JPH06126521A - End mill - Google Patents

Abstract

PURPOSE:To provide an end mill, having a long life and improved surface accuracy. CONSTITUTION:Plural bottom cutting edges 1 are provided on a bottom surface of an end mill. The lands 2 of the cutting edges 1 are composed of surfaces forming recessed parts 3, in which depth is increased in proportion to near the center O of the bottom surface of the end mill from the end E of the bottom surface of the end mill, and the recessed part forming surface is composed of a protruded curved surface. The protruded curved surface is composed including the circular arc component of a circle the center P of which is positioned in the vicinity of the side surface of the end mill. The radius R of the circle is set larger than the radius (r) of the end mill. Thus the lands 2 of the bottom edges 1 are extended toward the tangent line direction of the circle from the end E, and a length to the center O from the ends E of the lands 2 is increased. This can improve the strength of the edge parts of the bottom cutting edges 1, of the strength of whole bottom cutting edges 1, of cutting efficiency, and of surface accuracy, and so on.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an end mill having a bottom blade.

[0002]

2. Description of the Related Art As one type of end mill having a bottom blade, the land of the bottom blade forms a recess whose depth increases from the end of the bottom surface of the end mill toward the center of the bottom surface of the end mill. Some are made up of surfaces.

Generally, this type of end mill is
The recess forming surface of the land was flat.

[0004]

Therefore, even if the edge portion of the bottom blade, that is, the portion of the land located at the end of the bottom surface of the end mill has a short life and the other portion of the bottom blade has cutting ability. There was a problem that the end mill had to be replaced due to a chipped edge or the like.

Further, there is a problem that the work accuracy is low because a feed mark due to the edge portion of the bottom blade remains on the work material.

In view of the above problems, it is an object of the present invention to provide an end mill which has a long life and can improve the surface accuracy.

[0007]

In order to solve the above-mentioned problems, an end mill according to the present invention has a bottom blade, and the land of the bottom blade is located from the end of the bottom surface of the end mill to the center of the bottom surface of the end mill. In the end mill composed of the surface forming the concave portion whose depth increases toward
The recess forming surface of the land is formed of a convex curved surface.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of an end mill according to this embodiment, FIG. 2 is a side sectional view showing a first cutting edge angle of a bottom blade of the end mill, FIG. 3 is a bottom view of the end mill, and FIG. The perspective views of the end mills are shown respectively.

The end mill has a plurality of bottom blades 1 on the bottom surface, as shown in FIGS. 1, 3 and 4.

The land 2 of the bottom blade 1 is composed of a surface forming a concave portion 3 whose depth increases from the end E of the bottom surface of the end mill toward the center O of the bottom surface of the end mill.
As shown in FIGS. 1 and 4, this concave portion forming surface is a convex curved surface. This convex curved surface is configured to include an arc component of a circle whose center P is located near the side surface of the end mill. The radius R of the circle is set larger than the radius r of the end mill. The first cutting edge angle θ of the bottom blade shown in FIG. 2 is 0 ° to about 1
It is set within the range of 5 °.

As described above, in the end mill according to this embodiment, the land 2 of the bottom blade 1 is a convex curved surface whose depth increases from the edge E of the bottom surface toward the center O, and this convex curved surface , The center P is located near the side surface of the end mill, and the radius R includes an arc component of a circle larger than the end mill radius r.

For this reason, the land 2 of the bottom blade 1 starts to extend in the tangential direction of the circle from the end E, and the length from the end E of the land 2 to the center O increases, so that the bottom blade 1
It is possible to improve the strength of the edge portion, the strength of the entire bottom blade 1, the cutting efficiency, and the surface accuracy.

Although the above-mentioned embodiment shows a two-blade end mill, the present invention is not limited to this, and can be easily applied to a three-blade, four-blade end mill and the like. It goes without saying that you can do it.

[0015]

As is clear from the above description, according to the present invention, it is possible to provide an end mill which has a long life and is capable of improving the surface accuracy.

[Brief description of drawings]

FIG. 1 is a side view of an end mill according to an embodiment.

FIG. 2 is a side sectional view showing a first cutting edge angle of a bottom blade of the end mill.

[Fig. 3] Bottom view of the end mill

FIG. 4 is a perspective view of the end mill.

[Explanation of symbols]

 1 Bottom blade 2 Land 3 Recess E End of bottom of end mill O Center of bottom of end mill P Center of circle forming convex curved surface

Claims (2)

[Claims] 1. A bottom blade is provided, and a land of the bottom blade is formed by a surface forming a recess whose depth increases from the end of the bottom surface of the end mill toward the center of the bottom surface of the end mill. The end mill, wherein the recess forming surface of the land is a convex curved surface. 2. The convex curved surface according to claim 1,
An end mill comprising an arc component of a circle whose center is located near the side surface of the end mill.