JPH09309020A - Three-dimensional machining cemented solid end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a mill usable in a curved surface, tilt surface, etc., particularly in molding work of metal mold, improve discharging of a cutting chip and decrease cutting resistance, by forming a crate angle of a bottom edge in a prescribed range, and a radius of a corner R edge in the specified. SOLUTION: In a three-dimensional machining cemented solid end mill providing an edge part 2 of twisted peripheral cutting edge and a bottom edge 6 successively connected to a corner R edge 7 in one end and a neck part of diameter a little smaller than an edge diameter and a shank in the other end, a crate angle γ of the bottom edge 6 is set to 5 deg. to 20 deg., and a radius of the corner R edge 7 is set to 1/5 or less an edge diameter. Here, when the crate angle γ exceeds 20 deg., strength of the bottom edge 6 and its corner part is decreased, so that 5 deg. to 20 deg. is suited. In the corner R edge 7, a corner part of the sharp bottom edge 6 is reinforced, an effect is provided in prevention of crack and chipping during cutting, but excessiveness increases cutting resistance. Accordingly, a radius is provided in 1/5 or less the edge diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end mill used for machining in a three-dimensional direction such as a curved surface or an inclined surface by a machine tool such as a machining center equipped with a numerical controller.

[0002]

2. Description of the Prior Art As a conventional end mill suitable for three-dimensional machining, a corner radius end mill (hereinafter referred to as a conventional product) described in Japanese Utility Model Laid-Open No. 60-142021.
This is because the bottom surface of the gash forming the rake face of the bottom blade is formed in a convex curved shape from the center of the bottom blade toward the chip discharge groove, and the rake face of the bottom surface and the bottom blade and the chip discharge groove. And the boundary ridgeline with the rake face of the outer peripheral cutting edge is located on the side opposite to the tip side from the bottom edge corner.
This is to improve the cutting performance by improving the chip discharge property and setting the rake angle to a uniform positive angle.

[0003]

However, in the case of the conventional product, although the effect similar to the lateral feeding is recognized in the chip discharging property, for example, the end mill is advanced by giving the approach angle to the workpiece from the horizontal direction. For bevel cutting,
Since the cutting edge from the corner portion of the bottom blade to the vicinity of the center of the tool is involved in the cutting, the cutting resistance is increased, and sometimes there is a risk of damage. Further, since the tip clearance of the bottom blade cannot be made large, there is a problem that it is difficult to discharge chips in deep-bottom cutting of a die, for example.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is a three-dimensional processing which has a good chip discharge and a small cutting resistance, which is used for forming a curved surface or an inclined surface, especially a mold. It provides a solid carbide end mill for use.

[0005]

In order to achieve the above-mentioned object, the present invention has a plurality of twisted outer peripheral cutting edges 5 at one end of a tool body 1 and a coil which is smoothly continuous with a rounded edge.
A bottom blade 6 connected through a nare blade 7 and a neck portion 3 having a diameter slightly smaller than the blade diameter of the end mill at the other end.
In the solid carbide end mill for three-dimensional processing, which is provided with a shank 4 through the neck portion, the water mark angle γ of the bottom blade is more than 5 ° and 20 ° or less, and the radius of the corner blade 7 is the blade diameter. Of 1/5 or less. Also, penetrating the blade part 2,
The opening is provided with a coolant hole 8 positioned at the flank of the bottom blade 6 or the corner blade 7. Further, it has a feature that the blade length is within twice the blade diameter.

[0006]

By applying the present invention, the chip discharging property in the three-dimensional processing in the molding process of the mold is improved, the cutting resistance is reduced, and the life of the end mill can be extended. That is, in three-dimensional machining, in the case of inclined cutting in which an approach angle is given to the workpiece from the horizontal direction to advance the end mill, in the case of curved-line cutting that passes through a portion with a large curvature in curved surface cutting, there is a shift from drilling to horizontal cutting. For example, cutting with large load fluctuation is forced. In particular, in the molding process of dies and the like, it is often the case that the end mill having a small tool rigidity has to be resorted to due to the restriction of the machining shape, and the improvement in the machinability cannot be ignored even if it is trivial.

Here, in inclined cutting with an approach angle of 2 ° to enter the work piece, if the watertight angle of the bottom blade is 5 ° or less as in an ordinary end mill, the length from the corner of the bottom blade toward the tool center. 60% or more of the above is involved in the cutting at the same time, which causes an increase in the cutting resistance, and sometimes there is a risk of damage. Further, if the watermelon angle of the bottom blade exceeds 20 °, the strength of the bottom blade and the corner portion of the bottom blade decreases, so the watermelon angle of the bottom blade is preferably more than 5 ° and 20 ° or less. When a large water-feed angle is used in the horizontal feed, the gap between the cutting edge and the cutting surface is enlarged, so that the chips can be less likely to interfere with the cutting edge. The corner edge reinforces the corner portion of the sharp bottom blade and is effective in preventing chipping and chipping during cutting. However, if this is too large, the portion involved in cutting becomes long and cutting resistance increases. Therefore, 1 / of the blade diameter
The radius is 5 or less, preferably ⅛ or less.

Further, by providing a coolant hole which penetrates the blade portion and whose opening is located on the flank of the bottom blade or the corner blade, cooling of the blade edge and smooth removal of chips are facilitated. Therefore, the tool life can be greatly extended. In order to perform deep engraving, a neck is provided between the shank and the blade, and the neck diameter is made smaller than the blade diameter.By reducing the difference and keeping the blade length short, the tool rigidity can be reduced. The decrease can be mitigated and the cutting efficiency can be maintained even in the case of curve feed or horizontal feed. By coating the hard film, the life can be further extended. Hereinafter, examples will be described in detail.

[0009]

FIG. 1 shows an embodiment of the present invention. FIG. 2 shows the details of the blade portion of the embodiment, in which the blade diameter of the end mill is 10 mm, the blade length is 15 mm, the total length is 100 mm, the number of blades is 2, and the right blade is right-handed with a helix angle of 30 °. The watermelon angle of the bottom blade is 10
The corner radius of the corner blade was approximately 1 mm.
The neck diameter is 9 mm and the shank diameter is 10 mm. A fine grain type cemented carbide was used as a tool material, and a TiAlN film which is a hard substance was further coated. Here, for comparison, a product having a bottom blade having a water-repellent angle of 3 ° having a comparative shape (hereinafter, comparative product 1) and 5 ° (comparative product 2) was similarly used.
S50C material which is carbon steel for machine structure as work material, hardness HB
Using 180, the number of revolutions was 2500 rpm, the feed rate was 500 mm / min, and the inclined cutting was performed from the top surface of the workpiece at an approach angle of 2 °.

In Comparative Product 1, 80% of the length from the end corner portion of the bottom blade toward the tool center is involved in cutting, which causes cutting vibration due to increase in cutting resistance and further bottom blade chipping. It was In Comparative product 2, 60% of the length toward the tool center was involved in cutting and the cutting resistance was slightly increased, but cutting was possible. In the product of the present invention, 30% of the length toward the center of the tool is involved in cutting and is about 1/2 or less of the comparative product 1, the cutting resistance of the bottom blade is reduced, the cutting state is stable, and the tool is not damaged. It was good.

FIG. 3 shows another embodiment of the present invention.
In this embodiment, a through hole having the same lead as the outer peripheral cutting edge is provided from the bottom blade to the shank end, and the bottom blade side is open to the flank. S50C material, which is carbon steel for machine structure, with hardness HB180, is used as the work material, the end mill speed is 3800 rpm, and the feed rate is 760 mm /
It was cut at a min and an approach angle of 2 °. Despite the high speed cutting conditions, the coolant improved the cooling of the cutting edge and the discharge of chips, resulting in a longer tool life and a good machined surface.

[0012]

As described above, according to the present invention, it is possible to obtain a solid carbide end mill for three-dimensional processing, which has good chip discharge and has a small cutting resistance, which is used for forming a sloped surface or a curved surface, especially for molding of a die. Has become possible.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a partially enlarged view showing another embodiment of the present invention.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a front view showing an example of a conventional product.

FIG. 6 is an explanatory diagram showing inclined cutting.

[Explanation of symbols]

 1 Main body 2 Blade part 3 Neck part 4 Shank 5 Outer peripheral cutting edge 6 Bottom blade 7 Corner edge 8 Currant hole a Part involved in cutting γ Water mark λ Entry angle

Claims (3)

[Claims] 1. A plurality of twisted outer peripheral cutting edges (5) at one end of the tool body (1) and a core which is smoothly rounded with the cutting edges.
A bottom blade 6 connected through a nare blade 7 and a neck portion 3 having a diameter slightly smaller than the blade diameter of the end mill at the other end.
In the solid carbide end mill for three-dimensional processing, which is provided with a shank 4 through the neck portion, the water mark angle γ of the bottom blade is more than 5 ° and 20 ° or less, and the radius of the corner blade 7 is the blade diameter. Carbide solid end mill for three-dimensional machining characterized by being set to 1/5 or less. 2. The cemented carbide solid end mill for three-dimensional machining according to claim 1, wherein the coolant penetrates through the blade portion 2 and the opening is located on the flank of the bottom blade 6 or the corner blade 7. A solid carbide end mill for three-dimensional machining characterized by having holes 8. 3. The cemented carbide solid end mill for three-dimensional processing according to claim 1, wherein the blade length is 2 of the blade diameter.
Carbide solid end mill for three-dimensional machining characterized by being within double.