CN115135440A - End mill and method for manufacturing cut product - Google Patents

Abstract

The end mill has a body extending along a rotational axis from a first end to a second end. The main body has: a chisel edge at the first end; a first cutting edge extending from the chisel edge toward the outer periphery; a first flank surface connected to the first cutting edge rearward in the rotational direction of the rotating shaft; a first cutter groove connected to the first cutting edge in front of the rotation direction; and a discharge slot located closer to the second end than the first slot. The first pocket has a bottom, a first wall surface between the bottom and the first cutting edge, and a second wall surface located forward in the rotational direction with respect to the bottom. The first wall extends to a position closer to the second end than the second wall.

Description

End mill and method for manufacturing cut product

Cross reference to related applications

This application claims priority to Japanese patent application No. 2020-033543, filed on 28/2/2020, and the entire disclosure of this prior application is incorporated herein by reference.

Technical Field

The present disclosure relates generally to rotary tools used in rotary cutting machining of a workpiece. Examples of the rotary tool include an end mill. Examples of the end mill include a square end mill and a ball end mill.

Background

As a cutting tool used for rotary cutting of a workpiece, for example, a ball end mill described in japanese patent application laid-open No. 2010-105093 (patent document 1) can be cited. The ball nose end mill described in patent document 1 is an example of an end mill. The end mill described in patent document 1 includes a cutting edge, a first center groove portion, a second center groove portion, and a chip discharge groove. The first central slot portion and the second central slot portion are respectively in a V-shaped slot shape.

In patent document 1, the first and second center groove portions have a V-groove shape. Therefore, at a portion away from the cutting edge, the chip may not pass through the first central groove portion and may be blocked by the first central groove portion.

Disclosure of Invention

An end mill of an undefined aspect of the present disclosure has a body extending along a rotational axis from a first end to a second end. The main body has: a chisel edge at the first end; a first cutting edge and a second cutting edge respectively extending from the chisel edge toward the outer periphery; a first flank surface connected to the first cutting edge rearward in a rotation direction of the rotating shaft; a second flank surface connected to the second cutting edge rearward in a rotation direction of the rotation shaft; a first pocket connected to the first cutting edge in front of the rotation direction; and a discharge slot located closer to the second end than the first slot. The first knife slot has: a bottom; a first wall surface between the bottom and the first cutting edge; and a second wall surface located forward in the rotation direction with respect to the bottom. The first wall surface extends to a position closer to the second end than the second wall surface.

Drawings

Fig. 1 is a perspective view showing an end mill of an undefined embodiment.

Fig. 2 is a plan view of the end mill shown in fig. 1 as viewed from the first end side.

Fig. 3 is a side view of the end mill shown in fig. 2 as viewed from a direction a 1.

Fig. 4 is a side view of the end mill shown in fig. 2 as viewed from a2 direction.

Fig. 5 is a side view of the end mill shown in fig. 2 as viewed from a direction a 3.

Fig. 6 is a side view of the end mill shown in fig. 2 as viewed from a direction a 4.

Fig. 7 is an enlarged view of a region B1 shown in fig. 3.

Fig. 8 is an enlarged view of the same area as that shown in fig. 7.

Fig. 9 is a cross-sectional view of section IX of the end mill shown in fig. 8.

Fig. 10 is a cross-sectional view of the end mill shown in fig. 8 in section X.

Fig. 11 is a cross-sectional view of the XI section of the end mill shown in fig. 8.

Fig. 12 is a sectional view of the XII section of the end mill shown in fig. 8.

Fig. 13 is an enlarged view of a region B2 shown in fig. 5.

Fig. 14 is a schematic view showing one step in the method for producing a machined product according to an embodiment which is not limited to the above.

Fig. 15 is a schematic view showing one step in the method for producing a machined product according to an embodiment which is not limited to the above.

Fig. 16 is a schematic view showing a step in a method for producing a machined product according to an embodiment which is not limited to the above.

Detailed Description

The end mill 1 of the embodiment which is not limited will be described in detail with reference to the drawings. In an embodiment that is not limited, a ball end mill may be shown as an example of the end mill. However, the end mill is not limited to the ball end mill, and may be, for example, a square end mill.

In the drawings referred to below, for convenience of explanation, only main members among members constituting an embodiment which is not limited are shown in a simplified manner. Therefore, the end mill 1 may include any constituent member shown in each drawing which is not referred to in the present specification. The dimensions of the members in the drawings do not faithfully show the actual dimensions of the constituent members and the dimensional ratios of the members. These cases are also the same in the method of manufacturing a machined product described later.

As shown in fig. 1 and the like, the end mill 1 may also have a cylindrical body 3 having a rotation axis R1 and extending from a first end 3a to a second end 3b. In general, the first end 3a is referred to as a "front end" and the second end 3b is referred to as a "rear end".

The end mill 1 in the unconfined example shown in fig. 1 may have a rod-shaped body 3 extending along the rotation axis R1 from the first end 3a to the second end 3b. The body 3 is rotatable in the direction of an arrow R2 about a rotation axis R1 as shown in fig. 1, which is an example of an unconfined case, during cutting of a workpiece for manufacturing a cut product.

In an example shown in fig. 1, which is not limited, the lower left end of the body 3 may be a first end 3a, and the upper right end may be a second end 3b. In an unlimited example shown in fig. 3 to 6, the left end of the main body 3 may be a first end 3a, and the right end may be a second end 3b.

Fig. 3 to 6 are views showing a state in which the end mill 1 shown in fig. 2 is rotated by a predetermined angle in the rotation direction R2. Fig. 3 is a view of the end mill 1 shown in fig. 2 as viewed from a direction a 1. Fig. 4 is a view of the end mill 1 shown in fig. 2 as viewed from a direction a 2. Fig. 4 is a view seen from a direction shifted by 90 ° from fig. 3. Fig. 5 is a view of the end mill 1 shown in fig. 2 as viewed from a direction a 3. Fig. 5 is a view seen from a direction shifted by 90 ° from fig. 4. Fig. 6 is a view of the end mill 1 shown in fig. 2 as viewed from a direction a 4. Fig. 6 is a view seen from a direction shifted by 90 ° from fig. 5.

The body 3 in the non-limited example shown in fig. 1 may be cylindrical. The cylindrical shape means not only a strictly cylindrical shape but also a shape having minute irregularities or curves. The shape of the body 3 is not limited to a cylindrical shape.

The outer diameter D of the body 3 may be set to 4mm to 25mm, for example. When the length of the body 3 in the direction along the rotation axis R1 is L, the relationship between L and D can be set to 4D to 15D, for example. At this time, the outer diameter of the body 3 may be constant or may vary from the first end 3a side to the second end 3b side. For example, the outer diameter of the body 3 may be smaller from the first end 3a side to the second end 3b side.

The body 3 may also have a chisel edge 5, a first cutting edge 7, a second cutting edge 9, a first relief surface 11, a second relief surface 13, a first flute 15, and a first discharge flute 17.

The chisel edge 5 may be located at the first end 3a of the body 3. The chisel edge 5 may also intersect the rotation axis R1. In other words, the chisel edge 5 may include the rotation axis R1 as viewed from the front of the first end 3a in the direction along the rotation axis R1. The front view from the first end 3a in the direction along the rotation axis R1 is also generally referred to as a front end view.

The first cutting edge 7 and the second cutting edge 9 may be located near the first end 3a, respectively, and may also extend from the chisel edge 5 toward the outer periphery, respectively. The first cutting edge 7 may be connected to one end of the chisel edge 5, and the second cutting edge 9 may be connected to the other end of the chisel edge 5. The chisel edge 5, the first cutting edge 7, and the second cutting edge 9 can be used to cut the workpiece.

The first cutting edge 7 and the second cutting edge 9 may be located at positions where the rake face and the flank face (the first flank face 11 and the second flank face 13) intersect. On the other hand, the chisel edge 5 may be located at a position where these flank surfaces 11, 13 intersect. The cutting edge formed by the chisel edge 5, the first cutting edge 7, and the second cutting edge 9 may have a shape rotationally symmetrical at 180 ° about the rotation axis R1 when viewed from the tip.

In the case where the end mill 1 is a ball end mill as an unconfined example shown in fig. 1, the first cutting edge 7 and the second cutting edge 9 may have a convex curved shape as viewed from the side as shown in fig. 3 and the like. As described above, when the end mill 1 is a square end mill, the first cutting edge 7 and the second cutting edge 9 may have a linear shape extending in a direction perpendicular to the rotation axis R1.

The first flank surface 11 may be connected to the first cutting edge 7 rearward of the rotation axis R1 in the rotation direction R2. The first flank surface 11 may be a flat surface or a curved surface. When the first flank surface 11 is a flat surface, the first flank surface 11 may be formed of 1 flat surface, or may be formed of a plurality of flat surfaces.

The second relief surface 13 may be connected to the second cutting edge 9 rearward of the rotation axis R1 in the rotation direction R2. The second flank surface 13 may be a flat surface or a curved surface, as in the first flank surface 11. When the second flank 13 is a flat surface, the second flank 13 may be constituted by 1 flat surface, or may be constituted by a plurality of flat surfaces.

The first cutting edge 7 may also be connected to the first cutting flute 15 in front of the direction of rotation R2. That is, the first cutting edge 7 may be located at a position where the first flank surface 11 intersects the first insert groove 15. The first pocket 15 may also have a function of improving the strength of the first cutting edge 7.

The first blade groove 15 may also extend from the outer peripheral surface of the main body 3 substantially toward the rotation axis R1. At this time, the first notch 15 may be closer to the first end 3a as going toward the rotation axis R1. As an example not limited to the example shown in the drawing, the first sipe 15 may have a V-groove shape, and may have a first bottom 19, a first wall surface 21, and a second wall surface 23.

The first wall 21 may also be located between the first bottom 19 and the first cutting edge 7. Here, the first wall surface 21 may be connected to the first cutting edge 7 in front of the rotation direction R2. In this case, the first wall surface 21 may function as the rake surface. The second wall 23 may also be located in front of the direction of rotation R2 with respect to the first bottom 19. At this time, the second wall surface 23 may also function as a breaker for bending the chip. In other words, the first bottom 19 may be located between the first wall 21 and the second wall 23.

When the first sipe 15 having a V-groove shape is viewed in a cross section orthogonal to the extending direction of the first sipe 15, the first wall surface 21 may be a straight line or a curved line. In the same cross section, the second wall surface 23 may be a straight line or a curved line. Also, in the same cross-section, the first bottom 19 may also be concave curved. In this case, cracks due to the cutting load are less likely to occur in the first bottom portion 19, and therefore the durability of the end mill 1 can be improved.

The first sipe 15 having a V-groove shape may extend straight, or may extend spirally about the rotation axis R1 as shown in fig. 1 as an example which is not limited. The twist angle of the first blade groove 15 when the first blade groove 15 extends spirally is not limited to a specific value, and may be set to, for example, 5 ° to 60 °. In the case where the first slot 15 extends spirally, the first wall surface 21 and the second wall surface 23 may also be curved surfaces, respectively, and are represented by straight lines in the above-described cross section.

The first discharge slot 17 may be located closer to the second end 3b than the first slot 15. The first discharge flute 17 may have a function of sending out chips generated by the first cutting edge 7 toward the second end 3b and discharging the chips to the outside. The first discharge groove 17 extends toward the second end 3b, but need not extend to the second end 3b, and may be located away from the second end 3b.

The first discharge groove 17 may extend straight toward the second end 3b, or may extend spirally about the rotation axis R1 as shown in fig. 1 as an example which is not limited thereto. The twist angle of the first discharge groove 17 when the first discharge groove 17 extends in a spiral shape is not limited to a specific value, and may be set to, for example, 5 ° to 60 °.

The end mill 1 shown in fig. 1 is not limited to this, and the first pocket 15 and the first discharge groove 17 are right-handed because the end mill 1 is a tool used for right rotation. For example, even if the cutter is used in left rotation and the first insert pocket 15 and the first discharge pocket 17 are left-twisted, there is no problem.

As an example shown in fig. 7, which is not limited, the first wall surface 21 may extend to a position closer to the second end 3b than the second wall surface 23. In this case, the chips flowing on the first wall surface 21 easily advance toward the portion located forward in the rotational direction R2 with respect to the first flute 15 in the region of the first wall surface 21 located closer to the second end 3b than the second wall surface 23. Therefore, the first flutes 15 are less likely to be clogged with chips, and chip discharge performance is high. Examples of the portion located forward of the first sipe 15 in the rotation direction R2 include the first discharge groove 17 and an undefined second sipe 25 described later as shown in fig. 7.

The first wall surface 21 may be connected to the first discharge groove 17, and the second wall surface 23 may be separated from the first discharge groove 17. In this case, the chips flowing on the first flutes 15 easily advance toward the first discharge flutes 17. In addition, as described later, in the case where the main body 3 has the second sipe 25, the chips flowing in the first sipe 15 easily advance toward the second sipe 25 in addition to the first discharge groove 17.

The second wall surface 23 may have a portion where the width W becomes smaller as it approaches the second end 3b. The entire second wall surface 23 may be configured such that the width W decreases as it approaches the second end 3b. In the case where the width W of the second wall surface 23 at a portion located in the vicinity of the first end 3a, in other words, in the vicinity of the cutting edge, is relatively large, the chips can be stably bent at the second wall surface 23.

Also, in the case where the second wall surface 23 has a portion where the width W becomes smaller as approaching the second end 3b, the width W becomes smaller at a portion in the vicinity of the second end 3b in the second wall surface 23. Therefore, the chips can be easily caused to pass over the second wall surface 23 while being stably bent. The width W may be a width in the radial direction of the bar-shaped body 3. The width W may be evaluated in a cross section perpendicular to the rotation axis R1, for example, as shown in fig. 9.

The width W may be continuously reduced at a portion of the second wall surface 23 where the width W becomes smaller as approaching the second end 3b. When the width W is continuously reduced and no edge is present at the upper end of the second wall surface 23, abrasion of the second wall surface 23 is less likely to progress, and a notch is less likely to be formed in the second wall surface 23. Therefore, the end mill 1 can be used stably for a long period of time.

The first pocket 15 may be connected with the second flank surface 13. In this case, chips generated by the chisel edge 5 and the first cutting edge 7 can stably flow into the first pocket 15. Therefore, the chips are less likely to be clogged in the vicinity of the chisel edge 5 and the first cutting edge 7.

At this time, the ridge line L1 where the second flank surface 13 and the second wall surface 23 intersect may have a portion that is inclined rearward in the rotational direction R2 as it goes away from the rotational axis R1 when viewed from the front of the first end 3a, i.e., when viewed from the front end. In this case, the amount of the first chip groove 15 located forward in the direction in which the cutting load is applied to the second cutting edge 9 can be reduced, and the thickness of the portion of the body 3 located forward in the direction in which the cutting load is applied to the second cutting edge 9 can be ensured to be thick. Therefore, the durability against the cutting load applied to the second cutting edge 9 is high.

The body 3 may also have a second sipe 25 in addition to the first sipe 15. The second sipe 25 may be connected to the first sipe 15 in front of the rotation direction R2, as shown in an unconfined example in fig. 7. Here, the first wall surface 21 may be connected to the second sipe 25 at a position closer to the second end 3b than the end of the second wall surface 23 on the second end 3b side.

In this case, the chips flowing on the first wall surface 21 easily advance toward the second pocket 25 located forward in the rotational direction R2 with respect to the first pocket 15 in the region of the first wall surface 21 located closer to the second end 3b than the second wall surface 23.

The first pocket 15 and the second pocket 25 may be portions that are each referred to as a center groove. For example, the first sipe 15 may be positioned as a first central groove and the second sipe 25 may be positioned as a second central groove.

The second sipe 25 may have a V-groove shape, and may also have a second bottom 27, a third wall surface 29, and a fourth wall surface 31. As an unconfined example shown in fig. 7, the third wall surface 29 may be located relatively rearward in the rotation direction R2, the fourth wall surface 31 may be located relatively forward in the rotation direction R2, and the second bottom portion 27 may be located between the third wall surface 29 and the fourth wall surface 31.

Here, the first wall surface 21 in the first pocket 15 may extend to a position closer to the second end 3b than the second wall surface 23, and on the other hand, the third wall surface 29 and the fourth wall surface 31 in the second pocket 25 may extend to a position at the same distance from the second end 3b. Since the second pocket 25 is located forward in the rotational direction R2 with respect to the first pocket 15, the space for the flow of chips is large, and the chips are less likely to be clogged in the second pocket 25 than in the first pocket 15. Therefore, even if the fourth wall surface 31 extends toward the second end 3b to the same extent as the third wall surface 29, the chip is less likely to be clogged, and the chip can be stably bent by the fourth wall surface 31.

The term "the same degree" means that the distance from the second end 3b to the third wall surface 29 is about 95 to 105% of the distance from the second end 3b to the fourth wall surface 31.

The second cutting edge 9 has an inner end portion 9a connected to the chisel edge 5. In the tip end view, a virtual straight line that is orthogonal to the tangent line of the second cutting edge 9 at the inner end portion 9a and passes through the inner end portion 9a is defined as a reference line L3. At this time, the first sipe 15 may be located rearward of the reference line L3 in the rotation direction R2, and the second sipe 25 may intersect the reference line L3.

When the first insert groove 15 is located rearward of the reference line L3 in the rotation direction R2, the thickness of the body 3 can be ensured to be thick at a portion located forward in the direction in which the cutting load is applied to the second cutting edge 9 and at a portion located near the second cutting edge 9. Therefore, the durability against the cutting load applied to the second cutting edge 9 is high.

Even when the second sipe 25 intersects the reference line L3, that is, the second sipe 25 is partially located forward in the direction in which the cutting load is applied to the second cutting edge 9, the durability of the second cutting edge 9 is less affected. This is because the second sipe 25 is located forward in the rotational direction R2 with respect to the first sipe 15. On the other hand, when the second pocket 25 is partially located forward in the direction in which the cutting load is applied to the second cutting edge 9, a space in which chips generated in the first cutting edge 7 flow is largely secured. Therefore, the chip discharge performance is higher.

The angle at which the first pocket 15 intersects the second pocket 25 may also become smaller as the second end 3b is approached. Specifically, in a cross section orthogonal to the rotation axis X1, an angle at which the first sipe 15 intersects with the second sipe 25 is set as an angle θ. The angle θ may also become larger as it approaches the second end 3b.

In the case where the angle θ at which the first pocket 15 intersects with the second pocket 25 at a portion located near the first end 3a in the ridge line L2 at which the first pocket 15 intersects with the second pocket 25 is relatively small, chips can be stably bent in the first pocket 15. In the case where the angle θ at which the first sipe 15 intersects with the second sipe 25 at the portion located in the vicinity of the second end 3b in the ridge line L2 where the first sipe 15 intersects with the second sipe 25 is relatively large, chips can easily be caused to pass over the second wall surface 23.

Therefore, in the case where the angle θ at which the first pocket 15 intersects with the second pocket 25 becomes smaller as approaching the second end 3b, it is possible to stably bend chips and easily flow the chips toward the second pocket 25.

The first sipe 15 may also have a portion smoothly connected to the second sipe 25 on the second end 3b side. As an example shown in fig. 11 and 12, which is not limited, the angle θ of a portion of the ridge line L2 where the first sipe 15 intersects with the second sipe 25, which is located in the vicinity of the second end 3b, is 180 °, that is, the first sipe 15 may also have a portion smoothly connecting with the second sipe 25. In this case, the chips can be more easily caused to flow into the second sipe 25.

The body 3 may also have a third sipe 33, a fourth sipe 35, and a second discharge groove 37.

The third sipe 33 may connect with the second cutting edge 9 in front of the rotation direction R2. That is, the second cutting edge 9 may be located at a position where the second relief surface 13 intersects the third sipe 33. The third sipe 33 may have a function of improving the strength of the second cutting edge 9.

The relationship of the third pocket 33 with respect to the second cutting edge 9 may be the same as the relationship of the first pocket 15 with respect to the first cutting edge 7. That is, the third sipe 33 may have the third bottom 39 as a surface corresponding to the first bottom 19 in the first sipe 15, the fifth wall surface 41 as a surface corresponding to the first wall surface 21 in the first sipe 15, and the sixth wall surface 43 as a surface corresponding to the second wall surface 23 in the first sipe 15.

As an example not limited to the one shown in fig. 13, the fourth sipe 35 may be connected to the third sipe 33 in front of the rotation direction R2. The relationship of the fourth pocket 35 with respect to the second cutting edge 9 may be the same as the relationship of the second pocket 25 with respect to the first cutting edge 7. That is, the fourth sipe 35 may have the fourth bottom 45 as a face equivalent to the second bottom 27 in the second sipe 25, the seventh wall surface 47 as a face equivalent to the third wall surface 29 in the second sipe 25, and the eighth wall surface 49 as a face equivalent to the fourth wall surface 31 in the second sipe 25. Here, the sixth wall surface 43 may be connected to the fourth pocket 35 at a position closer to the second end 3b than the end of the sixth wall surface 43 on the second end 3b side.

Examples of the material of the body 3 include cemented carbide and cermet. Examples of the composition of the cemented carbide include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. Herein, WC, TiC, and TaC are hard particles, and Co is a binder phase. The cermet may be a sintered composite material obtained by compounding a ceramic component with a metal. Specifically, the cermet includes a titanium compound containing titanium carbide (TiC) or titanium nitride (TiN) as a main component.

The surface of the body 3 may be coated with a coating film by a Chemical Vapor Deposition (CVD) method or a Physical Vapor Deposition (PVD) method. Examples of the composition of the coating include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al) ₂ O ₃ ) And the like. The thickness of the coating film may be set to 0.3 μm to 20 μm, for example. The preferable range differs depending on the composition of the coating film.

While the end mill 1 according to the embodiments has been described above by way of example, the present invention is not limited thereto, and any other form may be adopted without departing from the spirit of the present invention.

< method for producing machined product >

Next, a method for manufacturing the machined product 101 according to the embodiment not limited will be described in detail by taking, as an example, a case where the end mill 1 according to the embodiment not limited above is used. The following description will be made with reference to fig. 14 to 16. Fig. 14 to 16 illustrate a step of drilling the workpiece 103 as an example of a method of manufacturing the machined product 101. In fig. 14 to 16, the cut workpiece 101 and the workpiece 103 are viewed in cross section to facilitate visual understanding.

The method for producing the machined product 101 according to the embodiment which is not limited to the above may include the following steps (1) to (3).

(1) The end mill 1 can be rotated in the direction of the arrow R2 about the rotation axis R1, and the end mill 1 can be moved closer to the workpiece 103 in the Y1 direction (see fig. 14).

This step can be performed, for example, by fixing the workpiece 103 to a table of a machine tool to which the end mill 1 is attached, and bringing the end mill 1 close while rotating. In this step, the workpiece 103 may be relatively close to the end mill 1, or the workpiece 103 may be close to the end mill 1.

(2) By bringing the end mill 1 closer to the workpiece 103, the rotating end mill 1 can be brought into contact with a desired position on the surface of the workpiece 103, thereby cutting the workpiece 103 (see fig. 15).

In this step, the chisel edge, the first cutting edge, and the second cutting edge may be brought into contact with desired positions on the surface of the workpiece 103.

(3) The end mill 1 can be moved away from the workpiece 103 in the Y2 direction (see fig. 16).

In this step, as in the step (1) described above, the end mill 1 may be relatively separated from the workpiece 103, and the workpiece 103 may be separated from the end mill 1, for example. As the cutting process, for example, in addition to the hole drilling process shown in fig. 16, a non-through hole drilling process, a grooving process, a milling process, and the like can be given.

Through the above steps, excellent workability can be exhibited.

In the case where the cutting process of the workpiece 103 is performed a plurality of times or more, for example, in the case where a plurality of cutting processes are performed on 1 workpiece 103, the step of bringing the end mill 1 into contact with different portions of the workpiece 103 may be repeated while keeping the end mill 1 in a rotated state.

Description of the reference numerals

End mill

Main body

A first end

Second end

A chisel edge

A first cutting edge

A second cutting edge

Inner end portion

A first flank face

A second flank face

A first knife slot

A first discharge chute

First bottom

First wall surface

A second wall surface

A second knife slot

A second bottom part

A third wall

A fourth wall surface

A third knife groove

35

A second discharge chute

Third bottom

A fifth wall surface

43.. sixth wall surface

45.. fourth bottom

47.. seventh wall

49.. eighth wall surface

Cutting the work

103

R1

R2

Width of W

L1.. ridge (second flank and second wall)

L2.. ridge (first and second knife grooves)

L3

Angle (the angle at which the first and second pockets intersect).

Claims (9)

1. An end mill, wherein,

the end mill has a body extending along an axis of rotation from a first end to a second end,

the main body has:

a chisel edge located at the first end;

a first cutting edge and a second cutting edge respectively extending from the chisel edge toward the outer periphery;

a first flank surface connected to the first cutting edge rearward in a rotation direction of the rotating shaft;

a second flank surface connected to the second cutting edge rearward in a rotation direction of the rotation shaft;

a first pocket connected to the first cutting edge in front of the rotation direction; and

a discharge slot located closer to the second end than the first slot,

the first knife slot has:

a bottom;

a first wall surface between the bottom and the first cutting edge; and

a second wall surface located forward in the rotation direction with respect to the bottom,

the first wall surface extends to a position closer to the second end than the second wall surface.

2. The end mill according to claim 1,

the first wall surface is connected to the discharge groove, and the second wall surface is separated from the discharge groove.

3. The end mill according to claim 1 or 2,

the width of the second wall surface becomes smaller as it approaches the second end.

4. The end mill according to any one of claims 1 to 3,

when the first end is viewed from the front, a ridge line where the second flank surface and the second wall surface intersect is inclined rearward in the rotational direction as being distant from the rotational axis.

5. The end mill according to any one of claims 1 to 4,

the main body further has a second blade groove connected to the first blade groove in front of the rotational direction,

the first wall surface is connected to the second sipe at a position closer to the second end than an end portion on the second end side in the second wall surface.

6. The end mill according to any one of claims 1 to 5,

the main body further has a second blade groove connected to the first blade groove in front of the rotational direction,

the second cutting edge has an inner end connected to the chisel edge,

when the first end is observed in a front view,

an imaginary straight line orthogonal to a tangent line of the second cutting edge at the inner end portion and passing through the inner end portion is a reference line,

the first sipe is located rearward in the rotation direction with respect to the reference line,

the second sipe intersects the reference line.

7. The end mill according to any one of claims 1 to 6,

the main body further has a second blade groove connected to the first blade groove in front of the rotational direction,

the angle at which the first sipe intersects the second sipe becomes larger as the second end is approached.

8. The end mill according to claim 7,

the first sipe has a portion smoothly connected to the second sipe at the second end side.

9. A method for manufacturing a machined product, wherein,

the method for manufacturing the machined product comprises the following steps:

rotating the end mill according to any one of claims 1 to 8;

bringing the rotating end mill into contact with a workpiece; and

and a step of separating the end mill from the workpiece.

Images