width that increases from the base to the tip edge, The shaft supporting the blade portion Equipped with, The tip edge of the blade portion has a plurality of apex portions that contact the bottom of the groove of the dovetail groove, The distance between one end of the tip edge in the blade width direction and the central axis of the shaft, when viewed in the blade thickness direction, is greater than the distance between the other end of the tip edge in the blade width direction and the central axis, when viewed in the blade thickness direction. Tool bits.

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