JPH10315031A - Ball end mill and throwaway tip therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance throwaway type ball end mill which uses a round tip as throwaway tip for use in the ball end mill, in which the round tip itself forms the cutting edge-diameter of the end mill, and which is excellent in the cutting property to have high tip-attaching strength and tip-attaching accuracy. SOLUTION: In a throwaway type ball end mill in which a throwaway tip can be mechanically attached and detached, the throwaway tip has the cutting edge-shapes which correspond to the center of rotation for every about one fourth of a circle, and on the bottom face and/or on the rake face of the tip, straight, projected parts 7 or recessed parts are provided so that they are parallel and/or perpendicular to the cutting edge-shape which corresponds to the center of rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter throw-away type ball end mill used in a milling machine and the like and an improvement in a fixing and mounting structure of a throw-away tip used therein.

[0002]

2. Description of the Related Art A throw-away type ball end mill is
In order to make the rotation trajectory spherical, most of the throw-away tips used for this purpose are composed of a combination of an arc and a straight cutting edge, and have a very special shape. In the throw-away type ball end mill using such a special shape, the limit of the blade diameter is about 20 mm. However, there is a circular throw-away tip conventionally called a round tip. For example, Japanese Patent Application Laid-Open No. HEI 8-215916 discloses a positive tip, which uses a positive round tip to operate as a single blade.
There is an example in which the radius of the / 4 circle is reduced. 8m round tip
Since diameters of m, 10 mm, and 12 mm have been put to practical use in various applications, if the size of the insert can be used as the blade diameter of the end mill, a small-diameter throwaway can be achieved.

However, the disadvantage of the round tip is that there is no straight part, and there is no fixed surface. Therefore, when the tip is mechanically attached, the tip loosens during use, or when the tip is severe, the tip turns. It may come off and cause an accident. To prevent this, Japanese Patent Application Laid-Open
-93110, in particular, FIGS. 5 (a) and (b),
In (c), a flat portion is provided on the flank of the round tip, and as shown in FIG. 4, it is devised so as to be fixed by a locator by two-face restraint.

[0004]

As described above, if the fixing of the round tip is devised, it can be sufficiently used for a rotary tool, and the face mill has a sufficiently large blade diameter as in the above-mentioned example, so that the dimensions of the locator and the like are not sufficient. On the other hand, in order to apply the diameter of a round tip itself as a blade diameter as in a ball end mill, such a structure cannot be taken, and there has been a problem of how to fix it with high accuracy and firmly.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and uses a round tip for a throw-away tip used for a ball end mill, and the round tip itself has an edge diameter of an end mill, and is excellent in machinability. It is an object of the present invention to provide a high-performance throw-away type ball end mill and a throw-away tip with good tip mounting strength and mounting accuracy.

[0006]

To achieve the above object, the present invention relates to a throw-away type ball end mill for mechanically attaching and detaching a throw-away tip, wherein a round tip is used as the throw-away tip, and , Having two or more cutting edge shapes corresponding to the center of rotation, and having a rake face and / or bottom face of the tip straight and parallel and / or perpendicular to the cutting edge shape corresponding to the center of rotation. The ball end mill body is further provided with a convex portion or a concave portion. Further, the ball end mill body is mechanically fixed to the tool main body through the concave portion or the convex portion to fit the convex portion or the concave portion, so that the mounting strength and mounting of the chip are It achieves precision. Further, in order to further reinforce them, a part of the fitting of the chip is reinforced with a pin or the like. In addition, indexable tips include:
A round tip is used and has two or more cutting edge shapes corresponding to the center of rotation, and the rake face and / or bottom face of the tip is parallel and / or parallel to the cutting edge shape corresponding to the center of rotation. Alternatively, a linear projection or depression is provided vertically, and usable corners are two or more.

[0007]

According to the present invention, since the round tip itself can be used as the blade diameter, it is advantageous for a small one having a diameter of about 8 to 15 mm. However, at such a blade diameter,
The space for fixing the chip is small, the cutting amount is small, and the entire 1/4 arc is rarely used as a blade. Rather, it is often used for low cutting as represented by three-dimensional machining. For the reasons described above, the round chip is designed to be used by dividing it into two or more corners. In the case of a large blade diameter, it can be divided into eight corners. However, since the rotation locus does not become spherical, it can be used only for low cutting.

Further, when the shape of the cutting edge of the indexable insert is S-shaped or f-shaped, the cutting resistance can be reduced, so that more stable cutting can be performed. In particular, the cutting edge at the time of cutting is formed by making the cutting edge shape corresponding to the center of rotation of the arc-shaped blade portion in the bottom view substantially the same for each quarter circle, and having a substantially S-shape for both. The ridge becomes three-dimensional, so that a smooth cutting can be performed without receiving a mechanical impact at the time of biting by all the cutting blades at once.

Further, the provision of the linear convex portion or concave portion is as follows.
The cutting resistance at the time of cutting is received by the constraint surface of the linear convex portion or the concave portion, and the chip mounting strength and the chip mounting accuracy can be significantly improved. However, these protrusions or recesses eliminate the advantage of being able to be used all around, which is a feature of the round tip, and make it possible to use only a specific number of corners.However, depending on the cutting specifications, for example, the axial depth of cut is small. In many cases, it can be compensated by setting a small value when it is large. Further, the convex portion or the concave portion may be provided on the rake face side of the throw away tip,
Either of them may be provided on the bottom surface side, but either may be used. However, in the case of a small diameter, the effect is great because the thickness of the rake side is thin due to the space. Further, when the diameter is relatively large, it is possible even on the bottom side because the thickness of the holder portion is greater than the thickness of the chip.

Further, the ball end mill main body and the indexable insert are fixed to each other by mechanically fixing the insert main body to the tool main body by using a part of the linear convex portion or the concave portion of the insert. be able to. Further, in order to further increase the mounting strength, it can be improved by providing a groove extending in the axial direction of the tool main body only on the shank side of the tip and fixing it with a pin or the like.
It is more effective to provide a pin from outside to fix the pin. Also, a screw portion or the like may be provided on a part of the pin to perform the mechanical operation, or a part of the set screw may be used to make the pin stronger. . Due to these synergistic effects, the increase in cutting force caused by smooth cutting can be reduced by improving the tip
Accuracy was maintained and improved. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011]

1 to 3 show a throw-away type ball end mill according to the present invention, in which a round tip 3 is inserted into a tip ball portion 2 of a tool body 1 so as to be sandwiched from both sides.
It is detachably fixed by a set screw 5 through the mounting hole 4. On the tip side 6 of the tool body having the mounting holes 3,
Protrusions 7, 8, 9 are provided crosswise in the axial direction of the tool. The reason why the convex portion is provided on the holder side is to secure the wall thickness even a little because of the small diameter and to increase the rigidity. Furthermore,
Groove 1 on the shank side from the mounting hole in the tip seat of the tool body
0 is provided, and the groove 11 is formed so as to intersect the groove 10 at a right angle.
A pin 12 for fixing is inserted into the groove 10, and a pin 1 for preventing the pin 12 from coming off is inserted into the groove 11.
3 is provided to ensure more secure mounting.

Next, FIGS. 4 and 5 show details of the throw-away tip. The round chip 3 has concave portions 14, 15, 16 corresponding to the convex portions 7, 8, 9 and a pin 12.
Are provided at four points symmetrical with respect to the center mounting hole of the rake face. Further, the cutting edge 5 is arranged so as to be an S-shaped cutting edge around the cut portion 18 serving as the center of rotation. In addition, the linear concave portion or convex portion of the chip has been described in the example of the four chip rake face sides. However, depending on the purpose of use, as shown in FIG. The concave portions may be provided. To use more corners, six concave portions may be provided point-symmetrically with respect to the center mounting hole as shown in FIG.

[0013]

The present invention relates to a bow end mill using a round insert in a throw-away type ball end mill and using the size of the round insert itself as a blade diameter,
At the same time that the throw-away of the small diameter can be measured, to compensate for the mounting strength, which is a disadvantage of the small diameter, and further increase the mounting accuracy,
The round tip is supplemented as a shape that can use only a specific number of corners. In addition, the entire cutting edge portion is substantially S-shaped or f
Since it has a character shape, the cutting edge portion is excellent in machinability, and the entire cutting edge portion is not subjected to the impact at the same time at the same time. In addition, since a linear concave or convex portion is used for restraining the chip, the chip mounting strength and mounting accuracy are excellent. In addition, since the concave portion or the convex portion is fixed to the tool main body via a pin or the like, the fixing to the tool main body is further strengthened, and excellent performance is exhibited.

[Brief description of the drawings]

FIG. 1 is a front view of a throw-away type ball end mill according to the present invention.

FIG. 2 shows a side view of FIG. 1;

FIG. 3 is a sectional view of a main part of FIG. 1;

FIG. 4 shows a front view of a throw-away tip.

FIG. 5 shows a side view of FIG. 4;

FIG. 6 shows a front view of another embodiment.

FIG. 7 shows a front view of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tool main body 2 Tip ball part 3 Round tip 4 Mounting hole 5 Set screw 6 Tip side of tool main body having mounting hole 3 7, 8, 9 Convex part 10 Groove part 11 Groove part 12 Pin 13 Pin for retaining 14, 15, 16 Recess 17 Recess 18 Cut part to be the center of rotation

Claims (3)

[Claims] 1. A throw-away type ball end mill for mechanically attaching and detaching a throw-away tip, wherein a round tip is used as the throw-away tip.
In addition to having two or more cutting edge shapes corresponding to the center of rotation, the rake face and / or bottom surface of the tip is provided with a straight line parallel and / or perpendicular to the cutting edge shape corresponding to the center of rotation. A ball end mill, wherein the ball end mill main body is mechanically fixed to the tool body via the concave or convex portion in order to fit into the convex or concave portion. . 2. The ball end mill according to claim 1, wherein a pin or the like is used for a part of the fitting of the chip. 3. A throw-away insert used for a throw-away ball end mill, wherein a round tip is used as the throw-away tip, and at least two cutting edge shapes corresponding to a rotation center are provided. A throwaway tip, wherein a straight convex or concave portion is provided on a rake face and / or a bottom face in parallel and / or perpendicular to a cutting edge shape corresponding to the rotation center.