JP3246163B2 - Cutting tools - Google Patents

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 milling cutter or an end mill, on which a plurality of throw-away tips having a substantially rhombic shape are mounted. Cutting tool).

[0002]

2. Description of the Related Art An example of this type of cutting tool is shown in FIG.
There is a face mill 1 as shown in FIG. FIG.
In the partial bottom view and the partial side view of the front milling machine 1 shown in FIG. 11, the seat portion 3 is fixed to a wall surface of the front milling machine 1 which faces the rotation direction of the groove 2 formed on the outer peripheral end portion, and is illustrated on the upper portion thereof. A throw-away tip 4 having a triangular plate shape shown in FIG. 12 is placed, and the tip 4 is fixed by a wedge member 5. The indexable insert 4 has a main cutting edge 6 provided on each ridge on an upper surface opposed to a seating surface, and a sub cutting edge 8 provided on one side between the corner blade 7 and the main cutting edge 6. I have. And this throwaway tip 4
Is positive, and in the mounted state, the axial rake angle is set to be positive with respect to the rotation axis of the face milling machine 1 (see FIG. 11), and the radial rake angle is also set to be positive with respect to the axis in the radial direction (see FIG. 11). (See FIG. 10). A plurality of such throw-away chips 4 are arranged on the face mill 1 in a circumferentially dispersed manner.

At the time of cutting, as shown in FIG. 12, the main cutting edge 6 located on the outer periphery and the sub cutting edge 8 on the distal end side perform a right angle cutting (90 ° shoulder wall cutting) of the work material w. The main cutting edge 6 forms a right-angled wall, and the sub cutting edge 8
The finish cutting of the bottom surface is performed. In particular, since the indexable insert 4 has a positive (double positive) rake angle for both axial and radial, the sharpness during cutting is good.

Further, as another example shown in FIGS.
There is a face mill 11 equipped with a throw-away tip 10 having a substantially square plate shape. This indexable tip 10
Is positive, the axial rake angle is set to positive in the mounted state (see FIG. 14), and the radial rake angle is set to negative (see FIG. 13). As a result, when the face mill 11 is rotationally cut, a right-angle wall surface of the work material W can be cut with the main cutting edge 12 forming the outer peripheral edge of the throw-away insert 10 as shown in FIG. The clearance angle α on the front side can be given depending on the angle (see FIG. 16), and the square cutting can be performed by using the square tip 10.

[0005]

However, in the case of the face milling machine 1 using the above-mentioned triangular indexable insert 4, the sharpness at the time of cutting is good, but the insert 4 is 3.
Only corners can be used, and each corner has an acute angle of about 60 degrees, and both the axial rake angle and the radial rake angle are positive,
There is a practical drawback that the cutting edge strength is small and chipping easily occurs. Also, in the case of the face mill 11 using the rectangular throw-away tip 10, although the tip 10 can be used at four corners, the cutting edge is inferior to the positive one because the radial rake angle is negative. There are drawbacks in that the resistance is high and the finish of the finished surface is poor. In addition, as can be understood from FIG. 16, there is also a disadvantage that the front clearance angle α is small (30 ′ in the figure), and the wear of the bottom blade at the time of cutting becomes large, and the life of the chip is deteriorated.

[0006] In view of such circumstances, the present invention provides a cutting tool that uses a throw-away insert that can be used in four corners, can perform right-angle cutting, has good cutting performance, and can improve the life of the insert. The purpose is to:

[0007]

According to the present invention, there is provided a cutting tool having a plurality of substantially rhombic or parallelogram plate-like throw-away tips mounted thereon, wherein the throw-away tips have cutting edges at sharp corners. As a first throw-away tip having a positive axial rake angle and a radial rake angle, and a second throw having a positive axial rake angle and a negative radial rake angle using an obtuse corner as a cutting edge. The first throwaways are respectively arranged as away chips.
The tip and the second indexable tip are
The main cutting edge is in the position where it overlaps in the rotation direction, and the bottom edge on the tip side is
The second throw-away tip is the first throw-away tip.
Be positioned so that it is closer to the proximal end than the tip.
And features.

[0008] The first throw-away chips and the second throw-away tips are characterized by being arranged alternately and in the same number in the rotational direction. The sharp corners of the throw-away insert are formed with a large-diameter circular ridge between the main cutting edge and the sub-cutting edge, and the obtuse-angled corners are formed with a small-diameter circular ridge. It is characterized by being formed in. The boundary point between the arcuate ridge line of each corner forming the cutting edge of the first and second throwaway tips and the main cutting edge on the outer peripheral side is located at a position overlapping in the rotation direction of the throwaway tip. .

[0009] The sharp corner portion of the throw-away insert may have a chamfer with a large ridge at the corner between the main cutting edge and the sub-cutting edge. The edge line is formed in a chamfer having a small length. A boundary point between the chamfer of each corner forming the cutting edge of the first and second throw away tips and the main cutting edge on the outer peripheral side is located at a position overlapping in the rotation direction of the throw away tip.
The cutting tool is a face mill.

[0010]

[Function] When performing right-angle cutting of a work material, each of the throw-away inserts can be used at four corners, rough cutting is performed with a second throw-away insert, and finish cutting is performed with a first throw-away insert. In addition, sharp cutting can be performed, and the life of the insert can be improved without lowering the cutting performance of each indexable insert.
Moreover, the clearance angle on the front side of the first throw-away tip is
The bottom blade of the second indexable insert, in addition to the large one
Since cutting is not performed, the life of the insert is further improved.
In addition, the fact that the lifetimes of the first and second chips differ greatly is
Absent. Also, by alternately disposing the same number of the first throw-away tips and the second throw-away tips, the cutting performance is stabilized.

[0011]

Preferred embodiments 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. FIG. 1 is a bottom view of the face mill according to the present embodiment, FIG. 2 is a perspective view of the throw-away tip, FIG. 3 is a view showing a state in which the throw-away tip having an acute corner as a cutting edge is attached to the face mill, and FIG. FIG. 5 is a partial side view of the face mill shown in FIG. 1, FIG. 5 is a view similar to FIG. 3 showing a mounted state of a throw-away tip with an obtuse corner as a cutting edge, and FIG. FIG. 7 is a view showing a state where the throw-away tips shown in FIG. 5 are stacked, and FIG. 7 is an enlarged view of a portion B in FIG. In the face mill 14 shown in FIG. 1, an even number (six in the figure) of grooves 15 are formed at substantially equal intervals along the outer periphery of the tip. In each groove 15, a sheet portion 16 is fixed to a wall surface of the face mill 14 facing the rotation direction, and a roughly rhombic plate-like throw-away tip 17 as shown in FIG. Or it is fixed by a wedge or the like.

As shown in FIG. 2, the throw-away tip 17 has two pairs of ridges on four sides on a substantially diamond-shaped upper surface 19 facing a lower surface 18 forming a seating surface, respectively, as main cutting edges 20. An auxiliary cutting edge 23 is formed between a pair of main cutting edges 20 facing each other and one main cutting edge 20 adjacent thereto. The sub-cutting edge 23 is formed to be inclined inward by a small angle with respect to the main cutting edge 20 on the same side. One edge of the main cutting edge 20 and the sub cutting edge 23 has an acute angle (for example, 88
Corner portions 19a are provided to face each other, and between the two adjacent main cutting edges 20, the obtuse corner portions 19b are provided to face each other. A relatively large-diameter corner blade 21 is formed on the ridge line of the acute corner portion 19a, and a relatively small-diameter corner blade 22 is formed on the ridge line of the obtuse corner portion 19b.
In the center of the upper surface 19, a screw hole 24 is formed to penetrate the lower surface 18 and to insert a screw for screwing (in other drawings, the screw hole 24 is omitted. There). Further, between the upper surface 19 and the lower surface 18, flank side surfaces 25, which are inclined outward from the ridge line of the lower surface 18 toward the ridge line of the upper surface 19, are formed on four sides. The chip may be fixed by other appropriate means such as a wedge.

When such a throw-away tip 17 is mounted on the face mill 14, one tip 17 uses the sharp corner 19a as a cutting edge, and the sharp corner 19a is formed on the outer periphery of the face mill 14 as shown in FIG. It is fixed on the seat portion 16 of the groove 15 by screwing or the like so as to be located on the tip side. In this case, the axial rake angle of the throw-away tip 17 is set positive as shown in FIG. 4, and the radial rake angle is also set positive as shown in FIG. The throw-away tip 17 mounted in this manner is referred to as a DP tip 17a. In the groove 15 for receiving the DP chip 17a, an acute angle corner 19 located on the opposite side to the acute angle corner 19a forming the cutting edge so that the cutting edge is fixed at a predetermined position in the mounted state.
An acute-angled side receiving portion 26a corresponding to a is formed (see FIG. 3). As a result, in the DP chip 17a, the right wall surface w1 of the workpiece W is cut by the main cutting edge 20 serving as the outer peripheral blade, and the other wall surface w2 is finished by the sub cutting blade 23 located on the distal end side. Will be. In addition, since the main cutting edge 20 on the bottom edge side (tip side) forms one side of the acute corner portion 19a, the clearance angle α on the front side can be made large.

The throw-away tip 17 mounted in the groove 15 adjacent to the DP tip 17a in the circumferential direction in FIG. 1 has an obtuse corner portion 19b as shown in FIG.
Is used as a cutting edge, and is similarly fixed on the sheet portion 16 of the groove 15 so that the obtuse corner portion 19b is located on the outer peripheral tip side of the face milling cutter 14. In this case, the axial rake angle of the throw-away tip 17 is set to be positive, and the radial rake angle is set to be negative as shown in FIG. The throw-away tip 17 mounted in this manner is referred to as an NP tip 17b. An obtuse corner portion 19b forming a cutting edge is provided in the groove 15 for receiving the NP chip 17b so that the cutting edge is fixed at a predetermined position in a mounted state.
An obtuse angle side surface receiving portion 26b corresponding to the obtuse angle corner portion 19b located on the opposite side is formed (see FIG. 5).
As a result, the NP tip 17b is cut at the right angle wall w1 by the main cutting edge 20 forming the outer peripheral edge, but the main cutting edge 20 located on the tip side is the bottom blade (sub cutting edge 23) of the DP tip 17a.
It is arranged so as to be located more proximally.

When the DP chip 17a and the NP chip 17b in each mounted state are viewed in the rotational direction, as shown in FIG. 6, the main cutting edges 20 forming the outer peripheral edge overlap with each other. As shown, a boundary point P1 between the main cutting edge 20 on the outer periphery of the DP tip 17a and the large-diameter corner blade 21.
And the boundary point P2 between the main cutting edge 20 on the outer periphery of the NP tip 17b and the small-diameter corner blade 22 is overlapped. The DP chips 17a and the NP chips 17b are arranged alternately in the circumferential direction of the front milling machine 14.

Since the present embodiment is constructed as described above, when the workpiece W is cut at right angles by the face mill 14 in which the DP chips 17a and the NP chips 17b are alternately arranged, an acute angle is obtained. DP whose corner 19a forms a cutting edge
Since both the axial and radial rake angles of the tip 17a are positive, sharp cutting can be performed with the main cutting edge 20 on the outer periphery and the sub cutting edge 23 on the tip side, and the work material W
Finished surface cutting can be performed. In addition, since the front main cutting edge 20 can have a larger clearance angle on the front side than the conventional square tip, wear of the main cutting edge 20 in this portion can be suppressed and the life thereof can be extended. In the NP chip 17b, (coarse) cutting is performed only by the main cutting edge 20 on the outer periphery, and cutting is not performed by the bottom blade. Therefore, even if the radial rake angle is negative, high cutting resistance or sharpness is obtained. There is no inconvenience such as poor finish quality of the finished surface. Moreover, the DP chip 17a and the NP chip 1
7b is located at a position where the main cutting edge 20 on the outer periphery overlaps in the rotation direction, so that the lifespans of both do not greatly differ.
Moreover, four corners can be used. Also, the cutting performance is better than that of a conventional throw-away insert that can use four corners.

As described above, according to the present embodiment, four corners can be used, and only a cutting edge having a small cutting resistance and sharpness is used for cutting, so that the finished surface is good and the cutting performance is good. There is an advantage. In addition, the clearance angle on the front side can be made larger than that of the conventional square chip, and the chip life can be improved. Even if the same indexable insert 17 is provided as the DP chip 17a and the NP chip 17b, the life of these chips does not greatly differ from each other, and the cutting performance is improved by arranging the both alternately. Stabilize.

The DP chip 17a and the NP chip 17b
It is not always necessary to arrange them alternately, and any arrangement is possible, such as continuous chips of the same type. In addition, the number of both chips does not necessarily have to be the same, and therefore the number of indexable inserts 17 provided in one cutting tool may be an odd number.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described below. FIG. 8 is a front view of the throw-away tip used in the second embodiment, showing a state in which the DP tip and the NP tip are overlapped in the rotation direction, and FIG. 9 is an enlarged view of a portion C in FIG. In the cutting tool according to the second embodiment, the indexable insert 28 shown in FIG. 8 has a chamfer instead of the arc-shaped one of the first embodiment. That is, the throw-away tip 2 according to the present embodiment.
8, a chamfer 29 having a relatively large length is formed at each of two opposed acute corners 19a. Further, a chamfer 30 having a relatively short length is formed in each of the other two obtuse corner portions 19b. Then, in the DP chip 28a, the acute angle corner portion 19a having the long chamfer 29 is used as a cutting edge, and in the NP chip 28b, the obtuse angle corner portion 19b having the small length chamfer 30 is used as a cutting edge. Each is arranged.

The side receiving portions 26a and 26b for receiving the chip side surfaces may be the same as those in the first embodiment, or may have shapes corresponding to the side surfaces of the acute corner portion 19a and the obtuse corner portion 19b. May be formed. Also, the DP chip 28a, NP
With both the chips 28a and 28b superposed in the rotation direction with the chips 28b mounted, both the chips 28a and 28b
The main cutting blades 20 on the outer peripheral side of a and 28b are arranged so as to overlap on the same line (see FIG. 8). In addition, as shown in FIG. 9, in the corner portion used as a cutting edge, N
A chamfer 30 having a small length of the P-tip 28b is disposed so as to overlap with the boundary point with the main cutting edge 20 on the outer peripheral side. In this case, the bottom blade (main cutting edge 2) of the NP tip 28b
0) is located closer to the base end than the bottom blade (sub cutting edge 23) of the DP tip 28a, and is separated from the cutting surface w2 of the workpiece W.

According to the second embodiment, in addition to the above-described effects, by forming the corner blades on the chamfers 29 and 30, the edge strength of this portion is improved. In each of the embodiments described above, the throw-away tips 17 and 28 have a substantially rhombic plate shape, but may have a parallelogram plate shape. In addition, although the face mill 14 is used as a cutting tool to which these throw-away tips are mounted, it goes without saying that other milling cutters, end mills, and the like may be used.

[0022]

As described above, in the cutting tool according to the present invention, the plurality of indexable inserts to be mounted have a positive axial rake angle and a positive radial rake angle by using the sharp corners as cutting edges. as an indexable inserts, and the radial rake angle and a positive an axial rake angle with a corner portion of the obtuse angle as a cutting edge as the second cutting insert and negative, they are disposed respectively, and, the first throwaway Chip and second
The indexable insert means that the main cutting edge on the outer circumference
And the bottom blade on the tip side is the second throw-out
Way tip is more proximal than first throw-away tip
Side, so that the work material can be cut at right angles and each indexable insert
In addition to being able to be used at corners, rough cutting and sharp cutting can be performed, and the cutting performance of each indexable insert can be favorably maintained, and the insert life can be improved. In addition, the front side of the first indexable insert
In addition to providing a large clearance angle, negative radial rake
In the bottom blade of the second indexable insert with a sharp corner,
Without cutting, only cutting edge with low cutting resistance and sharpness
Since it is used for cutting, the cutting performance is good and the chip life is long.
Further improve. Also, the life of the first and second chips is long.
There is no difference. Further, since the first throw-away tips and the second throw-away tips are arranged alternately in the rotation direction and in the same number, the cutting performance is stabilized.
Further, since the corner portion of the throw-away tip is formed in the chamfer, the cutting edge strength is further increased and the tip life is prolonged.

[Brief description of the drawings]

FIG. 1 is a bottom view of a face mill according to a first embodiment of the present invention.

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

FIG. 3 is a view showing a state in which a throw-away tip (DP tip) having a sharp corner as a cutting edge is attached to a front milling machine.

FIG. 4 is a side view showing the throw-away tip mounted on the front milling machine in FIG. 1;

FIG. 5 is a view similar to FIG. 3 showing a mounted state of a throw-away tip (NP tip) having an obtuse corner as a cutting edge.

6 and FIG. 5 in the direction of rotation of the face mill;
FIG. 5 is a view showing a state where the throw-away tips shown in FIG.

FIG. 7 is an enlarged view of a portion B in FIG. 6;

FIG. 8 is a view showing a state similar to FIG. 6 for a throw-away tip used in a second embodiment of the present invention.

FIG. 9 is an enlarged view of a portion C in FIG. 8;

FIG. 10 is a partial bottom view showing a conventional front milling machine with a throw-away tip attached thereto.

FIG. 11 is a partial side view of the front milling machine of FIG. 10;

FIG. 12 is a longitudinal sectional view of the face mill shown in FIG. 10;

FIG. 13 is a view similar to FIG. 10 showing another example of a conventional face milling machine.

FIG. 14 is a partial side view of the front milling machine of FIG. 13;

FIG. 15 is an enlarged view of a portion A in FIG.

FIG. 16 is a partial vertical sectional view of the face mill shown in FIG.

[Explanation of symbols]

 14 Face Milling 17, 28 Throw-away Tip 17a, 28a DP Tip 17b, 28b NP Tip 19a Sharp Corner 19b Obtuse Corner 20 Main Cutting Edge 21, 22 Corner Edge 23 Secondary Cutting Edge 29, 30 Chamfer

Claims (7)

(57) [Claims] 1. A cutting tool provided with a plurality of substantially rhombic or parallelogram plate-like throw-away tips, wherein the throw-away tips use an acute corner portion as a cutting edge, and an axial rake angle and a radial rake angle. Are arranged as a first throw-away tip having a positive and a second throw-away tip having an axial rake angle as a positive and a radial rake angle as a negative using the obtuse corner as a cutting edge , and The first throw-away tip and the second throw
An away tip is one in which the main cutting edge on the outer peripheral side
The bottom blade on the tip side is the second indexable
Tip is proximal to the first throw-away tip
Characterized by being arranged so as to be placed
Utensils. 2. The cutting tool according to claim 1, wherein the first throw-away tips and the second throw-away tips are arranged alternately and in the same number in the rotation direction. 3. An acute angle corner portion of the indexable insert is formed so that a ridge line of a corner between a main cutting edge and a sub cutting edge has a large diameter, and an obtuse angle corner portion has a ridge line of a corner. cutting tool according to claim 1 or 2, characterized in that it is formed in a circular arc shape smaller. 4. A boundary point between an arc-shaped ridge line of each corner forming a cutting edge of the first and second throwaway tips and a main cutting edge on an outer peripheral side overlaps in a rotational direction of the throwaway tips. The cutting tool according to claim 3 , wherein: 5. The sharp corner of the throw-away insert has a chamfer with a large ridge at the corner between the main cutting edge and the sub-cutting edge. The obtuse corner has a long ridge at the corner. cutting tool according to claim 1 or 2, characterized in that it is formed in a small chamfer having of. 6. A boundary point between a chamfer of each corner forming a cutting edge of the first and second throwaway tips and a main cutting edge on an outer peripheral side is located at a position overlapping in a rotation direction of the throwaway tips. The cutting tool according to claim 5 , characterized in that: 7. A cutting tool according to any one of claims 1 to 6, characterized in that said cutting tool is a face milling cutter.