JPS59214510A - Ball end mill - Google Patents

Abstract

PURPOSE:To make it possible to perform high speed cutting and as well the cutting of ultra-hard materials, by constituting a main chip with a rod-like center side chip made of a high-pressure phase sintered member and having a substantially quarter circle cross sectioned shape, and an outer peripheral side chip which is made by sintering and securing a cutting knife layer formed of high-pressure phase sintered member on an ultra-hard alloy substrate. CONSTITUTION:A main cutting knife chip 4 is formed of a rod-like center side chip made of a high-pressure phase sintered material of cubic boron nitride, diamond or the like and having a substantially quarter circle cross-sectioned shape, and an outer peripheral side chip 6 which is made by sintering and securing a cutting knife layer 12 made of a high-pressure phase sintered material, on a substrate 10 made of, for example, ultra-hard alloy. In this case, the cutting face 9 of the center side chip 5 is formed as an arcuated surface or a plurality of stepped surfaces, and the planar cutting face 10 of the outer peripheral side chip 6 is made continuous to the cutting surface 9. With this arrangement, high speed cutting and as well the cutting of ultrahard materials may be made.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ball end mill, and in particular, the cutting performance is improved by rationally mounting cutting blades and chips equipped with high-pressure phase sintered bodies such as cubic boron nitride and diamond. The aim is to improve the

Conventionally, this type of ball end mill has been disclosed, for example, in Japanese Utility Model Publication No. 53-40794. These ball end mills exhibit excellent cutting performance due to the arrangement and shape of the cutting blade, the shape of the chip pocket, etc.

However, the modification of the mold material after heat treatment is currently carried out by grinding because of its high hardness. Therefore, there is a demand for the development of a ball end mill that can sufficiently handle the grinding process by cutting.

The present invention has been made in view of the above-mentioned points, and enables a cutting tip equipped with a high-pressure phase sintered body such as cubic boron nitride or diamond to be rationally attached to a tool body, thereby achieving high-speed cutting and high-speed cutting. This enables cutting of hard materials.

'Hereinafter, one embodiment of the ball end mill of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, (1) is a cylindrical tool body, the tip of which is provided with a flute groove (2), and a chip seat (3) recessed in the flute groove (2). )
Inside, the main cutting tip (4) is attached, for example by brazing.

This main cutting edge tip (4) is composed of a center tip (5) and an outer tip (6), and has an arc-shaped cutting edge (7) and an outer cutting edge (8). The continuous structure allows it to be applied to cutting of profile materials, etc. Further, the starting end of the arc-shaped cutting edge (7) starts at or near the center of rotation.

The center tip (5) is rod-shaped with a cross section of approximately 1/4 circle, and is made of a high-pressure phase sintered body such as cubic boron nitride or diamond. The center of rotation is brazed by coating it with a certain metal. In this case, the center side chip (5
The rake face (9) formed by ) is an arcuate surface as seen in FIG. 3 or a multi-step surface having an angle of θ1 to θ4 as seen in FIG. 4. This rake face (
9), the planar rake face (l (1 is continuous) of the tip (6) on the first circumference side.
A cutting edge layer Q2 made of a high-pressure phase sintered body of cubic boron nitride, diamond, etc. is sintered and fixed under high-temperature and high-pressure conditions on a base (tl) of cemented carbide, high-speed mountain, etc. be. The high-pressure phase sintered body may contain not only cubic boron nitride, diamond, etc., but also a binder made of metal, carbide, etc., which is appropriately selected depending on the cutting conditions.

In the thus constructed ball end mill, cutting is performed by the cutting edge (force (8)), and chips are discharged from the chip pocket formed by the flute groove (2).

In this case, the cutting edge (force) formed on the center tip (5) exhibits a convex curve, especially in the direction of rotation, so it can withstand heavy cutting and performs an effective cutting action.

Furthermore, the one shown in FIGS. 5 and 6 is provided with a sub-cutting tip (19) in addition to the main cutting tip (5), and is particularly designed to reduce cutting vibration from the viewpoint of cutting stability. The aim is to

The auxiliary cutting edge tip (6) is made of a base (made of cemented carbide, high speed steel, etc.) like the outer peripheral tip (6) of the main cutting edge tip (5).
t6) A cutting edge layer θ made of a high-pressure phase sintered body is sintered and fixed on top, and the arcuate cutting edge ridge (7) extends toward the outer circumference from the middle excluding the rotation center portion. .

In this case, for reasons of cutting function, the center side edge of the minor cutting edge tip ←9 is located on the main cutting edge tip (4) on its rotation trajectory.
It is preferable that the joint between the center tip (5) and the outer tip (6) does not overlap.

In addition, in this embodiment, the main cutting edge tip (4) and the auxiliary cutting edge tip (19) are attached by brazing, but the present invention is not limited to this, and a clamping method using a presser foot or the like may be used. be.

As explained above, the main cutting edge tip of the present invention is divided into a center tip and an outer peripheral tip to have a rational cutting edge configuration, and a high pressure phase sintered body is used as the cutting edge layer. Since it is used in the cutting process, it is particularly suitable for cutting high-hardness materials and cutting edges such as high-speed cutting.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one row of ball end mills according to the present invention, FIG. 2 is a bottom view thereof, and FIG.
Fig. 4 is a partially enlarged sectional view showing a modified example, Fig. 5 is a front view showing an embodiment based on the second invention, and Fig. 6 is a partially enlarged sectional view taken along ma. It is a bottom view.

Claims (2)

[Claims] (1) At the tip of the cylindrical tool body, the starting end of the arc-shaped cutting edge starts at or near the center of rotation and extends toward the outer periphery of the tool body as an outer peripheral cutting edge ridge. Bow with a main cutting edge))/'y-
In the end mill, the main cutting edge tip has a central tip made of a rod-shaped high-pressure phase sintered body of cubic boron nitride, diamond, etc. having an approximately 1/4 circular cross section located at its center of rotation. A rake face exhibiting an arcuate surface or a plurality of stepped surfaces is formed, and the remaining outer peripheral portion is made of a base made of cemented carbide or the like. A ball end mill characterized in that the tip is positioned so that the rake face of the cutting edge layer is continuous with the rake face exhibiting an arcuate surface or a plurality of stepped surfaces. (2) At the tip of the cylindrical tool body, the starting end of the arc-shaped cutting edge starts at or near the center of rotation,
A main cutting edge tip that extends as an outer cutting edge ridge toward the outer periphery of the tool body, and a secondary cutting edge tip that has an arcuate cutting edge ridge extending toward the outer periphery from the middle excluding the center of rotation. In the ball end mill, the main cutting edge tip includes, at its center of rotation, a rod-shaped cubic boron nitride having an approximately 1/4 circular cross section;
By positioning the center tip made of a high-pressure phase sintered body such as diamond, a rake surface exhibiting a circular arc surface or a multi-step surface is formed, and the remaining outer peripheral portion is placed on a base made of cemented carbide or the like. By positioning the outer peripheral tip in which a cutting edge layer made of a high-pressure phase sintered body is sintered and fixed, the rake face of this cutting edge layer is continuous with the rake face exhibiting an arcuate surface or a plurality of stepped surfaces. The auxiliary cutting edge tip consists of a cutting edge layer made of a high-pressure phase sintered body sintered and fixed on a base of cemented carbide, etc., and this cutting edge layer corresponds to the cutting edge layer of the main cutting edge tip. A ball end mill characterized by having a rake face formed so as to