WO2016080486A1

WO2016080486A1 - Cutting insert and cutting edge-replaceable rotary cutting tool

Info

Publication number: WO2016080486A1
Application number: PCT/JP2015/082546
Authority: WO
Inventors: 尚則村; 忠広日畑; 智洋村田; 雅史野下
Original assignee: 三菱日立ツール株式会社
Priority date: 2014-11-21
Filing date: 2015-11-19
Publication date: 2016-05-26
Also published as: JP5983901B1; JPWO2016080486A1

Abstract

In this present invention, a side surface section (4) is configured from corner surface portions (13) and intermediate portions (14) each of which being arranged between the corner surface portions. Each corner surface portion (13) is provided with: a first corner side surface part (13a) which intersects at an obtuse angle (α) with a reference plane which is parallel to a middle plane M; and a second corner side surface part (13b) which intersects at an acute angle (β). Each intermediate portion (14) is configured from a side surface formed at a right angle with respect to the reference plane parallel to the middle plane (M). Furthermore, a third corner surface part (13c) which intersects at a right angle with the reference plane parallel to the middle plane (M) may be disposed between the first corner side surface part (13a) and the second corner side surface part (13b) of the corner surface portion.

Description

Cutting insert and cutting edge exchangeable rotary cutting tool

The present invention relates to a double-sided type cutting insert for detachably attaching to a blade-tip-exchange-type rotary cutting tool for performing milling, and a blade-tip-exchange-type rotary cutting tool equipped with this cutting insert. In particular, the present invention is a double-sided cutting insert having a substantially triangular shape in plan view, and is a double-sided cutting insert capable of performing flat cutting and inclined surface cutting on a work material at a high feed rate. About.
This application claims priority on November 21, 2014 based on Japanese Patent Application No. 2014-236067 filed in Japan, the contents of which are incorporated herein by reference.

A cutting insert to be mounted on a cutting edge exchange type rotary cutting tool for milling a work material is expensive because it is manufactured from a hard material such as WC-Co. For this reason, in order to effectively use the region of the cutting edge formed on the ridge line portion where the surface portion (upper surface portion) and the side surface portion of the cutting insert intersect with each other, the shape of the surface portion is changed to a triangular shape (substantially triangular). Including a shape), a polygonal shape such as a quadrangular shape (including a substantially quadrangular shape), or a circular shape, a plurality of cutting edge regions are provided in a ridge line portion where the surface portion and the side surface portion intersect. When one cutting edge region wears, after rotating this cutting insert attached to the blade-tip-replaceable rotary cutting tool, for example, around a clamp screw, the other cutting edge region is unused by remounting it. Used as a cutting edge.

In order to further increase the cutting edge area of the cutting insert, a so-called double-sided (or negative-type) cutting insert has been proposed. Double-sided cutting inserts have a cutting edge at the ridgeline where the front and side surfaces intersect, and the ridgeline where the back (bottom surface) and side surfaces formed opposite to this surface. While being provided, the side surface portion is a cutting insert formed so as to be orthogonal to the front surface portion and the back surface portion.

In this double-sided cutting insert, for example, when one of a plurality of cutting edge regions formed on the ridge line portion of the surface portion wears, the cutting insert is reattached to another unused cutting edge region of the surface portion. Is used as a cutting edge. When the cutting edge of the double-sided type is worn on the entire cutting edge area of the front surface, the front and back of the cutting insert are reversed and remounted on the insert mounting seat of the blade-tip-replaceable rotary cutting tool. It is the cutting insert which uses the some cutting edge area | region currently formed in (3) sequentially like a surface part as a cutting edge.

In such a double-sided type cutting insert, for example, a double-sided type cutting insert having a substantially triangular shape, since three corner portions are provided on the front surface portion and the back surface portion, three cutting edge regions on the front surface portion, Three cutting edge regions can be provided on the back surface, and therefore a total of six cutting edge regions can be provided on one cutting insert. Thereby, in the double-sided type cutting insert which makes a substantially triangular shape, the life of one cutting insert can be extended, and the cost of milling can be reduced. As a configuration example of such a double-sided cutting insert, for example, Japanese Patent Laid-Open No. 2003-275920 has been proposed.
In the following description, the double-sided or negative-type cutting insert described above will be described as “double-sided cutting insert”.

In recent years, high-feed machining is required to improve machining efficiency when performing flat surface milling or rough surface machining for roughing a work material. When performing high-feed machining on a work material using a blade-tip-exchange-type rotary cutting tool equipped with a double-sided cutting insert, the double-sided cutting insert has the following problems.

That is, when high-feed machining is performed, the machining cutting load acting on the cutting edge becomes large, so that the cutting edge is liable to be damaged. Therefore, there is a need for a cutting insert with a measure for improving the strength of the cutting edge.
Furthermore, when high-feed inclined surface machining is performed in the roughing process on the work material, it is necessary to reliably prevent the cutting insert part other than the cutting edge used for the cutting work from interfering with the work material. is there. If this interference occurs during the cutting process, the surface properties of the machined surface of the work material will deteriorate, and the cutting edge used for the cutting process will be damaged.

In order to improve the above-described problems, for example, the following countermeasures have been conventionally taken against double-sided cutting inserts.
First, improve the shape of the cutting edge of the double-sided cutting insert and the shape of the side surface that is the flank corresponding to this cutting edge to increase the strength of the cutting edge and improve the chip resistance of the cutting edge is doing. Secondly, when the inclined surface machining is performed at a high feed rate on the work material, the shape of the side surface portion of the double-sided cutting insert is improved, and other portions than the cutting edge used for the cutting work are the work material. Preventing interference.

A number of inventions with countermeasures have been proposed in the past for the problems to be improved in the double-sided cutting insert in order to carry out the above-described high-feed cutting. For example, the inventions described in Patent Documents 1 to 3 below have been proposed.

Patent Document 1 (Japanese Patent Publication No. 2010-523352) proposes an invention relating to a double-sided cutting insert that has a triangular shape effective for high-speed milling. The cutting insert described in Patent Document 1 includes an upper surface portion and a lower surface portion, a peripheral surface connecting the upper surface portion and the lower surface portion, a portion (ridge line portion) where the upper surface portion and the peripheral surface intersect, an upper surface portion and the periphery Cutting edges are formed at portions where the surfaces intersect (ridge line portions). The cutting edge is located between two vertices (corners) of the triangular shape, and the main cutting edge has a convex shape and the secondary cutting edge has a concave shape in a side view. The blades are connected continuously. When the surface that bisects the cutting insert between the upper surface portion and the lower surface portion of the cutting insert is an intermediate surface (M), the main flank of the main cutting blade is parallel to the intermediate surface (M). The first reference surface (P1) forms an obtuse angle (α) in the insert, and the sub-flank of the sub-cutting blade has a second reference surface (P2) parallel to the intermediate surface (M) and an acute angle in the insert (β). It has a structure to make.

In the cutting insert described in Patent Document 1 having the above-described configuration, the main cutting blade has a convex shape in a side view, thereby exerting an effect of strengthening the main cutting blade and increasing its wedge angle. Is described. In addition, by making the secondary cutting blade concave when viewed from the side, it is effective in removing chips from the secondary cutting blade toward the outer edge of the tool body, and also reducing the wedge angle of the secondary cutting blade Is described.

In Patent Document 2 (Japanese Patent Laid-Open No. 2013-176634), when high-feed machining is performed on a work material, abnormal damage to the main cutting edge can be prevented, and the feed amount can be further increased to improve efficiency. Double-sided cutting inserts that can perform high-feed machining have been proposed. The cutting insert described in Patent Document 2 has a polygonal plate shape, and a main cutting edge is formed at an intersecting ridge line portion where a rake face (upper surface portion, lower surface portion) and a flank surface (side surface portion) intersect, A corner blade is formed in the part. The main cutting edge (5) has a configuration in which a cutting edge (5a) having a convex curve shape and a cutting edge (5b) having a concave curve shape are connected at a contact point (5c) when viewed from the direction facing the rake face. I have. 1 and 2 of the same patent document show an embodiment of a cutting insert having a substantially equilateral triangular plate shape, and an upper surface portion (front surface) and a lower surface portion (back surface) forming a triangular surface are symmetrically reversed. Has been.

The main cutting edge (5) provided in this double-sided cutting insert has the other end of the convex curved cutting edge (5a) connected to one corner blade, and the other end of the concave curved cutting edge (5b). Are connected to the other corner blades, and the main cutting edge (5) has an inverted symmetrical shape with respect to the polygonal surfaces of the upper surface portion and the lower surface portion. Furthermore, the radius of curvature of the concave curve formed by the concave curve-shaped cutting edge (5b) is made larger than the radius of curvature of the convex curve formed by the convex-curved cutting edge (5a), and the convex curve-shaped cutting edge (5a). The clearance angle is larger than the clearance angle of the concave curved cutting edge (5b) on the positive side.

And when attaching the said double-sided type cutting insert to an end mill main body, while making a main cutting edge protrude in the front end side of an end mill main body, a convex curve-shaped cutting edge (5a) is directed from the inner peripheral side of an end mill main body to an outer peripheral side. The concave curved cutting edge (5b) is arranged toward the outer peripheral side of the end mill body. Furthermore, the approximate center part of the convex curve-shaped cutting edge (5a) is the protruding end that protrudes most to the end of the end mill body, and a negative axial rake angle is set for the main cutting edge used for cutting. It is described that a cutting insert is mounted so that a negative radial rake angle is given to the main cutting edge used.

It is described that the effects described in the following (1) to (3) can be exhibited in the cutting insert and the cutting edge exchangeable cutting tool described in Patent Document 2 having the above configuration.

(1) Since the cutting angle of the main cutting edge gradually decreases from the protruding end protruding from the end of the end mill body toward the outer peripheral side of the end mill body, the burden of the main cutting edge particularly at the cutting boundary can be reduced. . Thereby, the strength of the main cutting edge can be ensured, and more efficient high-feed machining can be performed.

(2) In the polygonal surface opposite to the polygonal surface on which the main cutting edge used for cutting is located, the end mill is disposed on the opposite side of the convex cutting edge (5a) of the main cutting edge in the insert thickness direction. The concave curve-shaped cutting edge (5b) directed to the front end side of the main body is positioned, and a sufficient escape amount can be ensured. For this reason, it is not necessary to set the axial rake angle of the main cutting edge used for cutting larger than necessary on the negative angle side, and sharpness can be sharpened to reduce cutting resistance and improve chip dischargeability ( Paragraph (0087)).

(3) Furthermore, since a large escape amount is secured on the opposite side of the convex cutting edge (5a) of the main cutting edge, it is possible to prevent interference between the insert body and the work material when performing ramping. it can.

Patent Document 3 (Japanese Patent Laid-Open No. 2013-107198) proposes an invention relating to a double-sided cutting insert suitable for face milling and oblique feed machining of a work material, and a rolling tool equipped with this cutting insert. Yes.

The cutting insert described in Patent Document 3 includes an upper surface (21), a lower surface (22), a central axis (A) extending perpendicularly through the upper surface (21) and the lower surface (22), and an upper surface. An upper cutting edge (23) extending around (21) and forming at least two upper cutting edge portions (24) each having a length corresponding to the index angle (α) with respect to the central axis (A); A lower cutting edge (25) extending around (22) and forming at least two lower cutting edge portions (26) each having a length corresponding to the index angle (α) with respect to the central axis (A); A double-sided cutting insert (10) having an edge side surface (30) extending around the insert (10). Each upper cutting edge portion (24) is displaced with respect to one of the lower cutting edge portions (26) with a displacement angle (β) with respect to the central axis (A), and this displacement angle (β) is zero. A cutting insert that is larger and smaller than the index angle (α).

Furthermore, the cutting insert described in Patent Document 3 is provided with a transition portion (40) that extends around the edge side surface (30) and forms a groove shape, and has an upper cutting edge portion (24) and a lower cutting edge portion (26). In other words, the flank face of the upper cutting edge portion (24) and the flank face of the lower cutting edge portion (26) are divided (see FIGS. 4 and 5).

In the cutting insert described in Patent Document 3 having the above-described configuration, each upper cutting edge portion (24) has a displacement angle (β) with respect to the central axis (A) with respect to one of the lower cutting edge portions (26). Since it is displaced, it is described that any one of the upper cutting edge portions (24) or any other portion of the cutting insert does not interfere with the work material during the cutting process. .

Japan Special Table of Contents 2010-523352 (A) Japanese Unexamined Patent Publication No. 2013-176834 (A) Japanese Unexamined Patent Publication No. 2013-107198 (A)

In the double-sided cutting insert described in Patent Document 1, the main clearance surface of the main cutting blade has a first reference surface (P1) parallel to the intermediate surface (M) and an obtuse angle (α) in the insert, The sub-flank of the sub-cutting blade is configured to form a second reference surface (P2) parallel to the intermediate surface (M) and an acute angle (β) in the insert, but does not include a corner blade. For this reason, although the intensity | strength of a main cutting blade can be improved, the means to improve the intensity | strength of a corner blade is not disclosed.

The double-sided cutting insert described in Patent Document 2 includes a cutting edge (5a) having a convex curve shape and a cutting edge having a concave curve shape when the main cutting edge (5) is viewed from the direction facing the rake face. (5b) is connected at the contact (5c). When the double-sided cutting insert is mounted on the end mill body, the main cutting edge is projected from the tip side of the end mill body, and the convex cutting edge (5a) is arranged from the inner peripheral side to the outer peripheral side of the end mill main body. is doing. As a result, the cutting angle of the main cutting edge gradually decreases from the protruding end protruding from the tip of the end mill body toward the outer peripheral side of the end mill body. The strength of the cutting edge can be ensured. However, Patent Document 2 does not disclose a measure for improving the clearance angle of the flank of the main cutting edge (5) in order to improve the strength of the main cutting edge (5) of the double-sided cutting insert.

The double-sided cutting insert described in Patent Document 3 is a cutting insert having a configuration that does not interfere with the work material during cutting of an inclined surface, and each upper cutting edge portion (24) One of the cutting edge portions (26) is displaced with a displacement angle (β) with respect to the central axis (A), the flank of the upper cutting edge portion (24), and the lower cutting edge portion (26). The flank is provided with a configuration in which a transition portion (40) having a groove shape is provided in the central portion of the side surface portion. Therefore, the flank of the cutting edge is inclined in the direction of the central axis (A) of the cutting insert. Therefore, the double-sided cutting insert described in Patent Document 3 does not include means for improving the strength of the upper cutting edge portion (24) and the lower cutting edge portion (26).

Accordingly, an object of the present invention is to improve the shape of the side surface portion on which the flank face is formed, particularly for the double-sided cutting insert having a substantially triangular shape, and in particular by appropriately setting the flank angle corresponding to the cutting edge. The strength of the cutting edge can be ensured even when roughing is performed at high feed on the work material, and even if the inclined surface is processed on the work material, other than the cutting edge used for this cutting work It is providing the double-sided type cutting insert which can prevent that the part of a cutting insert contacts or interferes with a workpiece.

The double-sided cutting insert according to the first aspect of the present invention includes a front surface portion and a back surface portion having three corner portions and a substantially triangular shape, and a side surface portion in which the both surface portions of the front and back surfaces are connected via a crossed ridge line. A screw insertion hole penetrating from the center of the front surface portion to the center portion of the back surface portion, and a contact surface formed around the opening portion of the screw insertion hole of the both surface front and back surfaces, both surfaces of the front and back surfaces In the double-sided type cutting insert having the same shape facing the opposite direction, the side part is a corner side part that connects between the opposite corner parts between the front and back side parts. The intermediate side surface portion connecting between the adjacent corner side surface portions, and the corner side surface portion includes a flank surface formed so as to protrude with a gentle convex surface with respect to the intersecting ridge line. ,in front Of the diagrams constituting the plan view or projection view of the surface portion, a contact point of a circumscribed circle circumscribing the figure formed by the outermost closed continuous line around the center point P of the screw insertion hole is defined as a contact point G, A straight line connecting the contact point G and the center point P of the screw insertion hole is defined as a straight line GP, and the distance between the contact surfaces formed on both the front and back surfaces is divided into two equal parts, and the screw insertion hole In the longitudinal section along the straight line GP of the cutting insert, the side surface portion on the corner portion side is the side surface portion constituting the corner side surface portion when a plane perpendicular to the central axis of A first corner side surface having a cross-sectional ridge line intersecting the intermediate surface M or a reference plane parallel to the intermediate surface M at an obtuse angle α (degrees), and an acute angle β (degrees). Second corner side with cross-sectional ridges intersecting It is characterized in that it comprises and. *

The double-sided cutting insert according to the second aspect of the present invention is the double-sided cutting insert according to the first aspect, wherein the intermediate side surface portion is relative to the intermediate surface M or a reference surface parallel to the intermediate surface M. It is the double-sided type cutting insert formed as a side part which intersects at right angle.

The double-sided cutting insert according to the third aspect of the present invention is the double-sided cutting insert according to the first or second aspect, wherein the corner side surface constituting the side surface is the straight line GP of the cutting insert. And a first corner side surface having a cross-sectional ridge line intersecting at an obtuse angle α (degrees) with respect to the intermediate plane M or a reference plane parallel to the intermediate plane M, and an acute angle β ( It is a double-sided type cutting insert provided with the 2nd corner side part which has a cross-sectional ridgeline which intersects at a degree, and the 3rd corner side part which has a cross-sectional ridgeline which intersects at right angle.

The double-sided cutting insert according to the fourth aspect of the present invention is the double-sided cutting insert according to the third aspect, wherein the third corner side surface portion includes the first corner side surface portion and the second corner. A double-sided cutting insert formed integrally with the first and second corner side surfaces between the side surfaces.

The double-sided cutting insert according to the fifth aspect of the present invention is the double-sided cutting insert according to the first or second aspect, wherein the first corner side surface portion extends from the intersecting ridge line portion of the surface portion to the back surface. The lower end portion and the vicinity thereof do not reach the cross ridge line portion of the back surface portion, and the second corner side surface portion extends from the cross ridge line portion of the back surface portion to the surface. The upper end portion and the vicinity thereof are formed so as not to reach the intersecting ridge line portion of the surface portion, and the lower end portion and the vicinity thereof of the first corner side surface portion are formed in the second corner. The double-sided cutting insert is connected to the side surface, and the upper end of the second corner side surface and the vicinity thereof are connected to the first corner side surface.

The double-sided cutting insert according to the sixth aspect of the present invention is the double-sided cutting insert according to any one of the first to fifth aspects, wherein the straight line GP passing through each of the corner parts is opposed to the corner part. When the intersections intersecting the intersecting ridge line are defined as an intersection S1, an intersection S2, and an intersection S3 in the counterclockwise direction, the counterclockwise direction centering on the center point P with respect to the straight line GP passing through the intersection S2 It passes through the center point P in a range where the angle is κ (degrees) and a range where the angle is λ (degrees) in the clockwise direction around the center point P with respect to the straight line GP passing through the intersection S3. The side surface portion in a longitudinal section of the cutting insert along a straight line includes the intermediate side surface portion having a cross-sectional ridge line that intersects the intermediate surface M or a reference plane parallel to the intermediate surface M at a right angle, and the corner The value of degree κ (degree) is equal to the value of angle λ (degree), and the angle κ (degree) and angle (λ) are set in a range of 10 ≦ (κ, λ) ≦ 30. This is a double-sided cutting insert.

The double-sided cutting insert according to the seventh aspect of the present invention is the double-sided cutting insert according to any one of the first to sixth aspects, wherein the center point P is the center of the straight line GP. Straight lines forming an angle δ (degrees) in the clockwise direction and an angle ε (degrees) in the clockwise direction are a straight line K and a straight line N, respectively, in the range of the angle δ (degrees) and the range of the angle ε (degrees). The side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P has the first corner side surface portion having a cross-sectional ridge line intersecting at an obtuse angle α (degrees), and an acute angle β ( The second corner side surface portion having cross-sectional ridge lines intersecting at a degree), the value of the angle δ (degrees) is equal to the value of the angle ε (degrees), and the angle δ (degrees) The value of the angle ε (degrees) is in a range of 3 ≦ (δ, ε) ≦ 25. Is a double-sided cutting insert being constant.

A double-sided cutting insert according to an eighth aspect of the present invention is the double-sided cutting insert according to the third or fourth aspect, wherein the double-sided cutting insert is counterclockwise about the center point P with respect to the straight line GP. Straight lines forming an angle δ (degrees) and an angle ε (degrees) in the clockwise direction are a straight line K and a straight line N, respectively, and the center point P is within the range of the angle δ (degrees) and the range of the angle ε (degrees). The side surface portion in a longitudinal section of the cutting insert along a straight line passing through the first corner side surface portion having a cross-sectional ridge line intersecting at the obtuse angle angle α (degrees) and the acute angle angle β (degrees). The second corner side surface portion having a cross-sectional ridge line intersecting at a right angle and the third corner side surface portion having a cross-sectional ridge line intersecting at a right angle, and the value of the angle δ (degrees) and the angle ε ( The value of degrees is equal and the angle δ (degrees) The value of the angle epsilon (in degrees) is, 3 ≦ (δ, ε) ≦ 25, a double-sided cutting insert is set in a range of.

A double-sided cutting insert according to a ninth aspect of the present invention is the double-sided cutting insert according to any one of the first to eighth aspects, wherein the center point P is the center of the straight line K. When a straight line forming an angle μ (degrees) in the clockwise direction is a straight line L, and a straight line forming an angle η (degrees) in the clockwise direction around the center point P with respect to the straight line N is a straight line R Further, the value of the angle μ (degree) is set to μ = 60− (δ + λ), the value of the angle η (degree) is set to η = 60− (ε + κ), and the angle The side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P in the range of μ (degrees) has a cross-sectional ridge line intersecting at an acute angle β (degree). And a side portion having a cross-sectional ridge line intersecting at a right angle, the angle η (degrees) The side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P within the range of the first corner side surface portion having a cross-sectional ridge line intersecting at an obtuse angle α (degrees) It is the double-sided type cutting insert provided with the side part which has a cross-sectional ridgeline which cross | intersects.
Here, the side surface portion having a cross-sectional ridge line intersecting at a right angle may be, for example, the intermediate side surface portion or the third corner side surface portion.

A double-sided cutting insert according to a tenth aspect of the present invention is the double-sided cutting insert according to any one of the first to ninth aspects, wherein the double-sided cutting insert is formed between a front surface portion, a back surface portion, and the side surface portion. In the intersection ridgeline, the intersection of the straight line K and the intersection ridgeline is A, the intersection of the straight line N and the intersection ridgeline is B, the intersection of the straight line R and the intersection ridgeline is C, the straight line L and the intersection ridgeline And the intersection ridge line in the range from the intersection A to the intersection B is the first ridge line portion, the intersection ridge line in the range from the intersection B to the intersection C is the second ridge line portion, and from the intersection C The intersection ridgeline in the range up to the intersection S2 is the third ridgeline portion, the intersection ridgeline in the range from the intersection A to the intersection D is the fourth ridgeline portion, and the intersection ridgeline in the range from the intersection D to the intersection S3 is the fifth. When the ridgeline part is used, the side part is configured. The corner side surface portion includes the first ridge line portion and the second ridge line portion on the back surface from the corner crossing ridge line including the first ridge line portion, the second ridge line portion, and the fourth ridge line portion of the front surface portion. And the intermediate side surface portion constituting the side surface portion is formed from the third ridge line portion and the fifth ridge line portion of the front surface portion to the third of the back surface portion. It is the double-sided type cutting insert currently formed to the ridgeline part and the said 5th ridgeline part.

The double-sided cutting insert according to the eleventh aspect of the present invention is the double-sided cutting insert according to any one of the first to tenth aspects, wherein the intermediate side surface portion is from the third ridge line portion of the surface portion. A first intermediate side surface portion formed up to the third ridge line portion of the back surface portion, and a second intermediate side surface portion formed from the fifth ridge line portion of the surface portion to the fifth ridge line portion of the back surface portion. It is the double-sided type cutting insert comprised from these.

The double-sided cutting insert according to the twelfth aspect of the present invention is the double-sided cutting insert according to the tenth or eleventh aspect, wherein the first ridge line portion is a corner blade and the second ridge line portion is a main cutting edge. The third ridge line portion is a double-sided cutting insert that is a secondary cutting edge.

The double-sided cutting insert according to the thirteenth aspect of the present invention is the double-sided cutting insert according to the tenth or eleventh aspect, wherein the first ridge line portion is a corner blade and the second ridge line portion is a main cutting edge. The third ridge line part and the fifth ridge line part are double-sided cutting inserts that are sub-cutting edges.

In a fourteenth aspect of the present invention, the blade-tip-exchange-type rotary cutting tool is detachable from the double-sided cutting insert according to the twelfth or thirteenth aspect by a screw fastening means on an insert mounting seat formed at the tip of the tool body. The tool body is constrained between a seating surface formed to face forward in the rotational direction of the tool body and the intermediate side surface portion of the double-sided cutting insert. When the double-sided cutting insert is fixed to the insert mounting seat by the screw fastening means, the double-sided cutting insert has the abutment surface of the front surface portion or the back surface portion attached to the insert. One of the corner blades is on the outer peripheral side of the tool body in a state of being in close contact with the seating surface of the seat, and the main cutting blade and the sub cutting blade connected to the main cutting blade are the tool. While being disposed at the distal end portion side of the body, which is the indexable rotary cutting tool is characterized in that the intermediate side portion is in contact with the restraining wall of the insert mounting seat of the double-sided cutting insert.

The double-sided cutting insert of the present invention having a substantially triangular shape in plan view is configured such that the corner side surface portion of the side surface portions has the first corner side surface portion and the second corner side surface portion. And it is the longitudinal cross-sectional view from the surface part of this double-sided type cutting insert, Comprising: The 1st corner side part shown by sectional drawing which cut | disconnected this corner side part by the straight line (GP) which passes along the centerline of a screw penetration hole The cross-sectional ridge line intersects the reference plane parallel to the intermediate surface (M) at an obtuse angle (α), and the cross-sectional ridge line of the second corner side surface also intersects at an acute angle (β). I have. Further, the side surface portion includes an intermediate side surface portion, and this intermediate side surface portion is used as a restraint surface exclusively for restraint that comes into contact with the insert mounting seat of the tool body. Thereby, the double-sided cutting insert of the present invention can obtain the following effects (1) to (3).

(1) Since the edge angles of the corner blade and the main cutting edge provided on the front surface portion and the back surface portion can be set large, it is possible to improve the strength of the corner blade and the main cutting edge. Thereby, it is possible to provide a double-sided cutting insert particularly suitable for high-feed roughing for a work material. Furthermore, as a corner side surface portion, a third corner side surface portion intersecting at a right angle with respect to a reference plane parallel to the intermediate surface (M) between the first corner side surface portion and the second corner side surface portion. By providing, it becomes possible to set the value of the said angle ((alpha)) and angle ((beta)) to a larger value, Therefore The intensity | strength of the cutting edge of a cutting insert can further be improved.

(2) Due to the effect (1), when this cutting insert is attached to the tool body in order to use the cutting edge on the front surface (or back surface) of the double-sided cutting insert for cutting, the tool at the time of cutting During rotation of the main body, the rear end portion in the rotation direction of the cutting insert can avoid interference with the work material, and the side surface portion is composed of two types of corner side surface portions and intermediate side surface portions. Therefore, it is possible to provide a double-sided cutting insert that can increase the degree of freedom in designing the cutting edge shape.
As a result, by standardizing the specifications of the shape including the side part of the cutting insert, it is possible to contribute to the common use of the tool body for mounting on the insert mounting seat for different types of cutting inserts. Become.

(3) The point (C) connecting the second ridge line portion serving as the main cutting edge and the third ridge line portion serving as the first sub cutting edge provided in the cutting insert of one aspect of the present invention, or the vicinity thereof, By attaching this cutting insert to the blade-tip-exchange-type rotary cutting tool so as to be the lowest point of the cutting edge in the exchange-type rotary cutting tool, the first sub-cutting edge is inclined with high feed with respect to the work material. It becomes possible to function effectively as a cutting edge for processing.

1 is a perspective view showing a first embodiment of a cutting insert of one aspect of the present invention (hereinafter referred to as “the cutting insert of the present invention”). It is a top view which shows the structure of the surface part about the cutting insert shown in FIG. It is a side view of the cutting insert shown in FIG. It is the figure which drawn the circumcircle which circumscribes the outline ridgeline represented by the projection figure from the central axis direction of a screw insertion hole about the surface part of the cutting insert shown in FIG. It is a figure for demonstrating the characteristic of this invention based on the top view of the cutting insert shown in FIG. It is a longitudinal cross-sectional view along the straight line (GP1) about the cutting insert shown in FIG. It is a perspective view which shows 2nd Embodiment about the cutting insert of this invention. It is a side view of the cutting insert shown in FIG. It is a top view for demonstrating the structure of the surface part 2 about the cutting insert shown in FIG. It is a longitudinal cross-sectional view along the straight line (GP1) shown in FIG. 9 about the cutting insert shown in FIG. It is one Embodiment of the blade-tip-exchange-type rotary cutting tool of 1 aspect of this invention (henceforth "the blade-tip-exchange-type rotary cutting tool of this invention"), Comprising: The state when not mounting | wearing with the cutting insert of this invention FIG. It is one Embodiment of the blade-tip-exchange-type rotary cutting tool of this invention, Comprising: It is a perspective view which shows a state when the cutting insert of this invention is mounted | worn. It is a side view of the blade-tip-exchange-type rotary cutting tool shown in FIGS. 11A and 11B. It is the front view seen from the front-end | tip part side of a tool main body about the blade-tip-exchange-type rotary cutting tool shown to FIG. 11A and FIG. 11B. FIG. 13 is a partial side view showing, in an enlarged manner, a cutting insert attached to an insert mounting seat and the vicinity thereof in the cutting edge exchange type rotary cutting tool shown in FIG. 12. It is a figure which shows an example of the path | route of the feed control of a milling tool when implementing the cutting of a pocket in a workpiece. It is a figure which shows the state when cutting to a work material using the blade-tip-exchange-type rotary cutting tool of the present invention. Indicates the state when It is a figure which shows the state when cutting to a work material using the blade-tip-exchange-type rotary cutting tool of the present invention, and when performing a plane cutting process on the work material It is a figure which shows a state.

(First embodiment of double-sided cutting insert)
An embodiment of the double-sided cutting insert of the present invention will be described. 1 to 3 are views showing a basic configuration of the first embodiment of the double-sided cutting insert according to the present invention. FIG. 1 is a perspective view of the double-sided cutting insert 1, and FIG. FIG. 3 is a side view of the same.
In the following description, the “double-sided cutting insert 1” according to the first embodiment may be simply referred to as “cutting insert 1”. In addition, as for the reference numerals of the parts shown in each figure, when an alphabetic code other than a numeral is given, it is written in parentheses for easy reading.

As shown in FIGS. 1 and 2, the cutting insert 1 connects the front surface portion 2, the back surface portion 3 formed at the opposite position facing the front surface portion 2, and the front surface portion 2 and the back surface portion 3 (connection). Side surface portion 4 is provided. Furthermore, intersecting ridge lines 5 are formed on the entire periphery of the portion that intersects the side surface portion 4 in the periphery of the front surface portion 2 and the back surface portion 3. When the cutting insert 1 is viewed from the front surface portion 2 side or the back surface portion 3 side, the shape formed by the entire circumference of the intersecting ridge line 5, that is, the shape formed by the front surface portion 2 and the back surface portion 3 is a substantially triangular shape (hereinafter referred to as “the shape”). The three corner portions are

corner portions

6a, 6b, and 6c each having an arc shape. In addition, about the code | symbol "6a", "6b", "6c" provided to the corner part, code | symbol "6a" in order of the counterclockwise direction centering on the center point (P) shown by FIG. 6b "and" 6c "are assigned. The intersecting ridge line 5 in each

corner portion

6a, 6b, 6c includes an intersecting ridge line 7 having an arc shape or a substantially arc shape (hereinafter referred to as “arc-shaped intersecting ridge line 7”).

The surface portion 2 of the cutting insert 1 having a substantially triangular shape includes a screw insertion hole 8 formed at the center thereof, a contact surface 9 formed around the opening 8a of the screw insertion hole 8, and each corner portion. A rake face 10 formed from 6a, 6b, 6c toward the abutting face 9 is provided. As shown in FIG. 6, the screw insertion hole 8 penetrates the cutting insert 1 from the central portion of the front surface portion 2 to the central portion of the back surface portion 3. The symbol “P” shown in FIG. 2 is the center point of the screw insertion hole 8, and the direction of the central axis (P1) (see FIG. 6) of the screw insertion hole 8 passes through the center point (P). In the thickness direction. The rake face 10 is formed as an inclined surface that inclines downward from each

corner portion

6a, 6b, 6c toward the contact surface 9. The inclined surface of the rake face 10 is a flat surface or a surface that gently protrudes upward (outside of the cutting insert 1 in the thickness direction of the cutting insert 1). In the following description, the center point (P) of the screw insertion hole 8 may be simply referred to as the center point (P).

1 and 2 is a boundary portion between the contact surface 9 and the rake face 10.

End portions

11 a and 11 b of the boundary portion 11 are formed so as to reach the intersecting ridge line 5. Although the contact surface 9 shown in FIG. 1 has shown the example currently formed in the area | region except the opening part 8a of the screw penetration hole 8, and the scoop surface 10 in the surface part 2, it is not limited to this Absent. The rake face 10 is formed as a rake face of a corner blade, a main cutting edge, and a sub cutting edge, which will be described later.

The screw insertion hole 8 is a clamp screw 45 (FIGS. 11A and 11B) when the cutting insert 1 is mounted and fixed to an insert mounting seat 42 (see FIGS. 11A and 11B) provided in the cutting edge exchange type rotary cutting tool. This is a hole for inserting a fastening means such as When the cutting insert 1 is fixed to the insert mounting seat of the cutting edge exchange type rotary cutting tool, the contact surface 9 formed on the front surface portion 2 or the back surface portion 3 of the cutting insert 1 is brought into contact with the seating surface of the insert mounting seat. Then, the clamping screw is tightened with the cutting insert 1 positioned at an appropriate position. The abutting surface 9 is also formed on the back surface portion 3, and the abutting surface 9 of the front surface portion 2 and the abutting surface 9 of the back surface portion 3 form a plane parallel to each other and the center of the screw insertion hole 8. It is formed as a plane orthogonal to the axis (P1).

Each rake face 10 is inclined downward from the end of each

corner

6a, 6b, 6c, that is, from the center of the arcuate intersection ridge line 7 of the corner or near the center toward the contact surface 9. However, it is desirable that the inclination angle is set to have an inclination angle of about 25 ° with respect to the contact surface 9. Therefore, the central portion of the arcuate intersection ridge line 7 or the vicinity thereof is the highest portion in the thickness direction of the cutting insert 1 in the surface portion 2. In addition, following the downward inclination of the rake face 10, the cross ridge line 5 is inclined downward from the center part of the arcuate cross ridge line 7 at the corner part or the vicinity thereof toward the

ends

11a and 11b of the boundary part 11. .

Reference numeral “12” shown in FIG. 2 is a part of the side surface portion 4 and is a clearance surface formed in an upper portion on the surface portion 2 side of the corner side surface portion 13 described later. The flank 12 is a flank of a corner blade, a main cutting edge, and a secondary cutting edge, which will be described later. In FIG. 2 which shows the top view of the surface part 2, the flank 12 connected to the intersection ridge line 5 is shown, as the longitudinal side view of the cutting insert 1 shown in FIG. It shows that it has a shape protruding from the intersecting ridge line 5 of the part 2 in a convex arc shape in the outer direction of the cutting insert 1. More specifically, the corner side surface portion 13 is formed so as to protrude with a gentle convex surface with respect to the intersecting ridge line 5 when the cutting insert 1 is viewed from the front surface portion 2 side or the back surface portion 3 side. A flank 12 is provided. Here, the contour lines corresponding to the flank 12 are

contour ridge lines

15a, 15b, and 15c.
For example, in the plan view of the insert 1 in FIG. 2, the arcuate intersecting ridgeline 7 in the corner portion and each of the contoured

ridgelines

15a, 15b, and 15c are compared with each other. In this case, each of the

contour ridge lines

15a, 15b, and 15c projects outward from the center point (P) of the screw insertion hole 8 with respect to the arcuate intersection ridge line 7 of the corresponding corner portion, and the contour ridge line The curvature radius at the outermost point from the center point (P) of each of 15a, 15b, and 15c is larger than the curvature radius at the outermost point from the center point (P) of the arcuate intersection ridge line 7 of the corresponding corner portion. Means that the two are satisfied at the same time.
The outermost points of the

contour ridgelines

15a, 15b, and 15c from the center point (P) correspond to the intersections of the

contour ridgelines

15a, 15b, and 15c and the straight lines GP1, GP2, and GP3, respectively.
The outermost point from the center point (P) of the arcuate intersection ridgeline 7 at the corner portion exists between the intersections of the straight line K and the straight line GP on the arcuate intersection ridgeline 7 at the corner portion. The position can be specified by actually measuring the distance from the center point (P).

In the cutting insert 1 according to the first embodiment, since the shape of the front surface portion 2 (back surface portion 3) is substantially equilateral triangle, the three corner portions provided on the front surface portion 2 (back surface portion 3) are provided. 6a, 6b, 6c are arranged at intervals of 120 ° around the center point (P) of the screw insertion hole 8 in the plan view of the front surface portion 2 (back surface portion 3), and have the same shape.

Since the cutting insert of the present invention has the structure of a double-sided cutting insert, the front surface portion 2 and the back surface portion 3 have opposite so-called reverse-inverted shapes, and the shapes of the respective portions thereof. Are the same. Therefore, the back part 3 is also provided with the same structure as the structure with which each site | part of the above-mentioned surface part 2 is provided. And when the cutting insert 1 shown in FIG. 1 is reversed and the back surface part 3 is viewed from above, the arrangement and the shape of each part of the back surface part 3 are the same as the surface part 2 shown in FIG. 1 (FIG. 2). Become. The cutting insert of the present invention is preferably applied to a double-sided cutting insert having an inscribed circle with a diameter of about 6 mm to 16 mm and having a substantially equilateral triangle shape.

Then, the structure of the side part 4 with which the cutting insert 1 used as 1st Embodiment is provided is demonstrated. FIG. 3 shows a side view of the cutting insert 1 shown in FIG. The side surface portion 4 includes a corner side surface portion 13 and an intermediate side surface portion 14. The corner side surface portion 13 is a side surface portion that connects between the

corner portions

6 a, 6 b, 6 c facing each other on the front surface portion 2 and the back surface portion 3, and the intermediate side surface portion 14 is a side surface portion that connects these adjacent corner side surface portions 13. It is. Accordingly, the side surface portion 4 includes three corner side surface portions 13 and three intermediate side surface portions 14. The configuration provided in the corner side surface portion 13 and the intermediate side surface portion 14 constituting the side surface portion 4 is a feature of the double-sided cutting insert of the present invention, and the feature of the configuration will be described later. As shown in FIG. 3 (FIG. 1), the intermediate side surface portion 14 is configured by integrally connecting the first intermediate side surface portion 14a and the second intermediate side surface portion 14b, and the central axis (P1). The crossing angle of the intermediate side surface portion 14a and the second intermediate layer surface portion 14b with respect to the direction is set to be a predetermined angle. This crossing angle is preferably set to 160 to 180 degrees, for example. The intersection angle is more preferably 165 degrees to 175 degrees, and even more preferably 167 degrees to 173 degrees, but is not limited thereto.

Subsequently, based on a projection view seen from the central axis (P1) direction of the screw insertion hole 8 of the surface portion 2 of the double-sided cutting insert 1, the side surface portion 4 of the double-sided cutting insert of the present invention is provided with features. explain. FIG. 4 is a projection view of the surface portion 2 as seen from the direction of the central axis (P1) of the screw insertion hole 8 of the surface portion 2. Initially, the figure and code | symbol described in the projection figure of the surface part 2 shown in FIG. 4 are demonstrated. FIG. 4 shows a projection of the surface portion 2 and a circumscribed circle circumscribing the figure shown in the projection.

(1) Reference numeral “15” shown in FIG. 4 indicates a closed continuous line that is a closed contour line located on the outermost side of the surface portion 2 in the projection view of the surface portion 2. This closed continuous line is referred to as “contour edge 15” in the following description. The contour ridge line 15 is the same as the cross ridge line 5 shown in FIGS. 1 and 2, but the contour line of the flank 12 as viewed from the central axis (P1) direction of the screw insertion hole 8 is added instead of the arc-shaped cross ridge line 7 at the corner. FIG.
(2) The contour ridgeline 15 shows three arc-shaped

contour ridgelines

15a, 15b, and 15c. These

contour ridgelines

15a, 15b, and 15c indicate contours corresponding to the flank 12 of the side surface portion 4 shown in the plan view of the surface portion 2 in FIG.
(3) Reference numeral “16” indicates a circumscribed circle circumscribing the figure formed by the entire circumference of the contour edge 15.
(4) Symbol “G” is a contact point between the contour edge 15 and the circumscribed circle 16. In the figure formed by the contour edge 15, the positions farthest from the center point (P) exist on the arc-shaped contour edges 15 a, 15 b, and 15 c, respectively. Therefore, there is one point of contact (G) on each of the

arcuate contour edges

15a, 15b, 15c, and a total of three contacts (G) are generated on the contour edge 15 at 120 ° intervals.

(5) The straight line (GP) is a straight line connecting the center point (P) of the screw insertion hole 8 and the contact point (G). As shown in FIG. 4, three straight lines (GP1) are used as the straight line (GP). , (GP2) and (GP3) exist.
(6) Symbol “S1” is a point where the straight line (GP1) intersects the contour ridgeline 15 existing at a position facing the arcuate contour ridgeline 15a (contact (G)), and symbol “S2” is a straight line (GP2). Intersects with the contour ridge 15 existing at a position facing the arc-shaped contour ridge 15b, and “S3” denotes a contour ridge 15 existing at a position where the straight line (GP3) faces the arc-shaped contour ridge 15c. It is a point that intersects. In the following description, when the straight lines (GP1), (GP2), and (GP3) are collectively described, they are described as a straight line “GP”.

4 is different from the plan view of the surface portion 2 shown in FIG. 2 in the presence or absence of the circumscribed circle 16. The circumscribed circle does not exist in the plan view of the surface portion 2 shown in FIG. 2, but in the projection view, for example, first, a projection view of the surface portion 2 is created using three-dimensional CAD software, and then, Thus, it is possible to easily draw the circumscribed circle 16 that circumscribes the arc-shaped

contour ridgelines

15a, 15b, and 15c. Therefore, the plan view of the surface portion 2 shown in FIG. 2 and the projection view of the surface portion 2 shown in FIG. 4 are substantially the same figure except for the circumscribed circle 16. That is, in the projection view shown in FIG. 4, the diagram of each part such as the intersecting ridge line 5 and the screw insertion hole 8 shown in the plan view of FIG. 2 is displayed as it is. Also, each symbol shown in FIG. 4 and its position on the drawing, for example, a position on the drawing such as a straight line (GP1), (GP2), (GP3), etc. correspond to the projection view of FIG. 2 can be displayed on the plan view of the surface portion 2 in FIG.

The circumscribed circle 16 described above can be created using the plan view of the surface portion 2 shown in FIG. 2 and drawn on this plan view. For example, when a plan view of the surface portion 2 is drawn using CAD software for two-dimensional drawing, the attribute is stored in the storage means for each diagram of the created figure. Therefore, the coordinate value of each diagram can be acquired by displaying a plan view created with two-dimensional CAD software on the screen and using the coordinate acquisition function interactively to specify the position that will be the origin coordinate of the drawing. . And, for example, using a function for drawing a circumscribed circle, a figure formed by a closed continuous line located on the outermost side in the plane figure of the surface portion 2 of the cutting insert 1 (a figure including the outline of the flank 12) ) And the coordinate value of the contact point G can be obtained. Accordingly, the circumscribed circle 16 shown in FIG. 4 can be created from the projection or plan view of the surface portion 2 and displayed superimposed on the plane figure of the surface portion 2.

Subsequently, features of the double-sided cutting insert 1 of the present invention will be described with reference to FIGS. FIG. 5 is a plan view (FIG. 2) of the surface portion 2 of the cutting insert 1 showing the straight line (GP) given in FIG. It is the figure which added the straight line and the code | symbol etc. which were newly provided to. FIG. 6 is a longitudinal sectional view of the cutting insert 1 for explaining the characteristics of the cutting insert 1 based on FIG.

The three straight lines (GP) shown in FIG. 5 (GP1), (GP2), and (GP3) are the same straight lines as the straight lines (GP1), (GP2), and (GP3) shown in FIG. A straight line (K) and a straight line (N) shown in FIG. 5 are straight lines that form an angle δ (degrees) in the counterclockwise direction through the center point (P) with reference to the straight line GP (GP1) viewed from the projection view. It is a straight line that forms an angle ε (degrees) in the rotation direction.
Similarly, the straight line (L) is a straight line having an angle μ (degrees) in the counterclockwise direction around the center point (P) with respect to the straight line (K). The straight line (R) is a straight line that forms an angle η (degrees) in the clockwise direction around the center point (P) with reference to the straight line (N). Further, an angle formed between the straight line (L) and the straight line (GP3) is defined as an angle (λ) (degrees), and an angle formed between the straight line (R) and the straight line (GP2) is defined as an angle (κ) (degrees).

Further, points (A), (B), (C), and (D) shown in FIG. 5 are defined as follows. That is, the point (A) indicates the intersection between the straight line (K) and the intersecting ridge line 5, the point (B) indicates the intersection between the straight line (N) and the intersecting ridge line 5, and the point (C) is represented by the straight line (R). The intersection with the intersecting ridge line 5 is shown, and the point (D) is defined as the intersection between the straight line (L) and the intersecting ridge line 5.
Furthermore, the intersecting ridgeline 5 in the range from the point (A) to the point (B) is the first ridgeline part 17, the intersecting ridgeline 5 in the range from the point (B) to the point (C) is the second ridgeline part 18, and the point ( The intersection ridge line 5 in the range from C) to the point (S2) is the third ridge line part 19, the intersection ridge line 5 in the range from the point (A) to the point (D) is the fourth ridge line part 20, and the point from the point (D) The intersecting ridge line in the range up to (S3) is defined as the fifth ridge line portion 21. The arc-shaped ridge line portion composed of the first ridge line portion 17, the second ridge line portion 18, and the fourth ridge line portion 20 becomes the arc-shaped intersecting ridge line 7 of the above-described corner portion.

In FIG. 5, the straight lines (K), (L), (N), and (R) and the intersections (A), (B), (C), and (D) are the corner portions 6 a of the surface portion 2. Side, that is, the range of the angle (θ) (θ is 120 degrees) with the center point (P) as the center, the

other corner portions

6b and 6c are similarly shown in the range of the angle (θ). Each straight line and each intersection point are defined. Furthermore, the back surface portion 3 of the cutting insert 1 is similarly defined.

In addition, the intermediate side surface part 14 shown in FIG. 1 (FIG. 3) has a ridge line connecting (S1) points, (S2) points, and (S3) points on the intersecting ridge line 5 of the front surface part 2 and the back surface part 3. As a boundary, the first intermediate side surface portion 14a and the second intermediate layer surface portion 14b are constituted by two side surfaces, and the first intermediate side surface portion 14a and the second intermediate layer surface portion 14b are predetermined as described above. It is desirable to form so as to intersect with each other.

When the cutting insert 1 according to the present invention is mounted on a blade-tip-exchange-type rotary cutting tool and the workpiece is cut, the first ridge line portion 17 serves as the corner blade 25 and the second ridge line portion 18 serves as the main cutting edge 26. As a result, the third ridge line portion 19 becomes a cutting edge that functions as a secondary cutting edge (first secondary cutting edge) 27. Further, the fifth ridge line portion 21 also becomes a cutting edge that acts as the second auxiliary cutting edge 28. In addition, the 1st sub cutting edge 27 in the corner part 6a is connected with the 2nd sub cutting edge 28 with which the corner part 6c which adjoins via the intersection (S2). As will be described later, when the cutting insert of the present invention is mounted and the cutting edge provided in the corner portion 6a is used to perform an inclined cutting process on the work material, the first auxiliary cutting edge 27 of the corner portion 6a, Cutting can be performed using both of the second sub cutting edges 28 of the corner portion 6c connected to the sub cutting edge 27.

Although not shown in FIGS. 1 and 2, etc., the rake face 10 and the first ridge line part 17, the second ridge line part 18, and the third ridge line part 19 are improved in order to improve the strength of the cutting edge. It is preferable to provide a land surface having a predetermined width therebetween. Furthermore, it is preferable to provide a land surface between the rake face 10 or the contact surface 9 along the fourth ridge line part 20 and the fifth ridge line part 21.

In the cutting insert 1 of the present invention, the distance between the contact surfaces 9, 9 formed on the front surface portion 2 and the back surface portion 3 is equally divided into two and intersects with the central axis (P 1) of the screw insertion hole 8 perpendicularly. When the plane is the intermediate surface (M), the side surface portion 4 of the cutting insert 1 has the following basic configuration.

That is, the side surface portion 4 has a side surface (first side surface portion) that intersects at an obtuse angle with respect to a reference surface parallel to the intermediate surface (M) or the intermediate surface (M), and a side surface (second surface) that intersects at an acute angle. 1 type, 2 types, or 3 types of side surfaces (third side surface portion or intermediate side surface portion) intersecting at right angles with the right angle portions are arranged in the central axis (P1) direction of the screw insertion hole 8. It consists of a configuration.
Hereinafter, the structural feature of the side surface part provided in the cutting insert 1 of the first embodiment will be described.

[Feature 1]
The corner side surface portion 13 constituting the side surface portion 4 includes three corner side surface portions 13 as shown in FIG. Each corner side surface portion 13 includes a first corner side surface portion 13a and a second corner side surface portion 13b. The first corner side surface portion 13a intersects the configuration of the first side surface portion described above, that is, the intermediate surface (M) or the reference surface parallel to the intermediate surface (M) at an obtuse angle (α). It consists of sides. The second corner side surface portion 13b intersects the configuration of the second side surface portion described above, that is, the intermediate surface (M) or the reference surface parallel to the intermediate surface (M) at an acute angle (β). It consists of sides.

Furthermore, as shown in FIG. 1 and FIG. 3, the first corner side surface portion 13a extends in the direction of the back surface portion 3 from both ends of the arc-shaped intersection ridge line 7 of the corner portion or the vicinity thereof on the surface portion 2, It is formed to have a curved surface shape in which the width in the direction orthogonal to the central axis (P1) is gradually reduced. Further, the lower end portion 13 a 1 of the first corner side surface portion 13 a is formed so as not to reach the intersecting ridge line 5 of the back surface portion 3.
The first corner side face 13a described above gradually decreases the width in the direction orthogonal to the central axis (P1) so that the area of the intermediate side face 14, particularly the first intermediate side face 14a, is increased. Thus, the function of the intermediate side surface portion 14 as a restraint surface to be described later is reliably exhibited.

As shown in FIGS. 1 and 3, the second corner side surface portion 13 b is smoothly connected to the counterclockwise end of the first corner side surface portion 13 a, and the corner portion of the back surface portion 3 has a circular shape. It is formed so as to extend from both ends of the arcuate intersection ridge line 7 or its vicinity in the direction of the surface portion 2 and to gradually reduce the width in the direction perpendicular to the central axis (P1). The upper end portion 13 b 1 of the second corner side surface portion 13 b is formed so as not to reach the intersecting ridge line 5 of the surface portion 2. Furthermore, the lower end portion 13a1 of the first corner side surface portion 13a and the vicinity thereof are connected to the second corner side surface portion 13b. Similarly, the upper end portion 13b1 of the second corner side surface portion 13b and the vicinity thereof are The configuration is connected to the corner side surface portion 13a.

The interval between the lower end portion 13a1 of the first corner side surface portion 13a and the intersecting ridge line 5 of the back surface portion 3, and the interval between the upper end portion 13b1 of the second corner side surface portion 13b and the intersecting ridge line 5 of the surface portion 2 are as follows. It is desirable to provide 0.3 mm or more in a length corresponding to the thickness direction of the cutting insert 1. In addition, the first corner side surface portion 13a and the second corner side surface portion 13b have different angles with respect to the intermediate surface M or the reference surface parallel to the intermediate surface M. The surface of the corner side surface portion 13 including the boundary ridge line portion connected to the corner side surface portion 13b is ground so as to have a smooth surface.

The cutting insert 1 according to the first embodiment can exhibit the effects described in the following (Effect 1) by being provided with the above feature 1.

(Effect 1)
In the corner side surface portion 13 of the cutting insert 1, it becomes possible to widen a region where the angle (α) is an obtuse angle and the angle (β) is an acute angle, and the volume of the corner side surface portion 13 is increased. Strength can be improved. This makes it possible to appropriately design the shape and angle of the flank 12 in consideration of the cutting edge shapes of the corner blade 25 and the main cutting edge 26. The degree of freedom can be expanded.

[Feature 2]
The feature 2 further provided in the corner side surface portion 13 will be described with reference to FIG. FIG. 6 is a longitudinal sectional view of the cutting insert 1 along a straight line GP (GP1) in the plan view of the surface portion 2 shown in FIG. Symbols “M1” and “M2” shown in FIG. 6 indicate reference surfaces that are parallel to the intermediate surface (M), and the right side of the paper surface of FIG. The cross-sectional ridge line 23 of the 1st corner side surface part 13a and the cross-sectional ridge line 24 of the 2nd corner side surface part 13b are shown. The symbol “f1” shown in FIG. 6 is an intersection of the

cross-sectional ridgelines

23 and 24 appearing in this vertical cross-sectional view.

As shown in FIG. 6, since the first corner side surface portion 13a has the configuration of the first side surface portion described above, the angle (α) formed by the cross-sectional ridge line 23 with respect to the reference surface (M1). Is an obtuse angle, and the angle (β) formed by the cross-sectional ridge line 24 of the second corner side surface portion 13b with respect to the reference surface (M2) is an acute angle. Note that an angle α shown in FIG. 6 is an angle formed by the cross-sectional ridge line 23 and the reference plane (M1) and is an angle facing the direction of the intermediate plane (M). On the other hand, the angle β is an angle formed by the cross-sectional ridge line 24 and the reference plane (M2) and indicates an angle facing the opposite side with respect to the intermediate plane (M).

Thus, the fact that the cross-sectional ridge line 23 of the first corner side surface portion 13a becomes an obtuse angle (α) with respect to the reference surface (M1) is formed from the arcuate intersecting ridge line 7 at the corner portion of the surface portion 2. The first corner side surface portion 13a is formed so as to incline downward toward the back surface portion 3 at a predetermined angle toward the outside of the cutting insert 1 with respect to the central axis (P1) direction of the screw insertion hole 8. It shows that. That is, the flank 12 formed from the arcuate intersecting ridgeline 7 at the corner of the surface portion 2 has a predetermined angle (α) outside the cutting insert 1 with respect to the central axis (P1) of the screw insertion hole 8. Inclined downward in the direction of the back surface 3. Similarly, the second corner side surface portion 13b formed from the arcuate intersecting ridge line 7 at the corner portion of the back surface portion 3 has a predetermined angle (β toward the outside of the cutting insert 1 with respect to the central axis (P1). ) To be inclined upward in the direction of the surface portion 2.

In the cutting insert of the present invention, the angle (α) described above is more preferably set to 90 ° <α ≦ 110 °, preferably in the range of 98 ° to 102 °, and more preferably 100 °.
The angle (β) is more preferably set to 70 ° ≦ β <90 °, preferably in the range of 72 ° to 82 °, and more preferably 80 °.
The reason for this is that by setting the angle (α) value to a large value exceeding 90 °, the blade angles of the main cutting edge and the corner cutting edge are increased, which is effective in improving the strength. On the other hand, when the angle (α) value is larger than 110 °, the cutting resistance at the time of cutting is increased, which causes a disadvantage that the machined surface quality of the work material deteriorates due to the influence of vibration or the like. It is.
In addition, the angle (β) is the same as the reason for the angle (α) value because the insert has a shape that is reversely symmetric.

Since the cutting insert 1 is provided with the above-described feature 2, the effect described in the following (Effect 2) can be achieved.
(Effect 2)
Since the blade angles of the corner blade 25 and the main cutting edge 26 provided on the front surface portion 2 and the back surface portion 3 can be set large, the strength of the corner blade 25 and the main cutting edge 26 can be improved. . This makes it possible to provide a double-sided cutting insert suitable for high-feed roughing.

[Feature 3]
Then, the characteristic 3 with which the cutting insert 1 is provided is demonstrated. As described above, in the cutting insert 1 according to the present invention, a clock with a predetermined angle about the center point (P) of the screw insertion hole 8 with the straight line GP (GP1, GP2, GP3) shown in FIG. When straight lines extending in the rotation direction and the counterclockwise direction are drawn, the cross-sectional ridgeline of the side surface portion 4 appearing in the longitudinal cross-sectional view of the cutting insert 1 along these straight lines is the intermediate surface (M) or the intermediate surface (M The angle formed with respect to the reference plane parallel to) is as follows.
That is, the side surface portion 4 has the first side surface portion whose cross-sectional ridge line is an obtuse angle (α), the second side surface portion that is an acute angle (β), and the third angle that is perpendicular. 1 type, 2 types, or 3 types of the cross-sectional ridgeline of the side surface part is formed. A specific example of this embodiment will be described with reference to a straight line (GP1) within an angle (θ) including the corner portion 6a of the surface portion 2 shown in FIG.

With reference to the straight line (GP1) shown in FIG. 5, a straight line (K) forming an angle (δ) counterclockwise around the center point (P) of the screw insertion hole 8 and an angle (ε In the longitudinal sectional view of the surface portion 2 of the cutting insert 1 along the straight line passing through the center point (P) within the range surrounded by the straight line (N) forming a The corner side surface portion 13 is formed so as to have the resulting configuration.
That is, within this range, the first corner side surface portion comprising the first side surface portion intersecting at an obtuse angle (α) with respect to the intermediate surface (M) or the reference surface parallel to the intermediate surface (M). Side surface portion 4 (corner side surface portion 13) so that cross-sectional ridge line 23 of 13a and cross-sectional ridge line 24 of second corner side surface portion 13b intersecting at an acute angle (β) made of the second side surface portion appear. Is forming.

In the longitudinal sectional view similar to the above in the range of the angle (η) shown in FIG. 5, that is, in the range surrounded by the straight line (N) and the straight line (R), the intermediate surface (M) or the intermediate surface The cross-sectional ridge line 23 of the first corner side surface portion 13a made of the first side surface portion having an obtuse angle (α) with respect to a reference surface parallel to (M), and the third side surface portion forming a right angle. The side surface portion 4 (corner side surface portion 13) is formed so that the cross-sectional ridgeline of the above appears. The third side surface portion that forms this squareness indicates the intermediate side surface portion 14.
Similarly, in the range of the angle (μ) surrounded by the straight line (K) and the straight line (L), an acute angle (β) with respect to the intermediate plane (M) or the reference plane parallel to the intermediate plane (M) ) So that the cross-sectional ridge line 24 of the second corner side surface portion 13b made of the second side surface portion and the third side surface portion having a right angle, that is, the cross-sectional ridge line of the intermediate side surface portion 14 appears. 4 (corner side surface portion 13) is formed.

Furthermore, in the longitudinal sectional view similar to the above in the range of the angle (κ), that is, in the range surrounded by the straight line (R) and the straight line (GP2), the reference plane parallel to the intermediate plane (M) The side surface portion 4 is formed so that only the third side surface portion having a right angle, that is, only the cross-sectional ridge line of the intermediate side surface portion 14 or most of the cross-sectional ridge line of the intermediate side surface portion 14 appears. Similarly, in the longitudinal sectional view similar to the above within the range of the angle (λ) surrounded by the straight line (L) and the straight line (GP3), the intermediate plane (M) or the reference plane parallel to the intermediate plane (M) The side surface portion 4 is formed so that only the cross-sectional ridge line of the intermediate side surface portion 14 that forms a right angle with respect to the cross-sectional ridge line of the intermediate side surface portion 14 appears.

In the cutting insert of the present invention, the values of the angles δ, ε, η, μ, κ, and λ are as follows:
δ = ε, μ = η, λ = κ, and
3 degrees ≦ δ ≦ 25 degrees,
10 degrees ≦ λ ≦ 30 degrees,
μ = 60 degrees− (δ + λ),
It is desirable to set to.
The reason for setting δ = ε, μ = η, and λ = κ among the above angles is that the cutting insert has a shape that is symmetrical with the front and back reversed.
In addition, the reason for setting 10 degrees ≦ λ ≦ 30 degrees is that when the λ value is less than 10 °, a sufficient restraint area cannot be ensured, so that the cutting insert is stably attached to the tool body. This is because it cannot be fixed. On the other hand, when the λ value exceeds 30 ° and is considered to be replaced with the κ value, the main cutting edge length is shortened, leading to a reduction in cutting efficiency. is there. The range of λ is preferably 15 degrees ≦ λ ≦ 25 degrees, more preferably 17 degrees ≦ λ ≦ 23 degrees, but is not limited thereto.
Further, the reason for setting 3 degrees ≦ δ ≦ 25 degrees is a range necessary for adjusting the shape of the corner side surface portion 13 and adjusting the balance so that the length of the corner cutting edge is appropriate. It is. The range of δ is preferably 8 degrees ≦ δ ≦ 20 degrees, more preferably 10 degrees ≦ δ ≦ 18 degrees, but is not limited thereto.
The reason why μ = 60 degrees− (δ + λ) is set is that the cutting insert 1 has a substantially equilateral triangle shape, and the sum of μ, δ, and λ is 1/3 of 360 °, which is half of 120 °. This is because the angle obtained by subtracting δ and λ from the sum corresponding to the region (60 °) is defined as μ.

Since the double-sided cutting insert 1 has the above-described feature 3, it is possible to achieve the effect described in the following (Effect 3).
(Effect 3)
The cutting insert 1 according to the first embodiment of the present invention has the second side surface with a β value that is an acute angle within the range of an angle (μ) surrounded by the straight line (K) and the straight line (L). A portion (second corner side surface portion 13b) and a third side surface portion (intermediate side surface portion 14) are formed. As a result, when the cutting insert 1 is mounted on the tool body of the rotary cutting tool having a replaceable blade edge in order to use the cutting edge of the surface portion 2 of the cutting insert 1 for the cutting process, the tool body is rotated during the cutting process. 2, the second side surface portion (second corner side surface portion 13 b) having an acute β value is located on the rear end side in the rotational direction of the cutting insert 1. Therefore, since the rear end side of the cutting insert 1 can be prevented from interfering with the work material, it is possible to favorably maintain the properties of the processed surface of the work material. Similarly, when the cutting edge of the back surface portion 3 is used for cutting, the rear end side in the rotation direction of the cutting insert 1 can be prevented from interfering with the work material.

As described in [Feature 1] above, in the corner side surface portion 13, the second corner is located in the region between the lower end portion 13 a 1 of the first corner side surface portion 13 a and the vicinity thereof and the intersecting ridge line 5 of the back surface portion 3. The side surface portion 13b is formed. Similarly, the first corner side surface portion 13a is formed in a region between the upper end portion 13b1 of the second corner side surface portion 13b and the vicinity thereof and the intersecting ridge line 5 of the surface portion 2 ( 1 and 3). By providing such a configuration, it becomes possible to widen the above-described angle (α) at an obtuse angle and an angle (β) at an acute angle in the corner side surface portion 13, and the volume of the corner side surface portion 13. And the strength of the cutting edge can be improved.

Furthermore, the cutting insert 1 according to the first embodiment has the following feature 4.
[Feature 4]
The three side face parts intersecting the side face part 4 at a right angle with respect to the three corner side face parts 13 having the above-described configuration and characteristics and the reference plane parallel to the intermediate face (M) or the intermediate face (M). 14. That is, in the cutting insert 1 in which the front surface portion 2 and the back surface portion 3 have a substantially triangular shape or a substantially equilateral triangular shape, the side surface portion 4 has a configuration in which the intermediate side surface portion 14 is disposed between the adjacent corner side surface portions 13. Yes. By providing such a configuration, the cutting insert 1 can achieve the effects described in the following (Effect 4) and (Effect 5).

(Effect 4)
It becomes possible to provide a double-sided cutting insert that can increase the degree of design freedom with respect to the shape of the cutting edge. The reason is as follows.
By constituting the side surface portion 4 of the cutting insert 1 from two types of the corner side surface portion 13 and the intermediate side surface portion 14, when the cutting insert 1 is mounted on the tool body of the blade-tip-exchange-type rotary cutting tool, One or two of the intermediate side surface portions 14 are used as side surfaces dedicated to restraining to contact the insert mounting seat of the tool body. As a result, the corner side surface portion 13 does not have a function as a side surface dedicated for restraint, and can be formed as a separate and independent side surface portion 4 as the flank 12 corresponding to the corner blade 25 and the main cutting edge 26. is there. And since the corner side surface part 13 is formed in the state which contact | connected the 1st ridgeline part 17 and the 2nd ridgeline part 18, it considers the cutting edge shape of the corner blade 25 and the main cutting edge 26, and its flank Appropriately designing the shape of 12 and the clearance angle thereof, that is, the design flexibility of the shape of these cutting edges can be expanded.

(Effect 5)
For other types of substantially triangular cutting inserts having a cutting edge shape different from that of the cutting insert of the present invention, it is possible to use the tool body of a blade cutting type exchangeable cutting tool to which these cutting inserts are mounted in common. It becomes possible. That is, the tool body can be shared. The reason is as follows.
The cutting insert 1 according to the present invention includes an intermediate side surface 14 formed so as to be orthogonal to a reference surface parallel to the intermediate surface (M) and the intermediate surface (M). It is a side surface dedicated to restraint that comes into contact with the restraint wall. Even with other types of cutting inserts with different cutting edge shapes, different types of cutting inserts with an intermediate side surface dedicated for restraint that contacts the insert mounting seat of the tool body are standardized. This is because the tool body of the cutting edge exchange-type rotary cutting tool can be used in common for these cutting inserts.

(Second embodiment of double-sided cutting insert)
Subsequently, a second embodiment of the double-sided cutting insert of the present invention will be described with reference to FIGS. 7 is a perspective view of a double-sided cutting insert 31 according to the second embodiment, FIG. 8 is a side view of the double-sided cutting insert 31 shown in FIG. 7, and FIG. It is a top view for demonstrating a structure, Comprising: It becomes the same as the top view of the cutting insert 1 used as 1st Embodiment shown in FIG. FIG. 10 is a longitudinal sectional view of the double-sided cutting insert 31.

The main difference between the double-sided cutting insert 31 of the second embodiment and the double-sided cutting insert 1 according to the first embodiment is that the side surface portion 4 has a corner side surface portion. The configuration is different. Therefore, in the following description, it demonstrates using the code | symbol same as the code | symbol of each site | part provided to the above-mentioned cutting insert 1 except the structure of the site | part regarding the side part of the double-sided type cutting insert 31. FIG. Moreover, since the structure of the surface part of the double-sided type cutting insert 31 and a back surface part becomes the same as the structure of the surface part of the cutting insert 1 shown in above-mentioned FIG. 2, it is detailed about the structure of this surface part (back surface part). Description is omitted. In the following description, the double-sided cutting insert 31 of the second embodiment may be simply referred to as “cutting insert 31”.

As shown in FIGS. 7 and 8, the cutting insert 31 is similar to the cutting insert 1 described above, the front surface portion 2, the back surface portion 3 formed at a position facing the front surface portion 2, and the front surface portion 2. A side surface portion 4 for connecting (connecting) the back surface portion 3 is provided. Crossed ridge lines 5 are formed on the entire circumference of the portion where the front surface portion 2 and the back surface portion 3 intersect with the side surface portion 4, and the shapes of the front surface portion 2 and the back surface portion 3 are substantially triangular or equilateral triangular. Each corner includes

corner portions

6a, 6b, and 6c each having an arc shape. Further, the front surface portion 2 and the back surface portion 3 have a shape that is symmetrical with the front and back reversed.

The structure of the side surface part 4 which is the characteristic of the cutting insert 31 is demonstrated based on FIG.7 and FIG.8. Similar to the cutting insert 1 according to the first embodiment, the side surface portion 4 is composed of the intermediate side surface portion 14 and the corner side surface portion 32. The corner side surface portion 32 is further composed of the first corner side surface portion 32a, It is characterized by being composed of a second corner side surface portion 32b and a third corner side surface portion 32c.
The first corner side surface portion 32a has the configuration of the first side surface portion, the second corner side surface portion 32b has the configuration of the second side surface portion, and the third corner side surface portion 32c has The third side surface portion is provided.
That is, in the second embodiment, a third corner side surface portion 32c that is not provided in the cutting insert 1 of the first embodiment is newly provided.

As shown in FIG. 7, the first corner side surface portion 32 a includes the first ridge line portion on the intersecting ridge line 5 of the surface portion 2 from the point (A) to the point (B), the second ridge line portion, Extending from the corner crossing ridge line 33 including the points (B) to (C) to the back surface portion 3, and the lower end portion 32 a 1 and the vicinity thereof are formed so as not to reach the cross ridge line 5 of the back surface portion 3. ing.

The second corner side surface portion 32b extends from the corner portion intersecting ridge line 33 of the back surface portion 3 in the direction of the surface portion 2, and the upper end portion 32b1 and the vicinity thereof are formed so as not to reach the intersecting ridge line 5 of the surface portion 2. ing.

As shown in FIG. 7, the third corner side surface portion 32 c is interposed between the first corner side surface portion 32 a and the second corner side surface portion 32 b, and the first corner side surface portion 32 a and the second corner side surface portion 32 b It is formed so as to be integrally connected to the corner side surface portion 32b. Further, the third corner side surface portion 32 c is formed such that the upper end portion on the surface portion 2 side is formed up to the intersecting ridge line 5 of the surface portion 2, and the lower end portion on the back surface portion 3 side is formed up to the intersecting ridge line 5 of the back surface portion 3. ing.

The configuration of the third corner side surface portion 32c will be further described. As shown in FIG. 7, the lower end portion 32a1 of the first corner side surface portion 32a and its vicinity are points (D) on the intersecting ridge line 5 of the back surface portion 3. To the (A) point (the fourth ridge line portion 20) and the third corner side surface portion 32c formed from the point (A) is integrally engaged.
Similarly, the upper end portion 32b1 of the second corner side surface portion 32b and the vicinity thereof are from the point (A) to the point (D) on the intersecting ridge line 5 of the surface portion 2 (the fourth ridge line portion 20; And a third corner side surface portion 32c formed from an angle μ (degree range).
Thus, the cutting insert 31 is characterized in that the configuration of the corner side surface portion 32 is such that the third corner side surface portion 32c is interposed between the first corner side surface portion 32a and the second corner side surface portion 32b. There is.

The cutting insert 31 which becomes above-mentioned 2nd Embodiment is equipped with the structural characteristic as described in the following (feature 5).
[Feature 5]
In the plan view of the surface portion 2 shown in FIG. 9, the cross-sectional ridgeline of the corner side surface portion 32 displayed in FIG. 10 that is a vertical cross-sectional view of the cutting insert 31 along the straight line (GP1) has the following characteristics. .
As shown in FIG. 10, the angle formed by the cross-sectional ridge line 34 a of the first corner side surface portion 32 a and the reference surface (M 3) parallel to the intermediate surface (M) is the first obtuse angle (α). The corner side surface portion 32a is formed. This angle (α) is desirably set to the same or substantially the same value as the angle (α) shown in the cutting insert 1 of the first embodiment shown in FIG.

Similarly, the second corner side surface portion 32b is formed such that the angle formed by the cross-sectional ridge line 34b of the second corner side surface portion 32b and the reference surface (M4) parallel to the intermediate surface (M) is an acute angle (β). Is forming. This angle (β) is desirably set to the same or substantially the same value as the angle (β) shown in the cutting insert 1 of the first embodiment shown in FIG.

Similarly, the angle (γ) formed by the cross-sectional ridge line 34c of the third corner side surface portion 32c and the reference plane parallel to the intermediate surface (M) or the intermediate surface (M) is a square (90 degrees). 3 corner side surfaces 32c are formed. In FIG. 10, reference numeral “f2” indicates a point where the cross-sectional ridge lines 34a and 34c intersect, and reference numeral “f3” indicates a point where the cross-sectional ridge lines 34c and 34b intersect.

Since the cutting insert 31 has the feature 5 described above, it is possible to achieve the effect described in the following (Effect 6).
(Effect 6)
By setting the angle (γ) between the cross-sectional ridge line 34c of the third corner side surface portion 32c and the reference plane parallel to the intermediate surface (M) or the intermediate surface (M) to be a right angle, A shape part can be made small and it can be set as a smoother corner side surface, and the intensity | strength of the cutting insert 31 itself can be improved. For example, the point f1 where the

cross-section ridgelines

23 and 24 shown in FIG. 6 intersect forms a convex part, but the points f2 and f3 shown in FIG. 10 have a large obtuse angle, and the convex part is small. And it has a smoother side.
Further, the values of the angle (α) and the angle (β) can be set to larger values as compared with the cutting insert 1 of the first embodiment. Thereby, since the blade angle | corner of the corner blade 25 and the main cutting edge 26 can be enlarged, the intensity | strength of these cutting edges can be improved compared with the cutting insert 1 used as 1st Embodiment.

In the cutting insert 31, the angle is within the range of the straight line (K) that becomes an angle (δ) in the counterclockwise direction around the center point (P) with respect to the straight line (GP1) shown in FIG. Within the range of the straight line (N) to be (ε), the cross-sectional ridge line has the above-described characteristics on the corner side surface portion 32 displayed in the vertical cross-sectional view of the cutting insert 31 along the straight line passing through the center point (P). 5, that is, the angle formed with the reference surface (M3) parallel to the intermediate surface (M) is the first corner side surface portion 32a that is an obtuse angle (α), and the second angle that is also an acute angle (β). The corner side surface portion 32 is formed so that cross-sectional ridge lines corresponding to the corner side surface portion 32b and the third corner side surface portion 32c having the same squareness (γ) appear. The angles (α) and (β) are desirably set to the same or substantially the same values as the angles (α) and (β) shown in the cutting insert 1 of the first embodiment shown in FIG.
In addition, in the corner crossing ridge line 33 shown in FIG. 9, along the straight line connecting the point from the point (B) to the center of the point (B) and the point (C) or the vicinity of the center and the center point (P). Also in the longitudinal sectional view, the corner side surface portion 32 may be formed so as to have the configuration of the characteristic 5 described above.

Further, the cross-sectional ridge line of the corner side surface portion 32 displayed in the longitudinal cross-sectional view of the cutting insert 31 along the straight line passing through the center point (P) within the range of the angle (μ) shown in FIG. ) And the cross-sectional ridgeline of the second corner side surface portion 32b at the angle (β), or the cross-sectional ridgeline of the third corner side surface portion 32c at the angle (γ). The corner side surface portion 32 and the intermediate side surface portion 14 are formed so that a cross-sectional ridge line of the intermediate side surface portion 14 that intersects the ridge line at a right angle appears.
In addition, the cross-sectional ridge line of the corner side surface portion 32 displayed in the vertical cross-sectional view of the cutting insert 31 along the straight line passing through the center point (P) within the range of the angle (η) is the first angle (α). The cross-sectional ridgeline of the first corner side surface portion 32a having the angle (α) or the cross-sectional ridgeline of the first corner side surface portion 32a having the angle (γ) described above, The corner side surface portion 32 and the intermediate side surface portion 14 are formed so that a cross-sectional ridge line of the intermediate side surface portion 14 that intersects at an angle appears.
Similarly, the cross-sectional ridgeline of the corner side surface portion 32 displayed in the longitudinal cross-sectional view of the cutting insert 31 along the straight line passing through the center point (P) within the range of the angle (λ) shown in FIG. 9, and the angle (κ) The cross-section ridgeline of the corner side surface portion 32 displayed in the longitudinal cross-sectional view of the cutting insert 31 along the straight line passing through the center point (P) within the range of the above includes a third side surface portion intersecting at the perpendicularity described above, The side part 4 is formed so that this cross-sectional ridgeline appears. Here, the third side surface portion includes the intermediate side surface portion 14.

(Embodiment of a blade cutting type rotary cutting tool)
Next, an embodiment of a blade-exchange-type rotary cutting tool in which a double-sided cutting insert according to another aspect of the present invention is detachably mounted will be described with reference to FIGS. 11A to 14.
FIG. 11A and FIG. 11B are perspective views of a blade-tip-exchange-type rotary cutting tool 40 showing an embodiment of the present invention. FIG. 11A shows a state when the cutting insert of the present invention is not mounted, and FIG. The state when mounting | wearing with the cutting insert of this invention is shown. FIG. 12 is a side view of the blade-tip-exchange-type rotary cutting tool 40 shown in FIG. 11B, FIG. 13 is a front view of the blade-tip-exchange-type rotary cutting tool 40 shown in FIG. It is the partial side view which expanded and showed the cutting insert and its vicinity in the exchange-type rotary cutting tool. The blade-tip-exchange-type rotary cutting tool 40 shown in these drawings shows an example in which five cutting inserts 31 according to the second embodiment are mounted among the above-described double-sided cutting inserts of the present invention.
In addition, the symbol “O” shown in each of these drawings is the rotation axis of the blade-tip-exchange-type rotary cutting tool 40. When cutting the workpiece by attaching the cutting edge replaceable rotary cutting tool 40 to a cutting apparatus that performs cutting based on 3D NC control or the like, the cutting edge replaceable rotating cutting tool 40 is shown in FIGS. 11A and 11B. It rotates in the direction of the arrow (T) shown.

The cutting edge replaceable rotary cutting tool 40 includes a tool body 41 having a substantially cylindrical shape. The tool body 41 shown in FIGS. 11A and 11B is an example in which five insert mounting seats 42 are provided for detachably mounting the cutting insert 31 from the tip 41a of the tool body 41 toward the outer periphery 41c. Show. The insert mounting seats 42 are formed in the tool body 41 at equal intervals (equal angles) or unequal intervals (unequal angles) about the rotation axis (O). Each insert mounting seat 42 includes a seating surface 43 for closely contacting the contact surface 9 formed on the front surface portion 2 (or the back surface portion 3) of the cutting insert 31 when the cutting insert 31 is mounted. A screw hole 43 a is formed in the center of the seating surface 43 in a direction perpendicular to the seating surface 43. This threaded hole 43a is a threaded hole for screwing the threaded portion of the clamp screw 45 through which the threaded insertion hole 8 of the cutting insert 31 is inserted when the cutting insert 31 is mounted and fixed to the insert mounting seat 42. It is. The rear end portion 41b of the tool body 41 is a portion connected to the main shaft of the cutting apparatus.

The seating surface 43 is formed so as to face the front direction of the rotational direction (T) of the pre-exchangeable rotary cutting tool 40, and the planar shape of the seating surface 43 is slightly smaller than the shape of the contact surface 11. . Further, the seating surface 43 is formed so as to form an appropriate angle set in advance with respect to the direction of the rotation axis (O) and the radial direction of the tool body 41.

As shown in FIG. 11A, the insert mounting seat 42 is a constraining wall 44 erected from the end of the seating surface 43 on the rotating shaft (O) side and the end of the tool body 41 on the rear end 41b side via a groove. It has. The constraining wall 44 positions the cutting insert 31 at a precise and accurate position with respect to the insert mounting seat 42, and the cutting insert 31 that is firmly fixed to the insert mounting seat 42 by tightening the clamp screw 45 during the cutting process. This is a means for preventing displacement. The constraining wall 44 is in contact with both or one of the first and second intermediate

side surface portions

14a and 14b constituting the intermediate side surface portion 14 of the cutting insert 31 by the tightening operation of the clamp screw 45, and the cutting insert 31. It becomes a means to bind firmly.

It is desirable that the restraint wall 44 provided in the insert mounting seat 42 has the following configuration.
The shape of the restraint surface in which the restraint wall 44 faces the seating surface 43 is made to have a shape corresponding to the shape of the intermediate side surface portion 14 of the cutting insert 31. That is, the shape of the constraining surface is such that, for example, both the first intermediate side surface portion 14a and the second intermediate side surface portion 14b constituting the intermediate side surface portion 14 of the cutting insert 31 are constrained. It is desirable that the surface shape of the constraining surface has a shape including two constraining surfaces corresponding to the intersection angle of the first and second intermediate

side surface portions

14a and 14b. Thereby, when the cutting insert 31 is fixed to the insert mounting seat 42 by tightening the clamp screw 45, the restraining force is further strengthened. The height of the restraint wall 44 from the seating surface 43 is set to about 2/3 of the height of the intermediate side surface portion 14 of the cutting insert 31 (height in the thickness direction of the cutting insert 31).

Next, in the cutting edge replaceable rotary cutting tool 40 of the present invention, when the cutting insert 31 is mounted and fixed to the insert mounting seat 42 by tightening the clamp screw 45, the orientation of the cutting insert 31, that is, The positional relationship of each cutting edge provided in the cutting insert 31 will be described with reference to FIG. FIG. 14 is an enlarged view of the cutting insert 31 displayed on the lower right side of the paper surface of FIG. 12 and the vicinity thereof. The cutting insert 31 shown in FIG. 14 (FIG. 12) uses the abutment surface 9 of the back surface portion 3 of the cutting insert 31 as an insert mounting seat 42 in order to use the cutting edge formed on the front surface portion 2 for cutting. The case where the cutting insert 31 is mounted so as to be in contact with the seating surface 43 and the cutting edge formed on the surface portion 2 is used for cutting is shown.

When the cutting insert 31 is mounted and fixed on the insert mounting seat 42, one of the three corner blades 25 provided in the cutting insert 31 is placed on the outer peripheral portion 41c side of the tool body 41 as shown in FIG. At the same time, the corner blade 25 is projected outward from the outer peripheral portion 41 c of the tool body 41. FIG. 14 shows a case where the corner blade 25 formed in the corner portion 6 a of the cutting insert 31 is arranged on the outer peripheral portion 41 c side of the tool body 41.
In addition, the main cutting edge 26 connected to the corner edge 25 and the first sub cutting edge 27 connected to the main cutting edge 26 are arranged on the tip 41a side of the tool body 41, and the main cutting edge 26 and the first cutting edge 26 are connected to the main cutting edge 26. One auxiliary cutting edge 27 is projected from the tip 41a. Furthermore, the point (C) where the main cutting edge 26 and the first sub cutting edge 27 are connected or the vicinity of the point (C) is the lowest point in the direction of the rotation axis (O) of the blade-tip-exchange-type rotary cutting tool 40. The cutting insert 31 is fixed to the insert mounting seat 42 as described above. This makes it possible to cause the third ridge line portion 19 to function as the first auxiliary cutting edge 27 when performing an inclined cutting process on the work material. Further, as shown in FIG. 14, the second auxiliary cutting edge 28 connected to one end portion of the first auxiliary cutting edge 27 and formed in the direction of the corner portion 6 c can also function as a cutting edge. become.

(Inclined cutting)
An example of a processing procedure when performing an inclined cutting process on a work material using the cutting edge exchange type rotary cutting tool of the present invention will be described. When a die or the like is manufactured by cutting, for example, pocket processing may be performed on a work material that is a die material (various types of steel for die). In such pocket machining, a method is generally employed in which a milling tool is used to sequentially and repeatedly perform inclined cutting on a work material several times.

FIG. 15 shows feed control of a milling tool (such as the cutting edge exchangeable rotary cutting tool 40 of the present invention) when the machining of the pocket (H) is performed on the work material W1 by using an NC control cutting machine. Shows the route. In the example shown in FIG. 15, an example is shown in which the path of the inclined cutting process performed on the work material W <b> 1 is sequentially repeated several times as g <b> 1, g <b> 2,.

When the inclined cutting performed when the pocket (H) shown in FIG. 15 is cut, the cutting edge exchangeable rotary cutting tool of the present invention can be used to perform favorable cutting. Hereinafter, the operation of each cutting edge included in the cutting insert 31 according to the present invention when the inclined cutting process is performed using the blade-tip-exchange-type rotary cutting tool 40 of the present invention will be described.

FIG. 16A shows that the cutting insert 31 mounted on the cutting edge exchange type rotary cutting tool 40 of the present invention is applied to the work material (W2) while being given feed control in the Z-axis direction and feed control in the X-axis direction. On the other hand, the state when the slant cutting process of the lower left is implemented in the arrow (X1) direction is shown. In FIG. 16A, the blade-tip-exchange-type rotary cutting tool 40 is applied to the unmachined surface (W2a) of the work material (W2) while feed control in the X1 direction (lateral feed) is performed by, for example, a 3-axis control machine. Inclined cutting is performed to obtain an inclined surface (W2b).

In the inclined cutting process in the X1 direction shown in FIG. 16A, the main cutting edge of the cutting insert 31 on the left side of the rotation axis (O) of the blade-tip-exchange-type rotary cutting tool 40 contributes to the cutting process, and the right cutting insert 31 is used. The first auxiliary cutting edge 27 connected to the main cutting edge 26 also contributes to the cutting process.
At this time, the first auxiliary cutting edge 27 of the right cutting insert 31 acts as a cutting blade for the lateral feed in the X1 direction with respect to the unmachined surface (W2a) of the work material (W2).
In the inclined cutting process, the main cutting edge 26 and the first auxiliary cutting edge 27 are also used for cutting when performing a downward cutting process (an inclined cutting process in the direction opposite to the X1 direction shown in FIG. 16A). Contribute.
Further, in this inclined cutting process, when the cutting amount in the Z-axis direction is set large, the second auxiliary cutting edge 28 connected to the first auxiliary cutting edge 27 also acts as a cutting edge. .

On the other hand, FIG. 16B shows a state in which planar processing is performed on the work material (W2) by feed control in the X2 direction (transverse feed) of the cutting edge exchange type rotary cutting tool 40. In this plane machining, the main cutting edge 26 can cut the cut and removed portion (W2d) of the work material (W2) to obtain a machined surface (W2e) obtained by plane cutting.

The cutting insert of the present invention includes four cutting edge regions (corner blade 25, main cutting edge 26, and first and second auxiliary cutting edges 27, 28 for each corner portion of the front surface portion 2 and the back surface portion 3. Area). As a result, when the cutting edge in the cutting edge region of one cutting insert is worn, the cutting insert is repeatedly mounted on the insert mounting seat 42 of the tool main body 41, whereby a total of six

corner portions

6a and 6b are obtained. , 6c can be sequentially used as cutting edges. Furthermore, since the cutting insert of the present invention has the above-described characteristics, the cutting insert can ensure the strength of the cutting edge even when used for high-feed roughing applications on the work material. The cutting edge exchange-type rotary cutting tool equipped with can contribute to cost reduction particularly in a high-feed roughing process of a work material.

(Production method)
The manufacture of the cutting insert according to the present invention described above is performed, for example, by pressing a cemented carbide powder obtained by adding Co powder and a binder to WC (tungsten carbide) powder with a powder molding apparatus, thereby pressing the cutting insert. Are manufactured through a molding process for producing a high-hardness sintered body by firing the press-molded body for a predetermined time at a temperature close to 1300 ° C. to 1400 ° C. Moreover, about the sintered compact (cutting insert), a finishing process is performed using the diamond grindstone etc. in the site | part which needs a finishing process. The cutting insert of the present invention may be made of a hard material such as cermet or sialon-based ceramics in addition to the cemented carbide.

Also, the tool body 41 can be manufactured using a NC machine tool made of a round bar material made of alloy tool steel such as SKD61. The processing of the insert mounting seat 42 on the tool body 41 can be formed by cutting using a cutting tool such as an end mill. The detailed shape of the insert mounting seat 42 may be precisely processed using a small-diameter end mill or the like.

In milling, it is possible to perform high-feed roughing while suppressing interference with the work material, so that it is possible to perform milling with higher efficiency.

1 cutting insert (double-sided cutting insert (first embodiment))
2 Surface portion 3 Back surface portion 4 Side surface portion 5

Crossing ridge lines

6a, 6b, 6c Corner portion 7 Arc-shaped crossing ridgeline at corner portion 8 Screw insertion hole 8a Opening portion 9 Contact surface 10 Rake face 11 Boundary portion,
11a, 11b End of boundary portion 12 Flank 13 Corner side surface portion 13a First corner side surface portion 13a1 Lower end portion of first corner side surface portion 13b Second corner side surface portion 13b1 Upper end portion of second corner side surface portion 14 Intermediate side surface portion 14a First intermediate side surface portion 14b Second intermediate side surface portion 15

Contour ridge lines

15a, 15b, 15c Arc-shaped contour ridge line 16 circumscribed circle 17 first ridge line portion 18 second ridge line portion 19 third ridge line portion 20 first 4 ridge line portions 21 5th ridge line portion 23 cross-sectional ridge line of first corner side surface portion 13a 24 cross-sectional ridge line of second corner side surface portion 13b 25 corner blade 26 main cutting edge 27 sub cutting edge (first sub cutting edge)
28 Second Sub Cutting Edge 31 Cutting Insert (Double-Sided Cutting Insert (Second Embodiment))
32 corner side surface portion 32a first corner side surface portion 32a1 lower end portion in the direction of the back surface portion of the first corner side surface portion 32b second corner side surface portion 32b1 upper end portion in the direction of the surface portion of the second corner side surface portion 32c first 3 corner side surfaces 33 Corner portion intersecting ridge line 34a Cross section ridge line of first corner side surface portion 32a 34b Cross section ridge line of second corner side surface portion 32b 34c Section ridge line of third corner side surface portion 32c 40 Cutting edge exchange type rotary cutting tool 41 Tool body 41a Front end portion 41b Rear end portion 41c Outer peripheral portion 42 Insert mounting seat 43 Seating surface 43a Screw hole 44 Restraint wall 45 Clamp screw A Intersection of intersecting ridge line and straight line (K) in projected view of front surface or rear surface B Intersection of intersection ridge line and straight line (N) in front or back projection C Surface Or, in the projected view of the back surface portion, the intersection of the intersecting ridge line and the straight line (R) D In the projected view of the front surface portion or the back surface portion, the intersection of the intersecting ridge line and the straight line (L) G contact GP, GP1, GP2, GP3 G) A straight line that connects the center point of the screw insertion hole H Pocket K A straight line that forms an angle (δ) counterclockwise around the center point (P) with respect to the straight line (GP) N Straight line (GP) A straight line that makes an angle (ε) in the clockwise direction around the center point (P) with respect to the reference L An angle (μ) in the counterclockwise direction around the center point (P) with respect to the straight line (K) A straight line R that forms an angle (η) in the clockwise direction around the center point (P) with respect to the straight line (N). M A distance between the contact surface formed on the front surface portion and the back surface portion. A plane (intermediate surface) that bisects and intersects the center line of the screw insertion hole perpendicularly
M1, M2, M3 A plane parallel to the intermediate surface (M) O The rotation axis of the tool body P The center point of the screw insertion hole P1 The center axis of the screw insertion hole S1 The straight line (GP1) exists at a position facing the corner 6a. Intersection with the intersecting ridgeline S2 Intersection with the intersecting ridgeline where the straight line (GP2) faces the corner 6b S3 Intersection with the intersecting ridgeline where the straight line (GP3) faces the corner 6c T Tool body Rotating direction W1, W2 Work material W2a Unmachined surface of work material W2b Work surface of inclined cutting W2c, W2d Cutting removal part M2e Work surface of plane cutting X1, X2 Feed direction of cutting tool at the time of cutting f1 1st Intersection of the cross-sectional ridge line 23 of the corner side surface portion and the cross-sectional ridge line 24 of the second corner side surface portion f2 The cross-sectional ridge line 34a of the first corner side surface portion and the third corner side surface portion Intersection point with the cross-sectional ridge line 34c f3 Intersection point between the cross-sectional ridge line 34c of the third corner side surface part and the cross-sectional ridge line 34b of the second corner side surface part g1, g2, ..., g8 When performing inclined cutting on the work material In the longitudinal sectional view of the surface portion along the straight line (GP), the angle formed by the cross-sectional ridgeline of the first corner side surface with respect to the reference surface parallel to the intermediate surface (M) β In the longitudinal sectional view of the surface portion along the straight line (GP), the angle formed by the cross-sectional ridge line of the second corner side surface portion with respect to the reference plane parallel to the intermediate surface (M) γ The surface portion along the straight line (GP) The angle θ formed by the cross-sectional ridgeline of the third corner side surface portion with respect to the reference plane parallel to the intermediate surface (M), the straight line connecting the center point (P) and the point (S3), and the center point ( Angle formed by a straight line connecting P) and the point (S2) δ Straight line (G ), The angle formed in the counterclockwise direction around the center point (P) ε The angle formed in the clockwise direction around the center point (P) with respect to the straight line (GP) μ Straight line (K) The angle λ (S3) formed in the clockwise direction around the center point (P) with respect to the angle η straight line (N) as the center and the angle η formed in the counterclockwise direction with respect to the center point (P). The angle formed in the clockwise direction around the center point (P) with respect to the straight line (GP3) passing through, and the counterclockwise around the center point (P) with respect to the straight line (GP2) passing through the point κ (S3). Angle to make in the rotation direction

Claims

From the center of the front surface portion to the center portion of the back surface portion, the front surface portion and the back surface portion having three corner portions and having a substantially triangular shape, the side surface portion connected between the both surface portions of the front and back surfaces via a crossing ridge line A screw insertion hole that penetrates and an abutment surface formed around the opening of the screw insertion hole on both sides of the front and back sides, and the both sides of the front and back sides are symmetrical with each other in the opposite shape. In double-sided cutting inserts,
The side surface portion is composed of a corner side surface portion connecting between the opposite corner portions between the front and back side surface portions, and an intermediate side surface portion connecting between the adjacent corner side surface portions,
The corner side surface portion includes a flank surface formed so as to protrude with a gentle convex shape with respect to the intersecting ridge line,
A contact point of a circumscribed circle circumscribing a figure formed by a closed continuous line located on the outermost side with the center point P of the screw insertion hole as a center in a diagram constituting a plan view or a projection view of the surface portion is defined as a contact point G. A straight line connecting the contact point G and the center point P of the screw insertion hole is defined as a straight line GP, and the distance between the contact surfaces formed on both the front and back surfaces is divided into two equal parts, and the screw insertion When a plane perpendicular to the center axis of the hole is defined as an intermediate plane M,
In the longitudinal section along the straight line GP of the cutting insert, the side portion on the corner portion side is a side portion constituting the corner side portion,
The first corner side surface having a cross-sectional ridge line intersecting at an obtuse angle α (degrees) with respect to the intermediate surface M or a reference plane parallel to the intermediate surface M, and a cross-sectional ridge line intersecting at an acute angle β (degrees) A double-sided cutting insert, comprising: a second corner side surface portion having:
2. The double-sided cutting insert according to claim 1, wherein the intermediate side surface portion is formed as a side surface portion that intersects the intermediate surface M or a reference surface parallel to the intermediate surface M at a right angle. Double-sided cutting insert.
The double-sided cutting insert according to claim 1 or 2, wherein the corner side surface portion constituting the side surface portion is in a longitudinal section along the straight line GP of the cutting insert,
A first corner side surface portion having a cross-sectional ridge line intersecting at an obtuse angle α ° with respect to the intermediate surface M or a reference plane parallel to the intermediate surface M, and a second cross-sectional ridge line intersecting at an acute angle β °. A double-sided cutting insert comprising: a third corner side surface having a cross-sectional ridge line intersecting at a right angle with a corner side surface of
4. The double-sided cutting insert according to claim 3, wherein the third corner side surface portion includes the first and second corners between the first corner side surface portion and the second corner side surface portion. A double-sided cutting insert characterized in that it is formed in a state of being integrally connected to a side surface portion.
In the double-sided type cutting insert according to claim 1 or 2,
The first corner side surface portion extends from the cross ridge line portion of the front surface portion in the direction of the back surface portion, and the lower end portion and the vicinity thereof are formed so as not to reach the cross ridge line portion of the back surface portion,
The second corner side surface portion extends from the cross ridge line portion of the back surface portion in the direction of the surface portion, and the upper end portion and the vicinity thereof are formed so as not to reach the cross ridge line portion of the surface portion,
The lower end portion of the first corner side surface portion and the vicinity thereof are connected to the second corner side surface portion, and the upper end portion of the second corner side surface portion and the vicinity thereof are connected to the first corner side surface portion. Double-sided cutting insert characterized by
The double-sided cutting insert according to any one of claims 1 to 5, wherein the straight line GP passing through each of the corner portions counters a crossing point where the intersecting ridge line facing the corner portion intersects the counterclockwise direction. When the intersection S1, the intersection S2, and the intersection S3 are set,
A range having an angle κ ° in the counterclockwise direction around the center point P with respect to the straight line GP passing through the intersection point S2, and the center point P as a center with respect to the straight line GP passing through the intersection point S3. In the range of the angle λ ° in the clockwise direction, the side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P is:
The intermediate side surface portion having a cross-sectional ridge line intersecting at a right angle with respect to the intermediate surface M or a reference plane parallel to the intermediate surface M,
The angle κ ° and the angle λ ° are equal, and the angle κ ° and the angle λ are set in a range of 10 ≦ (κ, λ) ≦ 30. Die cutting insert.
In the double-sided type cutting insert in any one of Claims 1-6,
Straight lines having an angle δ ° in the counterclockwise direction around the center point P with respect to the straight line GP and an angle ε ° in the clockwise direction are defined as a straight line K and a straight line N, respectively, and the range of the angle δ °. And the side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P in the range of the angle ε °,
The first corner side surface having a cross-sectional ridge line intersecting at an obtuse angle α °, and the second corner side surface having a cross-sectional ridge line intersecting at an acute angle β °;
The value of the angle δ ° is equal to the value of the angle ε °, and the value of the angle δ ° and the angle ε ° is
3 ≦ (δ, ε) ≦ 25,
A double-sided cutting insert characterized by being set in the range of
In the double-sided cutting insert according to claim 3 or 4,
Straight lines having an angle δ ° in the counterclockwise direction around the center point P with respect to the straight line GP and an angle ε ° in the clockwise direction are defined as a straight line K and a straight line N, respectively, and the range of the angle δ °. And the side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P in the range of the angle ε °,
The first corner side surface having a cross-sectional ridge line intersecting at an obtuse angle α °;
The second corner side surface having a cross-sectional ridge line intersecting at the acute angle β °;
The third corner side surface portion having a cross-sectional ridge line intersecting at a right angle,
The value of the angle δ ° is equal to the value of the angle ε °, and the value of the angle δ ° and the angle ε ° is
3 ≦ (δ, ε) ≦ 25,
A double-sided cutting insert characterized by being set in the range of
In the double-sided type cutting insert in any one of Claims 1-8,
A straight line having an angle μ ° in the counterclockwise direction centered on the center point P with respect to the straight line K is defined as a straight line L, and a straight line centered on the center point P with respect to the straight line N in a clockwise direction. When a straight line forming an angle η ° is a straight line R,
The value of the angle μ ° is set to μ = 60− (δ + λ), and the value of the angle η ° is set to η = 60− (ε + κ),
The side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P in the range of the angle μ °,
Comprising a side surface portion having a cross-sectional ridge line intersecting at right angles with the second corner side surface portion having a cross-sectional ridge line intersecting at an acute angle β °;
The side surface portion in the longitudinal section of the cutting insert along a straight line passing through the center point P in the range of the angle η °,
A double-sided cutting insert comprising a side surface portion having a cross-sectional ridge line intersecting with the first corner side surface portion having a perpendicular angle with a cross-sectional ridge line intersecting at an obtuse angle α °.
In the double-sided cutting insert according to any one of claims 1 to 9, in the intersecting ridge line formed between the front surface portion and the back surface portion and the side surface portion,
A point of intersection between the straight line K and the intersecting ridge line is A,
The intersection of the straight line N and the intersecting ridge line is B,
The intersection of the straight line R and the intersecting ridge line is C,
Let D be the intersection of the straight line L and the intersecting ridgeline,
A crossing ridge line in a range from the intersection A to the intersection B is a first ridge line portion,
A cross ridge line in a range from the intersection B to the intersection C is a second ridge line portion,
A cross ridge line in a range from the intersection C to the intersection S2 is a third ridge line portion,
A crossing ridge line in a range from the intersection A to the intersection D is a fourth ridge line portion,
When the intersection ridge line in the range from the intersection D to the intersection S3 is the fifth ridge line part,
The corner side surface portion constituting the side surface portion is
From the first ridgeline portion, the second ridgeline portion, and the fourth ridgeline portion of the back surface portion from the corner portion intersecting ridgeline composed of the first ridgeline portion, the second ridgeline portion, and the fourth ridgeline portion of the front surface portion. Is formed up to the corner crossing ridge line,
The intermediate side surface portion constituting the side surface portion is formed from the third ridge line portion and the fifth ridge line portion of the front surface portion to the third ridge line portion and the fifth ridge line portion of the back surface portion. Double-sided cutting insert.
The double-sided cutting insert according to claim 10, wherein the intermediate side surface portion is
A first intermediate side surface portion formed from the third ridge line portion of the front surface portion to the third ridge line portion of the back surface portion;
The double-sided cutting insert characterized by comprising the 2nd intermediate side surface part formed from the said 5th ridgeline part of the said surface part to the said 5th ridgeline part of the said back surface part.
The double-sided cutting insert according to claim 10 or 11, wherein the first ridge line portion is a corner blade, the second ridge line portion is a main cutting edge, and the third ridge line portion is a sub cutting edge. A double-sided cutting insert characterized by that.
The double-sided cutting insert according to claim 10 or 11, wherein the first ridge line portion is a corner blade, the second ridge line portion is a main cutting edge, and the third ridge line portion and the fifth ridge line portion. Is a double-sided cutting insert characterized by a secondary cutting edge.
A double-sided cutting insert according to claim 12 or claim 13, wherein the double-sided cutting insert is detachably attached to an insert mounting seat formed at a tip portion of a tool body by screw fastening means. Comprises a seating surface formed to face forward in the rotational direction of the tool body, and a restraint wall for restraining the intermediate side surface portion of the double-sided cutting insert,
When the double-sided cutting insert is fixed to the insert mounting seat by the screw fastening means,
In the double-sided cutting insert, one of the corner blades is disposed on the outer peripheral side of the tool main body in a state where the abutment surface of the front surface portion or the back surface portion is in close contact with the seating surface of the insert mounting seat. While the cutting edge and the auxiliary cutting edge connected to the main cutting edge are arranged on the tip end side of the tool body,
The cutting edge exchange type rotary cutting tool, wherein the intermediate side surface portion of the double-sided cutting insert is in contact with the restraining wall of the insert mounting seat.