JP2002126932A - End mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of corner flank wear while ensuring the cutting edge strength of the corner of an end mill. SOLUTION: A recess 32 is formed on the intersection line of first and second flanks 20a and 20b of an outer peripheral blade 16 with first and second flanks 22a and 22b of a bottom blade 18, and in a position separated away by a given size t from a corner 24. The given size t is dimension within a range of 0.2-0.3 mm and the recess 32 is formed of a single flat surface formed such that an approximate triangular conical protrusion part consisting of the first and second flanks 20a and 20b of the outer peripheral blade 16 and an approximate protrusion part consisting of the second flank 20b of the outer peripheral blade 16 are both removed by chamfering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an end mill,
In particular, the present invention relates to a technique for suppressing flank wear while ensuring the edge strength of a corner where an outer peripheral blade and a bottom blade are connected.

[0002]

2. Description of the Related Art End mills having an outer peripheral edge and a bottom edge are widely used in various cutting processes. FIG.
Figures showing an example of such a conventional end mill, in which (a) is a front view seen from a direction perpendicular to the axis, (b) is a bottom view seen from the tip side (bottom blade side), and (c) is a view. (a) is an enlarged view of a portion C, and (d) is an enlarged view of a portion D in (b). The end mill 10 has a shank 12 and a blade portion 14 continuously and integrally in the axial direction, and a large number (eight in the figure) of outer peripheral blades 16 twisted clockwise on the outer peripheral surface of the blade portion 14. At the tip of the blade portion 14, a number of bottom blades 18 are provided so as to be continuous with the outer peripheral blade 16, and are rotated clockwise as viewed from the shank 12 side to cut. Perform processing. Further, the outer peripheral blade 16 is provided with a first flank 20a and a second flank 20b, and the bottom blade 18 is provided with a first flank 22a and a second flank 22b.

[0003]

However, in such a conventional end mill 10, as shown in FIG. 4 (c), the cutting edge of the corner 24 connecting the outer peripheral blade 16 and the bottom blade 18 has the same shape. of one to be sharpened in accordance with the helix angle, per back occurs with insufficient drop of the corner 24, flank wear width VB _C of the corner flank wear 26 (hatched portion in FIG. 4 (c)) increases easy. Further, the edge flank wear 26 causes the edge of the corner 24 to be rounded, and FIG.
When the end face is cut on the work 28 as shown in FIG. 3B, the dimension of the corner R cut by the corner 24 is enlarged as shown in FIG.

On the other hand, the first flank 20 of the outer peripheral blade 16
If the clearance angle a is increased, the back contact of the corner 24 is reduced and the corner flank wear 26 is suppressed, but the edge strength of the corner 24 is reduced and chipping is likely to occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress corner flank wear while securing the edge strength of a corner.

[0006]

According to a first aspect of the present invention, there is provided an end mill having an outer peripheral edge and a bottom edge, wherein the end mill has a flank of the outer peripheral edge and a flank of the bottom edge. A relief is provided at a position separated by a predetermined distance from a corner where the outer peripheral blade and the bottom blade are connected.

A second invention is the end mill according to the first invention, wherein the clearance is 0.1 mm to 0.5 m from the corner.
It is characterized by being provided with a predetermined distance within the range of m.

A third invention is the end mill according to the first invention or the second invention, wherein the flank of the outer peripheral edge has a first flank and a second flank, and the flank is the first flank. , The second flank, and the substantially triangular pyramid-shaped convex portion formed by the flank of the bottom blade are chamfered and removed.

[0009]

In such an end mill, since the clearance is provided at a position separated by a predetermined distance from the corner on the intersection line between the flank of the outer peripheral blade and the flank of the bottom blade, the cutting edge of the corner is The progress of wear of the flank of the corner is suppressed while maintaining the strength, and the machining accuracy of the corner by the corner is favorably maintained, so that the life of the cutting edge is improved.

[0010] In the second aspect of the present invention, 0.1 mm to
Since the clearance is provided at a predetermined distance in the range of 0.5 mm, the above-mentioned effect can be enjoyed satisfactorily. In the third invention, the first flank, the second flank of the outer peripheral blade,
Since the substantially triangular pyramid-shaped convex portion formed by the flank of the bottom blade may be chamfered and removed, the flank can be easily processed.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an end mill for a twisted blade whose outer peripheral edge is located on a helical winding twisted around an axis, particularly when the cutting rotation direction and the torsion direction of the outer peripheral blade coincide with each other when viewed from the shank side. , But may also be applied to an end mill having a straight blade whose outer peripheral edge is parallel to the axis.

In addition to end mills in which an outer peripheral blade and a bottom blade are provided integrally with a body, various end mills such as an end mill in which an outer peripheral blade and a bottom blade are provided in a blade or a chip separate from the body. Can be applied. The number of outer peripheral blades and bottom blades is also determined as appropriate, such as a one-blade, two-blade, or three or more multi-blade end mill.

The shape of the clearance may be a single or a plurality of flat surfaces by C-chamfering, a curved surface by R-chamfering, etc., and various surface shapes are possible. The chamfering removal of the third invention may be C chamfering or R chamfering.

The escape position is 0.1 m as in the second invention.
It is desirable to provide a predetermined dimension in the range of m to 0.5 mm away from the corner, more preferably 0.2 mm to 0.5 mm.
The range of 0.3 mm is good. Depending on the size of the torsion angle of the outer peripheral blade, etc., generally, if the distance from the corner to the clearance is smaller than 0.1 mm, the edge strength of the corner will be impaired, and if it is larger than 0.5 mm, the corner flank wear will be reduced. The suppression effect cannot be obtained sufficiently.

In the third aspect, the first flank and the second flank are provided as the flank of the outer peripheral blade. However, the first flank and the second flank are similarly provided on the bottom blade. good. Further, the present invention is applicable to a case where both the outer peripheral blade and the bottom blade are formed only with a single flank, for example, the heel may be provided with a clearance.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The end mill 30 shown in FIGS. 1 to 3 is an embodiment in which the present invention is applied to the end mill 10 shown in FIG. 4, and is different from the end mill 10 only in that a relief 32 is provided. The other parts are denoted by the same reference numerals as those of the end mill 10, and the detailed description is omitted. FIGS. 1 (a) to (d) correspond to FIGS. 4 (a) to 4 (d), respectively.
2 is a perspective view showing the vicinity of the relief 32, and FIG. 3 is a sectional view taken along the line III-III in FIG. 1 (d).

In the end mill 30, the outer peripheral blade 1
6, the first flank 20a, the second flank 20b, and the bottom blade 18
A clearance 32 is provided on a line of intersection between the first flank 22a and the second flank 22b and at a position separated from the corner 24 by a predetermined dimension t. The predetermined dimension t is 0.2 mm
The relief 32 has a dimension within the range of about 0.3 mm,
6, a first flank 20a, a second flank 20b, and a substantially triangular pyramid-shaped convex portion formed by the first flank 22a of the bottom blade 18, and a first flank 22a, a second flank of the bottom blade 18. The flank 22b and the substantially triangular pyramid-shaped convex portion constituted by the second flank 20b of the outer peripheral blade 16 are provided so as to chamfer and remove both, and in this embodiment, a single flat surface is used. It is configured. FIG. 3 is a cross-sectional view perpendicular to the first flank 22 a and parallel to the axis of the end mill 30.
The inclination angle θ between the first flank 22a and the flank 32 is 3
In the range of 0 ° to 60 °, it is about 45 ° in this embodiment.

In such an end mill 30, the first flank 20a and the second flank 20b of the outer peripheral blade 16 and the first flank 22a and the second flank 22b of the bottom blade 18 intersect. , From the corner 24, the predetermined dimension t = 0.2-0.
Since the relief 32 is provided at a position separated by 3 mm, the progress of wear of the corner flank is suppressed while ensuring the strength of the edge of the corner 24, the machining accuracy of the corner portion by the corner 24 is maintained well, and the life of the edge is maintained. Is improved.

In this embodiment, a substantially triangular pyramid-shaped convex portion constituted by the first flank 20a and the second flank 20b of the outer peripheral blade 16 and the first flank 22a of the bottom blade 18 is provided. First flank 22a, second flank 2 of bottom blade 18
2b and a substantially triangular pyramid-shaped projection formed by the second flank 20b of the outer peripheral blade 16 are removed at a predetermined inclination angle θ ≒ 45 with respect to the first flank 22a.
Since it is only necessary to provide a flat chamfer so as to incline at an angle of °, the relief 32 can be easily processed.

Incidentally, the outer diameter of the outer peripheral blade 16 is φ14, the torsion angle is 30 °, and the relief 32 is not provided with the same size and material as the 8-flute end mill 30 made of cemented carbide. using a conventional end mill 10 of performs cutting under the following cutting conditions was measured corner flank wear width VB _C at 120m cutting was about 0.46mm in end mill 10 (conventional) On the other hand, in the end mill 30 (product of the present invention), the wear was suppressed by about 40% by about 0.27 mm. (Cutting conditions) Work material: FC250 (grey cast iron) Machine: Horizontal Machining method: Bottom finish Cutting oil: Water soluble Cutting speed: 180 m / min Feeding speed: 0.05 mm / t Cutting depth: _aa = 35 mm, _ar = 0.3mm

Although the embodiment of the present invention has been described in detail with reference to the drawings, this is merely an embodiment,
The present invention can be implemented in various modified and improved aspects based on the knowledge of those skilled in the art.

[Brief description of the drawings]

1A and 1B are diagrams showing an end mill according to an embodiment of the present invention, wherein FIG. 1A is a front view as viewed from a direction perpendicular to an axis, and FIG. 1B is a bottom view as viewed from a tip side (bottom blade side). , (C) is the C in (a)
(D) is an enlarged view of a D part in (b).

FIG. 2 is an enlarged perspective view showing a relief area of the end mill of FIG. 1;

FIG. 3 is a sectional view taken along the line III-III in FIG. 1 (d).

FIG. 4 is a view showing an example of a conventional end mill, and is a view corresponding to FIG.

5 (a) is a cross-sectional view for explaining end face cutting using the end mill of FIG. 4, and FIG. 5 (b) is an enlarged cross-sectional view showing a cut shape obtained by the cutting in FIG. 4 (a).

[Explanation of symbols]

16: Outer edge 18: Bottom edge 20a: First flank of outer edge 20b: Second flank of outer edge 22a: First flank of bottom edge 22b: Second flank of bottom edge 24: Corner 30: End mill 32: Run away

Claims (3)

[Claims] 1. An end mill having an outer peripheral edge and a bottom edge, wherein a predetermined dimension is defined from a corner on a line of intersection between a flank of the outer peripheral edge and a flank of the bottom edge and where the outer peripheral edge and the bottom edge are connected. An end mill characterized in that a relief is provided at a separated position. 2. The relief is 0.1 mm from the corner.
2. The end mill according to claim 1, wherein the end mill is provided at a predetermined distance in a range of 0.5 mm. 3. The flank of the outer peripheral blade includes a first flank and a second flank, wherein the flank includes the first flank, the second flank, and the flank of the bottom blade. The end mill according to claim 1 or 2, wherein a substantially triangular pyramid-shaped convex portion formed by chamfering is removed.