JP2022167663A - Rotary tool, and manufacturing method of cutting workpiece - Google Patents

Abstract

To suppress variation of a cutting load applied to a first blade and a cutting load applied to a second blade in a cutting work of a material to be cut, and increase durability of a rotary tool.SOLUTION: When a division angle between a first bottom blade (30) and a second bottom blade (38) is a first division angle (θ1), and a division angle between the second bottom blade (38) and a third bottom blade (46) is a second division angle (θ2), in the case of viewing from front toward a tip of a body (12), the second division angle (θ2) is set larger than the first division angle (θ1). When a tilt angle of the first bottom blade (30) for a rotational axis (S) is a first concave angle in the case of viewing the first bottom blade (30) from side, and a tilt angle of the second bottom blade (38) for the rotational axis (S) is a second concave angle in the case of viewing the second bottom blade (38) from side, the first concave angle is set smaller than the second concave angle.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present disclosure relates to a rotary tool used for cutting (rolling) a work material and a method for manufacturing a cut product.

2. Description of the Related Art For example, an end mill described in Patent Document 1 is known as a rotary tool used when milling a work material made of a metal material or the like. The end mill described in Patent Document 1 has a plurality of end cutting edges located on the tip side of the main body. The plurality of bottom cutting edges has one bottom cutting edge (main cutting edge) extending from the outer peripheral side to the chisel edge, and another bottom cutting edge (child cutting edge) extending from the outer peripheral side to a position away from the chisel edge. These bottom cutting edges are inclined in the radial direction (direction orthogonal to the rotation axis) so as to approach the rear end of the main body as they approach the rotation axis. At this time, the inclination angle of the child blade with respect to the radial direction is larger than the inclination angle of the main blade with respect to the radial direction.

JP 2010-201565 A

In a rotary tool having a main cutting edge and a bottom cutting edge, it is preferable to avoid premature wear or premature breakage of the main cutting edge.

A rotary tool according to an aspect of the present disclosure includes a cylindrical body extending along a rotation axis from a first end toward a second end and having a cutting portion on the first end side. The cutting portion has a plurality of cutting edges located on the first end side of the body, and a plurality of discharge grooves extending from the plurality of cutting edges toward the second end of the body. . The plurality of cutting edges include a first cutting edge extending from the outer peripheral side toward the rotating shaft, and a front cutting edge in the rotating direction of the rotating shaft with respect to the first cutting edge. and a third cutting edge positioned forward of the second cutting edge in the direction of rotation of the rotating shaft and extending from the outer peripheral side toward the rotating shaft. I'm in. A dividing angle between the first cutting edge and the second cutting edge when viewed from the front toward the first end of the main body is defined as a first dividing angle, and the second cutting edge and the third cutting edge and the second dividing angle is set larger than the first dividing angle. The first cutting edge is orthogonal to the rotation axis, or is inclined with respect to the radial direction (the direction orthogonal to the rotation axis) so as to approach the second end of the main body as it approaches the rotation axis. The second cutting edge is inclined with respect to the radial direction so as to approach the second end of the main body as it approaches the rotating shaft. The inclination angle of the first cutting edge with respect to the rotation axis when the first cutting edge is viewed from the side is defined as a first watermark angle, and the second cutting edge with respect to the rotation axis when the second cutting edge is viewed from the side. The first watermark angle is set smaller than the second watermark angle when the inclination angle of the blade is the second watermark angle.

According to one aspect of the present disclosure, the durability of the rotary tool can be improved by suppressing variations in the cutting load applied to the first blade and the cutting load applied to the second blade during cutting of a work material.

1 is a perspective view of an end mill according to an embodiment; FIG. FIG. 2 is an enlarged perspective view of a section II in FIG. 1; FIG. 2 is a front view of the end mill shown in FIG. 1; It is the side view seen from IV direction in FIG. FIG. 4 is a side view seen from the V direction in FIG. 3; 4 is an enlarged cross-sectional view of the VI-VI cross section in FIG. 3; FIG. 4 is an enlarged sectional view of the VII-VII section in FIG. 3; FIG. FIG. 5 is a partial side view of an end mill according to Modification 1 of the embodiment; It is a partial side view of the end mill which concerns on the modification 2 of embodiment. FIG. 11 is a partial side view of an end mill according to modification 3 of the embodiment; It is a mimetic diagram explaining a manufacturing method of a cutting thing concerning an embodiment. It is a mimetic diagram explaining a manufacturing method of a cutting thing concerning an embodiment. It is a mimetic diagram explaining a manufacturing method of a cutting thing concerning an embodiment. It is a mimetic diagram explaining a manufacturing method of a cutting thing concerning an embodiment.

Hereinafter, an end mill as an example of a rotary tool according to an embodiment of the present disclosure and a method for manufacturing a cut product will be described in detail with reference to the drawings. However, for convenience of explanation, each drawing referred to below shows only the constituent elements necessary for explaining the embodiment in a simplified manner. Accordingly, an end mill as an example of a rotary tool may include optional components not shown in the referenced figures. Also, the dimensions of the constituent elements in each drawing do not faithfully represent the actual dimensions of the constituent elements, the dimensional ratios of the respective constituent elements, and the like.

In the present disclosure, the rotation axis means the rotation axis (rotation axis) of the rotary tool, and the circumferential direction means the direction around the rotation axis. The radial direction is a direction orthogonal to the rotating shaft and the circumferential direction, the radial inner side is the direction toward or near the rotating shaft in the radial direction, and the radial outer side is: In the radial direction, it is the direction away from the rotation axis or the side away from it.

<End mill according to the embodiment of the present disclosure>
A configuration of an end mill 10, which is an example of a rotary tool according to an embodiment, will be described with reference to FIGS. 1 to 7. FIG. FIG. 1 is a perspective view of an end mill according to an embodiment. 2 is an enlarged perspective view of a section II in FIG. 1. FIG. 3 is a front view of the end mill shown in FIG. 1. FIG. 4 is a side view seen from the IV direction in FIG. 3. FIG. 5 is a side view seen from the V direction in FIG. 3. FIG. FIG. 6 is an enlarged sectional view of the VI-VI section in FIG. FIG. 7 is an enlarged sectional view of the VII-VII section in FIG.

As shown in FIGS. 1 and 2, an end mill 10, which is an example of a rotary tool according to the present embodiment, is an end mill used for cutting (rolling) a work W (see FIG. 8) made of a metal material or the like. be. The cutting of the work material W includes, for example, shoulder milling, grooving, R milling, copy milling, and the like. The end mill 10 is a solid type end mill made of hard material such as cemented carbide, cermet, and cBN. The end mill 10 includes a columnar body 12 that extends along a rotation axis S from a front end (first end) 12a toward a rear end (second end) 12b. The main body 12 has a cutting portion 14 on the tip 12a side thereof for performing milling in contact with the work material W (see FIG. 11). The main body 12 has a shank portion 16 mounted on the main shaft of the machine tool through an arbor on the rear end 12b side. As long as at least the cutting portion 14 is made of a hard material such as cemented carbide, cermet, and cBN, the end mill 10 does not have to be a solid type end mill.

As shown in FIGS. 1 to 5, the cutting portion 14 has a plurality of bottom cutting edges 18 as an example of a plurality of cutting edges. They are spaced apart. The cutting part 14 has a chisel edge 20 passing through the rotation axis S, and the chisel edge 20 is positioned on the tip 12 a side of the main body 12 . The chisel edge 20 has the effect of crushing a part of the work material W. As shown in FIG.

The cutting portion 14 has a plurality of discharge grooves 22 for discharging chips generated by cutting to the outside. A plurality of discharge grooves 22 are formed on the outer peripheral surface of the main body 12 at intervals in the circumferential direction, and spirally extend from the plurality of bottom cutting edges 18 toward the rear end 12 b of the main body 12 . A peripheral cutting edge 24 as an example of a cutting edge is positioned at the outer peripheral end of the wall surface of each discharge groove 22 on the side facing the rotation direction T of the rotating shaft S. As shown in FIG. The number of peripheral cutting edges 24 is the same as the number of discharge grooves 22 . A rake face 26 is positioned on the discharge groove 22 side of each peripheral cutting edge 24 , and a flank 28 is provided behind each peripheral cutting edge 24 in the rotation direction T of the rotating shaft S (on the opposite side of the rotation direction T). positioned. A peripheral cutting edge 24 is positioned on the intersection ridgeline of the rake face 26 and the flank face 28 .

The plurality of end cutting edges 18 include a first end cutting edge 30 as a first cutting edge, and the first end cutting edge 30 extends from the outer peripheral side toward the rotation axis S to a position away from the chisel edge 20. It is a small blade. A planar rake face 32 is positioned on the discharge groove 22 side of the first bottom cutting edge 30, and a flank 34 is positioned behind the first bottom cutting edge 30 in the rotation direction T of the rotation axis S. there is A first bottom cutting edge 30 is positioned on the intersection ridgeline between the rake face 32 and the flank face 34 . The radially outer end of the first bottom cutting edge 30 is smoothly connected to the tip of the peripheral cutting edge 24 via a corner portion 36 . The corner portion 36 functions as a cutting edge.

The plurality of end cutting edges 18 include a second end cutting edge 38 as a second cutting edge, and the second end cutting edge 38 is a main cutting edge extending from the outer peripheral side toward the rotation axis S to the chisel edge 20. . The second end cutting edge 38 is positioned ahead of the first end cutting edge 30 in the rotation direction T of the rotation axis S. A planar rake face 40 is positioned on the discharge groove 22 side of the second bottom cutting edge 38, and a flank face 42 is positioned behind the second bottom cutting edge 38 in the rotational direction T of the rotation axis S. there is A second bottom cutting edge 38 is positioned on the intersection ridgeline between the rake face 40 and the flank face 42 . The radially outer end of the second bottom cutting edge 38 is smoothly connected to the tip of the peripheral cutting edge 24 via a corner portion 44 . The corner portion 44 functions as a cutting edge.

The plurality of end cutting edges 18 include a third end cutting edge 46 as a third cutting edge, and the third end cutting edge 46 extends from the outer peripheral side toward the rotation axis S to a position away from the chisel edge 20. It is a small blade. The third end cutting edge 46 is located forward of the second end cutting edge 38 in the rotation direction T of the rotation axis S. The third end cutting edge 46 is rotationally symmetrical about the rotation axis S with respect to the first end cutting edge 30 . A planar rake face 48 is positioned on the discharge groove 22 side of the third bottom cutting edge 46, and a flank 50 is positioned behind the third bottom cutting edge 46 in the rotation direction T of the rotation axis S. there is A third bottom cutting edge 46 is positioned on the intersection ridgeline between the rake face 48 and the flank face 50 . A radially outer end of the third bottom cutting edge 46 is smoothly connected to the tip of the peripheral cutting edge 24 via a corner portion 52 . The corner portion 52 functions as a cutting edge.

The plurality of end cutting edges 18 include a fourth end cutting edge 54 as a fourth cutting edge, and the fourth end cutting edge 54 is a main cutting edge extending from the outer peripheral side toward the rotation axis S to the chisel edge 20. . The fourth bottom cutting edge 54 is positioned forward in the rotation direction T of the rotation axis S with respect to the third bottom cutting edge 46 . The fourth end cutting edge 54 is rotationally symmetrical about the rotation axis S with respect to the second end cutting edge 38 . A planar rake face 56 is positioned on the discharge groove 22 side of the fourth bottom cutting edge 54, and a flank face 58 is positioned behind the fourth bottom cutting edge 54 in the rotational direction T of the rotation axis S. there is A fourth bottom cutting edge 54 is positioned on the intersection ridgeline between the rake face 56 and the flank face 58 . The radially outer end of the fourth bottom cutting edge 54 is smoothly connected to the tip of the peripheral cutting edge 24 via a corner portion 60 . The corner portion 60 functions as a cutting edge. The flank 58 of the fourth bottom cutting edge 54 is connected to the flank 42 of the second bottom cutting edge 38 via the chisel edge 20 .

The end mill 10 as an example has four end cutting edges 18 (first end cutting edge 30, second end cutting edge 38, third end cutting edge 46, fourth end cutting edge 54). may be 3 or 5 or more.

As shown in FIGS. 3, 6 and 7, the rake angle of the first end cutting edge 30 is defined as a first rake angle α1, and the rake angle of the second end cutting edge 38 is defined as a second rake angle α2. The first rake angle α1 may be set larger than the second rake angle α2. Compared with the second bottom cutting edge 38 which is the parent cutting edge connected to the chisel edge 20, the first bottom cutting edge 30 which is the child cutting edge located away from the chisel edge 20 cuts, for example, the end near the rotation axis S. Concentration of load may occur. However, when the first rake angle α1 is larger than the second rake angle α2, the cutting load applied to the first bottom cutting edge 30 can be reduced. Therefore, the durability of the plurality of bottom cutting edges 18 as a whole is high.

The rake angle of the third bottom cutting edge 46 is referred to as the third rake angle, and the rake angle of the fourth bottom cutting edge 54 is referred to as the fourth rake angle. The third rake angle may be set larger than the fourth rake angle. In this case, for the same reason as described above, the cutting load applied to the third bottom cutting edge 46, which is a child cutting edge, can be reduced. Therefore, the durability of the plurality of bottom cutting edges 18 as a whole is high.

The third rake angle may be set equal to the first rake angle α1, and the fourth rake angle may be set equal to the second rake angle α2. Making the two rake angles the same means that the difference between the two rake angles is within 1 degree. When the third rake angle is the same as the first rake angle α1, variations in the cutting load applied to the first end cutting edge 30 and the third end cutting edge 46 can be suppressed. Therefore, chattering vibration can be suppressed. Further, when the fourth rake angle is the same as the second rake angle α2, variations in the cutting load applied to the second bottom cutting edge 38 and the fourth bottom cutting edge 54 can be suppressed. Therefore, chattering vibration can be suppressed.

As shown in FIG. 3, the dividing angle between the first end cutting edge 30 and the second end cutting edge 38 when viewed from the front toward the tip 12a of the main body 12 is defined as a first dividing angle θ1, and the second end cutting edge The dividing angle between 38 and the third end cutting edge 46 is defined as a second dividing angle θ2, and the dividing angle between the third end cutting edge 46 and the fourth end cutting edge 54 is defined as a third dividing angle θ3. At this time, the second split angle θ2 may be set larger than the first split angle θ1. When the second splitting angle θ2 is larger than the first splitting angle θ1, the cutting load applied to the first end cutting edge 30 can be reduced. Therefore, the durability of the plurality of bottom cutting edges 18 as a whole is high.

The third split angle θ3 may be set to be the same as the first split angle θ1. Making the two division angles the same means that the difference between the two division angles is within 1 degree. When the dividing angle is set in this manner, variations in the cutting load applied to the first end cutting edge 30 and the third end cutting edge 46 can be suppressed.

As shown in FIGS. 4 and 5, the first bottom cutting edge 30 may be inclined with respect to the radial direction (direction orthogonal to the rotation axis S) so as to approach the rear end 12b of the main body 12 as it approaches the rotation axis S. good. Also, the first bottom cutting edge 30 may be perpendicular to the rotation axis S. The second bottom cutting edge 38 is inclined with respect to the radial direction so as to approach the rear end 12b of the main body 12 as it approaches the rotation axis S. As shown in FIG. Here, the radially outer end of the second end cutting edge 38 may be further away from the rear end 12 b of the main body 12 than the radially outer end of the first end cutting edge 30 . In such a case, the second end cutting edge 38, which is the main cutting edge, is likely to stably come into contact with the work material. Moreover, since the cutting load applied to the first bottom cutting edge 30, which is a child cutting edge, is suppressed, the durability of the first bottom cutting edge 30 can be enhanced.

As described above, when the first rake angle α1 is larger than the second rake angle α2, the durability of the first end cutting edge 30 tends to be lower than that of the second end cutting edge 38 . However, since the cutting load applied to the first end cutting edge 30, which is a child cutting edge, is suppressed, the first end cutting edge 30 is less likely to be damaged.

The third bottom cutting edge 46 may be inclined with respect to the radial direction so as to approach the rear end 12b of the main body 12 as it approaches the rotation axis S. Also, the third bottom cutting edge 46 may be orthogonal to the rotation axis S. The fourth bottom cutting edge 54 is inclined with respect to the radial direction so as to approach the rear end 12b of the main body 12 as it approaches the rotation axis S. As shown in FIG. Here, the radially outer end of the fourth bottom cutting edge 54 may be further from the rear end 12 b of the main body 12 than the radially outer end of the third bottom cutting edge 46 . In such a case, the fourth bottom cutting edge 54, which is the main cutting edge, is likely to stably come into contact with the work material. Moreover, since the cutting load applied to the third bottom cutting edge 46, which is a child cutting edge, is suppressed, the durability of the third bottom cutting edge 46 can be enhanced.

The radially outer end of the third end cutting edge 46 may be located at the same position in the direction along the rotation axis S as the radially outer end of the first end cutting edge 30 . In this case, the variation between the cutting load applied to the first end cutting edge 30 and the cutting load applied to the third end cutting edge 46 can be kept small. Therefore, the durability of the plurality of bottom cutting edges 18 as a whole is high. In addition, the radially outer end of the fourth bottom cutting edge 54 may be located at the same position in the direction along the rotation axis S as the radially outer end of the second bottom cutting edge 38 . In this case, the variation between the cutting load applied to the second end cutting edge 38 and the cutting load applied to the fourth end cutting edge 54 can be kept small. Therefore, the durability of the plurality of bottom cutting edges 18 as a whole is high.

The inclination angle of the first end cutting edge 30 with respect to the rotation axis S when the first end cutting edge 30 is viewed from the side is defined as a first watermark angle β1, and the second bottom cutting edge 38 is viewed from the side with respect to the rotation axis S. The inclination angle of the blade 38 is defined as a second watermark angle β2. The inclination angle of the third end cutting edge 46 with respect to the rotation axis S when the third end cutting edge 46 is viewed from the side is defined as a third watermark angle β3, and the fourth bottom cutting edge 46 with respect to the rotation axis S when the fourth end cutting edge 54 is viewed from the side. The inclination angle of the blade 54 is defined as a fourth watermark angle β4.

At this time, the first watermark angle β1 may be set smaller than the second watermark angle β2. In this case, the second bottom cutting edge 38 can be used as a so-called major cutting edge, and the first bottom cutting edge 30 can be used as a so-called wiper edge. When the first watermark angle β1 of the first end cutting edge 30 is relatively small, the inclination angle of the first end cutting edge 30 with respect to the machined surface of the workpiece is small. Therefore, the first bottom cutting edge 30 can be used as a wiper cutting edge.

For example, as described above, when the first rake angle α1 is larger than the second rake angle α2, the function of the first bottom cutting edge 30 as a wiper cutting edge is improved. Further, as described above, when the radially outer end of the second end cutting edge 38 is farther from the rear end 12b of the main body 12 than the radially outer end of the first end cutting edge 30 is, the second end cutting edge 38 Since the cutting load applied to the first end cutting edge 30 is suppressed compared to the end cutting edge 38, the first end cutting edge 30 is less likely to be damaged. Therefore, even when the first end cutting edge 30 is used as a wiper cutting edge, the first end cutting edge 30 is less likely to be damaged.
good too.

The third watermark angle β3 may be set equal to the first watermark angle β1, and the fourth watermark angle β4 may be set equal to the second watermark angle β2. Making the two watermark angles the same means that the difference between the two watermark angles is within 1 degree. When the watermark angle is set in this manner, the third bottom cutting edge 46 can be used as a so-called major cutting edge, and the fourth bottom cutting edge 54 can be used as a so-called wiper edge. Furthermore, variations in the cutting load applied to the first end cutting edge 30 and the third end cutting edge 46 used as wiper edges are small. In addition, variations in the cutting load applied to the second bottom cutting edge 38 and the fourth bottom cutting edge 54 used as major cutting edges are small. Therefore, the durability of the plurality of bottom cutting edges 18 as a whole is high.

As shown in FIG. 3, a thinning surface 62 is positioned on the rake surface 40 side of the second bottom cutting edge 38, and the thinning surface 62 has a diameter that approaches the rear end 12b of the main body 12 as it approaches the outer peripheral side. It is slanted with respect to the direction. A thinning surface 64 is positioned on the rake surface 56 side of the fourth bottom cutting edge 54, and the thinning surface 64 is inclined with respect to the radial direction so as to approach the rear end 12b of the main body 12 as it approaches the outer peripheral side. there is As a result, the core thickness of the end mill 10 can be increased while securing a space for the chips generated by the second end cutting edge 38 and the fourth end cutting edge 54 to flow.

As described above, the second split angle θ2 may be set larger than the first split angle θ1, and the third split angle θ3 may be set equal to the first split angle θ1. The first watermark angle β1 may be set smaller than the second watermark angle β2, and the third watermark angle β3 may be set equal to the first watermark angle β1. The first rake angle α1 may be set larger than the second rake angle α2, and the third rake angle may be set larger than the fourth rake angle. When the split angle and the watermark angle are set in this way, the cutting load applied to the first end cutting edge 30 and the third end cutting edge 46 during cutting of the work material W, the second end cutting edge 38 and the The durability of the end mill 10 can be enhanced by suppressing variations in the cutting load applied to the four bottom cutting edges 54 . In particular, the first rake angle α1 may be set to be greater than the second rake angle α2, and the third rake angle is set to be greater than the fourth rake angle, so that the aforementioned effects can be enhanced. .

<Modification 1 of the embodiment of the present disclosure>
A configuration of Modification 1 of the present embodiment will be described with reference to FIG. FIG. 8 is a partial side view of an end mill according to Modification 1 of the embodiment.

As shown in FIG. 8, in Modification 1 of the present embodiment, the second end cutting edge 38 includes an outer portion (first portion) 38e positioned radially outward and an inner portion (first portion) 38e positioned radially inward. 2 parts) 38i. When the second end cutting edge 38 is viewed from the side, the inclination angle of the outer portion 38e with respect to the rotation axis S is defined as an outer second watermark angle β2e, and the inclination angle of the inner portion 38i with respect to the rotation axis S is defined as an inner second watermark angle β2i. and

At this time, the inner second watermark angle β2i may be set larger than the outer second watermark angle β2e. A larger cutting load is likely to be applied to the outer portion 38e than to the inner portion 38i. However, when the outer second watermark angle β2e is set larger than the inner second watermark angle β2i, the durability of the outer portion 38e can be enhanced. Furthermore, since the inner second watermark angle β2i is larger than the outer second watermark angle β2e, it is easy to avoid an excessively large overall cutting load applied to the second end cutting edge 38 .

At least a portion of the outer portion 38 e of the second end cutting edge 38 may be further from the rear end 12 b of the main body 12 than the radially outer end of the first end cutting edge 30 . In this case, since the cutting load applied to the first end cutting edge 30, which is a child cutting edge, is suppressed, the durability of the first end cutting edge 30 can be enhanced. Here, at least a portion of the inner portion 38i of the second end cutting edge 38 may be closer to the rear end 12b of the main body than the radially inner end of the first end cutting edge 30 . In this case, excessive variation in the cutting load applied to the first end cutting edge 30 and the cutting load applied to the second end cutting edge 38 can be avoided.

The fourth bottom cutting edge 54 has an outer portion 54e positioned radially outward and an inner portion 54i positioned radially inward. At least part of the outer portion 54e of the fourth bottom cutting edge 54 may be further away from the rear end 12b of the main body 12 than the radially outer end of the first bottom cutting edge 30 as the first cutting edge. When the fourth bottom cutting edge 54 is viewed from the side, the inclination angle of the outer portion 54e with respect to the rotation axis S is defined as an outer fourth watermark angle β4e, and the inclination angle of the inner portion 54i with respect to the rotation axis S is defined as an inner fourth watermark angle β4i. and

At this time, the inner fourth watermark angle β4i may be set larger than the outer fourth watermark angle β4e. A larger cutting load is likely to be applied to the outer portion 54e than to the inner portion 54i. However, if the outer fourth watermark angle β4e is set larger than the inner fourth watermark angle β4i, the durability of the outer portion 54e can be enhanced. Furthermore, since the inner fourth watermark angle β4i is larger than the outer second watermark angle β4e, it is easy to avoid an excessively large overall cutting load applied to the fourth bottom cutting edge 54 .

At least a portion of the inner portion 54i of the fourth end cutting edge 54 may be closer to the rear end 12b of the body than the radially inner end of the first end cutting edge 30 . In this case, excessive variation in the cutting load applied to the first end cutting edge 30 and the cutting load applied to the fourth end cutting edge 54 can be avoided.

<Modification 2 of the embodiment of the present disclosure>
Modification 2 of the embodiment of the present disclosure will be described with reference to FIG. FIG. 9 is a partial side view of an end mill according to Modification 2 of the embodiment.

As shown in FIG. 9 , in Modification 2 of the present embodiment, the radially outer end of the second bottom cutting edge 38 as the second cutting edge is located farther from the radially outer end of the first bottom cutting edge 30 . may also be near the rear end 12b of the body 12. The radially outer end of the fourth end cutting edge 54 may be closer to the rear end 12 b of the body 12 than the radially outer end of the first end cutting edge 30 . In this case, the machined surface of the workpiece is likely to be formed by the second end cutting edge 38 and/or the fourth end cutting edge 54 . Therefore, the surface quality of the machined surface can be improved. This modified example is effective when it is required to produce a machined product with good surface quality.

<Modification 3 of the embodiment of the present disclosure>
Modification 3 of the embodiment of the present disclosure will be described with reference to FIG. FIG. 10 is a partial side view of an end mill according to Modification 3 of the embodiment.

As shown in FIG. 10, in Modification 3 of the present embodiment, the third split angle θ3 may be set smaller than the first split angle θ1. In this way, when the third split angle θ3 is different from the first split angle θ1, chatter vibration can be suppressed. The third bottom cutting edge 46 is inclined with respect to the radial direction so as to approach the rear end 12b of the main body 12 as it approaches the rotation axis. The first watermark angle β1 may be set smaller than the third watermark angle β3. When the watermark angle is set in this manner, the surface quality of the machined surface can be improved.

<Manufacturing method of machined product according to embodiment of the present disclosure>
A method for manufacturing a machined product according to an embodiment of the present disclosure will be described with reference to FIGS. 11 to 14. FIG. 11 to 14 are schematic diagrams for explaining the method for manufacturing a cut product according to the embodiment.

As shown in FIGS. 11 to 14, the method for manufacturing a cut product according to the present embodiment is a method for manufacturing a cut product M, which is a work material W that has been machined. , a second step, and a third step. The first step is a step of rotating the end mill 10 as a rotary tool. The second step is the step of bringing the rotating end mill 10 into contact with the workpiece W. As shown in FIG. The third step is the step of separating the end mill 10 from the workpiece W. As shown in FIG. The specific details of the method for manufacturing a cut product according to this embodiment are as follows.

As shown in FIGS. 11 and 12, the end mill 10 is rotated in the rotation direction T of the rotation shaft S and moved in the direction of the arrow D1 to approach the workpiece W. As shown in FIGS. Next, as shown in FIG. 13, the rotating end mill 10 is moved in the direction of arrow D2 while being brought into contact with the work W. As shown in FIG. As a result, the work material W is cut (rolled), and the side machining surfaces Ws are formed on the work material W by the plurality of peripheral cutting edges 24 , and the work material W is cut by the plurality of bottom cutting edges 18 . A bottom machined surface Wf is formed on W.

After that, as shown in FIG. 14, the end mill 10 is moved in the direction of the arrow D3 and separated from the work material W. Then, as shown in FIG. As a result, the cutting of the work material W is completed, and the machined product M, which is the work material W that has been cut, can be manufactured. Since the end mill 10 has excellent cutting ability for the reason described above, it is possible to manufacture a machined workpiece M with excellent machining accuracy.

In order to continue cutting, the end mill 10 may be repeatedly brought into contact with different portions of the workpiece W while the end mill 10 is being rotated. In this embodiment, the end mill 10 is brought closer to the work W, but the work W may be brought closer to the end mill 10, for example, because the end mill 10 and the work W should be brought relatively close to each other. In this respect, when the end mill 10 is separated from the work material W, the same is true.

The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to each embodiment described above. That is, the invention according to the present disclosure can be variously modified within the scope shown in the present disclosure, and the embodiments obtained by appropriately combining the technical means disclosed in different embodiments can also be applied to the invention according to the present disclosure. Included in the technical scope. In other words, it should be noted that a person skilled in the art can easily make various variations or modifications based on this disclosure. Also, note that these variations or modifications are included within the scope of this disclosure.

10 end mill (rotary tool)
12 main body 12a tip (first end)
12b rear end (second end)
14 cutting part 16 shank part 18 bottom edge (cutting edge)
20 Chisel edge 22 Ejection groove 24 Peripheral edge (cutting edge)
30 first bottom edge (first cutting edge, child edge)
38 Second bottom edge (second cutting edge, main edge)
38e outer part (first part)
38i medial site (second site)
46 Third bottom edge (third cutting edge, child edge)
54 4th bottom edge (4th cutting edge, parent edge)
54e outer part (first part)
54i medial site (second site)
S Rotational axis T Direction of rotation θ1 1st split angle θ2 2nd split angle θ3 3rd split angle α1 1st rake angle α2 2nd rake angle β1 1st watermark angle β2 2nd watermark angle β2e Outer 2nd watermark angle β2i 2nd inner watermark angle β3 3rd watermark angle β4 4th watermark angle β4e 4th outer watermark angle β4i 4th inner watermark angle W Work material Wf Bottom machined surface Ws Side machined surface M Machined product

Claims (11)

A cylindrical body extending along a rotation axis from a first end toward a second end and having a cutting portion on the first end side,
The cutting part is
a plurality of cutting edges located on the first end side of the body;
a plurality of discharge grooves each extending from the plurality of cutting edges toward a second end of the body;
The plurality of cutting edges are
a first cutting edge extending from the outer peripheral side toward the rotating shaft;
a second cutting edge located in front of the first cutting edge in the direction of rotation of the rotating shaft and extending from the outer peripheral side toward the rotating shaft;
a third cutting edge located in front of the second cutting edge in the direction of rotation of the rotating shaft and extending from the outer peripheral side toward the rotating shaft;
A dividing angle between the first cutting edge and the second cutting edge when viewed from the front toward the first end of the main body is defined as a first dividing angle, and the second cutting edge and the third cutting edge When the dividing angle between and is set as a second dividing angle, the second dividing angle is set larger than the first dividing angle,
The first cutting edge is orthogonal to the rotation axis or inclined with respect to the radial direction so as to approach the second end of the main body as it approaches the rotation axis,
The second cutting edge is inclined with respect to the radial direction so as to approach the first end of the main body as it approaches the rotating shaft,
The inclination angle of the first cutting edge with respect to the rotation axis when the first cutting edge is viewed from the side is defined as a first watermark angle, and the second cutting edge with respect to the rotation axis when the second cutting edge is viewed from the side. A rotary tool, wherein the first watermark angle is set smaller than the second watermark angle when the inclination angle of the blade is the second watermark angle. The cutting part is
a chisel edge located at a first end of the body and passing through the axis of rotation;
The second cutting edge is a parent edge extending to the chisel edge,
2. The rotary tool according to claim 1, wherein said first cutting edge and said third cutting edge are child edges each extending to a position separated from said chisel edge. 3. The rotary tool of claim 2, wherein the radially outer end of the second cutting edge is further from the second end of the body than the radially outer end of the first cutting edge. The second cutting edge is
a first portion positioned radially outward;
a second portion positioned radially inward;
When the second cutting edge is viewed from the side, the inclination angle of the first portion with respect to the rotation axis is defined as an outer second watermark angle, and the inclination angle of the second portion with respect to the rotation axis is defined as an inner second watermark angle. 4. The rotary tool according to claim 3, wherein said inner second watermark angle is set larger than said outer second watermark angle when . at least part of the first portion is further from the second end of the main body than the radially outer end of the first cutting edge;
5. The rotary tool according to claim 4, wherein at least a portion of the second portion is closer to the second end of the body than the radially inner end of the first cutting edge. 3. The rotary tool of claim 2, wherein the radially outer end of the second cutting edge is closer to the second end of the body than the radially outer end of the first cutting edge. 3. The radially outer end of the second cutting edge according to claim 2, located at the same position as the radially outer end of the first cutting edge in the direction along the rotation axis. rotary tool. When the rake angle of the first cutting edge is defined as a first rake angle and the rake angle of the second cutting edge is defined as a second rake angle, the first rake angle is set larger than the second rake angle. A rotary tool according to any one of claims 1 to 7, wherein The plurality of cutting edges are
further comprising a fourth cutting edge located in front of the third cutting edge in the direction of rotation of the rotating shaft and extending from the outer peripheral side toward the rotating shaft;
When the dividing angle between the third cutting edge and the fourth cutting edge when viewed from the front toward the first end of the main body is defined as a third dividing angle, the third dividing angle is equal to the first dividing angle. is set smaller than the splitting angle,
The third cutting edge is inclined with respect to the radial direction so as to approach the second end of the main body as it approaches the rotation axis,
The first watermark angle is smaller than the third watermark angle when the inclination angle of the third cutting edge with respect to the rotation axis when the third cutting edge is viewed from the side is defined as a third watermark angle. A rotary tool as set forth in any one of claims 2 to 8. The plurality of cutting edges are
further comprising a fourth cutting edge located in front of the third cutting edge in the direction of rotation of the rotating shaft and extending from the outer peripheral side toward the rotating shaft;
When the dividing angle between the third cutting edge and the fourth cutting edge when viewed from the front toward the first end of the main body is the third dividing angle, the third dividing angle is equal to the first dividing angle. is set equal to the splitting angle,
The third cutting edge is orthogonal to the rotation axis or inclined with respect to the radial direction so as to approach the second end of the main body as it approaches the rotation axis,
When the inclination angle of the third cutting edge with respect to the rotation axis when the third cutting edge is viewed from the side is defined as a third watermark angle, the third watermark angle is the same as the first watermark angle. A rotary tool as set forth in any one of claims 2 to 8. A step of rotating the rotary tool according to any one of claims 1 to 10;
contacting the rotating rotary tool with a work material;
and separating the rotary tool from the work material.

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