Cutting insert, rotary tool, and method of manufacturing a workpiece

Abstract

A rotating tool of one aspect has a main body, a relief surface located at a front end side of the main body, a discharge groove extending from the relief surface toward a rear end of the main body, and a ridge line located at an intersection of the relief surface and the discharge groove. The ridge line has a recessed portion recessed toward the rear end of the main body, an inner edge extending from the recessed portion toward a front end of the main body, and an outer edge extending from the recessed portion toward an outer periphery of the main body. The discharge groove has a groove extending along the outer edge. The groove is connected with the recessed portion and the outer edge, and the groove is separated from the inner edge.

Description

Technical Field

[0001] The present invention relates to a cutting insert and a rotary tool used in cutting. Examples of the rotary tool include a drill and an end mill. Background Art

[0002] As a rotary tool used for cutting workpieces such as metal, a drill bit described in Patent Document 1 is known. The drill bit described in Patent Document 1 has a cutting edge and a chip breaker formed at its tip. The cutting edge has a notch formed therein, dividing the cutting edge into an inner peripheral edge on the inner circumference and an outer peripheral edge on the outer circumference. The chip breaker is formed along the cutting edge, extending from the outer peripheral edge to a portion of the inner peripheral edge or the entire inner peripheral edge.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Utility Model Publication No. 58-191913 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In recent years, cutting inserts and rotary tools have been required to stabilize the flow of chips to achieve good chip discharge performance, and to ensure the strength of the cutting edge at the tip of the rotary tool to improve durability.

[0008] Solutions to Problems

[0009] In order to solve the above problems, a cutting blade of one embodiment of the present invention has a main body extending from a first end to a second end along a rotation axis, and the main body has: a first back cutting surface, which is located on the first end side; a first discharge groove, which extends from the first back cutting surface toward the second end; and a first ridge line, which is located at the intersection of the first back cutting surface and the first discharge groove, the first ridge line has: a first recess, which is recessed toward the second end; a first inner edge, which extends from the first recess toward the first end; and a first outer edge, which extends from the first recess toward the outer periphery of the main body, the first discharge groove has a first groove extending along the first outer edge, the first groove is connected to the first recess and the first outer edge, and the first groove is separated from the first inner edge.

[0010] Effects of the Invention

[0011] According to one aspect of the present invention, the flow of chips can be stabilized to obtain good chip discharge performance, and the strength of the cutting edge can be ensured to improve durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a perspective view of the rotary cutter according to the first embodiment.

[0013] Figure 2 yes Figure 1 An enlarged view of area A1 is shown.

[0014] Figure 3 It is a front view of the rotating tool.

[0015] Figure 4 It is from Figure 3 The side view of the rotating tool as viewed from direction B2 is shown.

[0016] Figure 5 yes Figure 4 An enlarged view of area A2 is shown.

[0017] Figure 6 yes Figure 5 An enlarged view of area A3 is shown.

[0018] Figure 7 yes Figure 5 Cross-sectional views along lines VII-A, VII-B and VII-C.

[0019] Figure 8 It is from Figure 3 The enlarged view of the front end portion of the side surface of the rotary cutter as viewed in the B1 direction is shown.

[0020] Figure 9 It is from Figure 3 The enlarged view of the front end portion of the side surface of the rotary cutter as viewed from the B3 direction is shown.

[0021] Figure 10 yes Figure 8 Cross-sectional views along the XD, XE and XF lines.

[0022] Figure 11 yes Figure 9 Cross-sectional views along lines XI-G, XI-H and XI-I.

[0023] Figure 12 It is a schematic diagram showing the steps of a method for manufacturing a machined product according to one embodiment.

[0024] Figure 13 It is a perspective view of the rotary cutter according to the second embodiment.

[0025] Figure 14 yes Figure 13 A perspective view of the blade of the rotary cutter is shown. DETAILED DESCRIPTION

[0026] The following drawings illustrate two types of rotary cutters as examples of the present invention. However, for ease of explanation, the following figures illustrate only simplified versions of the essential components necessary for the implementation. Therefore, the rotary cutters may include any components not shown in the drawings referenced herein. Furthermore, the dimensions of the components in the drawings do not accurately represent the actual dimensions of the components or the dimensional ratios of the components.

[0027] [Implementation Method 1]

[0028] In this embodiment, a rotary tool composed of a single member, generally called a solid tool, is exemplified. Note that a rotary tool composed of a shank and a cutting insert, generally called a tip-replaceable tool, will be described later in Embodiment 2.

[0029] (1. Rotating tool)

[0030] Figure 1 It is a perspective view of the rotary cutter 1 according to the present embodiment. Figure 2 yes Figure 1 An enlarged view of area A1 is shown. Figure 3 It is a front view of the rotary cutter 1. Figure 4 It is from Figure 3 The side view of the rotary cutter 1 as viewed from the direction B2 is shown. Figure 5 yes Figure 4 An enlarged view of area A2 is shown. Figure 6 yes Figure 5 An enlarged view of area A3 is shown. Figure 7 yes Figure 5 The cross-sectional view along line VII-A, line VII-B and line VII-C. Figure 7 In the figure, the figure marked 1001 is a cross-sectional view as viewed along line VII-A, the figure marked 1002 is a cross-sectional view as viewed along line VII-B, and the figure marked 1003 is a cross-sectional view as viewed along line VII-C.

[0031] like Figure 1 、 Figure 4 As shown, a drill can be given as an example of the rotary tool 1. In this example, a drill is shown. In addition, as the rotary tool 1, an end mill etc. can be given, for example.

[0032] The rotary tool 1 in this example is, for example, Figure 1 As shown in FIG. 1 , the main body 3 has a rod-shaped body 3 that can rotate around a rotation axis R1. A cutting portion 10 is formed at one end of the main body 3. The cutting portion 10 is used to contact the workpiece T (see FIG. 1 ) as the workpiece during the cutting process (drilling process) described later. Figure 12) contact part, and is the part that plays a major role in cutting. When cutting the workpiece T, the rotary tool 1 rotates around the rotation axis R1. It should be noted that, Figure 1 The arrow R2 in FIG. 1 indicates the rotation direction of the rotary cutter 1 .

[0033] In this specification, one end where the cutting portion 10 is formed is referred to as the front end (first end) of the main body 3, and the other end is referred to as the rear end (second end) of the main body 3. Figure 3 The front view is a view obtained by viewing the rotary blade 1 from the front end side, and the rotary blade 1 viewed from the front end side is expressed as a front view.

[0034] The body 3 can also be Figure 1 As shown, it has a portion called a shank 4 and a portion called a main body 5. The shank 4 is located on the rear end side of the main body 3, and the main body 5 is located on the front end side of the main body 3 compared to the shank 4. The shank 4 is a portion that can be gripped by a rotatable spindle or the like in a machine tool. The cutting portion 10 is provided on the front end side of the main body 5. A discharge groove 12 extending from the cutting portion 10 is formed in a spiral shape on the outer peripheral surface of the main body 5. From the viewpoint of smoothly discharging the chips to the outside, for example, the discharge groove 12 may also be in the shape of a concave curve in a cross section perpendicular to the rotation axis R1.

[0035] <Cutting part>

[0036] like Figure 2 、 Figure 3 As shown, the cutting portion 10 (main body 3) has a ridgeline R, a cutting edge 11, a discharge groove 12, and a flank surface 13. The flank surface 13 is located on the front end of the main body 3. The cutting edge 11 is formed on the ridgeline R at the intersection of the flank surface 13 and the discharge groove 12. The discharge groove 12 is formed to extend from the flank surface 13 toward the rear end of the main body 3. The discharge groove 12 has the function of discharging chips generated by cutting with the cutting edge 11. The portion of the discharge groove 12 that extends along the cutting edge 11 serves as the rake surface.

[0037] like Figure 2 、 Figure 3As shown, a recess 15 is formed on the ridge line R that is recessed toward the rear end of the main body 3. The recess 15 is a portion for reducing the width of the chips generated by the cutting portion 10, and can prevent the width of the chips from becoming too large. By reducing the width of the chips, the flow of the chips can be improved. For example, when the feed rate is relatively small and the thickness of the chips generated by the cutting edge 11 is thinner than the recess 15, two chips are generated that are disconnected by the recess 15. In addition, when the feed rate is relatively large and the thickness of the chips generated by the cutting edge 11 is thicker than the recess 15, the thickness of the chips generated by the recess 15 becomes relatively thin. Therefore, it is easy to disconnect the chips starting from the part of the chip generated by the recess 15.

[0038] By including such a recess 15 on the ridge R, the cutting edge 11 is divided into an inner cutting edge 16 extending from the recess 15 toward the front end of the main body 3 (the center of the main body 3), through which the rotation axis R1 passes, and an outer cutting edge 17 extending from the recess 15 toward the outer periphery of the main body 3. In other words, the ridge R can also be represented as including the recess 15, the inner cutting edge 16, and the outer cutting edge 17. It should be noted that the inner cutting edge 16 may also include a chisel edge or a sharpening edge. In this example, the inner cutting edge 16 includes a sharpening edge 16a located near the front end of the main body 3.

[0039] like Figure 5 As shown, the discharge groove 12 has a groove 20 extending along the outer edge 17. The groove 20 is a portion of the rake face and is recessed from the surface 12a of the discharge groove 12. The groove 20 is connected to the recess 15 and the outer edge 17, but is provided separately from the inner edge 16 and is not connected to the inner edge 16.

[0040] By providing the groove 20 separately from the inner blade 16, the flow of chips generated at the inner blade 16 can be stabilized, thereby improving the fluidity of the chips of the rotary tool 1. It should be noted that chips tend to be generated more frequently at the outer blade 17 located on the outer periphery. Therefore, even without providing the groove 20 on the inner blade 16, the chips generated at the inner blade 16 can be adequately discharged. Furthermore, by providing the groove 20 separately from the inner blade 16, the thickness of the sharpened edge 16a of the inner blade 16 can be ensured, thereby increasing its strength and thereby improving the durability of the rotary tool 1.

[0041] In contrast, in the drill described in the aforementioned patent document 1, a chip breaker groove equivalent to the groove 20 is formed on a portion of the inner peripheral edge of the cutting edge. Therefore, a portion connected to the chip breaker groove and a portion not connected to the chip breaker groove are generated on the inner peripheral edge. The flow of chips in the portion connected to the chip breaker groove and the portion not connected to the chip breaker groove are quite different, so the flow of chips generated on the inner peripheral edge becomes unstable. In addition, patent document 1 also discloses a drill in which the entire inner peripheral edge is connected to the chip breaker groove, but in such a structure, the thickness of the entire cutting edge becomes thinner, and in particular, the strength of the inner peripheral edge is likely to be reduced.

[0042] In addition, in this example, Figure 5 As shown, the groove 20 has a first surface 21 extending along the outer blade 17 and a second surface 22 located closer to the rear end of the main body 3 than the first surface 21. Figure 7 As shown in the figures with reference numerals 1002 and 1003, the second surface 22 is inclined relative to the first surface 21, and a bottom 23 is formed between the first surface 21 and the second surface 22. The second surface 22 is inclined relative to the first surface 21 in a direction opposite to the direction in which the groove 20 is concave, that is, in a convex direction. Figure 5 As shown, the bottom portion 23 is structured to approach the outer blade 17 as it approaches the outer periphery of the main body 3 .

[0043] With this structure, chips generated by outer blades 17 tend to move away from the outer periphery of body 3 when curled on second surface 22. Therefore, the chips are less likely to damage the machined surface of the workpiece (inner wall of the machined hole).

[0044] Furthermore, in the case where the bottom portion 23 is configured to approach the outer blade 17 as it approaches the outer periphery of the main body 3, the width w1 of the second surface 22 along the direction of the rotation axis R1 (see Figure 6 ) becomes larger as it approaches the outer periphery of the body 3. That is, in the groove 20, the bottom 23 approaches the outer edge 17 as it approaches the outer periphery of the body 3, and the width w1 of the second surface 22 becomes larger as it approaches the outer periphery of the body 3.

[0045] With this structure, when the chips generated by the outer blade 17 curl on the second surface 22, they are more likely to advance in a direction away from the outer periphery of the body 3. Therefore, the possibility of the chips damaging the machined surface of the workpiece is further reduced.

[0046] In addition, in this example, Figure 7 As shown in the figures with reference numerals 1001 and 1002, the structure is as follows: when the rake angle of the inner blade 16 is set to the inner rake angle θ1 and the rake angle of the outer blade 17 is set to the outer rake angle θ2, the outer rake angle θ2 is larger than the inner rake angle θ1. Figure 7 Similarly, the external rake angle θ2 ′ shown in the figure with reference numeral 1003 is larger than the internal rake angle θ1 .

[0047] Here, the rake angle in this example can be defined in a cross section perpendicular to the portion of the cutting edge 11 that is the object when viewed from the front. Figure 7 In the cross-sections shown in the figures with reference numerals 1001 to 1003 , the angle can be defined by the angle formed by the imaginary straight line Y1 parallel to the rotation axis R1 and the portion of the discharge groove 12 along the cutting edge 11 . Figure 7The angle θ1 formed between the imaginary straight line Y1 shown by reference numeral 1001 and the portion of the discharge groove 12 along the inner edge 16 is the inner rake angle. Figure 7 The angles θ2 and θ2′ formed by the imaginary straight line Y1 shown by reference numerals 1002 and 1003 and the portion of the discharge groove 12 along the outer blade 17 are the outer rake angles. Figure 5 The VII-A line, the VII-B line, and the VII-C line are respectively perpendicular to the cutting edge 11. That is, Figure 7 It is a cross section perpendicular to the cutting edge 11. Figure 7 In the drawings with reference numerals 1001 to 1003 , for convenience, the height positions of the imaginary straight line Y1 are aligned and shown.

[0048] The portion of the discharge groove 12 along the cutting edge 11 is located closer to the cutting edge 11 in the rotation direction R2 (see Figure 1 、 Figure 3 ) in the front position, the rake angle is a negative value. In addition, when the portion along the cutting edge 11 in the discharge groove 12 is a position behind the cutting edge 11 in the rotation direction R2, the rake angle is a positive value.

[0049] like Figure 7 As shown in the figures with reference numerals 1001 to 1003, in this example, the inner rake angle θ1 and the outer rake angles θ2 and θ2' are all positive values. Figure 7 The cross section shown in the figure with reference numeral 1001 has a positive internal rake angle θ1 because it is a portion close to the outer blade 17 , but the rake angle is a negative value at the chisel edge portion located at the front end of the body 3 .

[0050] By configuring the external rake angle θ2 (external rake angle θ2') to be larger than the internal rake angle θ1, the durability of the cutting edge 11 is enhanced, and the surface accuracy of the machined surface is improved. Since the cutting speed of the inner edge 16 is slower than that of the outer edge 17, a relatively large cutting load is likely to be applied to the inner edge 16. However, when the internal rake angle θ1 is smaller than the external rake angles θ2 and θ2', the wall thickness of the portion of the cutting portion 10 where the inner edge 16 is located is ensured to be thicker, thereby enhancing durability.

[0051] Furthermore, outer cutting edge 17 is positioned further from rotation axis R1 than inner cutting edge 16. When outer rake angles θ2 and θ2' are larger than inner rake angle θ1, the outer rake angles θ2 and θ2' are sharper. This makes it easier to suppress chatter vibration and improve the surface accuracy of the machined surface. As a result, the durability of cutting edge 11 is enhanced, and the surface accuracy of the machined surface is improved.

[0052] Furthermore, when the outer rake angle θ2 is configured to be larger than the inner rake angle θ1, the outer rake angle θ2 may be configured to be larger as it approaches the outer periphery of the main body 3. Figure 7 As shown in the figures with reference numerals 1002 and 1003 , the external rake angle θ2 ′ near the outer periphery of the main body 3 is larger than the external rake angle θ.

[0053] With this structure, the outer cutting edge 17 has higher durability closer to the rotation axis R1 and higher sharpness farther from the rotation axis R1. Therefore, the durability of the cutting edge 11 is further improved, and the surface accuracy of the processed surface is further improved.

[0054] And, in this case, if Figure 6 As shown, recess 15 includes a first portion 15a connected to groove 20 and a second portion 15b separated from groove 20. If the length of first portion 15a in a direction perpendicular to rotation axis R1 is defined as distance d1, and the length of second portion 15b in a direction perpendicular to rotation axis R1 is defined as distance d2, first portion 15a is longer than second portion 15b. In other words, the relationship d1 > d2 holds.

[0055] With such a structure, the chips generated by the outer blade 17 easily come into contact with the concave groove 20 , and the chips can be stably bent in the concave groove 20 .

[0056] <Structure with multiple cutting edges>

[0057] In addition, if Figure 3 As shown, in this example, three cutting edges (a first cutting edge 11-1, a second cutting edge 11-2, and a third cutting edge 11-3) are formed on the cutting portion 10 as the above-mentioned cutting edge 11, and three discharge grooves (a first discharge groove 12-1, a second discharge groove 12-2, and a third discharge groove 12-3) are also formed as the discharge groove 12 corresponding to the three cutting edges 11. When the cutting edges 11 are formed in a plurality of ways, the plurality of cutting edges 11 are preferably configured to be rotationally symmetrical with respect to the rotation axis R1. In this example, the three cutting edges 11 are formed in a rotationally symmetrical shape of 120° with respect to the rotation axis R1 when the rotary tool 1 is viewed from the front. It should be noted that the shape of the cutting edge 11 can be a straight line shape or a curved line shape when viewed from the front.

[0058] Furthermore, when the cutting edge 11 is formed into a plurality of pieces, as shown in FIG. Figure 3 As shown, it is preferable to provide the recesses 15 with their positions offset in the radial direction. By offsetting the recesses 15 in the radial direction, the formation positions of the grooves 20, whose formation positions are determined by the positions of the recesses 15, also differ.

[0059] Hereinafter, the cutting edge 11 having the recess 15 at the position closest to the front end of the main body 3 (the center of the main body 3) through which the rotation axis R1 passes will be referred to as the first cutting edge 11-1. In addition, the cutting edge 11 having the recess 15 at the position closest to the outer periphery of the main body 3 will be referred to as the third cutting edge 11-3. Furthermore, the cutting edge 11 having the recess 15 between the position of the recess 15 of the first cutting edge 11-1 and the position of the recess 15 of the third cutting edge 11-3 will be referred to as the second cutting edge 11-2. Figure 3 The first to third cutting edges 11 - 1 to 11 - 3 are arranged in a direction opposite to the rotation direction indicated by arrow R2 .

[0060] In addition, hereinafter, as needed, the recesses 15 provided on the first to third cutting edges 11-1, 11-3 will be referred to as first recesses 15-1, 15-3, and the grooves 20 corresponding to the first to third cutting edges 11-1, 11-3 will be referred to as first grooves 20-1, 20-3. The same applies to the discharge groove 12, the flank 13, the ridge line R, etc. That is, the structure corresponding to the first cutting edge 11-1 will be appended with "-1" after the reference numeral, the structure corresponding to the second cutting edge 11-2 will be appended with "-2", and the structure corresponding to the third cutting edge 11-3 will be appended with "-3". For example, the flank corresponding to the first cutting edge 11-1 is the first flank 13-1, the flank corresponding to the second cutting edge 11-2 is the second flank 13-2, and the flank corresponding to the third cutting edge 11-3 is the third flank 13-3.

[0061] In other words, the above structure means that the second recess 15 - 2 formed in the second cutting edge 11 - 2 is located closer to the outer periphery of the main body 3 than the first recess 15 - 1 formed in the first cutting edge 11 - 1 .

[0062] With this configuration, the second cutting edge 11-2, located downstream in the rotational direction R2, covers the chip residue generated by the recess 15 of the first cutting edge 11-1. Similarly, the third cutting edge 11-3, located downstream in the rotational direction R2, covers the chip residue generated by the recess 15 of the second cutting edge 11-2. This eliminates the chip residue caused by the recess 15.

[0063] Next, use Figures 8 to 11 , the preferred shape of the groove 20 in the structure in which a plurality of cutting edges 11 are provided will be described. Figure 8 It is from Figure 3 The enlarged view of the front end portion of the side surface of the rotary cutter 1 as viewed from the direction B1 is shown. Figure 9 It is from Figure 3 The diagram is an enlarged view of the front end portion of the side surface of the rotary cutter 1 as viewed from the direction B3. Figure 10 yes Figure 8 The cross-sectional view of the XD line, XE line and XF line. Figure 10 In the figure, the figure with reference numeral 1004 is a cross-sectional view as viewed along the XD line, the figure with reference numeral 1005 is a cross-sectional view as viewed along the XE line, and the figure with reference numeral 1006 is a cross-sectional view as viewed along the XF line. Figure 8 The XD line, the XE line, and the XF line are respectively perpendicular to the cutting edge 11 . Figure 11 yes Figure 9 The cross-sectional view of the XI-G line, XI-H line and XI-I line. Figure 11 1007 is a cross-sectional view taken along line XI-G, 1008 is a cross-sectional view taken along line XI-H, and 1009 is a cross-sectional view taken along line XI-I. It should be noted that lines XI-G, XI-H, and XI-I are perpendicular to the cutting edge 11.

[0064] like Figure 5 、 Figure 8 、 Figure 9 As shown, the positions of the first through third recesses 15-1, 15-3 are offset in the radial direction. More specifically, as described above, the first recess 15-1 is located closest to the front end of the main body 3 (the center of the main body 3), the second recess 15-2 is located closer to the outer periphery of the main body 3 than the first recess 15-1, and the third recess 15-3 is located closer to the outer periphery of the main body 3 than the second recess 15-2. This difference in the positions of the first through third recesses 15-1, 15-3 results in different positions and sizes of the first through third grooves 20-1, 20-3.

[0065] In this example, the first bottom 23-1 to the third bottom 23-3 of the first to third grooves 20-1 to 20-3 are linear. The angle formed by the rotation axis R1 and the bottom 23 when the rotary cutter 1 is viewed from the side is referred to as the inclination angle. Figure 5 The inclination angle of the first bottom 23-1 is set as the first inclination angle α1. Figure 8 The inclination angle of the second bottom 23-2 is set to the second inclination angle α2. Figure 9 The inclination angle of the third bottom portion 23-3 is set as the third inclination angle α3. In this example, among the three inclination angles, the second inclination angle α2 is larger than the first inclination angle α1, and the third inclination angle α3 is larger than the second inclination angle α2.

[0066] Because first recess 15-1 is closer to the center of main body 3 than second recess 15-2, first outer blade 17-1 is longer than second outer blade 17-2. Consequently, the width of the chips produced by first outer blade 17-1 is greater than that produced by second outer blade 17-2. In other words, the chips produced by first outer blade 17-1 are larger and heavier than those produced by second outer blade 17-2. As a result, when chips produced by first outer blade 17-1 come into contact with the machined surface of the workpiece, they are more likely to damage the machined surface than chips produced by second outer blade 17-2.

[0067] However, when the second inclination angle α2 is larger than the first inclination angle α1, in other words, when the first inclination angle α1 is smaller than the second inclination angle α2, the chips generated by the first outer cutting edge 17 - 1 tend to move away from the outer periphery of the main body 3 .

[0068] On the other hand, because the width of the chips produced by the second outer blade 17-2 is smaller than that of the chips produced by the first outer blade 17-1, the direction of travel of the chips produced by the second outer blade 17-2 tends to become unstable. Here, when the second inclination angle α2 is larger than the first inclination angle α1, the angle formed by the second outer blade 17-2 and the second bottom portion 23-2 in side view tends to be larger than the angle formed by the first outer blade 17-1 and the first bottom portion 23-1 in side view. Therefore, the chips produced by the second outer blade 17-2 tend to curl stably in the second groove 20-2.

[0069] Similarly, because second recess 15-12 is closer to the center of body 3 than third recess 15-3, second outer edge 17-2 is longer than third outer edge 17-3. Consequently, the width of the chips produced by second outer edge 17-2 is greater than that produced by third outer edge 17-3. In other words, the chips produced by second outer edge 17-2 are larger and heavier than those produced by third outer edge 17-3. As a result, when chips produced by second outer edge 17-2 come into contact with the machined surface of the workpiece, they are more likely to damage the machined surface than chips produced by third outer edge 17-3.

[0070] However, when the third inclination angle α3 is larger than the second inclination angle α2, in other words, when the second inclination angle α2 is smaller than the third inclination angle α3, the chips generated by the second outer cutting edge 17-2 tend to move away from the outer periphery of the main body 3.

[0071] On the other hand, because the width of the chips produced by third outer blade 17-3 is smaller than that of the chips produced by second outer blade 17-2, the direction of travel of the chips produced by third outer blade 17-3 tends to become unstable. Here, when third inclination angle α3 is larger than second inclination angle α2, the angle formed by third outer blade 17-3 and third bottom portion 23-3 in side view tends to be larger than the angle formed by second outer blade 17-2 and second bottom portion 23-2 in side view. Consequently, the chips produced by third outer blade 17-3 tend to curl stably in third groove 20-3.

[0072] It should be noted that, in order to distinguish the first surface 21 in the first groove 20-1 from the first surface 21 in the second groove 20-2, the first surface 21 in the second groove 20-2 may be renamed the third surface. Similarly, in order to distinguish the second surface 22 in the first groove 20-1 from the second surface 22 in the second groove 20-2, the second surface 22 in the second groove 20-2 may be renamed the fourth surface.

[0073] Furthermore, in this example, the rake angles corresponding to the first cutting edge 11-1 to the third cutting edge 11-3 satisfy the following relationship. Figure 7 The first outer edge 17-1 of the first cutting edge 11-1 shown in the figure with reference numeral 1002 (see Figure 5 ) is set as the first external rake angle θ2(1). Figure 10 The second outer edge 17-2 of the second cutting edge 11-2 shown in the figure with reference numeral 1005 (see Figure 8 ) is set as the second external rake angle θ2(2). Figure 11 The third outer edge 17-3 of the third cutting edge 11-3 shown in the figure with reference numeral 1008 (see Figure 9 ) is set to the third external rake angle θ2(3).

[0074] In addition, Figure 7 The first inner edge 16-1 of the first cutting edge 11-1 shown in the figure with reference numeral 1001 (see Figure 5 ) is set as the first inner rake angle θ1(1). Figure 10 The second inner edge 16-2 of the second cutting edge 11-2 shown in the figure with reference numeral 1004 (see Figure 8 ) is set as the second inner rake angle θ1(2). In addition, Figure 11 The third inner edge 16-3 of the third cutting edge 11-3 shown in the figure with reference numeral 1007 (refer to Figure 9 ) is set to the third inner rake angle θ1(3).

[0075] In this example, the main body 3 has a structure in which the second external rake angle θ2(2) is larger than the first external rake angle θ2(1). Similarly, as a more preferred structure, the main body 3 has a structure in which the third external rake angle θ2(3) is larger than the second external rake angle θ2(2). It should be noted that the structure of the main body 3 in which the second external rake angle θ2(2) is larger than the first external rake angle θ2(1) can also be θ2(1)<θ2(2)=θ2(3). In addition, the structure of the main body 3 in which the third external rake angle θ2(3) is larger than the second external rake angle θ2(2) can also be θ2(1)=θ2(2)<θ2(3).

[0076] As described above, the width of the chips produced by the second outer blade 17-2 is smaller than that of the chips produced by the first outer blade 17-1, and the direction of travel of the chips produced by the second outer blade 17-2 tends to become relatively unstable. However, when the second outer rake angle θ2(2) is larger than the first outer rake angle θ2(1), the chips produced by the second outer blade 17-2 tend to bend stably. Therefore, the chip discharge efficiency is improved.

[0077] Similarly, the width of the chips produced by the third outer blade 17-3 is smaller than that of the chips produced by the second outer blade 17-2, and the direction of travel of the chips produced by the third outer blade 17-3 tends to become relatively unstable. However, when the third outer rake angle θ2(3) is larger than the second outer rake angle θ2(2), the chips produced by the third outer blade 17-3 tend to bend stably. Therefore, the chip discharge efficiency is improved.

[0078] Furthermore, in this case, the first internal rake angle θ1(1), the second internal rake angle θ1(2), and the third internal rake angle θ1(3) may be made the same.

[0079] As described above, the cutting speed of the inner blade 16 is slower than that of the outer blade 17, so a relatively large cutting load is easily applied to the inner blade 16. When the first inner rake angle θ1(1), the second inner rake angle θ1(2), and the third inner rake angle θ1(3) are the same, the deviation of the cutting load applied to the first inner blade 16-1, the second inner blade 16-2, and the third inner blade 16-3 is small. The deviation of the cutting load at the portion where a relatively large cutting load is easily applied is small, so the durability of the pointed tip is high. In addition, the deviation of the cutting load at the portion where a relatively large cutting load is easily applied is small, so it is difficult to generate vibration when the rotary tool 1 cuts into the workpiece.

[0080] However, the condition that the first internal rake angle θ1(1), the second internal rake angle θ1(2), and the third internal rake angle θ1(3) are identical does not require that these angles be strictly identical. These angles may have a slight deviation of approximately ±3°. It should be noted that when the deviation of these angles is ±1° or less, the deviation of the cutting load described above is further reduced.

[0081] (2. Method for Manufacturing Cutting Work)

[0082] Next, use Figure 12 An example of a method for producing a machined product will be described. Figure 12 1 is a schematic diagram showing the steps of a method for producing a machined product according to one embodiment. Hereinafter, a method for producing a machined product U by cutting a workpiece T using a rotary tool 1 will be described.

[0083] The method for manufacturing a machined product U according to one embodiment may also include the following steps.

[0084] (1) a process of rotating the rotary tool 1;

[0085] (2) a step of bringing the rotary tool 1 into contact with the workpiece T; and

[0086] (3) A step of separating the rotary tool 1 from the workpiece T.

[0087] More specifically, first, if Figure 12 As shown in the figure with reference numeral 1010, a workpiece T is prepared just below the rotary tool 1, and the rotary tool 1 mounted on the machine tool is rotated around the rotation axis R1. Examples of the workpiece T include aluminum, carbon steel, alloy steel, stainless steel, cast iron, and nonferrous metals.

[0088] Then, if Figure 12 As shown in the figure 1011, the rotary tool 1 is brought close to the workpiece T, so that the rotary tool 1 contacts the workpiece T. The workpiece T is thereby cut by the cutting edge 11, forming a machined hole V. Chips from the workpiece T are discharged to the outside through the discharge groove 12. The method of bringing the rotary tool 1 and the workpiece T relatively close is not particularly limited. For example, the rotary tool 1 can be moved toward the fixed workpiece T, or the workpiece T can be moved relative to the fixed rotary tool 1.

[0089] Next, if Figure 12 As shown in the figure with reference numeral 1012, the rotary tool 1 is separated from the workpiece T. Thus, a machined product U, which is the workpiece T in which a machined hole V is formed, is produced.

[0090] [Implementation Method 2]

[0091] For the sake of convenience, components having the same functions as those described in the above embodiments are denoted by the same reference numerals, and their description will not be repeated.

[0092] In this embodiment, a rotary tool composed of a tool holder and a cutting insert (hereinafter, also simply referred to as an insert), which is generally called a tip-replaceable tool, will be described. Figure 13 It is a perspective view of the rotary cutter 100 according to the present embodiment. Figure 14 yes Figure 13 A perspective view of the blade 101 of the rotary cutter 100 is shown.

[0093] like Figure 13 As shown, the rotary tool 100 of this example is formed as a separate body with a blade 101 and a shank 110, and the blade 101 is mounted on the front end portion of the shank 110. The rotary tool 100 of this example is a single-blade drill bit with one blade 101 mounted thereon, but the rotary tool having the blade 101 is not limited to a single-blade drill bit.

[0094] The insert 101 of this embodiment has a main portion (body) 102 extending from the front end to the rear end, and a cutting portion 10 is formed on the front end side of the main portion 102. The main portion 102 has a shaft portion 103 extending along the rotation axis R1 on the rear end side.

[0095] The handle 110 extends along the rotation axis R1, and the shaft portion 103 of the blade 101 is fitted on the front end side of the handle 110. A blade groove 113 is provided on the front end side of the handle 110 to fit the shaft portion 103.

[0096] Examples of materials for the insert 101 include inorganic materials such as cemented carbide, cermet, and ceramics. Examples of cemented carbide compositions include WC (tungsten carbide)-Co, WC-TiC (titanium carbide)-Co, and WC-TiC-TaC (tantalum carbide)-Co.

[0097] Here, WC, TiC, and TaC are hard particles, and Co is a binder phase. Furthermore, cermets are sintered composite materials composed of a ceramic component and a metal. Specifically, examples of cermets include compounds primarily composed of TiC or TiN (titanium nitride). The material of blade 101 is, of course, not limited to this.

[0098] In addition, although not specifically shown in the figure, the blade 101 may also be a structure having a base containing the above-mentioned material and a coating covering the base. As the material of the coating, for example, titanium carbide, nitride, oxide, carbon oxide, nitrogen oxide, carbonitride and carbonitride oxide can be cited. The coating may contain only one of the above-mentioned materials, or it may contain multiple materials. In addition, the coating may consist of only one layer, or it may be a structure with multiple layers stacked. It should be noted that the material of the coating is not limited to this. The coating can be located on the base by using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method.

[0099] In the case of the rotary tool 1 in which the shank 110 and the blade 101 are formed of one member, the same material as that of the blade 101 can be used as the material of the member.

[0100] The application of the present application has been described based on each drawing and each embodiment. However, the application of the present application is not limited to the above-described each embodiment. That is, the application of the present application can be variously changed within the scope of the present application, and an embodiment obtained by appropriately combining the technical means respectively disclosed in different embodiments is also included in the technical scope of the application of the present disclosure. That is, it should be noted that various modifications or changes can be easily made by those skilled in the art based on the present application. In addition, it should be noted that these modifications or changes are included in the scope of the present application.

[0101] Explanation of Reference Numerals

[0102] 1, 100 Rotary tool

[0103] 3 Main body

[0104] 10 Cutting portion

[0105] 11 Cutting edge

[0106] 11-1 First cutting edge

[0107] 11-2 Second cutting edge

[0108] 12 Discharge groove

[0109] 12-1 First discharge groove

[0110] 12-2 Second discharge groove

[0111] 13 Rake face

[0112] 13-1 First rake face

[0113] 13-2 Second rake face

[0114] 15 Concave portion

[0115] 15-1 First concave portion

[0116] 15-2 Second concave portion

[0117] 15a First site

[0118] 15b Second site

[0119] 16 Inner edge

[0120] 16-1 First inner edge

[0121] 16-2 Second inner edge

[0122] 16a Sharpening blade

[0123] 17 Outer Blade

[0124] 17-1 First Outer Edge

[0125] 17-2 Second outer edge

[0126] 20 grooves

[0127] 20-1 First Groove

[0128] 20-2 Second Groove

[0129] Page 21

[0130] 22 Side 2

[0131] 23 bottom

[0132] 23-1 First Bottom

[0133] 23-2 Second bottom

[0134] 101 Blade

[0135] 102 Main part (main body)

[0136] 103 shaft

[0137] 110 handle

[0138] 113 Slots

[0139] R edge

[0140] R-1 First Ridge

[0141] R-2 Second Ridge

[0142] R1 Rotation Axis

[0143] R2 Rotation direction

[0144] θ1(1) first internal rake angle

[0145] θ1(2) Second internal rake angle

[0146] θ2(1) First external rake angle

[0147] θ2(2) Second external rake angle

[0148] α1 first tilt angle

[0149] α2 Second tilt angle.

Claims

1. A cutting insert, wherein: The cutting insert has a body extending from a first end to a second end along a rotational axis, The subject has: a first flank surface located at the first end side; a first discharge groove extending from the first relief surface toward the second end; and a first ridge line located at the intersection of the first flank surface and the first discharge groove, The first edge line has: a first recessed portion recessed toward the second end; a first inner edge extending from the first recess toward the first end; as well as a first outer blade extending from the first recess toward the outer periphery of the body, The first discharge slot has a first groove extending along the first outer edge, The first groove is connected to the first recess and the first outer edge, and the first groove is separated from the first inner edge, The first groove has: a first surface extending along the first outer edge; a second surface located closer to the second end side than the first surface and inclined relative to the first surface; as well as a first bottom portion, which is located between the first surface and the second surface; The first bottom portion approaches the first outer edge as it approaches the outer circumference of the main body.

2. The cutting insert according to claim 1, wherein The width of the second surface in the direction along the rotation axis increases as it approaches the outer periphery.

3. A cutting insert, wherein: The cutting insert has a body extending from a first end to a second end along a rotational axis, The subject has: a first flank surface located at the first end side; a first discharge groove extending from the first relief surface toward the second end; and a first ridge line located at the intersection of the first flank surface and the first discharge groove, The first edge line has: a first recessed portion recessed toward the second end; a first inner edge extending from the first recess toward the first end; as well as a first outer blade extending from the first recess toward the outer periphery of the body, The first discharge slot has a first groove extending along the first outer edge, The first groove is connected to the first recess and the first outer edge, and the first groove is separated from the first inner edge, The first recess has: a first portion connected to the first groove; as well as a second portion, which is separated from the first groove, The first portion is longer than the second portion.

4. A cutting insert, wherein: The cutting insert has a body extending from a first end to a second end along a rotational axis, The subject has: a first flank surface located at the first end side; a first discharge groove extending from the first relief surface toward the second end; and a first ridge line located at the intersection of the first flank surface and the first discharge groove, The first edge line has: a first recessed portion recessed toward the second end; a first inner edge extending from the first recess toward the first end; as well as a first outer blade extending from the first recess toward the outer periphery of the body, The first discharge slot has a first groove extending along the first outer edge, The first groove is connected to the first recess and the first outer edge, and the first groove is separated from the first inner edge, The subject also has: a second flank surface located at the first end side; a second discharge groove extending from the second relief surface toward the second end; as well as a second ridgeline located at the intersection of the second flank surface and the second discharge groove, The second edge line has: a second recessed portion, which is recessed toward the second end; a second inner edge extending from the second recess toward the first end; as well as a second outer blade extending from the second recess toward the outer periphery of the body, The second discharge groove has a second groove extending along the second outer edge, The second groove is connected to the second recess and the second outer edge, and the second groove is separated from the second inner edge, The second recess is located closer to the outer periphery of the main body than the first recess. The first groove has: a first surface extending along the first outer edge; a second surface located closer to the second end than the first surface and inclined in a convex direction with respect to the first surface; and a first bottom portion having a straight line shape, located between the first surface and the second surface, The second groove has: a third surface extending along the second outer edge; a fourth surface located closer to the second end than the third surface and inclined in a convex direction relative to the third surface; and a second bottom portion in a straight line shape, located between the third surface and the fourth surface, The angle formed between the rotation axis and the first bottom when viewed from the side is a first inclination angle, and the angle formed between the rotation axis and the second bottom when viewed from the side is a second inclination angle. The second inclination angle is greater than the first inclination angle.

5. The cutting insert according to claim 4, wherein The rake angle of the first outer edge is a first outer rake angle, and the rake angle of the second outer edge is a second outer rake angle. The second external rake angle is greater than the first external rake angle.

6. The cutting insert according to claim 5, wherein The front angle of the first inner edge is a first inner front angle, and the front angle of the second inner edge is a second inner front angle. The first inner rake angle is the same as the second inner rake angle.

7. The cutting insert according to any one of claims 1 to 6, wherein The rake angle of the first inner edge is the first inner rake angle, and the rake angle of the first outer edge is the first outer rake angle. The first external rake angle is greater than the first internal rake angle.

8. The cutting insert according to claim 7, wherein The first outer rake angle has a portion that becomes larger as it approaches an outer circumference of the body.

9. A rotary tool, wherein: The rotary cutter has: a knife handle having a knife groove located at a front end side; and The cutting insert according to any one of claims 1 to 8, wherein the cutting insert is located in the groove.

10. A rotary tool, wherein: The rotary cutter has: a rod-shaped body having a rotation axis and extending from a first end to a second end; a first flank surface located on the first end side of the main body; a first discharge groove extending from the first relief surface toward the second end; as well as a first ridge line located at the intersection of the first flank surface and the first discharge groove, The first edge line has: a first recessed portion recessed toward the second end; a first inner edge extending from the first recess toward the first end; as well as a first outer blade extending from the first recess toward the outer periphery of the body, The first discharge slot has a first groove extending along the first outer edge, The first groove is connected to the first recess and the first outer edge, and the first groove is separated from the first inner edge, The first groove has: a first surface extending along the first outer edge; a second surface located closer to the second end side than the first surface and inclined relative to the first surface; as well as a first bottom portion, which is located between the first surface and the second surface; The first bottom portion approaches the first outer edge as it approaches the outer circumference of the main body.

11. A method for producing a machined product, wherein: The method for manufacturing the machined product comprises: a step of rotating the rotary cutter according to claim 9 or 10; a step of bringing the rotating rotary tool into contact with a workpiece; and a step of separating the rotary cutter from the workpiece.

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