JP2003071626A - Radius end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radius end mill capable of suppressing chipping of a corner round blade and performing high feed cutting. SOLUTION: This radius end mill has a substantially quarter circular-arc shaped corner round blade in a corner part at a distal end of a tool. A surface forming a cutting face of the corner round blade is a convex surface from a roundness 90 deg. direction toward a roundness 0 deg. direction. An end gash surface from the vicinity of the roundness 0 deg. direction of the corner round blade toward a tool axial direction is constituted of a substantially planar surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a radius end mill used for machining a three-dimensional curved surface of a mold or the like and deep contouring.

[0002]

2. Description of the Related Art Ball end mills have been generally used for three-dimensional curved surface processing of metal molds and deep contouring processing. Recently, there has been a strong demand for high efficiency cutting, and a radius end mill has been used instead of the ball end mill. Compared to ball end mills, radius end mills have shorter cutting edge contact lengths with the work material,
With a ball end mill, the cutting speed cannot be obtained because the tool tip direction is on the tool axis, whereas with a radius end mill, a sufficient cutting speed is obtained, so the cutting resistance is small and the sharpness is high. Suitable for efficient cutting. Further, regarding the radius end mill, many improvements have been made according to the purpose of use and the like. For example, in JP-A-7-246508, an example in which a corner blade is reinforced is disclosed in JP-A-11-216609. Discloses an example in which the machinability is improved.

On the other hand, in the actual machining of dies and the like, there are machining in the corner direction and machining with a large tool protrusion such as deep engraving, and chatter vibration is likely to occur during cutting.
Generally, the method of lowering the feed rate that is easy to process in the NC program is adopted, but the method of lowering the feed rate not only lowers the machining efficiency, but also has less effect of suppressing chatter vibration, and the feed rate per blade is proportional. As a result, the number of contacts between the cutting edge and the work material increases, and wear progresses faster. In addition, there is a method to reduce the cutting speed, which has a high effect of suppressing chatter vibration, but with this alone, the feed rate decreases proportionally,
In any case, since the machining efficiency decreases, recently, as a means for performing high efficiency cutting, high feed cutting is used, which lowers the cutting speed but increases the feed rate, that is, extremely increases the feed rate per blade. .

[0004]

However, in the above radius end mill, if the feed amount of one blade is extremely increased,
There is a problem that the cutting load is concentrated on the corner round blade, the strength of the corner round blade cannot withstand the cutting load, and the chip is broken to reach the end of its life. In particular, when performing high-feed cutting in machining with a large depth of cut such as rough machining, cutting resistance is large and defects are more likely to occur.Therefore, the cutting conditions must be further reduced, and it is not a state that can be called high-efficiency cutting. It was The present invention has been made based on the above background, and an object of the present invention is to provide a radius end mill capable of performing high-feed cutting while suppressing the damage of the corner edge blade.

[0005]

Therefore, the present invention is
In a radius end mill having a corner rounded blade with an approximately 1/4 circular arc at the tool tip corner, the surface forming the rake face of the corner rounded blade is 0 from the direction of the round 90 ° direction.
The radius end mill is characterized in that it has a convex curved surface in the ° direction, and the end-gasch surface extending from the vicinity of the radius 0 ° direction of the corner round blade toward the tool axis direction is a substantially flat surface.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION By applying the present invention,
First, since the chips generated by the corner round blade are discharged through the rake face, the surface forming the rake face of the corner round blade has a convex curved surface from the 90 ° radius direction to the 0 ° direction. This reduces the amount of chips in the direction of contact with the rake face and reduces the cutting resistance. In addition, the cutting stress is not concentrated in one direction of the rake face but is dispersed in all directions, and there is no step direction that hinders the flow of chips.
Next, since the rake face of the end blade extending from the 0 ° direction of the corner radius blade toward the tool axis direction is made substantially flat, the rake face of the end blade and the boundary line between each rake face,
The chips produced by the corner blades are discharged without obstructing the flow. The rake angle from the 90 ° direction to the 0 ° direction of the corner radius blade may be a negative angle in both the radius normal direction and the tool radius direction, and a wide range of directions in which a cutting load such as three-dimensional curved surface processing is applied. Even in some cases, the cutting edge strength was obtained. Furthermore, since the end blade originally has poor machinability, it affects the connecting direction of the end blade and the corner round blade, that is, the radius 0 ° direction of the corner round blade,
There is a possibility of chipping, and the rake angle of the end blade is 0 ° for the corner radius to improve the cutting performance of the end blade.
The rake angle may be smaller than the normal rake angle of the direction, and the rake angle of the end blade is preferably a regular angle.

Here, in order to further improve the chip discharge property, a gashing process for the end blades and a gashing process for the corner round blades are performed in a series of processes to form a rake face for the corner blades. A convex curved surface may be formed between the end blade and the surface forming the rake face, and the corner edge may be prevented from being damaged. Further, in order to perform high efficiency cutting, it is advantageous to have a large number of blades, but in the case of a work piece having a corner direction, in a multi-blade end mill with four or more blades, simultaneous cutting blades in the corner direction are used. The number of blades is preferably three, because it is present and chatter vibration due to resonance is likely to occur. Further, it goes without saying that a long life can be achieved by applying a hard coating such as TiAlN or a Cr-based lubricating coating. Hereinafter, the present invention will be specifically described based on Examples.

(Example 1) As Example 1 of the present invention, made of ultrafine particle cemented carbide, tool diameter 12 mm, corner radius 2 m
It is manufactured with 3 m blades and TiAlN coating is applied. As shown in FIGS. 1 to 3, when the corner round blade is viewed from the rake face side, flank face side and end blade side, The surface forming the rake surface 2 of the blade 1 is radius 90
The end gash surface 7 which is a convex curved surface from the 3 ° direction to the 0 ° direction 4 and extends from the vicinity of the radius 0 ° direction 4 of the corner radius blade 1 toward the tool axis 5 direction is a substantially flat surface. The cutting specifications are that HRC40 pre-hardened steel is used as the work material, and the length is 150 mm, the width is 18 mm, and the depth is 30 mm.
The number of revolutions is 260 for grooved pocket processing with a side wall angle of 3 °.
The number of revolutions was 0, the feed rate was 1250 mm / min, the feed rate was 0.16 mm / blade, the tool axial pitch was 0.6 mm, the tool protrusion length was 65 mm, contouring was performed by air blow, and the tool damage state was observed. Also, for comparison, as Conventional Example 2, the end mill described in the conventional technique was used.

As a result, in Example 1 of the present invention, chatter vibration was extremely small even in the corner-direction machining of pocket machining, the cutting state was stable, and a tool up to a depth of 30 mm, that is, after completion of one-shape machining, was used. The damage state was normal wear, the wear width was slight, and the processed surface was also good. Conventional example 2 is 1
Since the blade feed amount is large, the cutting in the tool axis direction is 1.8
mm chipping occurs at the time of the 3rd pass machining, chatter vibration becomes large during corner direction machining, cutting noise is large, and the tool damage state after the completion of one shape machining has already disappeared due to the lack of the corner round blade. , The original processed shape could not be obtained.

(Example 2) Next, as Example 3 of the present invention, with the same specifications as those of Example 1 of the present invention, the rake angle from the radius 90 ° direction of the corner radius blade to the direction 0 ° is the normal direction of the radius and the tool. A cutting test was performed in the same manner as in Example 1 by manufacturing a negative one in both radial directions. As a result, in Invention Example 3, the cutting state was more stable, the tool wear width was smaller, and the machined surface was better than in Invention Example 1.

(Example 3) Next, as Examples 4 to 6 of the present invention, with the same specifications as Example 1 of the present invention, the rake angle of the end blade is the normal direction rake angle of the corner radius blade in the direction of 0 °. 5
And the rake angles of the end blades were -5 °, 0 °, and 5 °, and the same cutting test as in Example 1 was performed. As a result, in all the tools, chatter vibration was very small, the cutting state was stable, and the tool damage state was normal wear, the wear width was small, and the machined surface was good. Particularly, in the order of Inventive Examples 4, 5, and 6, the cutting noise was reduced and the wear width of the corner radius blade in the radius 0 ° direction was reduced.

[0012]

From the above results, by applying the present invention, it can be used for three-dimensional curved surface machining of a mold or the like, contour contour deep engraving, and the like, even in machining with a large cutting amount such as rough machining. It was possible to provide a radius end mill capable of performing high-efficiency cutting with a large single-flute feed while suppressing the loss of rounded blades.

[Brief description of drawings]

FIG. 1 is a view of a corner-edge blade of Example 1 of the present invention as seen from a rake face side.

FIG. 2 is a view of FIG. 1 viewed from a flank side.

FIG. 3 is a view of FIG. 1 viewed from the end blade side.

[Explanation of symbols]

1 corner blade 2 rake face of a corner blade 3 R 90 ° direction 4 are 0 degree direction 5 Tool axis 6 end blades 7 End gash surface

Claims (3)

[Claims] 1. A radius end mill having a corner radius edge of a substantially 1/4 circular arc at a tool tip corner portion, wherein a face forming a rake face of the corner radius edge is oriented from a 90 ° radius direction to a 0 ° direction radius. A radius end mill having a convex curved surface, wherein an end gash surface extending from the vicinity of the radius 0 ° direction of the corner radius blade toward the tool axis direction is a substantially flat surface. 2. The radius end mill according to claim 1, wherein the rake angle from the radius 90 ° direction of the corner radius blade to the direction 0 ° is a negative angle in both the normal direction of the radius radius blade and the tool radial direction. Characteristic radius end mill. 3. The radius end mill according to claim 1, wherein the rake angle in the axial direction of the end gash surface is
A radius end mill characterized in that it is smaller than the rake angle in the direction normal to the radius 0 ° of the corner radius blade.