JP2020116707A - Blade edge replaceable end mill - Google Patents

Abstract

To suppress force in a direction of thrust force by which the material to be cut is pulled up toward a rear end side of an end mill main body during cutting processing from acting on the material to be cut.SOLUTION: An outer peripheral cutting insert 10A is detachably attached to an outer peripheral insert attachment seat 4 formed at an outer periphery of a tip part of an end mill main body 1 that is rotated around a shaft line O and a tip cutting insert 10B is detachably attached to a tip insert attachment seat 5 formed on an apical surface of the end mill main body 1. The tip cutting insert 10B has a main cutting blade 14 as a bottom blade protruded to the tip side of the end mill main body 1, and the outer peripheral cutting insert 10A has a main cutting blade 14 as an outer peripheral blade protruded toward the outer periphery side of the end mill main body 1, where a rake angle in a positive shaft direction is formed in the bottom blade and a rake angle in a negative shaft direction is formed in the outer peripheral blade.SELECTED DRAWING: Figure 3

Description

INDUSTRIAL APPLICABILITY The present invention is such that an outer peripheral cutting insert is removably attached to an outer peripheral insert mounting seat formed on the outer periphery of a tip end portion of an end mill main body that is rotated around an axis, and a tip insert mounting seat formed on a front end surface of an end mill main body. Relates to a replaceable cutting edge end mill to which a tip cutting insert is detachably attached.

As such a cutting edge exchangeable end mill, for example, in Patent Document 1, a first insert pocket (tip insert mounting seat) and a second insert pocket located on the rear end side of the first insert pocket (peripheral insert mounting) are disclosed. And a holder (end mill body) that has a seat) and extends from the front end side toward the rear end side along the rotation axis, and is attached to the first insert pocket and partially protrudes from the front end surface and the outer peripheral surface of the holder. A cutting tool having a first cutting insert (tip cutting insert) and a second cutting insert (peripheral cutting insert) attached to a second insert pocket and partially protruding from the outer peripheral surface of the holder. Therefore, it is described that the axial rake of the first cutting insert is larger than the axial rake of the second cutting insert.

JP, 2016-101613, A

By the way, in the cutting edge exchange type end mill described in Patent Document 1, the axial rake (axial rake angle) of the outer peripheral blade of the first cutting insert is, for example, about 5° to 20°, and the outer periphery of the tip of the end mill body is The axial rake (axial rake angle) of the tip outer peripheral edge of the second cutting insert projected to the side is set to, for example, about 3° to 15°, and all are set to a positive axial rake angle.

However, when the axial rake angle of the first and second cutting inserts, that is, the axial rake angle of the outer peripheral blade is a positive axial rake angle as described above, the work material is cut into the end mill body during cutting. A force in the direction of the back force that acts to pull it up to the rear end side acts on the work material. For this reason, especially when performing a cutting process on a thin work material or a work material for which it is difficult to secure sufficient clamp rigidity, the work material is liable to bend or chatter vibration. However, there is a risk that the processing accuracy will be reduced.

And such a problem is that the main cutting edge, which is the outer peripheral edge of the second cutting insert, has a polygonal surface of the second cutting insert, as in the blade tip exchange type end mill described in Patent Document 1. Among the side faces arranged around it, when the polygonal face is formed at the ridge line intersecting with the long side face having a long circumferential direction, the length of the main cutting edge becomes long, so that Since the force in the force direction also becomes large, it becomes particularly remarkable.

The present invention has been made under such a background, and thus the main cutting edge, which is the outer peripheral blade, intersects with the polygonal surface of the outer peripheral cutting insert and the long side surface arranged around the polygonal surface. Even if the cutting edge length is long, it is possible to suppress the force in the direction of the back force that acts on the work material to pull it up to the rear end side of the end mill body during cutting. It is an object of the present invention to provide a replaceable end mill.

In order to solve the above problems and achieve such an object, the present invention is that an outer peripheral cutting insert is removably attached to an outer peripheral insert mounting seat formed on the outer periphery of a tip end portion of an end mill body rotated about an axis. The tip cutting insert is detachably attached to a tip insert mounting seat formed on the tip surface of the end mill body, and the outer peripheral cutting insert and the tip cutting insert are polygonal plates. A plurality of polygonal surfaces facing each other, and at least one long side surface having a long circumferential length of the polygonal surfaces arranged around these polygonal surfaces and the long side surface. The polygonal surface has two short side surfaces which are shorter than the long side surface and which are shorter than the long side surface and face each other, and a main cutting edge is provided at a ridge portion where the polygonal surface and the long side surface intersect with each other. While being formed, a sub-cutting edge that is continuous with the main cutting edge is formed at an intersecting ridge line portion between the long side surface and the short side surface, and the tip cutting insert uses the one polygonal surface as a tip flank surface. The main cutting edge formed at the intersection ridge of one of these polygonal surfaces and the long side surface is directed to the tip side of the end mill body and one of the long side surfaces as the rake surface in the end mill rotation direction. While projecting to the tip side of the end mill body as a blade, the auxiliary cutting edge connected to the outer peripheral side end of the end mill body of the bottom blade is projected to the outer peripheral side of the end mill body as a tip outer peripheral blade, The cutting insert directs one of the polygonal surfaces as an outer peripheral flank toward the outer peripheral side of the end mill main body and one of the long side surfaces as a rake surface in the end mill rotation direction. The main cutting edge formed on the ridge portion intersecting with the side surface is used as an outer peripheral blade, and the rotation locus around the axis is on the rear end side of the end mill body rather than the outer peripheral side end portion of the bottom blade of the tip cutting insert. It is projected to the outer peripheral side of the end mill body so as to be continuous with the tip outer peripheral blade, and the bottom blade is given a positive axial rake angle, and the outer peripheral blade is provided with a negative axial rake angle. Is given.

In the cutting edge replaceable end mill configured as described above, the bottom edge of the tip cutting insert is given a positive axial rake angle, while the outer edge of the peripheral cutting insert has a negative axial rake angle. In the case of the peripheral cutting insert that is given, and the main cutting edge formed on the ridge line intersecting the polygonal surface and the long side is the peripheral cutting edge, the work material is pulled up to the rear end side of the end mill body during cutting. The force in the direction opposite to the direction in which the back force force tends to press the work material against the tip side of the end mill body acts instead of the force in the back force direction.

Therefore, even if the bottom edge of the tip cutting insert is given a positive rake angle in the axial direction, the outer peripheral edge of the outer peripheral cutting insert can suppress the force in the direction of the spine component, and the work material can be end milled during cutting. It is possible to reduce the force of pulling up to the rear end side of the main body. Therefore, even when cutting a thin work material or a work material for which it is difficult to secure sufficient clamp rigidity, it is possible to avoid bending or chattering vibration of the work material. Therefore, it is possible to prevent the deterioration of the processing accuracy.

Here, at least the outer peripheral cutting insert is in the shape of a parallelogram plate, is formed in a reverse symmetrical shape with respect to the two parallelogram surfaces, and has an insert center line connecting the centers of these two parallelogram surfaces. Is formed in 180° rotational symmetry with respect to the outer peripheral surface of the end mill body, and one obtuse corner portion of the parallelogram surface is located on the tip end side of the end mill body on the end mill rotation direction side. It is desirable that they are attached.

The outer peripheral cutting insert can be used as an eccentric pentagonal plate-shaped cutting insert as described in Patent Document 1, but as the parallelogram plate-shaped cutting insert as described above, it is provided on the outer peripheral side of the end mill body. By positioning the obtuse angled corner portion of one parallelogram face facing the end mill rotation direction side at the tip end side of the end mill body, it is possible to mount the end mill body without overwhelming it and It is efficient and economical to use the four main cutting edges formed at the ridge portion where the parallelogram surface and the long side surface intersect each other.

Further, it is desirable that the peripheral cutting insert and the tip cutting insert are cutting inserts of the same shape and size. As a result, the outer peripheral cutting insert and the tip cutting insert can be made common, and the management of the cutting insert becomes easy. Further, when these cutting inserts are formed in a parallelogram plate shape as described above, even in the tip cutting insert, one cutting insert is used for each two ridges of the parallelogram surface and the long side surface. It is possible to use the four formed main cutting edges as the bottom blade, which is more efficient and economical. However, when a convex curved corner edge is formed at the corner portion where the main cutting edge and the sub cutting edge intersect, the outer peripheral cutting insert and the tip cutting insert are the radius of the corner edge. The cutting inserts having the same shape and the same size may be used except that they are different.

Further, on the outer periphery of the end portion of the end mill main body, a plurality of the outer peripheral cutting inserts, which are adjacent to each other in the axial direction, make the rotation trajectory of the outer peripheral blade around the axis line continuous, and the rear end of the end mill main body. It is desirable that the end mills are arranged and attached so as to face the rotation direction of the end mill. As a result, it is possible to cope with a case where a cutting process with a large cutting amount by the outer peripheral blade is performed while suppressing the force acting in the direction of the back force.

As described above, according to the present invention, even when the main cutting edge, which is the outer peripheral blade, is formed at the intersecting ridge line portion between the polygonal surface and the long side surface of the outer peripheral cutting insert, the work material during the cutting process. Can reduce the force in the direction of the back force that tries to lift the tool toward the rear end of the end mill body, and is suitable for work materials with thin wall thickness and work materials for which it is difficult to secure sufficient clamp rigidity. However, since it is possible to prevent the work material from bending and chattering vibrations, it is possible to prevent a reduction in processing accuracy.

It is a perspective view showing one embodiment of the present invention. It is the bottom view which looked at the embodiment shown in FIG. 1 from the front end side of the axial direction of the end mill main body. It is a side view of the arrow X direction view in FIG. FIG. 3 is a side view as seen from the direction of the arrow Y in FIG. 2. It is a perspective view of the cutting insert attached to the embodiment shown in FIG. It is the side view which saw the cutting insert shown in FIG. 5 from the direction which opposes a polygonal surface. It is the side view which looked at the cutting insert shown in Drawing 5 from the direction (arrow X direction in Drawing 6) which counters a long side. It is the side view which looked at the cutting insert shown in Drawing 5 from the direction (arrow Y direction in Drawing 6) which counters a short side.

1 to 4 show one embodiment of a cutting edge exchangeable end mill of the present invention, and FIGS. 5 to 8 show a cutting insert attached to the cutting edge exchangeable end mill of this embodiment. In the replaceable blade end mill of the present embodiment, the end mill body 1 is formed of a metal material such as steel into a cylindrical shape centered on the axis O, and has a rear end portion (upper right side portion in FIG. 1, FIG. 3, FIG. 4). In FIG. 1, the shank portion 2 remains cylindrical and the tip portion (lower left portion in FIG. 1; lower portion in FIGS. 3 and 4) is slightly smaller than the shank portion 2. The cutting edge portion 3 has a small-diameter outer cylindrical shape.

In such a cutting edge exchange type end mill, while the shank portion 2 is gripped by the main shaft of the machine tool and is rotated about the axis O in the end mill rotation direction T, the shank portion 2 is normally fed in a direction perpendicular to the axis O. Then, the outer peripheral cutting insert 10A detachably attached to the outer peripheral insert mounting seat 4 formed on the outer periphery of the cutting edge portion 3 and the tip formed on the tip surface of the end mill body 1 (the tip surface of the cutting edge portion 3). By the tip cutting insert 10B detachably attached to the insert mounting seat 5, cutting work such as grooving and shoulder milling is performed on the work material.

A plurality of (two in the present embodiment) chip discharge grooves 6 are provided on the outer periphery of the cutting edge portion 3 which is the outer periphery of the tip end portion of the end mill main body 1 as the end mill rotates toward the rear end side from the front end surface of the cutting edge portion 3. It is formed at equal intervals in the circumferential direction so as to be twisted in the direction T side. The outer peripheral insert mounting seat 4 is formed so as to be adjacent to and open on the side opposite to the end mill rotation direction T of these chip discharge grooves 6.

These outer peripheral insert mounting seats 4 are provided with a bottom surface 4a facing the outer peripheral side of the end mill main body 1, a wall surface 4b facing the end mill rotation direction T side, and a wall surface 4c facing the tip side of the end mill main body 1, and on the bottom surface 4a. Has a screw hole (not shown). In the present embodiment, a plurality (five) of outer peripheral insert mounting seats 4 are provided on the side opposite to the end mill rotation direction T of one chip discharge groove 6 as the end mill rotation direction increases toward the rear end side of the end mill body 1. It is formed to be shifted to the T side.

Further, a plurality (two in the present embodiment) of tip chip pockets 7 are circumferentially equidistantly provided on the tip end surface of the cutting edge portion 3 at intervals between the openings of the chip discharge groove 6 in the circumferential direction. Has been formed. The tip insert mounting seat 5 is formed so as to be adjacent to and open on the side opposite to the end mill rotation direction T of the tip chip pockets 7.

These tip insert mounting seats 5 are provided with a bottom surface 5a facing the tip end side of the end mill body 1, a wall surface 5b facing the end mill rotation direction T side, and a wall surface 5c facing the outer circumference side of the end mill body 1, and on the bottom surface 5a. Has a screw hole (not shown). The bottom surface 5a of the tip insert mounting seat 5 is inclined toward the tip side of the end mill body 1 as it goes toward the end mill rotation direction T.

In the present embodiment, the outer peripheral cutting insert 10A and the front cutting insert 10B attached to the outer peripheral insert mounting seat 4 and the tip insert mounting seat 5 have the same shape, the same size, and the same material as shown in FIGS. The cutting insert 10 is used. The cutting insert 10 is formed in a polygonal plate shape, specifically, a parallelogram plate shape, from a metal material such as cemented carbide having a hardness higher than that of the end mill main body 1, and has two pieces facing opposite sides. A polygonal surface (parallelogram surface) 11, two long side surfaces 12 arranged around the polygonal surface 11 and connected to two long sides of the polygonal surface 11 and facing opposite sides, and the polygonal surface 11 And two short side surfaces 13 that are opposite to each other and that are continuous with the two short sides.

However, the two polygonal surfaces 11 are rotationally symmetrical with respect to the insert center line C passing through the centers of the polygonal surfaces 11 by 180°, and are also symmetrical with respect to the front and back sides with respect to the two polygonal surfaces 11. That is, as shown in FIG. 6, when viewed from the direction facing one polygonal surface (parallelogram surface) 11 in the insert center line C direction, the acute angle of this one polygonal surface (parallelogram surface) 11 The obtuse corner portion B of the other polygonal surface (parallelogram surface) 11 is arranged on the opposite side of the corner portion A, and the other is provided on the opposite side of the obtuse corner portion B of one polygonal surface (parallelogram surface) 11. An acute-angled corner portion A of the polygonal surface (parallelogram surface) 11 of is arranged.

A main cutting edge 14 having the long side surface 12 as a rake surface is formed at an intersecting ridge line portion between the two polygonal surfaces 11 and the long side surface 12, and at the intersecting ridge line portion between the long side surface 12 and the short side surface 13. Sub cutting edges 15 are formed so as to be continuous with both ends of the main cutting edge 14. A convex curved corner edge such as a quarter convex arc is formed at the corner portion where the main cutting edge 14 and the sub cutting edge 15 intersect. It should be noted that the long side surface 12 is formed around the main cutting edge 14 and the sub cutting edge 15 so as to incline so as to be recessed toward the inside away from the main cutting edge 14 and the sub cutting edge 15.

Further, the cutting insert 10 is formed with a mounting hole 16 penetrating the cutting insert 10 with the insert center line C as the center, and opens at the center of the two polygonal surfaces 11. Further, on the long side surface 12, a convex portion 17 having a cylindrical surface that is coaxial with the mounting hole 16 is provided over the main cutting edge 14 over the concave portion inside the main cutting edge 14. It is formed at a height that is not present, and the long side surface 12 of the portion except the convex portion 17, the main cutting edge 14 and the sub cutting edge 15 which are recessed and inclined is flat.

In the cutting insert 10 as described above, as the tip cutting insert 10B, one polygonal surface 11 is used as a tip clearance surface toward the tip side of the end mill body 1, and the polygonal surface opposite to the one polygonal surface 11 is used. The surface 11 is brought into close contact with the bottom surface 5a of the tip insert mounting seat 5, one long side surface 12 is directed in the end mill rotation direction T, and the long side surface 12 opposite to the one long side surface 12 is attached to the tip insert mounting seat 5. Of the end mill in the end mill rotation direction T side, and one short side surface 13 is directed toward the outer peripheral side of the end mill body 1, and the short side surface 13 opposite to the one short side surface 13 is attached to the tip insert. The clamp screw 18 that is seated on the tip insert mounting seat 5 by being brought into contact with the wall surface 5c of the seat 5 that faces the outer peripheral side of the end mill body 1 and is inserted into the mounting hole 16 is screwed into the screw hole of the bottom surface 5a to be attached and detached. Can be attached.

In the tip cutting insert 10B thus mounted on the tip insert mounting seat 5, it is formed at the intersection ridge of the polygonal surface 11 directed toward the tip side of the end mill body 1 and the long side surface 12 directed in the end mill rotation direction T. The main cutting edge 14 formed as a bottom blade is projected to the tip side of the end mill body 1, and the main cutting edge 14 formed as the bottom blade is attached to the tip side of the end mill body 1 which is the outer peripheral side end portion of the end mill body 1. The auxiliary cutting edge 15 connected to the acute-angled corner portion A of the oriented polygonal surface 11 is projected as a tip outer peripheral blade toward the tip outer peripheral side of the cutting edge portion 3 of the end mill body 1. In addition, the main cutting edge 14 which is a bottom blade is provided with a watermark angle that inclines slightly toward the rear end side toward the inner peripheral side of the end mill body 1.

Since the bottom surface 5a of the tip insert mounting seat 5 inclines toward the tip side of the end mill body 1 as the bottom surface 5a of the tip insert mounting seat 5 moves toward the end mill rotation direction T side, the insert center line C is As it goes toward the rear end side of the end mill main body 1, it is inclined so as to face the T side in the end mill rotation direction, but the portion of the long side surface 12 that is continuous with the main cutting edge 14 and serves as the rake face on the side of the main cutting edge 14 is Since it inclines so as to be recessed as it goes away from the main cutting edge 14 toward the inside of the long side surface 12, the long side surface 12 which is the rake face of the part continuous with the main cutting edge 14 which is the bottom blade of the end mill body 1 It is arranged so as to extend in the direction opposite to the end mill rotation direction T toward the rear end side, whereby a positive axial rake angle is given to the main cutting edge 14 serving as the bottom blade.

In addition, the cutting insert 10 has, as the outer peripheral cutting insert 10A, one polygonal surface 11 as an outer peripheral flank facing the outer peripheral side of the end mill body 1 and a polygonal side opposite to the one polygonal surface 11. The surface 11 is brought into close contact with the bottom surface 4a of the outer peripheral insert mounting seat 4, one long side surface 12 is directed in the end mill rotation direction T, and the long side surface 12 opposite to the one long side surface 12 is mounted on the outer peripheral insert mounting seat 4. Of the end mill in the direction of rotation T of the end mill, and one short side surface 13 is directed toward the tip side of the end mill body 1, and the short side surface 13 opposite to the one short side surface 13 is attached to the outer peripheral insert. The clamp screw 18 that is seated on the outer peripheral insert mounting seat 4 by abutting against the wall surface 4c of the seat 4 that faces the tip side of the end mill body 1 and that is inserted into the mounting hole 16 is screwed into the screw hole of the bottom surface 4a, and thus can be attached and detached. Attached to.

In the outer peripheral cutting insert 10A thus mounted on the outer peripheral insert mounting seat 4, the outer peripheral cutting insert 10A is formed at the intersection ridge portion of the polygonal surface 11 facing the outer peripheral side of the end mill main body 1 and the long side surface 12 facing the end mill rotation direction T. The main cutting edge 14 thus formed is projected as an outer peripheral edge toward the tip side of the end mill body 1. Here, in the outer peripheral cutting insert 10A of the present embodiment in which the polygonal surface 11 is a parallelogram surface, one polygonal surface (parallelogram surface) 11 directed toward the outer peripheral side of the end mill body 1 as an outer peripheral flank 11 is formed. The obtuse-angled corner portion B is positioned on the tip side of the end mill body 1 on the T side in the end mill rotation direction.

The main cutting edge 14, which is the outer peripheral blade of the outer peripheral cutting insert 10A, extends from the obtuse corner B of the one polygonal surface (parallelogram surface) 11 facing the outer peripheral side of the end mill body 1 to the rear end. It is arranged so as to extend toward the side toward the end mill rotation direction T side as shown in FIGS. 3 and 4. Therefore, by this, a negative axial rake angle is given to the main cutting edge 14 which is the outer peripheral blade of the outer peripheral cutting insert 10A.

In addition, the main cutting edge 14 which is the outer peripheral blade of the outer peripheral cutting insert 10</b>A attached to the plurality (five) of outer peripheral insert mounting seats 4 formed adjacent to one chip discharge groove 6 is the end mill body 1. The rotation loci about the axis O are arranged so as to be continuous in the direction of the axis O. Further, among the outer peripheral cutting inserts 10A attached to these outer peripheral insert mounting seats 4, the outer peripheral cutting insert 10A attached to the outer peripheral insert mounting seat 4 formed on the most distal end side of the end mill main body 1 is the outer peripheral blade. The main cutting edge 14 has its obtuse corner portion B, which is the tip thereof, located slightly on the rear end side of the end mill body 1 than the tip of the auxiliary cutting edge 15 which is the tip outer peripheral blade of the tip cutting insert 10B. The auxiliary cutting edge 15 that is the outer peripheral edge and the rotation locus around the axis O are arranged so as to be continuous in the direction of the axis O.

In the replaceable cutting edge end mill configured as described above, the main cutting edge 14 that is the bottom blade of the tip cutting insert 10B is given a positive axial rake angle, while the outer circumference of the outer peripheral cutting insert 10A is The main cutting edge 14, which is a blade, is provided with a negative axial rake angle. For this reason, even if a force in the direction of the back force that acts to pull up the work material to the rear end side of the end mill body 1 acts from the main cutting edge 14 that is the bottom blade of the tip cutting insert 10B during cutting, On the contrary, from the main cutting edge 14 which is the outer peripheral blade of the outer peripheral cutting insert 10A, a force in the direction opposite to the spine force direction in which the work material is pressed against the tip side of the end mill body 1 acts. It will be.

Therefore, by this, it is possible to offset and reduce the force in the direction of the back force component that tends to pull up the work material to the rear end side of the end mill body 1 during cutting. Therefore, when the main cutting edge 14 which is an outer peripheral edge is formed at the ridge line portion where the polygonal surface 11 and the long side surface 12 of the outer peripheral cutting insert 10A intersect and the cutting edge length is long, a thin work piece is cut. Bending or chatter vibration occurs in the work material due to the force in the direction of the back force, even when performing cutting processing such as grooving or shoulder milling on the work material or work material for which it is difficult to secure sufficient clamp rigidity It is possible to prevent the deterioration of the machining accuracy, and it is possible to perform a high-precision cutting process while preventing the machining accuracy from decreasing.

Further, in this embodiment, the cutting insert 10, which is the outer peripheral cutting insert 10A, has a parallelogrammatic plate shape, and is formed in two sides of the parallelogrammic surface (polygonal surface 11) in a reverse symmetrical shape. At the same time, they are formed in 180° rotational symmetry with respect to the insert center line C connecting the centers of these two parallelogrammic surfaces (polygonal surface 11). In this respect, as the outer peripheral cutting insert 10A, it is possible to use, for example, an eccentric pentagonal plate-shaped cutting insert as described in Patent Document 1, but in such an eccentric pentagonal plate-shaped cutting insert. Whereas only one cutting insert can use two main cutting edges, in the present embodiment, one cutting insert 10 has two parallelogram faces (polygonal faces 11) and long side faces 12. Since it is possible to use the four main cutting edges 14 formed on the intersecting ridge portion, it is efficient and economical.

Moreover, in the present embodiment, such a parallelogram plate-shaped cutting insert 10 is used as the outer peripheral cutting insert 10A of one parallelogram surface (polygonal surface 11) directed toward the outer peripheral side of the end mill body 1. The obtuse-angled corner portion B is attached to the tip end side of the end mill body 1 so as to be located on the T side in the end mill rotation direction. Therefore, the wall surface 4c of the outer peripheral insert mounting seat 4 facing the tip side of the end mill body 1 and the short side surface 13 of the outer peripheral cutting insert 10A that abuts on the wall surface 4c are arranged along a plane perpendicular to the axis O of the end mill body 1. By doing so, it is possible to give the above-mentioned negative axial rake angle to the main cutting edge 14 which is the outer peripheral blade, and it is impossible to force the mounting posture of the outer peripheral cutting insert 10A to the end mill body 1. At the same time, the outer peripheral insert mounting seat 4 can be easily formed.

Further, in the present embodiment, the tip cutting insert 10B is the cutting insert 10 having the same shape and size as the outer peripheral cutting insert 10A. Therefore, it becomes possible to make the outer peripheral cutting insert 10A and the tip cutting insert 10B common, and the management of the cutting insert 10 becomes easy. Further, particularly when these cutting inserts 10 are formed in a parallelogrammatic plate shape as described above, even in the tip cutting insert 10B, one cutting insert 10 allows two parallelogrammic surfaces (polygonal surfaces 11). 4) and the long side surface 12 can be used as the bottom blade, the four main cutting edges 14 formed at the intersecting ridge line portion are more efficient and economical. However, the tip cutting insert 10B and the outer peripheral cutting insert 10A have different corner radii at the corners of the main cutting edge 14 and the sub cutting edge 15, and have the same shape except for the radius of this corner edge. It may be a large cutting insert.

Furthermore, in the present embodiment, a plurality of outer peripheral cutting inserts 10A, which are adjacent to each other in the axis O direction, are provided on the outer periphery of the cutting edge portion 3 which is the tip end portion of the end mill main body 1, and the main cutting edge 14 is a peripheral edge blade. The rotation loci about the axis O are continuous, and the end mill body 1 is arranged and attached so as to be directed in the end mill rotation direction T toward the rear end side. Therefore, it is possible to deal with the case where the cutting work with a large cutting amount by the outer peripheral blade is performed while suppressing the force acting in the direction of the back force.

1 End Mill Main Body 2 Shank Part 3 Cutting Edge Part 4 Peripheral Insert Mounting Seat 5 Tip Insert Mounting Seat 6 Chip Discharge Groove 7 Tip Chip Pocket 10 Cutting Insert 10A Peripheral Cutting Insert 10B Tip Cutting Insert 11 Polygonal Surface 12 Long Side 13 Short Side 14 Main cutting edge 15 Secondary cutting edge 16 Mounting hole 17 Convex portion 18 Clamp screw O End mill body 1 axis T End mill rotation direction A A Polygonal surface (parallelogram surface) 11 of cutting insert 10 B Corner of cutting insert 10 Obtuse corner of polygonal surface (parallelogram surface) 11 C Insert center line

Claims (5)

An outer peripheral cutting insert is removably attached to the outer peripheral insert mounting seat formed on the outer periphery of the tip of the end mill body rotated around the axis, and the tip cutting is mounted on the tip insert mounting seat formed on the end face of the end mill body. A replaceable cutting edge end mill with inserts that are detachably attached,
The outer peripheral cutting insert and the tip cutting insert are polygonal plate-shaped, and have two polygonal surfaces facing each other, and the circumferential lengths of the polygonal surfaces arranged around these polygonal surfaces. At least one long side surface and a long side surface connected to the long side surface, and two short side surfaces that face each other and have a circumferential length of the polygonal surface shorter than the long side surface. A main cutting edge is formed at the intersecting ridge line portion with the long side surface, and a sub cutting edge continuous with the main cutting edge is formed at the intersecting ridge line portion between the long side surface and the short side surface,
In the tip cutting insert, one of the polygonal surfaces is directed toward the tip side of the end mill main body as a tip flank, and one of the long side surfaces is directed as a rake surface in the end mill rotation direction. While projecting the main cutting edge formed on the ridge portion intersecting with the long side surface to the tip side of the end mill body as a bottom blade, the sub cutting edge connected to the outer peripheral side end portion of the end mill body of the bottom blade is As the tip outer peripheral blade, it is projected to the outer peripheral side of the end mill body,
The outer peripheral cutting insert is such that one of the polygonal surfaces serves as an outer peripheral flank and faces the outer peripheral side of the end mill body, and one of the long side surfaces serves as a rake surface in the end mill rotation direction. The main cutting edge formed on the ridge line intersecting with the long side surface is the outer peripheral blade, and the rotation locus around the axis is the rear end side of the end mill body rather than the outer peripheral side end portion of the bottom blade of the tip cutting insert. At the tip outer peripheral blade is projected to the outer peripheral side of the end mill body so as to be continuous,
A cutting edge exchangeable end mill, wherein the bottom blade is provided with a positive axial rake angle and the outer peripheral blade is provided with a negative axial rake angle. At least the outer peripheral cutting insert has a parallelogrammatic plate shape, is formed in an inverted symmetrical shape with respect to two parallelogrammic planes, and is 180° with respect to an insert center line connecting the centers of these two parallelogrammic planes. One obtuse corner portion of the parallelogram surface, which is formed in rotational symmetry and is directed to the outer peripheral side of the end mill body as an outer peripheral flank, is attached at the tip end side of the end mill body on the end mill rotating direction side. The cutting edge exchangeable end mill according to claim 1, wherein The cutting edge exchangeable end mill according to claim 1 or 2, wherein the peripheral cutting insert and the tip cutting insert are cutting inserts of the same shape and size. A convex curved corner edge is formed at the corner portion where the main cutting edge and the sub cutting edge intersect, and the outer peripheral cutting insert and the tip cutting insert are different in radius of the corner edge. Is a cutting insert of the same shape and size, and the cutting edge exchangeable end mill according to claim 1 or 2. On the outer periphery of the end portion of the end mill main body, a plurality of the outer peripheral cutting inserts, while adjoining one another in the axial direction to continue the rotation trajectory around the axis of the outer peripheral blade, on the rear end side of the end mill main body. The cutting edge exchangeable end mill according to any one of claims 1 to 4, wherein the end mill exchangeable end mill is arranged and attached so as to face the rotation direction of the end mill.

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