JPH10156616A - Throwaway type radius end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throwaway type radius end mill provided with a cutting edge to in the vicinity of a tool main unit center in the throwaway type radius end mill to be suited for cutting off work, drilling work and shoulder cutting. SOLUTION: A throwaway type radius end mill having a plurality of throwaway tips is constituted by using as a first tip a round tip, using as a second tip a tip formed by a circular arc side surface and a linear side surface continued thereto, extending the linear side surface to the vicinity of a tool main unit center shaft, and providing a chamfering edge in a corner part positioned in the vicinity of the center shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-functional indexable radius end mill used as a milling tool.

[0002]

2. Description of the Related Art Conventionally, a throw-away type end mill using a round tip is disclosed in Japanese Patent Application Laid-Open No. 4-93110, in which a round tip is attached to a tip end of a tool body having a straight shank. It is detachably attached with a clamp piece. This radius end mill is used for shoulder milling and grooving in a traverse direction orthogonal to a tool center line in a milling machine or a machining center. These tools are used for machining difficult-to-cut materials and high-feed machining of mold materials, because the edge strength, which is the characteristic of round inserts, is excellent and the corner angle can be substantially increased when the cutting depth is shallow. I have. Further, as an improvement of the round tip, there is an example using an oval type throwaway tip disclosed in Japanese Utility Model Laid-Open No. 5-41622.

[0003]

However, in a throw-away type radius end mill composed of a plurality of round inserts,
There is no cutting edge near the center of the tool main body, and there is a limitation in the depth in the thrusting / drilling, and there is a disadvantage that the thrusting / drilling can be performed only to a depth equal to or less than the protrusion amount of the tool main body and the indexable insert. Further, when an oval type throw-away tip is used, there is a problem that the tip is large and the back metal becomes small accordingly.

[0005]

Therefore, according to the present invention, in a throw-away type radius end mill having a plurality of throw-away tips, a round tip is used as a first tip, and a circular tip is connected to an arc side face as a second tip. Using a tip consisting of a straight side surface, the straight side surface is extended to near the center axis of the tool body as a cutting edge,
A throw-away type radius end mill characterized in that a chamfer is provided at a corner located near the center axis of the tool body. In addition, the second chip may save space by making a part of the arc portion on the arc side surface approximately half. Furthermore,
The feature is that the axial rake angle for attaching the insert to the tool body is made negative.

[0006]

First, the second insert is extended to the vicinity of the center axis of the tool body as a cutting edge, and the chamfering blade is provided.
It is possible to cut directly without a pilot hole such as punching and drilling. Further, the chip discharge direction during the axial cutting can be set to the tool rotation center axis direction by the breaker groove, thereby preventing the chip from coming into contact with the work standing wall. In addition, since the rake angle can be made more positive by providing the breaker groove, the free-cutting property can be improved. Next, at the time of deep engraving, the amount of protrusion becomes long, so that the amount of deflection of the tool becomes a problem. The amount of deflection is large,
If chatter occurs during cutting due to this,
If the axial rake angle is positive, the force acts in the direction in which the chip is pulled, so the chip may come off from the tool body, but in the present invention, by making the axial rake angle negative,
It works in the opposite direction so it doesn't slip out. Also,
When the second chip is attached to the tool main body, it is possible to raise the cutting edge ridge line, and the back metal of the tool main body is largely provided. Therefore, the rigidity of the tool body can be increased. Further, a breaker groove may be provided along the cutting edge line of each of the first chip and the second chip to reduce cutting resistance.

[0007]

1 to 5 show an embodiment of the present invention. FIG. 1 shows the first
1 shows a front view of a chip, and is a generally used round chip. In FIG. 2, the second tip is provided with an arc-shaped side surface and a linear side surface connected thereto, and a chamfering blade may be provided as necessary. FIG. 3 shows an example in which these chips are incorporated in the tool body, FIG. 4 shows a rear view of FIG. 3, and FIG. 5 shows a bottom view thereof.

As shown in these figures, a first tip 4, ie, a round tip is detachably attached to a tip 3 of a tool body 2 having a straight shank 1 by using a set screw 5, and the second tip 6 is substantially attached. It is similarly screwed through a central mounting hole using a chip consisting of a half-arc side surface and a straight side surface connected thereto. The straight side surface of the second tip 6 extends to near the center axis of the tool body 1,
The corner located near the center axis is provided with a chamfering blade 7.

Next, an example of the present invention will be described based on cutting data. FIG. 6 shows a test of the feed limit in shoulder milling using the above-described example of the present invention. Tool diameter 50φ, cutting speed 170m / min, axial depth of cut 5mm,
The cutting depth was 30 mm, the cutting method was dry, down cut, and the work material was S50C, while changing the feed amount fz per blade. FIG. 7 shows the result. For comparison, the same type of blade with only round inserts (hereinafter abbreviated as an end mill), and a throw-away type end mill using a commercially available square tip (hereinafter abbreviated as an end mill). ) Were similarly tested. FIG.
Therefore, in the end mill of the example of the present invention, fz = 0.6 mm /
The cutting can be stably performed up to the blade, and the end mill has almost the same performance as the example of the present invention, but the end mill has fz = 0.
3 mm / blade was the limit.

Subsequently, a test was conducted on the limit of the working depth of the punching shown in FIG. Cutting speed 17
0 m / min, radial depth of cut 30 mm, pick amount 20 mm, dry type, down cut, work material was S50C. In the punching process, the end mill has no cutting edge near the center axis, so it can be substantially only performed to a depth equal to or less than the protrusion amount of the tool body and the indexable insert, but in the present invention example, the cutting width, regardless of the pick amount Punching is possible, and as shown in FIG. 9, it can be processed to a depth of 20 mm, and can be continuously processed. At this time, vibrations such as chattering were small, and the chip did not come off, and stable cutting was performed.

[0011]

As described above, by applying the present invention, it is possible to obtain a multifunctional tool having sufficient cutting performance while maintaining high cutting performance in transverse feed cutting and also having sufficient performance for piercing. It can be used, and the number of tools can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a first chip used in an example of the present invention.

FIG. 2 is a front view of a second chip used in the example of the present invention.

FIG. 3 is a front view of a throw-away type radius end mill according to an example of the present invention.

FIG. 4 is a partially enlarged view of the first chip of FIG. 3 when the first chip comes to the front.

FIG. 5 shows a bottom view of FIG. 3;

FIG. 6 is a perspective view for explaining shoulder milling in a cutting test.

FIG. 7 is an explanatory diagram of a test result under the specifications of FIG. 6;

FIG. 8 is a perspective view for explaining a punching process in a cutting test.

FIG. 9 is an explanatory diagram of a test result under the specifications of FIG. 8;

FIG. 10 shows a front view of another example of the present invention of the second chip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Straight shank 2 Tool main body 3 Tip part 4 1st tip 5 Set screw 6 2nd tip 7 Chamfering blade Ad Axial cutting depth Rd Radial cutting depth P Pick amount

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[Procedure amendment]

[Submission date] February 4, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

[Title of the Invention] Throw-away type radius end mill

Claims (3)

[Claims] 1. A throw-away type radius end mill having a plurality of throw-away tips, wherein a round tip is used as a first tip, and a second tip comprises an arc side face and a straight side face connected thereto. A throw-away type radius end mill characterized in that a round side surface is extended to a position near a center axis of a tool body and a chamfering blade is provided on a part of a circular arc side surface located near the center axis. 2. The throw-away type radius end mill according to claim 1, wherein a part of the circular arc portion on the arc side surface of the second tip is substantially halved. 3. A throw-away type radius end mill according to claim 1, wherein the axial rake angle at which the tip is mounted on the tool body is made negative.