JPH08290319A - High speed cutting ball end mill - Google Patents

Abstract

PURPOSE: To discharge chips smoothly at the time of high speed cutting and high speed feed cutting by disposing the opening parts of holes in an end cutting edge of circular arc shape in the state of being shifted in the distance from a tool axis from the end face view. CONSTITUTION: In a ball end mill made of ultra-fine grain hard metal of about 10mm in diameter, about 15mm in length of cut, about 100mm in overall length with two cutting edges and a helix angle of 30 deg., helical holes 4 of about 1.2mm in diameter is provided on a diameter line in the tool axis end face view, in the position of about 20 deg. and 45 deg. from the tool axis with the center of a ball cutting edge as the center. These holes 4 have lead approximate to the peripheral cutting edge and are opened to chip space parts in the positions of about 1.7mm and 3.5mm from the tool axis. When this tool is used for three- dimensional cutting using a machining center, the discharge of chips is excellent regardless of the cutting direction of inclination, curved surface, and the like, and stable cutting is performed for many hours.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball end mill mainly used in a machine tool, and more particularly to a ball end mill used in a machine tool for high speed cutting used for three-dimensional forming of a die.

[0002]

2. Description of the Related Art As a conventional ball end mill, there is a tapered ball end mill with a hole described in Japanese Utility Model Laid-Open No. Sho 59-28410 shown in FIG. 1, and a coolant hole is provided to form a thin and deep portion. It is described that the chips are discharged also in the processing of.

[0003]

[Problems to be Solved by the Invention] Recently, the mold 3
In three-dimensional forming, there is an increasing need for shifting from manual finishing to high-speed finishing by machining, which makes it necessary to cut a long distance with a small incision. Has no choice but to use high-speed, high-feed cutting. However, when the above ball end mill is subjected to three-dimensional processing, since the blade shape and coolant hole are adapted to the use of deep grooves, etc., chips are discharged smoothly in high speed / high feed cutting. However, there is a problem that it is difficult for the cutting fluid or air supplied from the holes to act effectively.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and particularly provides a ball end mill for use in a machine tool for high-speed cutting used for three-dimensional molding of a die. It is a thing.

[0005]

In order to achieve the above object, the present invention is a ball end mill provided with a coolant hole, wherein a plurality of holes penetrate the shank portion and the blade portion in the axial direction of the tool. , The opening of the hole in the arcuate bottom blade is arranged at a distance from the tool axis in the end view, and in order to achieve this, the tool axis is used as the axis and the lead of the hole is the same. A plurality of through holes are provided. In addition, Al, Si, periodic table 4a, 5
a, 6a transition metal carbides, nitrides, borides and boron carbides, hard boron nitrides, hard carbons, and one or more hard substances selected from the group consisting of solid solutions or mixtures thereof. 1 layer or 2 or more layers,
The effect can be further exhibited by coating with a thickness of 0.2 to 20 μm.

[0006]

By applying the present invention, the openings of a plurality of holes are arranged so as to be displaced from the tool axis in the end view, so that the cutting fluid ejected from the holes spreads in a multi-circle shape during end mill cutting. It is possible to sufficiently apply the cutting fluid or the like even in three-dimensional cutting in which the cutting and feeding directions constantly change. As is well known, the cutting fluid has a lubricating and cooling effect as well as an effect of discharging and scattering chips. Sufficient coolant pressure, high speed cutting action,
By adopting a blade type, when chips are generated, they immediately act in a direction away from the rake face and are not stored in the chip pocket. Will be discharged smoothly. In order to further enhance the above action, it is desired that a coolant hole be opened for each blade and that the cutting fluid be sufficiently supplied to the cutting portion in the entire end mill regardless of the cutting direction. As a result, it is provided at a position where the distance from the tool axis is not equal in the end view. The position of the hole in the end view may be on the diameter passing through the tool axis, or may be at any position depending on the number of blades.

As described above, when the holes are provided at the positions where the distances are not equal to each other, it is conceivable to open a hole which is diagonally communicated with the blind hole formed in the tool shaft. In this case, there is an inconvenience that the position of the hole is changed by re-grinding frequently performed by the ball end mill. Therefore, it is preferable that at least the blade portion has a plurality of holes penetrating it in the tool axial direction. Hereinafter, examples will be described in detail.

[0008]

EXAMPLE FIG. 3 is an example of the present invention, which is made of ultrafine particle cemented carbide, diameter 10 mm, blade length 15 mm, total length 10
In a ball end mill having a blade length of 0 mm, a number of blades of 2 and a helix angle of 30 °, a diameter of 1. A twist hole of 2 mm is provided. This hole has a lead similar to the outer peripheral blade, and 1.7 from the tool axis.
mm and 3.5 mm at the blade groove. When this tool was subjected to three-dimensional cutting using a machining center, chips were discharged well regardless of the cutting direction such as inclination or curved surface, and stable cutting was possible for a long time.

[0009]

As described above, according to the present invention, improvements have been made in a ball end mill suitable for a machine tool for high-speed cutting, which is particularly used for three-dimensional molding of a die.
Highly efficient cutting with excellent chip discharge and excellent precision is now possible.

[Brief description of drawings]

FIG. 1 shows a front view of a conventional product.

FIG. 2 shows a front view of an embodiment of the present invention.

3 shows a side view of FIG.

FIG. 4 shows a front view of another embodiment of the present invention.

FIG. 5 shows a side view of FIG.

[Explanation of symbols]

 1 main body 2 blade part 3 ball blade 4 hole β helix angle

Claims (3)

[Claims] 1. A ball end mill having a coolant hole, wherein a plurality of holes penetrate through a shank portion and a blade portion in a tool axial direction, and an opening portion of the hole in an arc-shaped bottom blade is viewed from an end view. Ball end mill for high-speed cutting characterized in that the ball end mill is arranged at a distance from the tool axis. 2. The ball end mill for high speed cutting according to claim 1, wherein the hole is twisted. 3. The ball end mill for high speed cutting according to claim 1, wherein Al, Si and periodic table 4a, 5a, 6 are used.
One layer of one or two or more hard substances selected from the group consisting of carbides, nitrides, borides and boron carbides of group a transition metals, hard boron nitrides, hard carbons, and solid solutions or mixtures thereof. Or a multilayer of two or more layers, 0.2
A ball end mill for high-speed cutting, which is coated with a thickness of up to 20 μm.