JP2004195563A - Edge replaceable rotary tool and insert therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an insert used for an edge replaceable rotary tool such as a face milling cutter that particularly exhibits the effect in high feed machining, and the edge replaceable rotary tool attached with this insert. <P>SOLUTION: The substantially polygonal plate-like insert 1 is detachably installed in the edge replaceable rotary tool. The insert forms a cutting edge in a ridgeline 13 part of an upper surface 3 opposed to a bottom surface 2, and has a first cutting edge 6 and a second cutting edge 7 in the ridgeline part of the upper surface by sandwiching a corner part 9. The insert for the edge replaceable rotary tool is characterized by forming the height up to the first cutting edge from the bottom surface in a side view so as to become gradually low in the corner part direction, and the insert is installed in the edge replaceable rotary tool. The edge replaceable rotary tool is characterized by being installed so that a radial directional rake angle Rr becomes -45≤Rr≤0. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a substantially polygonal plate-shaped insert that can be used for a cutting edge-type rotary tool such as a face milling tool and the like, and is particularly effective in high-feed machining, and to a cutting edge-type rotary tool equipped with the insert. It is.
[0002]
[Prior art]
Patent Literatures 1, 2, and 3 below have been proposed as inserts suitable for high feed in rotary blade tools such as face milling tools.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-126920 (specifications, pages 3 to 5, FIGS. 1 and 4)
[Patent Document 2] Japanese Patent Application Laid-Open No. 2000-5921 (Specifications page 2 to 3, FIG. 1, FIG. 2, FIG. 3)
[Patent Document 3] Japanese Patent Application Laid-Open No. 2001-219315 (specifications, pages 3 to 5, FIG. 5)
[0003]
In Patent Document 1, a circular insert is used, which is tilted in two axial directions and mounted on the rotary tool body, thereby generating a cutting edge having a large arc radius to reduce the impact force during high-feed cutting. A face milling cutter to be effected is described. In Patent Document 2 described above, the thickness of the chip initially generated in contact with the material to be cut is thin, because the insert is a substantially square shape and the main cutting edge is formed in an arc shape in a front view. An insert capable of reducing the impact force applied to a tool by gradually generating a thick cutting edge and performing high-feed cutting with little cutting fluctuation is described. In Patent Document 3, the outer peripheral cutting edge is a convex curved cutting edge when viewed from the side, and the outer peripheral cutting edge is formed so that the height from the seating surface gradually decreases toward the corner portion. By doing so, there is described an insert designed to improve the machining accuracy of a right-angled wall.
[0004]
[Problems to be solved by the invention]
In the inserts disclosed in Patent Literature 1 and Patent Literature 2, a bottom surface of the insert and a top surface serving as a rake face are parallel to each other in a side view. For this reason, measures to secure an appropriate rake angle in the radial direction (hereinafter referred to as Rr) and reduce the impact force applied to the insert are to change the angle formed by the insert seating surface of the rotary tool body with the radial direction. Was supported. A conventional countermeasure will be described with reference to FIGS. The insert 25 has a bottom surface 26 serving as a seating surface, and an upper surface 27 serving as a rake surface facing the bottom surface 26. A cutting edge 29 is formed at a ridge line between the upper surface 27 and a side surface 28 serving as a flank, and the bottom surface 26 and the upper surface 27 are formed to be parallel in a side view. FIG. 22 shows an example in which Rr is -4 degrees when the bottom surface 26 of the insert 25 is mounted on the seating surface 31 of the rotary tool body 30, FIG. 23 shows an example in which Rr is -10 degrees, and FIG. Is shown. As described above, in the conventional insert 25, in order to set Rr to −4 degrees, −10 degrees, −20 degrees, or the like, the seating surface 31 provided on the rotary tool main body 30 has the radial direction r of the rotary tool main body 30. It was necessary to change the angle. Conventionally, by changing the angle formed by the insert seating surface 31 of the rotary tool body 30 and the radial direction r in this manner, Rr is set to an appropriate angle in the negative direction to improve the chipping resistance of the insert. Was. However, in this conventional method, since the edge strength of the insert 25 itself does not change, there is a limit to high-feed cutting. In addition, it is necessary to arrange several types of the rotary tool body 4 in which the angle formed by the seating surface 31 of the rotary tool body 30 and the radial direction r is set to an appropriate value in advance. The insert described in Patent Document 3 has a convex curved shape in which, when viewed from the side, the curved cutting edge portion serving as the outer peripheral edge gradually decreases in height from the seating surface toward the corner portion. Thus, it is improved so that a shoulder wall can be cut by 90 degrees. Therefore, this insert does not improve the shape of the cutting blade for the purpose of performing high feed machining.
[0005]
[Object of the present invention]
An object of the present invention is to improve the edge strength of an insert cutting edge, that is, to improve chipping resistance by forming the insert upper surface serving as a rake surface into a negative shape so as to secure Rr by the insert itself. An object of the present invention is to provide an insert for a rotary tool with a replaceable cutting edge capable of performing cutting by feeding, and a rotary tool with a replaceable cutting edge equipped with the insert.
[0006]
[Means for Solving the Problems]
The present invention is directed to a substantially polygonal plate-shaped insert detachably attached to a cutting edge replaceable rotary tool, wherein the insert has a cutting edge formed on a ridge portion of an upper surface opposed to a bottom surface, and a ridge portion of the upper surface. A first cutting edge and a second cutting edge sandwiching a corner portion, wherein a height from the bottom surface to the first cutting edge in a side view is formed so as to gradually decrease toward the corner portion direction; The insert for a replaceable rotary tool and the insert are mounted on a replaceable rotary tool, and the rake angle Rr in the radial direction is set so that -45 ≦ Rr ≦ 0. This is a rotary tool with a replaceable cutting edge.
[0007]
In the present invention, the first cutting edge is a main cutting edge in a cutting process, and serves as a bottom edge when an insert is attached to a rotary tool having a replaceable edge. On the other hand, the second cutting edge is a secondary cutting edge, and serves as an outer peripheral edge when an insert is mounted on a rotary tool with a replaceable edge. Next, in a side view, this is an insert for a cutting edge replaceable rotary tool formed such that an angle α of the first cutting edge with the bottom surface satisfies 0 <α ≦ 40. Further, in the insert of the present invention, the insert for a cutting edge replaceable rotary tool is provided with a breaker groove having a rake angle of 20 degrees or less on an upper surface serving as a rake surface.
[0008]
In the insert of the present invention having the above-described structure, the reason why the angle α is limited to be 0 <α ≦ 40 is that the first cutting edge is improved in chipping resistance when cutting is performed by being mounted on the rotary tool body. In order to achieve this, the upper surface of the insert is made to have a negative shape to secure Rr, and this is based on the technical idea of improving the edge strength of the insert. Therefore, these effects cannot be obtained unless the angle α is larger than 0 degree, and when the angle α is larger than 40 degrees, the angle between the first cutting edge near the corner portion connected to the first cutting edge and the flank is formed. Is an acute angle, and the strength of the first cutting edge portion is reduced. If the angle α is larger than 20 degrees, the chips come into strong contact with the upper surface (rake face) near the first cutting edge, and a large cutting resistance is likely to be applied to the first cutting edge due to the impact. Therefore, in the insert of the present invention, when the angle α exceeds 20 degrees, it is preferable to form a breaker groove at least on the upper surface along the ridge of the first cutting edge. The rake angle of the breaker groove is set to 20 degrees or less, preferably 10 degrees to 20 degrees.
[0009]
The reason for limiting Rr to -45 ≦ Rr ≦ 0 when the insert of the present invention is mounted on the rotary tool body is as follows. Generally, in a rotary tool main body to which an insert is mounted, a rotary tool whose seating surface is inclined at about −3 degrees to −5 degrees with respect to a radial direction of the tool main body is widely used. Therefore, when the insert of the present invention is mounted on a generally used rotary tool body, Rr can be set to −45 ≦ Rr ≦ 0, so that the first cutting edge can be fed at a high feed rate with the chipping resistance secured. Processing can be performed. Further, there is no need to manufacture a rotary tool main body in which the angle of the seating surface on which the insert is mounted is changed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a perspective view, a plan view, and a side view of an insert showing a first embodiment. As shown in FIGS. 1 to 3, the insert 1 of the first embodiment has a substantially square shape when viewed from the front, a bottom surface 2 serving as a seating surface for a tool body, an upper surface 3 facing the bottom surface 2, and a bottom surface 2. And a side surface 4 formed between the upper surface 3 and the upper surface 3. The upper surface 3 constitutes a rake face (hereinafter, referred to as a rake face 3) of the insert 1, the side face 4 constitutes a flank face, and a first cutting edge 6 is formed at a ridge line formed by the rake face 3 and the side face 4. I have. The insert of the present invention includes a first cutting edge 6, a second cutting edge 7 formed in a straight line, and R-shaped corner cutting edges 10 and 11 formed in corner portions 8 and 9. As shown in FIG. 2, a first cutting edge 6 and a second cutting edge 7 are formed so as to sandwich the corner cutting edges 10 and 11. A mounting hole 12 is provided at the center of the rake face 3 of the insert 1. The first cutting edge 6 is formed in an outwardly convex arc shape in plan view, and the first cutting edge 6, the corner cutting edges 10, 11, and the second cutting edge 7 are connected by a smooth curve. When the insert 1 is mounted on the rotary tool main body, one of the linear second cutting blades 7 is located outside the rotation axis, and the surface of the other second cutting blade 7 is mounted on the rotary tool main body. It becomes a constraint surface when. As shown in FIG. 3, the insert of the present invention is formed such that the height from the bottom surface 2 to the ridge line serving as the first cutting edge 6 gradually decreases toward the second cutting edge 7 in a side view. It has a characteristic. When the height from the bottom surface 2 to the ridge line of the first cutting edge 6 is gradually reduced in the direction of the second cutting edge 7 in this manner, as shown in FIG. 3 has a height higher than other portions, and a straight ridge line 13 substantially parallel to the second cutting edge 7 is formed. In the insert of the present invention, the angle α formed between the bottom surface 2 and the ridge line L of the first cutting edge 6 is set to 0 <α ≦ 40. In the insert 1 of the present invention, by setting the angle α to 0 <α ≦ 40, the rake face 3 of the insert has a negative shape, and Rr is secured when the insert is mounted on the rotary tool body. The fracture resistance of the insert can be improved. Further, an angle β (hereinafter, referred to as a blade edge angle) formed between the rake face 3 and the side face 4 as a flank near the first cutting edge 6, the second cutting edge 7, and the corner blade 10 is also shown in FIG. Can be made larger than the cutting edge constituting angle β of the conventional insert shown in FIG.
[0011]
A second embodiment of the present invention is shown in FIGS. In the insert according to the second embodiment, as shown in FIG. 5, the ridge line 13 formed on the rake face 3 is formed so as to be inclined toward the corner 9 with respect to the second cutting edge 7 in a front view. . The angle of inclination with respect to the second cutting edge 7 is preferably set to 10 to 20 degrees. With the configuration in which the ridge line 13 is inclined with respect to the second cutting edge 7 in this manner, the following effects can be further produced as compared with the insert of the first embodiment. Normally, the insert 1 is mounted in a state of being inclined by about 5 degrees with respect to the rotation axis of the rotary tool body, whereby the second cutting edge 7 is in a state of being inclined by about 5 degrees with respect to the rotation axis. Then, as shown in FIG. 5, assuming that the lowest point of the first cutting edge 6 is P and the intersection of the ridge line 13 with the first cutting edge 6 is S, the intersection S is shifted by a predetermined distance from the lowest point P. It is possible to prevent the intersection S from coming into contact with the workpiece during cutting. Although the intersection S has a minute angular shape, it does not come into contact with the work material, so that it is possible to prevent the intersection S from being lost during cutting. Also in the second embodiment, the first cutting edge 6 is formed such that the angle α formed between the bottom surface 2 and the ridge line L of the first cutting edge 6 satisfies 0 <α ≦ 40.
[0012]
A third embodiment of the present invention is shown in FIGS. In the third embodiment, a breaker groove 14 is formed on the rake face 3 along the cutting edge in the insert of the second embodiment. The breaker groove 14 is provided in order to reduce the impact of the chips generated during the cutting process contacting the rake face 3, and the rake angle of the breaker groove 14 may be 20 degrees or less. Although the example shown in FIG. 7 shows an example in which the breaker grooves 14 are formed along all the cutting edges, the first cutting edge 6, the corner cutting edge 10, and the insert having the breaker grooves 14 formed in the vicinity thereof are shown. It may be. In the insert of the present invention, when the angle α exceeds 20 degrees, the breaker groove 14 may be formed. The reason for this is that when the insert 1 having the above-mentioned angle α set to a large value is mounted on the rotary tool body and cutting is performed with Rr greater than −20 degrees, the impact force on the first cutting edge 6 increases. . This is because, as a countermeasure, the breaker groove 14 is provided to reduce the contact resistance at which the chips come into contact with the rake face 3, thereby enabling high feed machining.
[0013]
A fourth embodiment of the present invention is shown in FIGS. As shown in FIG. 12, the insert according to the fourth embodiment is characterized in that the ridge line of the first cutting edge 6 is formed in a convex arc shape upward when viewed from the side. In the fourth embodiment, the angle α formed between the bottom surface 2 of the insert 1 and the ridge line of the first cutting edge 6 is represented by R at the point where the corner cutting edge 10 and the arc-shaped first cutting edge 6 intersect in side view. Then, the angle between the tangent L of the arc-shaped first cutting edge 6 at the intersection R and the bottom surface 2 is shown, and 0 <α ≦ 40. By forming the ridge line of the first cutting edge 6 in a convex arc shape upward when viewed from the side, the blade edge angle β can be made larger than that of the insert of the first to third embodiments. The effect of further improving the strength of the first cutting edge 6, the second cutting edge 7, and the corner cutting edge 10 is produced.
[0014]
Another embodiment of the present invention will be described. FIG. 13 is a perspective view showing a fifth embodiment of the present invention, FIG. 14 is a perspective view showing a sixth embodiment of the present invention, FIG. 15 is a perspective view showing a seventh embodiment of the present invention, FIG. FIG. 16 is a perspective view showing an eighth embodiment of the present invention. Although not shown in the fifth to eighth embodiments, similarly to the first to fourth examples, the height from the bottom surface 2 to the first cutting edge 6 in a side view of the insert is similar to that of the first to fourth examples. Is formed so as to gradually decrease toward the corner portion, and the angle α is formed so as to satisfy 0 <α ≦ 40. Further, as shown in the third embodiment, a breaker groove may be formed on the rake face along the ridge line of the cutting blade. The fifth embodiment shown in FIG. 13 has a substantially circular shape in a front view, that is, the first cutting edge 6 has an arc shape, and four places of the insert 1 can be used as the first cutting edge 6, and The first cutting blade 6 is formed in a convex arc shape facing upward when viewed. The sixth embodiment shown in FIG. 14 has a substantially circular shape when viewed from the front similarly to the fifth embodiment described above, and forms a ridge line of the first cutting edge 6 in a straight line when viewed from the side. Is formed so that the ridge line 13 formed at the center crosses the central portion of the first cutting edge 6 in a front view. The seventh embodiment shown in FIG. 15 is an insert in which the shape of the insert is substantially triangular in a front view so that three first cutting blades 6 can be used. Furthermore, in this insert, the first cutting edge 6 and the second cutting edge 7 are continuously connected to the cutting edge ridge between the adjacent corner portions 8, and three places of the insert 1 can be used as the first cutting edge 6. It is like that. Further, the first cutting blade 6 is formed in a convex arc shape facing upward in a side view. The eighth embodiment shown in FIG. 16 is an insert having a substantially triangular shape when viewed from the front, as in the seventh embodiment described above, but forms the ridge line of the first cutting edge 6 in a straight line when viewed from the side. At the same time, the ridge line 13 formed on the rake face 3 intersects the center of each side of the three-sided cutting edge ridge line.
[0015]
The blade-exchangeable rotary tool equipped with the insert of the present invention will be described. As shown in FIGS. 17 and 18, a plurality of seating surfaces 21 that are substantially parallel to the radial direction r of the rotary tool main body 20 or are inclined at about 3 to 5 degrees are formed at the tip of the rotary tool main body 20. ing. Then, the insert 1 of the present invention is mounted and fixed on the seating surface 21 using the set screw 22. The insert 1 may be fixed by wedge clamping. When the insert 1 is mounted on the seating surface 21, as shown in the bottom view of FIG. 18, the rake face 3 of the insert 1 of the present invention has a negative shape, so that Rr is secured. That is, even if it is not necessary to prepare several kinds of rotary tool bodies 20 in which the angle between the seating surface 21 of the rotary tool body 20 and the radial direction r is changed in advance, if one kind of the rotary tool body 20 is retained. By using the insert 1 of the present invention, an appropriate Rr can be set and high feed processing can be performed. In the cutting edge replaceable rotary tool equipped with the insert of the present invention, Rr is set so that -45 ≦ Rr ≦ 0.
[0016]
FIG. 19 is a diagram illustrating a state in which the work material 23 is being cut using the insert 1 of the present invention. In the insert 1 of the present invention, since the first cutting edge 6 has a convex arc shape outward when viewed from the front and Rr can be set to a large negative value of −45 ≦ Rr ≦ 0, FIG. As a result, the thickness of the chips generated initially when the first cutting edge 6 comes into contact with the work material 23 is small, and it is possible to gradually generate chips with the rotation of the rotary tool. For this reason, the impact force applied to the insert 1 can be reduced, and in addition to the fact that the above-mentioned cutting edge constituting angle β can be made larger than that of the conventional insert, the insert of the present invention has a higher feed rate than the conventional insert. Cutting work becomes possible.
[0017]
For example, TiN, (TiAl) (NO), (TiSi) (NO), (TiB) (NO), (CrSi) (NO), (AlSi) (NO), CrN, It is desirable to form a hard coating layer such as Al ₂ O ₃ / TiN by a physical vapor deposition method or a chemical vapor deposition method to improve wear resistance.
[0018]
(Example 1)
One of the inserts shown in FIGS. 4 to 6 according to the second embodiment of the present invention is mounted on a rotary tool 20 having a tool diameter of 63 mm shown in FIGS. 17 and 18, and a hole having a diameter of 8 mm shown in FIG. High feed milling was performed on a large number of the workpieces 24 by single-blade cutting, and the cutting time until the cutting edge of the insert was chipped was tested. In this test, when the insert of the present invention was attached to the rotary tool 20, an insert made of a cemented carbide such that Rr shown in FIG. 18 became -4 degrees, -10 degrees, -15 degrees, and -20 degrees was used. Made 4 types. At this time, the insert angle α was set to 0.5 °, 6 °, 11 °, and 16 °, respectively. The material of the work material 24 is SCM440 and hardness HS40. The cutting conditions in this experiment were set as follows.
Cutting speed (V): 145m / min
Feed per tooth (fz): 1.5 mm / depth of cut (Ad): 1 mm
Cut width (Rd): 38mm
Cutting method: Dry
For comparison, a conventional cemented carbide insert formed so that the bottom surface 26 and the rake face 27 are parallel to each other as shown in FIG. 22 was manufactured, and when mounted on the seating surface of the rotary tool body, Rr was reduced. Cutting was performed in a state where -4, -10, -15, and -20 degrees were secured, respectively. The insert used in the above test had a hard coating layer made of TiN formed on the surface thereof.
FIG. 21 shows the test results. From FIG. 21, it has been clarified that in the example of the present invention, when the feed amount fz per blade is 1.5 mm / blade, and the high feed processing is performed, the time until the fracture is improved by 45 to 60%. . If the angle α is changed from 6 degrees to 11 degrees and Rr when mounted on the rotary tool is set from -10 degrees to -15 degrees, it is estimated that the tool life can be maximized.
[0019]
【The invention's effect】
By applying the present invention, it is possible to provide an insert which can obtain excellent fracture resistance even under high feed machining conditions and can be applied to high feed machining, and a cutting edge replaceable rotary tool equipped with the insert. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first embodiment of the present invention.
FIG. 2 is a front view showing the first embodiment of the present invention.
FIG. 3 is a side view showing a first embodiment of the present invention. FIG. 4 is a perspective view showing a second embodiment of the present invention.
FIG. 5 is a front view showing a second embodiment of the present invention.
FIG. 6 is a side view showing a second embodiment of the present invention.
FIG. 7 is a perspective view showing a third embodiment of the present invention.
FIG. 8 is a front view showing a third embodiment of the present invention.
FIG. 9 is a side view showing a third embodiment of the present invention.
FIG. 10 is a perspective view showing a fourth embodiment of the present invention.
FIG. 11 is a front view showing a fourth embodiment of the present invention.
FIG. 12 is a side view showing a fourth embodiment of the present invention.
FIG. 13 is a perspective view showing a fifth embodiment of the present invention.
FIG. 14 is a perspective view showing a sixth embodiment of the present invention.
FIG. 15 is a perspective view showing a seventh embodiment of the present invention.
FIG. 16 is a perspective view showing an eighth embodiment of the present invention.
FIG. 17 is a side view when the insert of the present invention is mounted on a rotary tool main body.
FIG. 18 is a bottom view when the insert of the present invention is mounted on a rotary tool main body.
FIG. 19 is a diagram for explaining a state during cutting.
FIG. 20 is a perspective view for explaining the shape of a work material.
FIG. 21 is a diagram illustrating a relationship between a rake angle in a radial direction and a cutting time;
FIG. 22 shows a conventional insert having a rake angle of -4 degrees in the radial direction.
FIG. 23 shows a conventional insert having a radial rake angle of −10 degrees.
FIG. 24 shows a conventional insert having a radial rake angle of −20 degrees.
[Explanation of symbols]
1: Insert 2: Bottom 3: Top (rake face)
4: Side (flank)
6: First cutting edge 7: Second cutting edge 8: Corner 9: Corner 10: Corner cutting blade 11: Corner cutting blade 12: Mounting hole 13: Ridge 14: Breaker groove 20: Rotating tool body 21: Seating surface 22: Set screw 23: Work material 24: Work material 25: Conventional insert 26: Conventional insert bottom surface 27: Conventional insert top surface 28: Conventional insert side surface 29: Conventional insert cutting edge

Claims (4)

In a substantially polygonal plate-shaped insert removably attached to a blade-replaceable rotary tool, the insert has a cutting edge formed on a ridge portion of an upper surface opposed to a bottom surface, and a corner portion is sandwiched between the ridge portions of the upper surface. A first cutting edge and a second cutting edge, wherein a height from the bottom surface to the first cutting edge in a side view is formed so as to gradually decrease toward the corner portion. Insert for rotary tool with replaceable cutting edge. 2. The insertable rotary tool insert according to claim 1, wherein an angle α degrees formed by the first cutting edge with the bottom surface in the side view is 0 <α ≦ 40. 3. Insert for rotary tools. 3. The insert according to claim 1 or 2, wherein a breaker groove having a rake angle of 20 degrees or less is provided on the upper surface serving as a rake surface of the insert. Insert for tools. The insert for a replaceable cutting edge tool according to any one of claims 1 to 3 is mounted on a replaceable rotary tool, and the rake angle Rr in the radial direction is set to -45 ≦ Rr ≦ 0. A rotary tool with a replaceable cutting edge.

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