JP3246164B2 - 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.

[0002]

2. Description of the Related Art As an example of this kind of cutting tool, there is a face mill 1 as shown in FIGS. In the bottom view and the longitudinal sectional view of the face mill 1 shown in FIGS. 9 and 10, the seat portion 3 is fixed to a wall surface of the face mill 1 facing the rotation direction of the groove 2 formed at the outer peripheral end portion, A diamond-shaped or parallelogram plate-shaped indexable tip 4 is placed, and the tip 4 is fixed by a wedge member 5. The indexable insert 4 has a main cutting edge 6 on one of the obtuse corners on the upper and lower surfaces forming a parallel plane, and a sub-cutting edge 7 near the corner on the other ridge. ing. In this indexable insert 4, an obtuse corner is used as a cutting edge, and FIG.
The main cutting edge 6 located on the outer peripheral side has a corner angle, and the sub cutting edge 7 is located near the corner of the cutting edge on the distal end side when attached to the front milling cutter 1 shown in FIG. The blade has a cutting angle.

The axial rake angle is set negative with respect to the rotation axis of the face mill 1, and the radial rake angle is set negative with respect to the radial axis (see FIG. 9). A plurality of such throw-away chips 4 are arranged on the face mill 1 in a circumferentially dispersed manner. And at the time of cutting, as shown in FIG.
The work material w is cut by the main cutting edge 6 located on the outer periphery and the sub cutting edge 7 on the distal end side.

[0004]

However, in the case of the face mill 1 using the above-mentioned diamond-shaped or parallelogram plate-shaped indexable insert 4, the insert 4 can use only four corners on the upper surface and the lower surface. However, there is a disadvantage that the chip life is short.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a cutting tool which can use eight corners of a throw-away tip, is inexpensive, and has an improved tip life.

[0006]

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 obtuse corners. As a first throw-away tip used as a cutting edge, and as a second throw-away tip using an acute corner as a cutting edge, a radial rake angle is arranged to be negative , and a first throw-away tip is provided. Tip and second
The indexable insert of which the main cutting edge on the outer circumference rotates
It is characterized by being located at a position overlapping in the direction.

Further, the first throw-away tips and the second throw-away tips are arranged alternately and in the same number in the rotational direction. The first and second throwaway tips are characterized in that an angle exceeding 90 degrees of the obtuse corner portion is substantially a corner angle. The first throwaway tip is characterized in that the clearance angle on the front side is set to 0 ° or a range exceeding 0 ° to about 1 °. In the second indexable insert, the cutting edge on the distal end side is gradually retreated toward the base end side of the cutting tool from the outer peripheral side toward the center side with respect to the cutting edge on the distal end side of the first indexable tip. It is characterized by the following. The throw-away tip is characterized in that it is formed in a rhombic prism shape. Further, the cutting tool is a face mill.

[0008]

[Function] In the cutting tool equipped with the indexable inserts as described above, the sharp corners and the obtuse angled corners can be used as the cutting edges, and since both upper and lower surfaces can be used, each indexable insert can use 8 corners. ,
Moreover, since a chip for a byte can be used, the cost is low and the chip life is greatly improved. Further
Then, finish cutting with the first indexable insert,
Rough cutting can be performed with the second indexable insert.
And the life of the first and second indexable inserts
Are not very different. Further, since the first throw-away inserts and the second throw-away inserts are arranged alternately and in the same number in the rotation direction, the cutting characteristics can be improved even if both the obtuse corners and the acute corners are used. Stabilize.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS.
This will be described below. 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 longitudinal sectional view of the state in which the throw-away tip is mounted on the face mill with the obtuse corner as a cutting edge, and FIG. FIG. 3 is a partial cross-sectional view showing a state where the indexable insert is mounted on a front milling cutter with an acute corner portion as a cutting edge. In the face mill 9 shown in FIG. 1, an even number (eight in the figure) of grooves 10 are formed at substantially equal intervals along the outer periphery of the tip. In each groove 10, a sheet portion 11 is fixed to a wall surface of the face mill 9 facing the rotation direction, and a roughly rhombic plate-like throw-away tip 12 as shown in FIG. The chip 12 is pressed and fixed, for example, by inserting a wedge member 13 and screwing it between the chip upper surface and the wall surface of the groove 10 facing rearward in the rotation direction.

As shown in FIG. 2, the throw-away tip 12 is formed in a rhombic prism shape having a lower surface 14 and an upper surface 15 forming a parallel plane, and a side surface 16 forming a flank perpendicular to both upper and lower surfaces. I have. On the upper surface 15 and the lower surface 14, opposing obtuse angle (for example, about 100 °) corner portions 17 a and acute angle corner portions 17 b are respectively formed, and each ridge is a main cutting edge 19.

When such a throw-away tip 12 is mounted on the face mill 9, one tip 12 uses the obtuse corner 17 a as a cutting edge, and as shown in FIG. It is fixed on the seat portion 11 of the groove 10 by a wedge member 13 so as to be located on the distal end side. In the mounted state, the main cutting edge 19 located on the outer peripheral side has an obtuse angle (for example, about 100 °) of which 9
An angle exceeding about 0 ° (about 10 °) is set as a corner angle (outer peripheral cutting edge angle) α. For the main cutting edge 19 located on the tip side, the front clearance angle β is set to, for example, 0 ° or a range exceeding 0 ° to 1 °. And this throwaway tip 1
The axial rake angle and the radial rake angle of No. 2 are set to be negative (see FIG. 1). The throw-away tip 12 mounted in this manner is attached to the first tip 12a.
And In the groove 10 for receiving the first chip 12a, an obtuse angle corresponding to the obtuse corner 17a located on the opposite side to the obtuse corner 17a forming the cutting edge so that the cutting edge is fixed at a predetermined position in the mounted state. Side receiving part 2 consisting of two sides
3a are formed (see FIG. 3).

The first chip 12a is shown in FIG.
As shown in FIG. 4, the indexable insert 12 mounted in the groove 10 adjacent in the circumferential direction has a sharp corner portion 17.
b is used as a cutting blade, and is similarly fixed on the sheet portion 11 of the groove 10 such that the acute-angle corner portion 17b is located on the outer peripheral tip side of the front milling cutter 9. In the mounted state, the main cutting edge 19 located on the outer peripheral side overlaps the main cutting edge 19 on the outer peripheral side of the first tip 12a in the rotation direction of the front milling cutter 9 with the corner angle α of the first tip 12a. It is set in the same way as For this reason, the cutting edge on the distal end, which forms an acute angle with the outer peripheral blade (main cutting edge 19), is located on the base end side with respect to the cutting edge on the distal end of the first tip 12a in the radial direction from the outer peripheral side toward the center side. And does not participate in the cutting of the work material W. And this throwaway tip 1
The axial rake angle and the radial rake angle of No. 2 are set to be negative (see FIG. 1). The throw-away tip 12 mounted in this manner is attached to the second tip 12b.
And

In the groove 10 for receiving the second chip 12b,
In order to fix the cutting blade in a predetermined position in the mounted state, a side receiving portion 23b formed of two acute angles corresponding to the acute corner 17b located on the opposite side to the acute corner 17b forming the cutting edge is formed. (See FIG. 4). Then, such first chips 12a and second chips 12b are arranged alternately in the circumferential direction of the front milling cutter 9 (see FIG. 1).

Since the present embodiment is constructed as described above, when the work material W is cut by the face mill 9 in which the first chips 12a and the second chips 12b are alternately arranged. , The first of which the obtuse corner 17a is a cutting edge
The tip 12a can be cut by the main cutting edge 19 on the outer periphery and the main cutting edge 19 on the tip side, and can cut the finished surface of the work material W. In the second chip 12b,
(Coarse) cutting is performed only by the main cutting edge 20 on the outer periphery, and cutting is not performed by the cutting edge (bottom blade) on the tip side. The first tip 12a and the second tip 12b are both located at positions where the main cutting edges 19 on the outer peripheral side overlap in the rotation direction, and the two types of tips 12a and 12b are alternately arranged in the same number. The life is not significantly different and the cutting performance is stable. In addition, according to the front milling cutter 9, the throw-away tip 12 can be used on the upper and lower surfaces 15 and 14, each having four corners, for a total of eight corners.
Therefore, the chip life can be doubled by using the same one as the conventional chip. In addition, since the throw-away tip 12 is in the shape of a rhombus prism, a throw-away tip for a cutting tool can be used for the face mill 9 and there is also an advantage that the cost is low.

As described above, according to the present embodiment, eight corners can be used using the same throw-away chip as the conventional one, and the chip life can be greatly improved. Even if the same throw-away chip 12 is provided as the first chip 12a and the second chip 12b, the life of these chips does not greatly differ from each other, and the two chips are alternately provided. , Cutting performance is stable.

The first chip 12a and the second chip 1
With respect to the order of arrangement with 2b, it is not always necessary to arrange them alternately, and an arbitrary arrangement is possible, such as continuous chips of the same type. Further, the number of both chips is not necessarily the same, and therefore, the number of indexable inserts 12 provided in one cutting tool may be an odd number. or,
It goes without saying that the obtuse angle and the acute angle of each corner can be set arbitrarily.

FIGS. 5 to 8 show the mounting structure of the throw-away tip 12. FIG. Next, these mounting structures will be described. FIG. 5 is a partial sectional view of the face mill 9 in the radial direction, and shows a structure similar to the chip mounting structure according to the above-described embodiment. That is, the seat portion 11 is provided on the wall surface 25a facing the rotation direction of the groove 25 having a step-like shape in cross section.
Are screwed with screws 26, and a recessed hole 25b that receives the lower end corner of the sheet portion 11 is formed in the back corner of the wall surface 25a. Upper surface 15 (lower surface 1) of first chip 12a (second chip 12b) mounted on sheet portion 11
The wedge member 26 is fitted between the 4) and the wall surface 25c facing rearward in the rotation direction of the groove 25, and the tip 12a is pressed and fixed by the screw 27. Wedge member 26
Has a concave curved surface shape similar to the concave curved surface of the chip discharging pocket 28 following the groove 25.

In the chip mounting structure shown in FIG. 6, the groove 30 is formed to have a right angle in cross section, and the first chip 12a is seated on the wall surface 30a as the chip seat facing the rotation direction, and penetrates the chip 12a. It is fixed by the screw 31 which is formed. The plane part in the rotation direction front is pocket 32
It has been. In the chip mounting structure shown in FIG.
And the pocket 35 are sequentially provided in the rotation direction, and the groove 3 is formed.
The first chip 12 is mounted on the wall surface 34a facing rearward in the rotation direction of the fourth chip 4.
a is pressed against the lower surface of the chip 12a and the groove 34.
The chip 12a is fixed by inserting the wedge member 36 between the chip 12a and the other wall surface 34b. The wedge member 36 is screwed by a screw 37.

FIG. 8 is a plan view showing another type of mounting structure of the chip 12a. The first chip 12a is placed on a concave chip seat 37 provided on the tool body of the front milling machine 9. A clamp member 38 for pressing and fixing the upper surface of the chip 12a is provided near the chip seat 37,
This clamp member 38 is fixed by screws 39.

In each of the above-described embodiments, a substantially rhombic plate is used as the throw-away tip 12, but a parallelogram plate may be used. In addition, a face mill 9 is used as a cutting tool for mounting these indexable inserts.
However, it goes without saying that other milling cutters or end mills may be used.

[0021]

As described above, in the cutting tool according to the present invention, the indexable insert is a first indexable insert using an obtuse-angled corner as a cutting edge, and an acute-angled corner as a cutting edge. As the second throw-away tips used, the radial rake angles are arranged with a negative angle, respectively, so that an acute corner portion and an obtuse angle corner portion can be used as cutting edges, and since both upper and lower surfaces can be used, each throw-down tip can be used. 8 away chips
Since a corner can be used and a chip for a bite can be used, it is inexpensive and the chip life is greatly improved. In addition, the first indexable tip and
2 indexable inserts, the main cutting edge on the outer circumference rotates
The first indexable
Finish cutting with a tip, and a second indexable insert
Can perform rough cutting with the first and second
The life of the indexable tips is not much different. or,
Since the first indexable insert and the second indexable insert are arranged alternately and in the same number in the rotational direction, the cutting performance is improved even if both the obtuse corner portion and the acute angle corner portion are used for cutting. Stabilize.

[Brief description of the drawings]

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

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

FIG. 3 is a cross-sectional view showing a state in which a throw-away tip (first tip) having an obtuse corner as a cutting edge is attached to a front milling cutter.

FIG. 4 is a cross-sectional view showing a state in which a throw-away tip (second tip) having an acute corner as a cutting edge is attached to a front milling machine.

FIG. 5 is a partial sectional view in the radial direction of a face mill showing an example of a mounting structure of a throw-away tip.

FIG. 6 is a partial sectional view in the radial direction of a front milling machine showing another example of a mounting structure of a throw-away tip.

FIG. 7 is a partial sectional view in the radial direction of a front milling machine showing still another example of a mounting structure of a throw-away tip.

FIG. 8 is a partial plan view showing still another example of a mounting structure for a throw-away tip.

FIG. 9 is a bottom view showing a conventional front milling machine with a throw-away tip attached thereto.

FIG. 10 is a longitudinal sectional view of the face mill shown in FIG. 9;

[Explanation of symbols]

 Reference Signs List 9 face milling 12 indexable insert 12a first insert 12b second insert 17a obtuse corner 17b acute corner 19 main cutting edge

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23C 5/20 B23C 5/06

Claims (7)

(57) [Claims] 1. A cutting tool equipped with a plurality of substantially rhombic or parallelogram plate-like throw-away tips, wherein the throw-away tip is a first throw-away tip using an obtuse corner as a cutting edge. And a second throw-away tip using a sharp corner portion as a cutting edge, each having a radial rake angle of negative , and the first throw-away tip
And the second indexable insert are the main cutting edge on the outer peripheral side
Characterized by the fact that they are located at positions overlapping in the direction of rotation
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. Wherein the first indexable insert and a second cutting insert, the angle exceeds 90 degrees obtuse corner portion, according to claim 1 or, characterized in that there is a substantially corner angle 3. The cutting tool according to 2 . 4. The front throw-away insert according to claim 1, wherein a front-side clearance angle of a cutting edge located at a front end side of the obtuse corner is zero.
The cutting tool according to any one of claims 1 to 3 , wherein the cutting tool is set to about {1}. 5. The cutting edge on the distal side of the second throw-away tip is gradually retracted from the outer peripheral side toward the center side toward the proximal side with respect to the cutting edge on the distal side of the first throw-away tip. The cutting tool according to any one of claims 1 to 4 , wherein the cutting tool is used. Wherein said throw-away tip according to claim 1 to 5, characterized in that it is formed in a prismatic rhombus
A cutting tool according to any one of the above. 7. A cutting tool according to any one of claims 1 to 6, characterized in that said cutting tool is a face milling cutter.