JP2720953B2 - Hard sintered body twisted tip - Google Patents

Description

The present invention relates to a cutting tool having a torsion blade such as a spiral end mill or a spiral reamer, and in particular, to cutting by increasing the torsion angle of a torsion blade made of a hard sintered body. The present invention relates to a cutting tool with improved performance.

[Conventional technology]

A hard sintered body mainly composed of diamond, high-pressure type boron nitride, or a mixture thereof is usually manufactured in a flat plate shape as shown in FIG. FIG. 1 illustrates a composite hard sintered body obtained by integrally forming a cemented carbide base metal 2 during ultra-high pressure sintering of the hard sintered body 1.

In a conventional cutting tool having a cutting edge of a hard sintered body, a flat chip 4 as shown in the figure is fixed to the tip of the blade of a predetermined tool as shown in FIG. Further, since the thickness of the hard sintered body 1 is generally as thin as 1 mm or less, the torsion angle of the cutting blade is set to 0 ° or a very gentle angle of 5 ° or less even when a torsion angle is applied.

[Problems to be solved by the invention]

When the above-mentioned flat hard sintered body is processed into a twisted chip, the cutting edge is displaced in the thickness direction of the hard sintered body toward the rear end due to the effect of the torsion. Should be less than the thickness of the body, ie less than 1 mm. It is for this reason that the magnitude of the torsion angle is limited to a small value of 5 ° or less. If the restriction is not eliminated, in the case of a tool having a cutting edge of a hard sintered body, the torsion angle is increased and the sharpness is increased. Even if we try to achieve higher performance in terms of cutting power and cutting power, that will not be realized.

An object of the present invention is to provide a cutting tool having a torsion blade of a hard sintered body having a large torsion angle, which solves such a problem.

[Means for solving the problem]

The cutting tool according to the present invention is characterized in that the cutting edge tip attached to the outer periphery of the tool body is a hard sintered body having a thickness of 1 mm or less mainly composed of diamond, high-pressure type boron nitride, or a mixture thereof, or a super hard alloy. The cutting tip is twisted at a torsion angle of 5 ° or more over the entire length thereof with substantially the same width and the same thickness. A twist blade having the above twist angle is formed.

The twisted tip of such a tool can be easily manufactured by a method in which a columnar or cylindrical material is cut so as to be spirally vertically divided from one end to the other end by wire cut electric discharge machining. The details of this method will be described in the embodiment section.

[Action]

Since the entire cutting edge chip used in the cutting tool of the present invention is twisted, it can be manufactured by the above-described manufacturing method.
In the insert obtained by this method, if the material diameter and the tool diameter are the same, displacement due to torsion of the cutting edge occurs on the outer peripheral surface of the material. Therefore, it is possible to eliminate the restriction on the setting of the torsion angle due to the thickness of the hard sintered body (the direction coincides with the radial direction of the material) by using the line of intersection between the outer peripheral surface of the material and the cut surface as a cutting edge, thereby A torsion angle of 5 ° or more, which is the upper limit of a conventional tool, can be added to the cutting edge, and the unique effect of the torsion blade is utilized to improve cutting performance.

〔Example〕

FIG. 1 shows a basic form of a torsion tip used for the cutting tool of the present invention. In FIG. 1, 1 is a hard sintered body mainly composed of diamond, high-pressure phase-type boron nitride, or a mixture thereof. Is a cemented carbide base metal integrated with 1,
Reference numeral 3 denotes an edge serving as a cutting blade. This twist tip 10
It is manufactured as follows.

That is, first, as shown in FIG. 2, a columnar material 11 in which a hard sintered body 1 having a constant thickness is integrally and concentrically arranged on the outer periphery of a base metal 2 is produced by ultra-high pressure sintering. Next, the end surface of the material 11 is made to face the cut wire 12 for electric discharge machining as shown in the figure. Then, cutting is started from the center of the end face by the cut wire 12, and as shown in FIG. 3, the material 11 is fed at a constant speed while rotating at a constant speed, and is cut to the other end. When this operation is performed twice while changing the cutting position, a chain line region shown in FIG. 4 is cut out. Each of the two chips formed by this cutting has the shape shown in FIG.

In addition, if the cutting of the material by this method is performed so that the cut surfaces at both ends in the width direction of the chip intersect at the axis of the material as shown in the figure, the material can be used without waste.

The basic torsion insert made in this way is fixed to the cutting edge of the tool by removing the sharp side of the base 2 and then, if necessary, for adjusting the rake angle, clearance angle and strengthening the cutting edge. After finishing, the cutting tool of the present invention is obtained. Note that the diameter of the material from which the chip 10 is cut does not necessarily have to match the diameter of the tool that uses the chip.

FIG. 5 shows a reamer made by using the wetting tip manufactured by the above method. As shown in the figure, the tip 10 is cut off by cutting off the sharp part of the base metal 2 existing in the basic type.
The hard sintered body 1 has a thickness substantially equal to that of the basic shape even after finishing processing.

〔effect〕

As described above, the cutting tool of the present invention is a cutting tool comprising a hard sintered body or a super hard alloy base material,
Since the shape is twisted with almost the same width and thickness over the entire length, a chip is cut out by cutting a part of a cylindrical or cylindrical material into two vertically twisted surfaces that intersect with the outer peripheral surface of the material. Is manufactured, the restriction on the setting of the torsion angle can be eliminated, and the effect of increasing the torsion angle of the cutting edge to 5 ° or more can further improve the cutting performance of the tool.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic form of a chip used in the tool of the present invention, FIGS. 2 to 4 are process diagrams showing a method of manufacturing the same chip, and FIG. 5 (a) is a reamer to which the present invention is applied. 6 (b) is a front view thereof, FIG. 6 is a perspective view of a conventional flat hard sintered chip, FIG. 7 (a) is a side view of a cutting tool using the conventional tip, and FIG. FIG. 2B is a front view of the same. 1 ... hard sintered body, 2 ... cemented carbide base metal, 3 ... edge (cutting edge), 10 ... twisted tip, 11 ... cylindrical material, 12 ... cut wire, 13 ... reamer.

Claims (1)

(57) [Claims] 1. A cutting blade tip attached to an outer periphery of a tool body,
This cutting edge tip is composed of a hard sintered body with a thickness of 1 mm or less mainly composed of diamond, high-pressure phase-type boron nitride, or a mixture thereof, or a composite hard sintered body in which a super-hard alloy base metal is integrated. A cutting tool having a helix angle of 5 ° or more formed by a hard sintered body of the cutting edge tip with a helix angle of 5 ° or more having substantially the same width and the same thickness over its entire length.