JP2006247774A - End mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end mill, to which a cutting edge tip is brazed, improving the surface roughness of a finished surface after cutting even in the case where the feed of the end mill is increased. <P>SOLUTION: In this end mill, the cutting edge tip 33 is joined to the outer periphery of the tip part of the end mill body rotated round the axis by brazing. A cutting edge 44 formed on the intersecting ridge line part of the cutting face 38 of the cutting edge tip 33 and a front flank 39 is formed like a projected curve, which is partially like a circular arc, seen from the direction opposite to the cutting face 38. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an end mill used for die cutting and the like, and relates to an end mill in which a cutting edge tip is brazed to the outer periphery of a tip end portion of the end mill.

  Conventionally, an end mill is used as a tool used for cutting a mold. In order to efficiently perform the cutting using the end mill, it is necessary to increase the feed amount of the end mill and increase the cutting amount per cutting edge of the end mill. However, when the feed amount of the end mill is increased, a large step occurs on the finished surface of the workpiece due to the trace of the cutting edge tip formed when the cutting tip of the end mill passes the workpiece. There was a problem that the surface roughness of the finished surface of the work material deteriorated.

  Therefore, Patent Document 1 proposes a cutting edge tip having a curved cutting edge in order to improve the surface roughness of the finished surface of the cutting material. The cutting edge chip described in Patent Document 1 is provided with a wiper blade having a curvature on the cutting edge chip to improve the surface roughness of the finished surface of the workpiece. However, the cutting edge chip described in Patent Document 1 is a cutting edge chip that can be attached to and detached from the end mill by screwing or the like, and cannot be applied to an end mill that brazes the cutting edge chip.

  On the other hand, in an end mill having a small diameter of φ15 or less, it is difficult to detachably attach the cutting edge tip by screwing or the like, and therefore, there are provided those in which the cutting edge tip is brazed to the outer periphery of the end mill tip. Although it is relatively easy to make the cutting edge curved when it is possible to form the cutting edge with a single cutting edge tip, in an end mill where the cutting edge tip is brazed, the cutting edge can be processed with a single cutting edge tip. Because it is not possible, it is very difficult to make the cutting edge curved. Therefore, in the end mill to which the cutting edge tip is brazed, generally, the cutting edge is formed in a straight line.

  6, 7, and 8 show an example of an end mill in which a conventional cutting edge tip is brazed. 6 is a side view of the end mill, FIG. 7 is a front view of the end mill, and FIG. 8 is a perspective view of the cutting edge tip. The end mill 1 includes an end mill body 2 that is rotated around an axis O and a plurality of cutting edge tips 3. A plurality of chip discharge grooves 4 are formed on the outer periphery of the end portion of the end mill main body 2, in which the end mill main body 2 is cut out so as to form a substantially L shape in a cross section perpendicular to the axis O. A cutting edge tip 3 is joined to a mounting seat 6 formed on a wall surface facing the front side in the end mill rotation direction T in the chip discharge groove 4 by brazing. The cutting edge tip 3 has a rake face 8, a front flank face 9, and a circumferential flank face 11, and a cutting edge 14 is linearly formed at the intersecting ridge line portion between the rake face 8 and the front flank face 9. The cutting edge 15 is linearly formed at the intersection ridge line portion between the rake face 8 and the circumferential flank face 11.

The end mill 1 having the above-described configuration is provided on the outer periphery of the end portion of the end mill body 2 by the end mill body 2 being rotated around the axis O and fed in the direction crossing the axis O direction and the axis O direction. The workpiece is cut by the plurality of cutting blade tips 3 formed, and a finished surface is formed on the workpiece.
FIG. 9 shows a schematic diagram when the workpiece is flattened by the end mill 1 having the above configuration. When the end mill main body is rotated around the axis O, the cutting edge tip 3 installed on the outer periphery of the tip end portion of the end mill main body enters the workpiece 16 and scrapes a part of the workpiece 16. The end mill body is moved in the horizontal direction while rotating, and the cutting edge tip 3 is fed in the direction of the arrow, so that a finished surface 17 is formed on the workpiece 16. On the finished surface 17, a step 19 is formed for each passage mark 18 of the cutting edge tip 3.
JP 2001-138122 A

  By the way, in the end mill having the above configuration, since the cutting edge is formed in a straight line, when the feed amount of the end mill is increased, the passing trace of the cutting edge tip remains as a step as shown in FIG. There was a problem that the finished surface was a saw blade and the surface roughness of the finished surface was deteriorated. Further, in the end mill having the above configuration, in order to improve the surface roughness, it is necessary to reduce the feed amount of the end mill, and there is a problem that the processing time is significantly increased.

In recent years, attention has been paid to small-diameter end mills due to the complexity and miniaturization of mold shapes. Even in small-diameter end mills with brazed cutting tips, finishing after cutting is required even when the feed amount is increased. What has good surface roughness is required.
The present invention has been made in view of the above circumstances, and even when the feed amount of the end mill is increased, the cutting edge tip that can improve the surface roughness of the finished surface after cutting is brazed. The purpose is to provide an end mill.

In order to solve the above problems, the present invention provides the following means.
The end mill according to claim 1 is an end mill in which a cutting edge tip is joined to the outer periphery of a tip portion of an end mill body rotated about an axis by brazing, and the rake face of the cutting edge tip and a front flank face The cutting blades formed on the intersecting ridge lines are characterized in that they are formed in a convex curve shape that is partially arcuate when viewed from the direction facing the rake face.
In the end mill having the above-described configuration, the cutting blade formed at the intersecting ridge line portion between the rake face and the front flank of the cutting edge tip is formed in a convex curve shape with a part of an arc shape, When the material to be cut is cut by an end mill, when the cutting edge tip passes through the material to be cut, an arc-shaped processing mark is formed on the finished surface of the material to be cut.

The end mill according to claim 2 is an end mill in which a cutting edge tip is joined by brazing to an outer periphery of a tip end portion of an end mill main body rotated about an axis, and includes a rake face and a circumferential flank face of the cutting edge tip. The cutting blades formed on the intersecting ridge lines are characterized in that they are formed in a convex curve shape that is partially arcuate when viewed from the direction facing the rake face.
In the end mill configured as described above, the cutting edge formed at the intersecting ridge line portion of the rake face and the circumferential flank face of the cutting edge tip is formed in a convex curve shape in which a part is an arc shape, When the material to be cut is cut by the end mill, when the cutting edge tip passes through the material to be cut, an arc-shaped processing mark is formed on the finished surface of the material to be cut.

The end mill according to claim 3 is an end mill in which a cutting edge tip is joined to the outer periphery of a tip portion of an end mill body rotated about an axis by brazing, and the rake face of the cutting edge tip and a front flank face When the cutting edge formed on the intersecting ridge line portion and the intersecting ridge line portion of the rake face and the circumferential flank face is viewed from the direction facing the rake face, a part of the cutting edge has a circular arc shape. It is characterized by being formed.
In the end mill having the above-described configuration, the cutting edge formed at the intersecting ridge line portion between the rake face of the cutting edge tip and the front flank face and the intersecting ridge line portion between the rake face and the circumferential flank face is formed on the rake face. When viewed from the opposite direction, a part is formed in a convex curve shape having an arc shape, and when the workpiece is cut by the end mill, the cutting edge tip passes through the workpiece In addition, an arc-shaped machining trace is formed on the finished surface of the workpiece.

The end mill according to claim 4 is the end mill according to any one of claims 1 to 3, wherein a radius of curvature R of the arc of the cutting edge is 10 mm to 500 mm when viewed from a direction facing the rake face. It is characterized by being within the range of.
In the end mill configured as described above, since the radius of curvature R of the arc of the cutting edge is 10 mm or more, a smooth machining trace having a radius of curvature of 10 mm or more is formed on the finished surface of the workpiece. For example, even when the feed amount per blade is 0.2 mm, the surface roughness of the finished surface can be satisfactorily finished at 1.6a if the curvature radius R is 10 mm.
Further, since the radius of curvature R of the arc of the cutting edge is 500 mm or less, the cutting into the workpiece is smoothly performed.

The end mill according to claim 5 is the end mill according to any one of claims 1 to 4, wherein an axial rake angle of the cutting edge is within a range of 0 ° to 20 °, and The radial rake angle is in the range of 0 ° to 20 °.
In the end mill configured as described above, the axial rake angle and the radial rake angle are within the range of 0 ° to 20 °, so that the main component force, the back component force, and the feed component force of the cutting force are adjusted. The Further, since the axial rake angle and the radial rake angle are set to 20 °, a smooth processing mark is formed on the finished surface.

  According to the first aspect of the present invention, when the workpiece is flattened or the like, an arc-shaped machining trace is formed on the workpiece, so that the feed amount of the end mill is increased and the cutting amount per blade is increased. Even if the amount is increased, the surface roughness of the finished surface of the workpiece can be improved. Therefore, even when the feed amount of the end mill is increased, it is possible to provide an end mill having a good finished surface roughness.

  According to the second aspect of the present invention, when the workpiece is subjected to a helical process or the like, an arc-shaped machining trace is formed on the workpiece, so that the feed amount of the end mill is increased and the cutting amount per blade is increased. Even if the amount is increased, the surface roughness of the finished surface of the workpiece can be improved. Therefore, even when the feed amount of the end mill is increased, it is possible to provide an end mill having a good finished surface roughness.

  According to the invention of claim 3, when the workpiece is flattened or helically processed, the finished surface of the workpiece can be obtained even if the feed amount of the end mill is increased and the cutting amount per blade is increased. The surface roughness can be improved. Therefore, even when the feed amount of the end mill is increased, it is possible to provide an end mill having a good finished surface roughness.

  According to the invention of claim 4, even if the feed amount of the end mill is increased and the cutting amount per blade is increased, the surface roughness of the finished surface can be improved and the cutting process can be performed smoothly. it can.

  According to the invention which concerns on Claim 5, while adjusting an axial rake angle and a radial rake angle, while being able to reduce cutting resistance, the surface roughness of the finished surface of a to-be-cut material can be made favorable.

A first embodiment of the present invention will be described.
1A, 1B and 2 show an end mill which is a first embodiment of the present invention. FIG. 1A is a perspective view of a cutting edge tip, FIG. 1B is a front view of the cutting edge tip as viewed from the surface facing the rake face, and FIG. 2 is a side view of the end mill. is there.

  The end mill 31 includes an end mill main body 32 and a cutting edge tip 33 that are rotated around the axis O. Four chip discharge grooves 34 formed by cutting the end mill main body 32 are formed on the outer periphery of the end portion of the end mill main body 32, and the chip discharge grooves 34 are formed on a wall surface facing the front side in the end mill rotation direction T. A cutting edge tip 33 made of a diamond sintered body is joined to the mounting seat 36 by brazing.

The cutting edge tip 33 has a rake face 38, a front flank face 39, and a circumferential flank face 41, and a cutting edge 44 is partly on the intersecting ridge line portion between the rake face 38 and the front flank face 39. It is formed in a convex curve shape having an arc shape with a curvature radius R = 50 mm, and a cutting edge 45 is formed in a straight line at the intersecting ridge line portion of the rake face 38 and the circumferential relief surface 41.
The cutting blade 44 is formed in a convex curve shape, in which a part of the cutting edge 44 is formed into an arc shape with a radius of curvature R = 50 mm, after the cutting blade tip 33 is brazed to the outer periphery of the tip end portion of the end mill main body 32. .

  The end mill 31 configured as described above is provided on the outer periphery of the end portion of the end mill main body 32 by the end mill main body 32 being rotated about the axis O and fed in the direction crossing the front end side in the axis O direction and the axis O direction. The material to be cut is cut by the cutting blades 44 and 45 of the plurality of cutting blade tips 33 to form a finished surface.

FIG. 3 shows a schematic diagram when the workpiece is planed by the end mill 31 having the above-described configuration. When the end mill main body 32 is rotated around the axis O, the tip of the cutting edge tip 33 is not easily cut by the workpiece 46 and a part of the workpiece 46 is scraped off. The end mill main body 32 is moved in the horizontal direction and the cutting edge tip 33 is fed in the direction of the arrow, so that a finished surface 47 is formed on the workpiece 46. The cutting edge 44 provided at the intersection ridge line portion of the rake face 38 and the front flank 39 of the cutting edge tip 33 is partially formed in a convex curve shape having an arc shape with a curvature radius R = 50 mm. When the cutting edge tip 33 passes through the workpiece 46, an arcuate machining mark 48 is formed on the finished surface 47 of the workpiece 46.
In the end mill 31 configured as described above, since the arc-shaped machining trace 48 is formed on the finished surface 47 of the workpiece 46, even when the feed amount per blade is increased, the surface roughness of the finished surface 47 is increased. Is good.

A second embodiment of the present invention will be described.
4 (a) and 4 (b) show a cutting edge tip of an end mill according to the second embodiment of the present invention. 4A is a perspective view of the cutting edge tip, and FIG. 4B is a front view of the cutting edge tip as viewed from the surface facing the rake face.
The cutting edge tip 53 is made of a diamond sintered body, has a rake face 38, a front flank face 39, and a circumferential flank face 41, and is cut at a cross ridge line portion between the rake face 38 and the front flank face 39. The blade 54 is formed in a straight line shape, and a cutting blade 55 is formed in a convex curve shape in which a part of the cutting blade 55 is formed in an arc shape having a curvature radius R = 50 mm at the intersecting ridge line portion of the rake face 38 and the circumferential relief surface 41. ing.

  The end mill to which the cutting edge tip 53 having the above configuration is brazed is mainly used for helical machining. Helical machining means that the end mill is rotated around the axis O while being fed toward the tip side in the direction of the axis O, and the end mill axis itself is moved in the circumferential direction, so that a hole on the cylinder is formed in the workpiece. To be processed. The wall surface of the cylindrical hole is cut by the cutting edge 55 of the cutting edge tip 53 of the end mill, and a finished surface is formed on this wall surface.

  In the end mill in which the cutting edge tip 53 having the above-described configuration is brazed, the cutting edge 55 formed at the intersecting ridge line portion of the rake face 38 and the circumferential flank 41 has a part of a circle having a curvature radius R = 50 mm. Since it is formed in an arc-like convex curve shape, an arc-shaped machining trace is formed on the finished surface. Therefore, in the above-mentioned end mill, the surface roughness of the finished surface is good even when the feed amount per blade is increased.

A third embodiment of the present invention will be described.
5 (a) and 5 (b) show a cutting edge tip of an end mill which is a third embodiment of the present invention. FIG. 5A is a perspective view of the cutting edge tip, and FIG. 5B is a front view of the cutting edge tip as viewed from the surface facing the rake face.

  The cutting edge tip 63 is made of a diamond sintered body, has a rake face 38, a front flank face 39, and a circumferential flank face 41, and is cut at the intersecting ridge line portion between the rake face 38 and the front flank face 39. A cutting edge 65 is formed at the intersection ridge line portion between the rake face 38 and the circumferential flank 41. The cutting blade 64 and the cutting blade 65 are each formed in a convex curve shape having an arc shape with a curvature radius R = 50 mm.

  In the end mill in which the cutting edge tip having the above-described configuration is brazed, the cutting edge 64 formed at the intersecting ridge line portion between the rake face 38 and the front flank 39, and the intersection of the rake face 38 and the circumferential flank 41. Since the cutting edge 65 formed in the ridge line part has a convex curve shape with a part of an arc shape having a curvature radius R = 50 mm, when used for planing or when used for helical machining, Even if the feed amount of the end mill is increased, the surface roughness of the finished surface is good.

In the above-described embodiment, the case of planing and helical machining using an end mill has been described. However, the same effect can be obtained in other machining such as grooving, end face machining, and taper machining.
In the above-described embodiment, the description has been given of the case where four cutting edge tips are provided on the outer periphery of the end portion of the end mill. However, the number of cutting edge tips may be any number.
In the above embodiment, the cutting edge tip made of a diamond sintered body has been described. However, the cutting edge tip material may be CBN (Cubic Boron Nitride), cemented carbide or the like. good.

The effectiveness of the present invention was verified by conducting a comparative test using the end mill according to the first embodiment.
As an example, the end mill shown in FIGS. 1 and 2 having an outer diameter of 25 mm and four cutting edges was used. As a comparative example, the end mill shown in FIGS. 6 and 7 having an outer diameter of 25 mm and four cutting edges was used.
The cutting conditions were a rotational speed of 8000 / min, a feed rate of 8000 mm / min, and high feed conditions of 0.5 mm and 1.0 mm per blade. Aluminum alloy was used as the work material.

  As the evaluation, the maximum height Rz was measured at three locations, that is, the upcut portion, the center cut portion, and the undercut portion, as the surface roughness of the finished surface after cutting. The test results are shown in Table 1.

  According to the present embodiment, Rz = 2 to 5 μm regardless of whether the feed amount is 0.5 mm or 1.0 mm, but in the comparative example, Rz = 10 to 20 μm. Therefore, according to the present Example, it was confirmed that the surface roughness of a finished surface can be made favorable.

It is detail drawing of the cutting-edge chip | tip of the end mill which is 1st embodiment of this invention. It is a side view of the end mill which is the first embodiment of the present invention. It is a schematic diagram at the time of planing the to-be-cut material using the end mill which is 1st embodiment of this invention. It is detail drawing of the cutting-edge chip | tip of the end mill which is 2nd embodiment of this invention. It is detail drawing of the cutting-edge chip | tip of the end mill which is 3rd embodiment of this invention. It is a side view of the end mill where the conventional cutting blade was brazed. It is a front view of the end mill where the conventional cutting blade was brazed. It is a perspective view of the cutting-edge chip | tip of the end mill to which the conventional cutting-blade was brazed. It is a schematic diagram at the time of planing a to-be-cut material using the end mill to which the conventional cutting blade was brazed.

Explanation of symbols

1, 31 End mill 3, 33, 53, 63 Cutting edge tip 8, 38 Rake face 9, 39 Front relief face 11, 41 Circumferential relief face 14, 15, 44, 45, 54, 55, 64, 65 Cutting edge 17 , 47 Finished surface

Claims (5)

An end mill in which a cutting edge tip is joined by brazing to the outer periphery of the end portion of the end mill body rotated around an axis,
The cutting edge formed at the intersection ridge line part of the rake face and the front flank face of the cutting edge tip is formed in a convex curve shape with a part of an arc when viewed from the direction facing the rake face. End mill characterized by being made. An end mill in which a cutting edge tip is joined by brazing to the outer periphery of the end portion of the end mill body rotated around an axis,
When the cutting edge formed at the crossing ridge line portion between the rake face of the cutting edge tip and the circumferential flank face is viewed from the direction facing the rake face, a part of the cutting edge has a convex curve shape having an arc shape. End mill characterized by being formed. An end mill in which a cutting edge tip is joined by brazing to the outer periphery of the end portion of the end mill body rotated around an axis,
When the cutting edge formed on the intersecting ridge line portion between the rake face of the cutting edge tip and the front flank face and the intersecting ridge line portion between the rake face and the circumferential flank face is viewed from the direction facing the rake face. An end mill characterized in that a part thereof is formed in a convex curve shape having an arc shape. In the end mill according to any one of claims 1 to 3,
An end mill characterized in that the radius of curvature R of the arc of the cutting edge is in the range of 10 mm to 500 mm when viewed from the direction facing the rake face. In the end mill according to any one of claims 1 to 4,
An end mill characterized in that an axial rake angle of the cutting blade is in a range of 0 ° to 20 °, and a radial rake angle of the cutting blade is in a range of 0 ° to 20 °.

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