JPH10225812A - End mill for machining tapered groove - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deeply cut a length corresponding to a neck part without making resistance excessive by arranging the neck part which has a taper angle equal to a main body and becomes a value of specific % of a diameter of the main body in a continuously connecting part with the main body and is composed of a part of a cone, between the main body and a shank. SOLUTION: This is a taper groove working end mill on which a cross section perpendicular to the axis of a main body 1 presents a regular hexagonal shape. The main body 1 is formed so as to gradually thin toward a cutting edge part 4 on the tip. In the cutting edge part 4, a bottom blade and an outer peripheral blade having respectively two blades are symmetrically arranged so as to be superposed on an edge 5 of the main body 1. A neck part 7 having the same taper angle as the main body 1 exists on the large end diameter side of the main body 1. This neck part 7 is composed of a part of a cone being a value of 90% to 98% of a diameter of the main body 1 in a continuously connecting part of this main body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end mill for processing a die for forming a rib groove of a resin product, an aluminum die-cast product, or the like or a tapered cross-sectional groove of a cavity portion.

[0002]

2. Description of the Related Art In general, a taper end mill is used for cutting a tapered cross-sectional groove, which is a rib forming portion of a resin mold or a die cast mold. However, in the case of a tapered end mill having a small diameter and a long blade length, the rigid shape or strength of the cutting edge is not sufficient, and the taper end mill having a normal shape is often unsatisfactory. An improved version of this is, for example, a tapered groove machining end mill (hereinafter referred to as a conventional product) shown in Japanese Utility Model Laid-Open No. 2-3317, which has a polygonal cross section as shown in FIG. A taper end mill having a tapered taper with a tapered ridge formed at the apex of each vertex of the polygon in the axial direction, and a taper end mill having a bottom blade and an outer peripheral blade connected to a tip of the body. A small amount of cut is made and a cutting feed is applied, and while repeating this, the notch is deepened and the groove is carved.

[0003]

However, in the conventional product, as the depth of the groove to be cut becomes deeper, the tapered portion of the main body, which plays a role of expanding the groove width, comes into contact with the work over a long range, and the resistance increases. However, although the tool rigidity is excellent, a depth of about 10 to 12 times the tip diameter has been the limit of cutting. An object of the present invention is to solve the above-described problem, and by providing a neck portion between the main body and the shank, and by devising the shape, even if the groove is deeper than the conventional product. An object of the present invention is to provide an excellent end mill for taper groove machining that can be used without impairing the machinability.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a polygonal cross section, and each vertex of the polygon has a torsion formed in the axial direction. An end mill for machining a tapered groove, comprising a main body having a tapered taper angle, a cutting blade portion provided with a bottom blade and an outer peripheral blade at the tip thereof, and a shank at the other end of the main body. Between the shaft and the shank, at a taper angle substantially equal to that of the main body, and 90% to 98% of the diameter of the main body at a portion connected to the main body.
Is provided with a neck portion formed of a part of a cone. Further, the axial cross section of the neck portion includes a part of a polygon extending from the main body.

[0005]

In the present invention, between the main body and the shank,
Since a neck portion having a taper angle substantially equal to that of the main body and a part of a cone having a value of 90% to 98% of the diameter of the main body is provided at a connecting portion with the main body, the length of the ridge of the main body even if it is cut deeply Since it does not come into contact with the workpiece beyond that point, the resistance does not become excessive and the length corresponding to the neck can be deeply cut. The diameter of the neck is slightly smaller than the diameter of the main body, but if the cross section is circular, the cross sectional area is usually larger than the polygon, and there is no remarkable decrease in strength. Further, since the neck has a taper angle substantially equal to that of the main body, the diameter of the neck becomes maximum at the shank side end of the neck where bending stress is greatest during cutting, and strength can be maintained.

When machining a deep taper groove using the product of the present invention, firstly, engrave about 8 to 10 times the tip diameter using a conventional product, and then use the product of the present invention to perform additional cutting in the depth direction. Perform Therefore, the previous groove processing with the conventional product
The groove width is determined in consideration of the cutting allowance by the product of the present invention. When the step at the seam becomes inconspicuous, the cutting is finished, but it is better to actually set a numerical value. As a means for making the step less noticeable, it is preferable to use the product of the present invention having a slightly smaller taper angle than the conventional product used earlier. When the groove depth reaches 20 times the end mill tip diameter,
Or, when the cut by the product of the present invention is relatively shallow,
The shape of the neck as a part of a cone is recommended because of its high rigidity, but when the size is about 15 times, the shape may include a part of a polygonal cross section. In this case, the main body having a polygonal cross section may be made long in advance, and a part of the shank side may be modified to reduce the diameter.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. 2 and 3 show a main body 1 according to an embodiment of the present invention.
Is an end mill for tapered groove machining whose cross section perpendicular to the axis has a regular hexagonal shape. The main body 1 is formed so as to gradually become thinner toward the cutting blade portion 4 at the tip. The cutting blades 4 are each 2
The bottom blade and the outer peripheral blade of the blade are provided symmetrically so as to overlap the ridge 5 of the main body 1. On the large-diameter side of the main body 1, there is a neck portion 7 formed of a part of a cone having the same taper angle as the main body 1. A shank 6 is provided as an extension of the shank 6 and is removably attached to the tip of a main shaft of a rotary cutting machine (not shown) via a chuck and is rotated around the axis in the direction indicated by the arrow. Here, the small end diameter of the cutting blade portion 4 at the tip is 2 mm, and the length to the base end of the main body is 35.
mm and the total length including the shank is 70 mm. Body 1
And the torsion angle of the cutting blade 4 is 10 ° to the left, the axial length of the cutting blade 4 is 1 mm, and the axial length of the body 1 is 15
mm, and the length of the neck 7 is 20 mm. The neck 7 has the same 1 ° angle of 1 ° as the main body 1 and a circular cross section.
And a step having a diameter of 0.2 mm is provided at the connecting portion with the above. Therefore, the cross-sectional area at the connecting portion is about 2.5% larger in the neck 7 than in the main body 1.

Using this, a rib groove having a depth of 32 mm was machined. First, a taper groove having a depth of 18 mm was cut using an end mill having a tip diameter of 2.5 mm, and then replaced with the product of the present invention to continue cutting. At this time, since the taper angle is 1 degree, the width of the upper end is set to 2.5 mm in the previous cutting, and a depth of 32 mm can be obtained by connecting the upper end to the upper end. In this way, it is possible to form by cutting even a deep groove which has been impossible in the past. 4 and 5 show an example in which the neck portion has a shape including a part of a polygonal cross section.

[0009]

According to the present invention, the neck portion is provided between the main body and the shank, and the shape is devised. As a result, an excellent end mill for taper groove machining that could be used was obtained.

[Brief description of the drawings]

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

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

FIG. 3 is a sectional view of a main part of FIG. 2;

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

FIG. 5 is a sectional view of a main part of FIG. 4;

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Bottom blade 3 Outer peripheral blade 4 Cutting blade part 5 Ridge 6 Shank 7 Neck

Claims (2)

[Claims] 1. A body having a polygonal cross section, wherein each of the vertices of the polygon has an apex formed in the axial direction and having a tapered taper angle at the tip thereof, and a bottom blade and an outer circumference blade connected to the end thereof. A tapered groove processing end mill having a cutting blade portion provided and a shank at the other end of the main body, wherein a taper angle substantially equal to that of the main body between the main body and the shank, and a connecting portion with the main body. 3. A taper groove machining end mill according to claim 1, further comprising: a neck portion having a value of 90% to 98% of the diameter of the main body, the neck portion including a part of a cone. 2. The end mill for taper groove machining according to claim 1, wherein the axial section of the neck portion includes a part of a polygon extending from the main body. .