JP2004338048A - Throwaway tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the finished surface roughness of a machined surface of a workpiece regarding a throwaway tip detachably mounted to a tool body of a throwaway type cutting tool to machine an outer diameter or the like mainly using a cutting edge ridgeline of approximately circular arc shape positioned at a nose part of a tip body formed in approximately polygonal plate shape. <P>SOLUTION: Round honing is applied after applying chamfer honing to the cutting edge ridgeline 15 having: the cutting edge ridge line 16 of approximately circular arc shape positioned at the nose part 14 of a rake face 11; and a cutting edge ridgeline 17 of approximately straight line shape positioned at the side part of the rake face 11. When viewed from a cross section orthogonal to the cutting edge ridgeline 15, the radius of curvature of an approximate curve formed by a chamfered face formed by round honing applied to the cutting edge ridgeline 16 of approximately circular arc shape is made larger than the radius of curvature of an approximate curve formed by a chamfered face formed by round honing applied to the cutting edge ridgeline 17 of approximately straight line shape. On the other hand, the radius of curvature of an approximate curve formed by a chamfered face formed by round honing applied to a connection part 16A of the cutting edge ridgeline 16 of approximately circular arc shape to the cutting edge ridgeline 17 of approximately straight line shape is made gradually smaller toward the side of the cutting edge ridgeline 17 of approximately straight line shape. The finished surface roughness of the machined surface of the machined workpiece is improved by the cutting edge ridgelines of such a tip. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a throw-away tip (hereinafter, referred to as a tip) removably attached to a tool body of a throw-away type cutting tool, and in particular, to a substantially polygonal flat plate-shaped tip body located at a nose portion of the tip body. The present invention relates to a tip for performing turning processing such as outer diameter processing mainly using an arc-shaped cutting edge ridgeline.
[0002]
[Prior art]
As disclosed in Patent Document 1, as this type of chip, a cutting edge ridge line which is an intersection ridge portion of a rake face and a flank face of a chip body having a substantially polygonal flat plate shape has a nose portion of a rake face. And a substantially straight cutting edge ridge located on the side of the rake face, and the substantially arc cutting edge and the substantially straight cutting edge ridge at the cutting edge. A curved concave portion is formed at a connection portion between the two.
When such a chip is mounted on the tool body, the cutting edge ridge line of the portion corresponding to the curved concave portion is retracted inward of the chip body in a plan view, so The projected radius of curvature (apparent radius of curvature) in plan view at the cutting edge ridgeline of the part to be formed is substantially larger than the design value of the standard product, and the finished surface roughness of the work surface of the work can be improved. It is possible.
[0003]
[Patent Document 1]
JP 2000-288803 A
[Problems to be solved by the invention]
By the way, recently, a so-called cBN sintered body tip in which at least a part of a tip body including a cutting edge ridge line acting on cutting is formed of a high-hardness cBN (cubic boron nitride) sintered body is often used. It is becoming.
However, while such a cBN sintered body chip has high hardness, it is poor in toughness and fragile as compared with a cemented carbide and the like, and tends to cause chipping and chipping. When trying to form a curved concave portion as described in the section of the cutting edge ridge line at the connection between the substantially arc-shaped cutting edge ridge line and the substantially straight cutting edge ridge line, chipping or chipping is liable to occur, making it difficult to manufacture At present, it cannot be an effective solution for improving the finished surface roughness.
[0005]
[Means for Solving the Problems]
Generally, in the case of a cBN sintered body chip, in order to prevent chipping and chipping, honing is performed on a cutting edge ridge, which is an intersection ridge between a rake face and a flank of the chip body, to improve its toughness. For example, the chamfer honing in which the intersection ridge portion of the rake face and the flank is chamfered in a substantially linear cross section is performed, or the intersection ridge line portion of the rake face and the flank is a substantially curved cross section The chamfered surface is rounded, and the chamfered surface of the chamfered surface with the chamfered surface is provided. A round honing in which a crossing ridge line portion with a flank is chamfered in a substantially curved cross section is applied.
The inventor of the present invention has conducted intensive studies focusing on this point, and as a result, has devised the shape of the round honing applied to the cutting edge ridge line, thereby obtaining a curved shape as described in Patent Document 1 described above. Even without forming the concave portion, in the state where the insert is mounted on the tool body, the projected radius of curvature in plan view at the cutting edge ridge line acting on cutting can be substantially larger than the design value of the standard product. Was found.
[0006]
According to the present invention made in this manner, the cutting edge ridge line, which is the intersection ridge portion between the rake face and the flank face of the chip body having a substantially polygonal flat plate shape, has a substantially arc-shaped cutting edge located at the nose portion of the rake face. In a throwaway insert having a blade ridge and a substantially straight cutting ridge located on a side of the rake face, the cutting ridge is subjected to round honing which is chamfered into a substantially curved cross section. When viewed in a cross section orthogonal to the cutting edge ridge line, the radius of curvature of a substantially curved line formed by the chamfered surface by the round honing applied to the substantially arc-shaped cutting edge ridge line is equal to the substantially straight cutting edge ridge line. The radius of curvature of a substantially curved line formed by the chamfered surface by the applied round honing is larger than the radius of curvature, and the chamfered surface by the round honing applied to a connection portion of the substantially arc-shaped cutting edge ridge line to the substantially straight cutting edge ridgeline. Radius of curvature of the approximate curve , And it is characterized in that it is gradually reduced as it gets closer to the substantially straight cutting edge ridge line side.
According to the insert of the present invention, by changing the radius of curvature of the substantially curved line formed by the cross section of the chamfered surface by the round honing applied to the cutting edge ridge line as described above, The projected radius of curvature in plan view at the cutting edge ridge acting on cutting can be substantially larger than the design value of the standard product, and the finish of the work surface of the workpiece processed by the cutting edge ridge of such a chip Surface roughness can be improved.
[0007]
Here, in the chip of the present invention, the cutting edge ridge is provided with chamfer honing in which an intersection ridge portion of the rake face and the flank is chamfered in a substantially straight cross section, and the chamfer honing is performed. The round honing in which the intersection ridge line portion of the chamfered surface and the flank is chamfered in a substantially curved cross-section is performed, and the radius of curvature of a substantially curved line formed by the cross-section of the chamfered surface by the round honing is as described above. Preferably, it is changed.
If only round honing is performed on the cutting edge ridge, for example, in order to improve the toughness of the cutting edge ridge made of a high-hardness cBN sintered body, a large round honing width is absolutely necessary. However, if round honing is performed after applying chamfer honing to the cutting edge ridge, it is necessary to sufficiently improve the toughness of the cutting edge ridge even if the round honing width is not so large. Can be. Therefore, the processing cost for performing the round honing on the cutting edge ridge constituted by the cBN sintered body of high hardness is not expensive, and when only the chamfer honing is performed on the cutting edge ridge. As compared with, the effect of improving the toughness of the cutting edge ridge line can be sufficiently obtained.
About such a round honing, if a specific numerical value is given, when viewed in a cross section orthogonal to the cutting edge ridge line, the round honing applied to the substantially arc-shaped cutting edge ridge line excluding the connecting portion is used. The radius of curvature of the substantially curved surface formed by the chamfered surface is set in the range of 0.025 mm to 0.050 mm, and the radius of curvature of the substantially curved surface formed by the chamfered surface by the round honing applied to the substantially straight cutting edge ridge line is 0. It is set in the range of 0.001 mm to 0.020 mm.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, a chip body 10 of a chip according to an embodiment of the present invention has a substantially rhombic flat plate shape (substantially polygonal flat plate shape) made of a hard material such as cemented carbide. The upper surface which is one substantially rhomboid surface (substantially polygonal surface) of the main body 10 is a rake face 11, and the lower surface which is the other substantially rhombic surface (substantially polygonal surface) of the chip main body 10 is a seating surface 12. The side surface of the chip body 10 connecting the rake face 11 and the seating face 12 is a flank face 13.
[0009]
Then, as shown in FIG. 2, in the rake face 11, the vicinity of one nose portion 14 having an apex angle θ set to an acute angle of, for example, 80 ° when viewed from above viewed from a direction opposite to the rake face 11 escapes. The intersection ridge line portion formed by intersecting with the surface 13 is a cutting edge ridge line 15 formed on the tip body 10.
The cutting edge ridgeline 15 is located at one nose portion 14 of the rake face 11 and has a substantially arcuate cutting edge ridgeline 16 and both ends of the substantially arcuate cutting edge ridgeline 16 (points P1, described later). Each of P1) has a pair of substantially straight cutting edge ridge lines 17, 17 which are connected to each other smoothly in a tangential shape when viewed from above and which are located on the sides of the rake face 11 and are substantially linear. It has become.
[0010]
Here, in a top view, since the substantially straight cutting edge ridge lines 17 are smoothly connected tangentially to both ends of the substantially arcuate cutting edge line 16, one nose of the rake face 11 is formed. Considering that the portion 14 has a vertex angle θ of 80 °, the substantially arc-shaped cutting edge ridge line 16 has a central angle of 100 ° with respect to the center O of the substantially arc formed by the substantially arc-shaped cutting edge ridge line 16. It has a substantially arc shape.
That is, in a top view, the substantially arc-shaped cutting edge ridge line 16 is inclined with respect to the bisector S through the above-described center O located on the bisector S of the nose portion 14 having the vertex angle θ of 80 °. When the straight lines S1 and S1 having the angle α1 of 50 ° are drawn, the straight lines S1 and S1 are connected to the substantially straight cutting edge ridge lines 17 and 17 at points P1 and P1 where the cutting edge ridge lines 15 intersect. It is being done.
[0011]
Further, a cutting edge chip obtained by integrally sintering a hard sintered body 18 of a cemented carbide or the like and a cBN sintered body 19 in a layered manner with respect to a concave portion formed in the chip main body 10 has a cBN sintered body 19 portion. Is joined to the rake face 11 side by brazing or the like, so that the vicinity of one nose portion 14 on the rake face 11 of the tip body 10 is formed of this cutting edge tip, and the cutting edge ridge line 15 is formed. Is formed on the cBN sintered body 19 in the cutting edge tip.
For this reason, the chip according to the present embodiment is a so-called cBN sintered body chip in which at least a part of the chip main body 10 including the cutting edge ridgeline 15 is formed of the high hardness cBN sintered body 19.
[0012]
In the cutting edge ridge line 15 formed of the cBN sintered body 19, as shown in FIG. 3 when viewed in a cross section orthogonal to the cutting edge ridge line 15, an intersection ridge line portion of the rake face 11 and the flank face 13 is substantially in cross section. By performing the chamfer honing, which is chamfered in a straight line, a chamfered surface 20 having a substantially straight cross section that intersects the rake face 11 and the flank 13 at an obtuse angle is formed.
Further, as shown in FIG. 3 as viewed in a cross section orthogonal to the cutting edge ridge line 15, the crossing ridge line portion between the chamfered surface 20 and the flank 13 by chamfer honing has a substantially curved cross section. By performing the round honing to be chamfered, a chamfered surface 21 having a substantially curved cross section is formed so as to intersect the chamfered surface 20 and the flank 13 by chamfer honing.
[0013]
In the present embodiment, the curvature of a substantially curved line formed by the cross section of the chamfered surface 21 due to the round honing when viewed in a cross section orthogonal to the cutting edge ridge line 15 for the round honing applied to the cutting edge ridge line 15. The radius R can be changed between a round honing applied to the substantially arc-shaped cutting edge ridge line 16 and a round honing applied to the substantially straight cutting edge ridge line 17.
[0014]
That is, when viewed in a cross section orthogonal to the cutting edge ridge line 15, the radius of curvature R1 of a substantially curved line formed by the cross section of the chamfered surface 21 formed by the round honing provided on the substantially arc-shaped cutting edge ridge line 16 excluding a connecting portion 16A described later. Is set to be a substantially constant value (for example, R1 = 0.030 mm) in the range of 0.025 mm to 0.050 mm, whereas the circle formed on the substantially straight cutting edge line 17 is The radius of curvature R2 of the substantially curved line formed by the cross section of the chamfered surface 21 formed by the honing is set to be a substantially constant value (for example, R2 = 0.010 mm) within the range of 0.001 mm to 0.020 mm. The radius of curvature R1 of the round honing provided on the substantially arc-shaped cutting edge ridgeline 16 is made smaller.
[0015]
In particular, the radius of curvature R3 of the substantially curved line formed by the cross-section of the chamfered surface 21 by the round honing applied to the connecting portion 16A of the substantially circular cutting edge ridge line 16 to the substantially straight cutting edge ridge line 17 excludes this connecting portion 16A. The radius of curvature R1 of the round honing applied to the substantially arc-shaped cutting edge ridgeline 16 is set to gradually decrease from the radius of curvature R2 of the round honing applied to the substantially straight cutting edge ridgeline 17.
[0016]
If the positions of the connecting portions 16A, 16A to the substantially linear cutting edge ridge lines 17, 17 in the substantially arcuate cutting edge line 16 are specifically shown in the case of the chip according to the present embodiment, FIG. As shown in the figure, a straight line S2 having an inclination angle α2 of 45 ° with respect to the bisector S through the center O located on the bisector S of the nose portion 14 having the apex angle θ of 80 °. When S2 is drawn, the straight line S2, S2 and the cutting edge ridgeline 15 (substantially arc-shaped cutting edge ridgeline 16) intersect at points P2, P2, which are located on the bisector S of the nose portion 14. When the straight lines S1 and S1 at which the inclination angle α1 with respect to the bisector S is 50 ° are drawn through the center O, the straight lines S1 and S1 and points P1 and P1 where the cutting edge ridge line 15 intersects are drawn. Such that the central angle with respect to the center O is 5 ° Indicating that the portion forming an arc.
[0017]
The tip according to the present embodiment having such a configuration has one nose portion 14 of the rake face 11 of the tip body 10 projecting from the tip of the tool body, and a pair of substantially straight cutting edge ridges at the cutting edge 15. 17 and 17 are attached to the tool main body so as to give a positive lateral clearance angle and a positive front clearance angle, and the cutting edge ridgeline 15 (substantially arc-shaped cutting) formed of the cBN sintered body 19 is provided. Using the blade ridgeline 16 and the substantially straight cutting blade ridgeline 17, 17), turning work such as outer diameter processing is performed on a work that is rotated around an axis.
[0018]
At this time, in the chip according to the present embodiment, each of the substantially straight cutting edge ridge lines 17 and 17 in the cutting edge ridge line 15 has a positive lateral clearance angle θ1 set to 5 ° (one substantially straight cutting edge ridge line). 17 with respect to the direction parallel to the axis of the work) or the positive front clearance angle θ2 also set at 5 ° (the direction of the other substantially straight cutting edge ridge line 17 perpendicular to the axis of the work). Tilt angle).
Therefore, in the top view of the chip body 10, the inclination angle α2 with respect to the bisector S is 45 ° through the center O located on the bisector S of the nose portion 14 having the vertex angle θ of 80 °. The straight lines S2 and S2 respectively extend substantially in a direction perpendicular to the axis of the work or in a direction parallel to the axis of the work.
[0019]
Here, the chip according to the present embodiment shown in FIG. 1 is of a negative type in which the flank 13 connected to the cutting edge ridgeline 15 is substantially perpendicular to the seating surface 12 and the rake surface 11 of the chip body 10. However, even with such a negative type insert, the flank 13 connected to the cutting edge ridge line 15 has a predetermined shape by being attached to the tool body so as to be inclined with respect to the reference plane of the tool body. A clearance angle is provided. In the case where the flank 13 connected to the cutting edge ridge 15 is a positive type chip in which the flank 13 is inclined toward the inner side of the chip body 10 toward the seating surface 12 of the chip body 10, of course. A predetermined clearance angle is given to the flank surface 13 connected to the cutting edge ridge line 15.
The point is that the insert is mounted on the tool body such that a predetermined clearance angle is given to the flank 13 connected to the cutting edge ridgeline 15.
[0020]
As described above, in the tip according to the present embodiment, the radius of curvature of the round honing applied to the cutting edge ridge line 15 at the connecting portion 16A of the substantially arc-shaped cutting edge ridge line 16 to the substantially straight cutting edge ridge line 17 is as described above. A large radius of curvature R1 (a substantially constant value within a range of 0.025 mm to 0.050 mm, for example, 0.030 mm) is obtained by changing R3 so as to gradually decrease toward the substantially straight cutting edge ridge line 17 side. (Excluding the connecting portion 16A) and a substantially linear cutting edge having a small radius of curvature R2 (a substantially constant value within a range of 0.001 mm to 0.020 mm, for example, 0.010 mm). The blade ridge line 17 is smoothly connected.
[0021]
Therefore, in a state where such a chip is mounted on the tool body, when viewed in a plan view from the direction opposite to the reference plane of the tool body, substantially along the direction orthogonal to the axis of the work or the direction parallel to the axis of the work. A substantially arc-shaped cutting edge ridge line 16 located near points P2 and P2 where the above-mentioned straight lines S2 and S2 extending and the cutting edge ridge line 15 (substantially arc-shaped cutting edge ridge line 16) intersects the tip body 10. Of the substantially arc-shaped cutting edge ridgeline 16 located near these points P2 and P2 in plan view is substantially larger than the design value of the standard product. Has become.
[0022]
Therefore, when the work surface of the workpiece is cut by such a cutting edge ridgeline 15, as shown by a solid line portion in FIG. 4, the curvature of the round honing applied to the chamfered cutting edge ridgeline 15 is obtained. When the radius R is set to 0.03 mm over the entire length of the substantially arc-shaped cutting edge ridge line 16 and the substantially straight cutting edge ridge lines 17 (shown by the upper dotted line in FIG. 4), The machining surface of the workpiece is compared with the case where the length is set to 0.01 mm over the entire lengths of the arc-shaped cutting edge ridgeline 16 and the substantially straight cutting edge ridgelines 17 (shown by the lower dotted line in FIG. 4). , The height of the point at the highest position can be reduced by t in FIG. 4, and the finished surface roughness can be improved.
[0023]
The radius of curvature R of the round honing applied to the chamfered cutting edge ridgeline 15 is determined in consideration of the toughness improvement effect and sharpness of the cutting edge ridgeline 15 made of the cBN sintered body 19. The radius of curvature R1 of the round honing applied to the substantially arc-shaped cutting edge ridgeline 16 excluding the connection portion 16A is set to a substantially constant value within a range of 0.025 mm to 0.050 mm, and the substantially straight cutting edge ridgeline is set. The radius of curvature R2 of the round honing applied to 17, 17 was set to a substantially constant value within the range of 0.001 mm to 0.020 mm. More preferably, the radius of curvature R1 was 0.030 mm to 0 mm. 0.040 mm, and the radius of curvature R2 is preferably in the range of 0.005 mm to 0.015 mm.
[0024]
In the present embodiment, one nose portion 14 of the rake face 11 of the chip body 10 has a vertex angle θ of 80 ° when viewed from above. However, the present invention is not limited to this. The nose portion 14 may have a vertex angle θ of 75 ° when viewed from the top (in this case, the above-mentioned inclination angle α1 is 52.5 °), or the nose portion 14 may have a vertex angle of 60 when viewed from the top. (In this case, the inclination angle α1 is 60 ° and the inclination angle α2 is 30 °).
Further, in the present embodiment, after the chamfer honing is performed on the cutting edge ridge line 15, further round honing is performed. However, only the round honing is performed on the cutting edge ridge line 15. The radius of curvature of the round honing may be changed.
[0025]
【The invention's effect】
As described above, according to the present invention, the radius of curvature of the substantially curved line formed by the cross-section of the chamfered surface formed by the round honing applied to the cutting edge ridge is changed as described above, so that the cutting edge is mounted on the tool body. In this state, the projected radius of curvature in plan view at the cutting edge ridge acting on the cutting can be substantially larger than the design value of the standard product, and the workpiece processed by the cutting edge ridge of such a chip The finished surface roughness of the machined surface can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a chip according to an embodiment of the present invention.
FIG. 2 is an enlarged top view of a main part showing a chip according to an embodiment of the present invention.
FIG. 3 is an enlarged sectional view of a main part orthogonal to a cutting edge ridge line of a tip according to an embodiment of the present invention.
FIG. 4 is an enlarged sectional view of a main part for explaining a processing surface when a workpiece is cut using a chip according to an embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 10 Chip body 11 Rake surface 13 Flank surface 14 Nose portion 15 Cutting edge ridgeline 16 Approximately arcuate cutting edge ridgeline 16A Connection portion of substantially arcuate cutting edge ridgeline to substantially linear cutting edge ridgeline 17 Nearly linear cutting edge ridgeline 19 cBN Sintered body 20 Chamfered surface by chamfer honing 21 Chamfered surface by round honing

Claims (4)

A cutting edge ridge line which is an intersection ridge line portion of a rake face and a flank of a chip body having a substantially polygonal flat plate shape, a substantially arc-shaped cutting edge ridge line located at a nose portion of the rake face, and a side portion of the rake face A throw-away insert having a substantially straight cutting edge ridgeline located at
The cutting edge is provided with a round honing that is chamfered in a substantially curved cross section,
When viewed in a cross section orthogonal to the cutting edge ridge line,
The radius of curvature of the substantially curved surface formed by the chamfered surface by the round honing applied to the substantially arc-shaped cutting edge ridgeline is larger than the radius of curvature of the substantially curved surface formed by the chamfered surface by the round honing applied to the substantially straight cutting edge ridgeline. The radius of curvature of a substantially curved surface formed by a rounded honing chamfered by a round honing applied to a portion of the substantially arc-shaped cutting edge ridge line that is connected to the substantially straight cutting edge ridge line is increased. A throw-away tip characterized by being progressively smaller as you go. The throw-away tip according to claim 1,
The chamfer honing in which the intersection ridge line portion of the rake face and the flank face is chamfered to have a substantially linear cross section is provided on the cutting edge ridge line, and the chamfered face formed by the chamfer honing intersects the flank face. A throw-away tip, wherein the round honing in which a ridge portion is chamfered into a substantially curved cross section is performed. The throw-away tip according to claim 2,
When viewed in a cross section orthogonal to the cutting edge ridge line,
A throw, wherein a radius of curvature of a substantially curved line formed by a chamfered surface formed by round honing provided on the substantially arc-shaped cutting edge ridgeline excluding the connection portion is set in a range of 0.025 mm to 0.050 mm. Away tip. In the throw away tip according to claim 2 or claim 3,
When viewed in a cross section orthogonal to the cutting edge ridge line,
A throwaway tip, wherein a radius of curvature of a substantially curved line formed by a chamfered surface formed by round honing provided on the substantially straight cutting edge ridge is set in a range of 0.001 mm to 0.020 mm.

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