JPH07237027A - Throwaway tip and cutting tool - Google Patents

Abstract

PURPOSE:To make a tip usable at four corners so as to prolong the service life of the tip and reduce cutting resistance. CONSTITUTION:First and second acute-angled corners 17a, 17b respectively positioned in pairs in diagonal directions from the top view, and two obtuse- angled corners 18 are formed on the upper face 15 and lower face 16 formed into almost drum shape. The first acute-angled corners 17a and the second acute-angled corners 17b are opposed on the upper and lower faces, and the ridgelines of the side faces intersecting each other are formed into main cutting edges 22. The main cutting edges 22 are inclined inward from the first acute- angled corners 17a on the upper and lower faces toward the opposed second acute-angled corners 17b on the lower and upper faces. The ridgelines of chamfer parts 23 formed by cutting out the respective first acute-angled corners 17a on the upper and lower faces are made auxiliary cutting edges 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool such as a throw-away tip having a substantially hourglass shape and an end mill equipped with the throw-away tip, which can be cut at a right angle (90 degree shoulder wall cutting). Regarding things.

[0002]

2. Description of the Related Art As an example of this type of cutting tool capable of cutting a work material at right angles, there is an end mill 1 as shown in FIGS. The throw-away tip 2 mounted on the end mill 1 is a positive throw-away tip having a substantially rhombic plate shape as shown in FIG. That is, the side surface 5 that extends outward from the seating surface 3 in the direction of the top surface 4 is formed with respect to the upper surface 4 that faces the seating surface 3. Then, one ridgeline of the acute-angled corner portion of the upper surface 4 serves as the main cutting edge 6, and a sub-cutting edge 7 is provided near the corner of the other ridgeline.

The throw-away tip 2 is
With the tip mounting seat 8 having a concave shape formed at the outer peripheral tip of the end mill main body 1a mounted, the sharp corner portion is mounted at the outer peripheral tip, and the main cutting edge 6 is the rotation axis L of the end mill main body 1a. It is a peripheral blade parallel to
The auxiliary cutting edge 7 located on the tip side is provided with an auxiliary cutting edge cutting angle. Moreover, as shown in FIGS. 13 and 14, the radial rake angle is set to be positive with respect to the radial axis M, and the axial rake angle is set to be positive with respect to the rotation axis L of the end mill 1. With such an end mill 1, the work material is cut at right angles.

Further, as another example, there is an end mill 1 shown in FIGS. 15 to 17, in which a diamond-shaped throw-away tip 10 similar to the above-mentioned throw-away tip is mounted as a vertical blade. In this throw-away tip 10, a ridge line where adjacent side surfaces 5 intersect at an acute corner is used as a main cutting edge 11, and a chamfered portion 12 is formed by cutting out an upper surface 4 of this acute corner. The ridgeline where the side surface 5 that faces the rotation direction intersects is defined as the sub cutting edge 13. The throw-away tip 10 is mounted on the tip mounting portion 8'of the end mill body 1a with the sharp corners of the upper surface 4 facing the outer peripheral tip side, and the main cutting edge 11 in the mounted state is the rotation axis l of the end mill body 1a. Parallel to
Moreover, it is arranged as a peripheral blade. Further, the upper surface 4 is located on the outer peripheral side of the tip with a clearance angle on the front side (see FIG. 1).
5). Moreover, as shown in FIGS. 16 and 17, the radial rake angle and the axial rake angle are set to be positive.

[0005]

However, in the case of the end mill 1 or the face milling machine using the above-described diamond-shaped or parallelogram-shaped throw-away tips 2 and 10, the throw-away tips are positive. Only the upper surface can use only two corners, which has a drawback that the chip life is short.

In view of the above situation, it is an object of the present invention to provide a throw-away tip which can be used at four corners and can improve the life of the tip, and a cutting tool equipped with the throw-away tip.

[0007]

A throw-away tip according to the present invention has a substantially hourglass plate shape, and has an upper surface and a lower surface each having a pair of first and second acute-angled corners located diagonally in plan view. And a side surface that intersects the upper surface and the lower surface, and the ridge line where the adjacent side surfaces intersect at each acute-angled corner is the main cutting edge, and these main cutting edges are the first acute-angled corners of the upper surface and the lower surface. Is inclined inwardly toward the second acute-angled corners of the lower surface and the upper surface facing each other. Further, each pair of first acute-angled corners of the upper surface and the lower surface is cut out to form a chamfered portion, and a ridge line intersecting with each chamfered portion and a side surface extending from the first acute-angled corner toward the obtuse-angled corner is a subordinate. It is characterized by being configured as a cutting edge.
The auxiliary cutting edge is characterized in that it is formed in a straight line or a straight line connected to a corner of an arc.

The side surface between the first and second acute-angled corners adjacent to each other in plan view is a flank of the main cutting edge, and the width thereof gradually increases from the first acute-angled corner toward the opposite lower surface or upper surface. It is characterized in that a notch surface is formed. Further, the flank of the main cutting edge is characterized in that it is formed on a convex side surface of a polygonal shape or a substantially arc surface shape that bends at an obtuse angle from the central region in the direction of the main cutting edge at both ends. The side surface formed between the first acute-angled corner and the obtuse-angled corner adjacent to the first acute-angled corner in a plan view is an inclined receiving surface that inclines inward from a ridgeline having a sub-cutting edge on the upper surface or the lower surface toward the lower surface or the upper surface facing each other. It is characterized as being.

Further, in a cutting tool in which a throw-away tip is mounted on the outer periphery of the tip of the tool body, the tip is one of the above-mentioned throw-away tips, and the main cutting edge is mounted so as to be the outer circumferential edge. It is characterized by being present. The front end and the rear end of the main cutting edge on the outer peripheral side are arranged so as to have the same radius of rotation with respect to the rotation axis of the tool body. The cutting tool is an end mill.

[0010]

In the throw-away tip according to the present invention, the first acute-angled corner area can be used as a cutting edge, and the first acute-angled corners are provided in pairs on the upper surface and the lower surface, respectively. it can. Moreover, each cutting edge at the 4th corner became positive,
Highly accurate cutting with small cutting resistance is possible. Further, since the auxiliary cutting edge connected to the main cutting edge is provided, when performing the right angle cutting, the main cutting edge can perform right angle wall surface cutting, and the sub cutting edge can perform finish cutting. Since a positive throw-away tip that can be used for 4 corners on the upper and lower surfaces is attached as a vertical blade to the cutting tool, right-angle wall surface cutting is performed with the main cutting edge that is the outer peripheral blade.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. 1 to 7 show a first embodiment of the present invention. 1 is a perspective view of a throw-away tip according to the present embodiment, FIG. 2 is a plan view of a throw-away tip, FIG. 3 is a side view in a flank direction, FIG. 4 is a side view in a rake face direction, and FIG. FIG. 6 is a partial front view showing a state in which the throw-away tip is mounted on the end mill, FIG. 6 is a partial side view of the end mill of FIG. 5 seen from the tip rake face direction,
FIG. 7 is a partial side view of the end mill of FIG. 5 seen from the outer peripheral direction. The throw-away tip 14 shown in FIGS.
In the above, the tip 14 is formed in a substantially drum shape, and the upper surface 15 and the lower surface 16 are formed so as to face each other, and four sharp corners 17a and 17b and two obtuse corners 18 are formed.
Are formed respectively. Each of the four acute-angled corners 17a and 17b of the upper and lower surfaces 15 and 16 has a pair of first acute-angled corners 17a provided in a diagonal direction and a pair of second acute-angled corners 17b provided in a diagonal direction intersecting the first acute-angled corners 17a.
It is composed of and. Moreover, the upper surface 15 and the lower surface 1
6 and 6, the first acute-angled corner 17a and the second acute-angled corner 17b are located so as to face each other.

Each side surface intersecting with the upper and lower surfaces 15 and 16 has first and second acute corners 17 adjacent to each other in plan view.
A pair of convex side surfaces 19 is provided between a and 17b,
In addition, when viewed in a plan view, the first two
Also, a pair of concave side surfaces 20 are provided to face each other between the second acute angle corners 17a and 17b. Also, the upper surface 15 and the lower surface 1
A screw hole 21 for inserting a screw for inserting the tip 14 into an end mill body to be described later is bored through the central portion of 6. Then, in a plan view, the chip 14 is formed point-symmetrically around the screw hole 21.

Further, between the first and second acute-angled corners 17a and 17b facing each other between the upper and lower surfaces 15 and 16,
The ridge lines at which the adjacent convex side surfaces 19 and concave side surfaces 20 intersect each other are the main cutting edges 22, and the main cutting edges 22 are connected to the first and second acute corners 17a, 17b of the upper surface 15 and the lower surface 16, respectively. It has been extended. The pair of first acute-angled corners 17a opposite to each other in the diagonal direction of the upper surface 15 are each formed with a chamfered portion 23 by cutting out the upper surface 15. From the chamfered portion 23 and the first acute-angled corner 17a, the obtuse corner 1 is formed.
The ridge line that intersects the concave side surface 20 extending in eight directions is the sub cutting edge 2
It is supposed to be 4. Also on the lower surface 16, a pair of first acute-angled corners 17a of the upper surface 15 which are diagonally intersecting in a plan view in a diagonal direction connecting the first acute-angled corners 17a are also cut out and chamfered. Part 2
3 are respectively formed, and the ridgeline where the chamfered portion 23 and the concave curved surface 20 extending from the first acute-angled corner 17a toward the obtuse-angled corner 18 intersect each other is a straight sub-cutting edge 24.

Further, in the convex side surface 19, a triangular cut is formed inward so that the width gradually increases from the first acute-angled corners 17a of the upper surface 15 and the lower surface 16 toward the lower surface 16 and the upper surface 15 which face each other. Notch surfaces 25 are respectively formed and serve as first flanks of the main cutting edge 22.
Therefore, as shown in FIG. 3, each convex side surface 19 has a substantially parallelogram-shaped flat surface portion 19 a orthogonal to the upper and lower surfaces 15 and 16.
And a pair of triangular notch surfaces (first flanks) 25 that are formed point-symmetrically on both sides thereof and are inclined with respect to the flat surface portion 19a. Then, in each concave side surface 20, a part of the concave side surface 20 inclines in a plane shape from a part of the ridge line extending from the first acute corner 17a of the upper surface 15 to the obtuse corner 18 toward the inner side of the lower surface 16. The receiving surface 27 is formed. Similarly, an inclined receiving surface 27 in which a part of the concave side surface 20 inclines like a plane is formed from a partial ridgeline extending from the first acute angle corner 17a of the lower surface 16 to the vicinity of the obtuse angle corner 18 toward the inner side of the upper surface 15. Has been done. This inclined receiving surface 27 constitutes the rake surface of the main cutting edge 22. Also, as shown in FIG.
The main cutting edge 22 and the sub cutting edge 24 are formed at a substantially right angle, and the main cutting edge 2
2 has an acute angle with respect to the upper surface 15 and is inclined by a small angle α with respect to a line orthogonal to the upper surface 15 or the lower surface 16. The auxiliary cutting edge 24 has the upper surface 15 (or the lower surface 16).
It is formed with a small angle β with respect to.

The throw-away tip 14 according to this embodiment.
Has the above-mentioned configuration, and next, a state in which the throw-away tip 14 is mounted on the end mill 29 will be described with reference to FIGS. 5 to 7. In FIG.
The throw-away tip 14 is attached to the tip surface 30a of the end mill body 30 as a vertical blade. End mill body 30
A concave tip mounting seat 31 is formed on the outer peripheral tip surface 30a, and the lower surface 16 (or the upper surface 15) of the throw-away tip 14 is mounted on the seat 31a on the bottom surface of the chip mounting seat 31, for example. In the mounted state, the throw-away tip 14 has the first acute-angled corner 1 having the auxiliary cutting edge 24.
7a is located on the outer peripheral tip side. The main cutting edge 22 connected to the sub cutting edge 24 is an outer peripheral edge and is positioned parallel to the rotation axis L of the end mill body 30 when viewed from the rake face direction (see FIG. 6). That is, the main cutting edge 22 has a front end and a rear end having a turning radius of substantially the same dimension with respect to the rotation axis L. Therefore, the sub cutting edge 24 has a sub cutting edge cutting angle of the angle α. A pocket 32 for discharging chips is formed on the front end surface of the outer periphery of the end mill body 30 in the front of the throw-away tip 14 in the rotation direction.

Moreover, the two side surface receiving portions 33 and 34 facing the outer peripheral direction of the tip mounting seat 31 and the front in the rotational direction are the throw-away tip 1 facing the center side of the end mill body 30.
The flat surface portion 19a of the convex side surface 19 of No. 4 and the inclined receiving surface 27 located on the outer peripheral side of the concave side surface 20 located rearward in the rotation direction of the throw-away tip 14 are respectively positioned to support the tip 14 by positioning it. It is like this. Further, since the tip 14 is formed in a substantially hourglass shape, the radial rake angle becomes positive by giving a positive angle γ to the radial axis M (see FIG. 5), and the axial rake angle rotates. A positive angle δ is added to the axis L to become positive (see FIG. 7). Moreover, the convex side surface 19 forming the flank of the main cutting edge 22 is held at a position retracted in the direction of the rotation center L so as not to contact the right-angled wall surface formed by the main cutting edge 22 during cutting.

Since the present embodiment has the above-mentioned structure, when the work material is cut at a right angle by the end mill 29 having the throw-away tip 14 according to the present embodiment, it is located on the outer peripheral side. Right angle wall surface cutting is performed by the cutting edge 22, and finish cutting is performed by the auxiliary cutting edge 24 located on the tip side. The chips generated by cutting use the inclined receiving surface 27 of the concave side surface 20 as a rake surface to form the pocket 3
It travels in two directions and is discharged. Moreover, since the convex side surface 19 forming the flank with respect to the main cutting edge 22 is located inside the plane of the rotation locus of the main cutting edge 22 in the circumferential direction about the rotation axis L of the cutter body 30, It never touches the right-angled wall. In addition, the throw-away tip 14 according to this embodiment
Can use 4 corners on each of the upper and lower surfaces 15 and 16 as cutting blades with each of the two first acute-angled corners 17a located in diagonal directions intersecting each other in a plan view. Moreover, the cutting edge rake angles of these four first acute-angled corners 17a are all positive because the tip 14 is in the shape of an hourglass plate, the cutting resistance is small, and highly accurate cutting is possible.

As described above, according to the present embodiment, the four corners can be used as the cutting edges on the upper and lower surfaces 15 and 16 of the throw-away tip 14 to improve the life of the tip, and further, to improve the cutting edge life. All rake angles are positive, enabling highly accurate cutting with low cutting resistance.

Next, FIGS. 8A and 8B show a modification of the above-described first embodiment, where FIG. 8A is a front view of the throw-away tip and FIG. 8B is a side view. . In the throw-away tip 50 shown in FIG. 8, at the first acute-angled corner 17a, the auxiliary cutting edge 36 formed at the intersecting ridgeline between the chamfered portion 23 and the ridgeline portion extending from the first acute-angled corner 17a to the obtuse-angled corner 18 is It is formed so as to be connected to the arc-shaped corner. This has the advantage of increasing the strength of the cutting edge.

FIGS. 9A and 9B show another modification of the first embodiment. FIG. 9A is a front view of the throw-away tip, and FIG. 9B is a side view. In the throw-away tip 60 shown in FIG. 9, the first acute-angled corner 17a
The secondary cutting edge is not formed on. Therefore, the chamfer 23
Well not formed. This throw-away tip 60
However, since the secondary cutting edge is not provided, finishing cutting cannot be performed, but the processing is easy and the manufacturing cost is reduced accordingly.
Moreover, the same effect as that of the first embodiment is obtained in which four corners can be used and the rake angle of each cutting edge is positive.

Next, a second embodiment of the present invention will be described with reference to FIGS. 10A is a front view of the throw-away tip according to the second embodiment, FIG. 10B is a side view, and FIG.
FIG. 1 is a front view of an end mill equipped with a throw-away tip. In the throw-away tip 38 shown in FIG. 10, the upper surface 15 and the lower surface 1 are provided at the center of the convex side surface 39.
6 is formed on the both sides adjacent to the flat surface portion 39a toward the respective main cutting edges 22.
Substantially triangular side surface portions 40, 40 having an obtuse angle with respect to and orthogonal to the upper and lower surfaces 15, 16 are formed. Moreover, on the convex side surface 39, the upper surface 15
And a triangular notch surface 4 extending from the apex of the first acute-angled corner 17a of the lower surface 16 toward the inside of the lower surface 16 and the upper surface 15 facing each other so as to gradually widen its width.
1 is formed as the first flank of the main cutting edge 22. Therefore, as shown in FIG. 10A, each convex side surface 39 is formed as a polygonal flank that is close to an arc in a plan view.

The throw-away tip 38 according to this embodiment.
Since it has the above-mentioned configuration, it can be mounted on an end mill having a smaller tip surface diameter than the end mill 29 according to the first embodiment described above. That is, FIG.
As shown in, when mounted on a small diameter end mill 43,
Since the convex side surface 39 is positioned and rotated so as not to contact the cutting surface of the work material cut by the main cutting edge 22, even if the right angle cutting is performed, the main cutting edge 22 is formed on the right-angled wall surface. The flank surface (convex side surface 39) does not contact.

In each of the above embodiments, the convex side surfaces 19, 3 are
Although the shape of 9 is a linear shape or a polygonal shape having two obtuse angles in a plan view, the shape is not limited to this and may be another polygonal shape or a curved shape. For example,
Each of the first acute-angled corners 17a is formed by forming the convex side surface into an arcuate curved surface.
It is also possible to form a notched surface that is inclined so that its width gradually increases in the direction of the upper surface 15 or the lower surface 16 facing from the apex. Further, although the end mills 29 and 43 are used as the cutting tools for mounting these throw-away tips, it goes without saying that a milling cutter such as a face milling cutter or other cutters may be used.

[0024]

As described above, the throw-away tip according to the present invention is in the shape of an hourglass plate and has an upper surface having a pair of first and second acute-angled corners which are diagonally positioned in a plan view. A ridge having a lower surface and side surfaces intersecting the upper surface and the lower surface, and adjacent side surfaces intersecting each other at each acute angle corner is defined as a main cutting edge, and these main cutting edges are the first acute angles of the upper surface and the lower surface. Since it is formed so as to incline inward from the corner toward the second acute-angled corners of the lower surface and the upper surface facing each other, the first acute-angled corner can be used as a cutting blade, and four corners can be used. The life is improved and each main cutting edge is set to positive, so that the cutting resistance is small and highly accurate cutting is possible. Further, since the pair of first acute-angled corners on the upper surface and the lower surface are cut out to form the auxiliary cutting edges, it is possible to perform finish cutting. Further, since the side surface forming the flank of the main cutting edge is formed into a convex side surface of a polygonal shape or a substantially arc surface shape that bends at an obtuse angle from the central region in the direction of the main cutting edge at both ends in plan view, it has a small diameter. Can be attached to cutting tools.
Further, in the cutting tool according to the present invention, since the above-mentioned throw-away tip is mounted so that the main cutting edge becomes the outer circumferential edge, it is possible to perform right-angle cutting and use the tip at four corners. The life is improved and high precision cutting with low cutting resistance becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view of a throw-away tip according to a first embodiment of the present invention.

FIG. 2 is a plan view of a throw-away tip.

FIG. 3 is a side view of the throw-away tip of FIG. 1 in a flank direction.

FIG. 4 is a side view of the throw-away tip of FIG. 1 in the direction of the rake face.

5 is a partial front view of the end mill equipped with the throw-away tip shown in FIG. 1. FIG.

FIG. 6 is a partial side view of the end mill in FIG. 5 seen from the rake face direction of the throw-away tip.

FIG. 7 is a partial side view of the end mill of FIG. 5 viewed from the outer peripheral direction.

8A and 8B show a modified example of the throw-away tip according to the first embodiment, wherein FIG. 8A is a plan view and FIG. 8B is a side view in the rake face direction.

9A and 9B show a second modification of the throw-away tip according to the first embodiment, wherein FIG. 9A is a plan view and FIG. 9B is a side view in the flank direction.

FIG. 10 shows a throw-away tip according to a second embodiment of the present invention, (A) is a plan view and (B) is a side view in the flank direction.

FIG. 11 is a front view of an end mill equipped with a throw-away tip according to a second embodiment.

FIG. 12 is a partial side view of a conventional end mill.

13 is a partial front view of the end mill shown in FIG.

FIG. 14 is a partial side view showing the axial rake angle of the end mill shown in FIG.

FIG. 15 is a partial side view showing another example of the conventional end mill.

16 is a partial front view of the end mill shown in FIG.

FIG. 17 is a partial side view showing the axial rake angle of the end mill shown in FIG. 15.

[Description of Reference Signs] 14, 50, 60 ... Throw-away tip, 15 ... Upper surface, 16 ... Lower surface, 17a ... First acute-angled corner, 17b ...
2nd acute angle corner, 18 ... obtuse angle corner, 19 ... convex side surface, 22 ... main cutting edge, 24 ... sub cutting edge, 25 ... notch surface,
27 ... inclined receiving surface, 29, 43 ... end mill.

Claims (9)

[Claims] 1. An upper surface and a lower surface having a pair of first acute corners and second acute corners, which are substantially hourglass-shaped and are located diagonally in a plan view, and side surfaces intersecting the upper and lower surfaces. And a ridgeline where adjacent side faces intersect at each acute angle corner is a main cutting edge, and these main cutting edges are the upper and lower surfaces facing each other from the first acute angle corners 2 A throw-away tip that is formed by sloping inward toward two sharp corners. 2. A chamfered portion is formed by cutting out a pair of first acute-angled corners on the upper surface and the lower surface, respectively, and the chamfered portion and the side surface extending from the first acute-angled corner toward the obtuse-angled corner. The throw-away tip according to claim 1, wherein the intersecting ridge line is formed as a secondary cutting edge. 3. The throw-away tip according to claim 2, wherein the sub-cutting edge is formed in a linear shape connected to a linear or arc-shaped corner. 4. The side surface between the first and second acute-angled corners adjacent to each other in plan view is a flank of the main cutting edge,
The throw-away tip according to any one of claims 1 to 3, wherein a notch surface whose width gradually increases from the first acute-angled corner toward the opposing lower surface or upper surface. 5. The side surface between the first and second acute-angled corners adjacent to each other in plan view is a flank of the main cutting edge,
The relief surface is formed on a convex side surface of a polygonal shape or a substantially arc surface shape that bends at an obtuse angle in a direction from the central region toward the main cutting edges at both ends. Throw away tip. 6. A side surface formed between the first acute-angled corner and an obtuse-angled corner adjacent to the first acute-angled corner in a plan view is inward from a ridge line having a sub-cutting edge on the upper surface or the lower surface toward the lower surface or the upper surface facing each other. The throw-away tip according to any one of claims 1 to 5, wherein the throw-away tip has an inclined receiving surface. 7. A cutting tool in which a throw-away tip is mounted on the outer periphery of the tip of a tool body, wherein the throw-away tip is the throw-away tip according to any one of claims 1 to 6. A cutting tool characterized in that the blade is mounted so as to be a peripheral blade. 8. The cutting according to claim 7, wherein the leading edge and the trailing edge of the main cutting edge are arranged so as to have a radius of gyration of substantially the same dimension with respect to the axis of rotation of the tool body. tool. 9. The cutting tool according to claim 7, wherein the cutting tool is an end mill.