JPS6232722Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a throw-away tip that has a polycrystalline sintered body of cubic boron nitride (hereinafter abbreviated as CBN), diamond, or a mixture thereof in the cutting edge. .

In recent years, with the development of ultra-high pressure sintering technology, CBN,
Polycrystalline sintered diamond powder or a mixed powder thereof is sintered with a suitable binder and is now being manufactured and used as cutting tools.

These sintered bodies have physical properties that are significantly different from conventional tool materials, are expensive, and are difficult to make into complex shapes. This requires selection and appropriate tool design.

Now, in diamond sintered bodies, round-piece chips are used for the purpose of mirror-finishing soft non-ferrous metals such as aluminum alloys, and in CBN sintered bodies, for finishing cutting of high-hardness rolling rolls, etc. ing.

When fixing such a round piece type chip to a holder, the rake face 2 of the chip 1 is usually clamped by pressing with a presser foot 20, as shown in FIGS. 1 and 2. However, with this clamping method, the fixation of the chip is uncertain;
Particularly when cutting high-hardness rolls, etc., when performing high-load cutting with large depths and large feeds, the chip 1 may move from the seat surface 31 of the holder 30, or
As a result, there are disadvantages such as chips being chipped, and furthermore, the presser foot 20 is often worn out due to cutting.

Further, as shown in FIG. 3, when clamping a chip 3 provided with a center hole 4, a clamp pin 21 having an eccentric shaft 22 is used. That is, by inserting the eccentric shaft 22 into the center hole 4 of the chip and rotating the pin 21, the side wall 32 of the holder 30 is
It was designed to push the tips. This mechanism is extremely simple and has the excellent feature that there is no obstacle to the flow of chips on the top surface of the chip, and there is no risk of wear and tear on the parts, so it can be used to clamp ordinary cemented carbide indexable chips. It is widely used as a mechanism.

However, when using a sintered body such as diamond, it is very difficult to provide a central hole, and
The above-mentioned clamping mechanism using an eccentric shaft is normally used for so-called negative-type throw-away chips in which the side surfaces of the chips are perpendicular to the top and bottom surfaces, but it is extremely difficult to apply it to clamp positive-type chips with excellent sharpness. It was hot.

The above negative means that the angle between the top surface (rake surface) and the side surface (flank surface) is 90° and
The angle is 90° or more, and positive means the case where it is 90° or less. Figure 4 is a negative example, and Figure 5 is a positive example.

This invention solves the above-mentioned problems and provides a composite round piece throw-away tip with a cutting edge made of a sintered body of diamond or the like, which can be clamped using a clamping mechanism as shown in Fig. 3. It is a purpose.

Furthermore, another object of the present invention is to provide a positive type composite round piece throw-away tip that can be clamped using the above-mentioned clamping mechanism.

Hereinafter, embodiments of this invention will be described based on FIGS. 4 to 7.

As shown in FIG. 4, the throw-away tip 10 of this invention has a cutting edge formed from a sintered body of CBN, diamond powder, or a mixture thereof on the upper surface of a cylindrical base 11 having a circular center hole 12. The discs 13 are firmly joined by brazing or other means.

The base 11 is made of steel, cemented carbide, or the like, and has an outer diameter that is equal to or slightly smaller than the outer diameter of the disk 13.

Note that the center hole 12 may be provided coaxially with the base 11 and may also penetrate through the base 11.

As shown in FIG. 5, a composite body consisting of the disk 13 and the base metal 14 joined thereto may be firmly bonded to the base 11 by brazing or the like. This base metal 14
For example, when sintering diamond powder, a part of the container used to hold the powder is used.
That is, when sintering raw material powder is placed in a cup-shaped container made of a pressed body of steel or cemented carbide powder, and hot pressed using an ultra-high pressure device, the sintered body inside is firmly bonded to the container. Therefore, when removing the container by cutting, etc., if you leave a part of it behind, it will become the base metal.

The side surface 15 of the composite body consisting of the disk 13 and the base metal 14 can be made at an acute angle with the top surface, as shown in FIG. Of course, only the disk 13 in FIG.
Similar acute angles and side surfaces (flank surfaces) may also be provided. With such a shape, a so-called positive type chip can be obtained. As will be explained later, one of the features of this invention is that sufficient support strength can be obtained even with such a positive type chip using a conventional clamping mechanism using an eccentric shaft.

When the chip 10 of this invention is to be clamped to a holder, as shown in FIG. 10 is pressed against the side wall 32 of the seat surface of the holder 30.
In this way, support strength sufficient to withstand high-load cutting can be obtained, and since there is nothing on the upper surface of the chip to obstruct the outflow of cuttings, the cuttings can be discharged smoothly.

Also, in the case of a chip with a positive flank as shown in Fig. 5, it is possible to easily clamp it using the same clamping mechanism as described above, but in this case, As shown in the figure,
It is necessary to further provide a recess 33 in the side wall 32 of the holder 30 so that the positive side surface of the chip 10 does not come into direct contact with the side wall 32 of the holder.

As described above, the throw-away tip of this invention uses a sintered body such as diamond as the cutting edge and has a circular hole in the base, so it can be easily clamped with a conventional clamping mechanism using an eccentric shaft. This also has the advantage that a similar clamping mechanism can be applied even if the flank is made positive.

Of course, the mechanism for clamping the throw-away tip is not limited to the eccentric shaft type described above; for example, the tip can be held in place by tilting an L-shaped wedge with one end passed through the hole in the tip. Any suitable clamping mechanism for a throw-away tip with a hole may be used, such as a method of pressing it against a wall.

[Brief explanation of the drawing]

Figure 1 is a side view showing the clamping mechanism of a conventional polycrystalline sintered indexable tip, Figure 2 is a plan view of the same, and Figure 3 is a partial longitudinal section showing the clamping mechanism of a conventional cemented carbide tip. 4 and 5 are side views, and FIGS. 4 and 5 are cross-sectional views of the compound round piece throw-away tip of this invention, and FIGS. 6 and 7 are partial longitudinal side views showing the throw-away tip of this invention in a clamped state. be. 10...Compound round piece throwaway tip, 11
... Cylindrical base, 12 ... Center hole, 13 ... Disc,
14... Base metal, 20... Presser foot, 21... Clamp pin, 30... Holder.

Claims (1)

[Claims for Utility Model Registration] (1) A disk serving as a cutting edge formed from a polycrystalline sintered body of cubic boron nitride, diamond, or a mixture thereof, with a diameter equal to or slightly smaller than that of cubic boron nitride, diamond, or a mixture thereof. In a throw-away chip joined to a cylindrical base having a circular center hole, a circular center hole is provided in the base, a grip piece is inserted into the circular center hole,
A compound round piece throw-away chip characterized in that the outer periphery of the chip is clamped by pressing against the side wall of a counterbore surface provided at the tip of the holder. (2) The composite round piece throw-away chip according to claim 1, wherein the side surface of the disc forms an acute angle with the top surface.