JPH058218A - Manufacture of diamond core bit - Google Patents

Abstract

PURPOSE:To constitute the title method so that setting of a diamond grain can be performed easily without damaging the diamond grain since securing of high perfect roundness of a diamond cutting edge can be performed sufficiently since an annular diamond cutting edge having the high perfect roundness is melted and removed by making use of a local heating source device such as an electron beam processing. CONSTITUTION:A diamond cutting edge 6 containing a diamond grain 10 is formed into an annular form, an individual of the annular diamond cutting edge 6 or a body 1 after joining is melted and removed by making use of a local heating source device such as an electron beam processing and a chip discharge groove 3 is formed. Since high perfect roundness of the diamond cutting edge 6 can be secured sufficiently by a process where dressing processing setting a diamond grain 10 is performed to the diamond cutting edge 6, the diamond grain 10 is constituted so that it is not damaged and intrinsic cutting performance possessed by a diamond core bit can be drawn out sufficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a diamond core bit used for drilling work of concrete, rock, brick, asphalt and the like.

[0002]

2. Description of the Related Art FIG. 11 shows the structure of a diamond core bit 9. At the tip of a cylindrical body 1, a plurality of arcuate diamond cutting blades 2 shown in FIG. 13 are arranged at predetermined intervals as shown in FIG. Here, the joint portion 4 is joined by brazing, for example. That is, as shown in FIG. 14 which is a cross section taken along the line AA ′ of FIG.
Is joined to the tip of the body 1. The number of intervals between the diamond cutting blades 2 is equal to the number of diamond cutting blades 2, and the intervals serve as the chip discharge grooves 3 during the boring operation. The diamond core bit 9 is attached to a manual or stationary electric tool or the like via the attachment portion 5 during the drilling work of concrete, rock, brick, etc., and is used for the drilling work in a dry or wet state.

As a method for manufacturing these diamond core bits 9, an arc-shaped diamond cutting edge 2 having a certain curvature larger than the outer diameter of the body 1 is fired and formed, and a plurality of diamond cutting edges 2 are used. The chip discharge groove 3 is formed so that the chip 1 is joined to the tip end surface of the body 1 by the brazing method, and then the dressing process is performed as the setting of the diamond abrasive grains 10.

[0004]

However, in the method of manufacturing the diamond core bit 9 described above, the diamond cutting edge 2 is fired and formed at a temperature at which the diamond abrasive grains are not damaged by heat. Generally 650-110
The sintering temperature is 0 ° C. Further, the diamond cutting edge 2 is joined to the body 1 by brazing mainly using a silver brazing material at a temperature lower than the sintering temperature so as not to impair the performance of the diamond cutting edge 2. When the drilling work becomes more severe than in the past and many works are performed in a short time, the thrust applied to the diamond cutting edge 2 or the lateral load such as bending and twisting acts largely, and the brazing diamond cutting edge 2 May be damaged from the joint portion 4, resulting in a decrease in work efficiency.

Further, since the diamond cutting edge 2 is a sintered molded product in which the diamond abrasive grains 10 and the metal powder are compounded,
It is difficult to secure accurate dimensional accuracy in an arc shape with a certain curvature, and if the diamond cutting edge 2 becomes thin, for example, 2 mm or less, chipping and cracks will occur during mold release after firing. It is easy to cause product defects.

Further, a plurality (for example, 4 to 30) of the diamond cutting blades 2 thus fired and formed are provided with the chip discharge groove 3.
In order to make the outer peripheral surface or the inner peripheral surface of the diamond cutting edge 2 equidistant with respect to the rotation axis, when it is joined to the cylindrical body 1 with high circularity by a method such as brazing However, it took a lot of time to improve the accuracy of the joining jig or to devise the mechanism mechanically.

In the dressing process in which the diamond abrasive grains 10 are sharpened on the surface of the diamond cutting edge 2, the accuracy of joining the diamond cutting edge 2 is not good, so that the dressing work using a grindstone of silicon carbide or alumina is difficult. I was letting it. That is, when the inner surface of the cutting edge 2 is dressed, the inner diameter of the cutting edge 2 is the smallest, and when the outer surface of the cutting edge 2 is the largest outer diameter of the cutting edge 2, the one-side contact phenomenon occurs, and the diamond abrasive grains 10 are evenly distributed. It was difficult to sharpen it. It took a long time for the dressing work to set all the diamond abrasive grains 10 uniformly, and moreover, the dressing grindstone was worn early and had to be replaced. Among the plurality of diamond cutting blades 2, the diamond abrasive grains 10 on the surface of the diamond cutting blade 2 which was sharpened early were damaged by the impact with the grinding stone for dressing many times. It causes chipping and dropout.

Regarding the machinability of the diamond core bit 9 obtained by the above manufacturing method, the roundness of the diamond cutting edge 2 was not good, and the cutting resistance at the time of punching work was large, so the biting and sharpness at the initial stage of cutting were poor. . Further, since the diamond abrasive grains 10 are damaged or fallen off, the entire cutting edge 2 is abraded and the life is shortened, and the original cutting performance of the diamond core bit 9 is not fully achieved.

An object of the present invention is to provide a method for producing a diamond core bit which eliminates the above-mentioned drawbacks of the prior art, eliminates damage to diamond abrasive grains, and can sufficiently bring out the original cutting performance.

[0010]

The above-mentioned object can be achieved by joining a diamond cutting edge formed in a ring shape to the tip of the body. The chip discharge groove is formed by melting and removing the ring-shaped diamond cutting edge at a predetermined interval by electron beam, laser beam, electric discharge machining or the like.

[0011]

According to the above manufacturing method, the diamond cutting edge formed in a ring shape with high roundness is joined to the tip of the body. Therefore, the high roundness of the diamond cutting edge is ensured. This makes it easier to stand out the abrasive grains.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. 1 and 2 are a front view and a side view showing a diamond cutting edge 6 formed in a ring shape while ensuring high roundness,
The diamond cutting edge 6 is obtained by firing and molding a metal powder containing a certain amount of diamond abrasive particles 10 in a mold formed with high precision.

Diamond cutting edge 6 formed in a ring shape
Is joined to the tip of the body 1 by brazing as shown in FIG. After that, the diamond cutting edges 6 are melted and removed at predetermined intervals along the circumferential direction by electron beam, laser beam or electric discharge machining to form the chip discharge grooves 3 shown in FIGS. 4 and 5. Since these processing methods have a high energy density, they are convenient because there is almost no thermal influence on a portion other than the portion to be melted and removed in forming the chip discharge groove 3. A plurality of the chip discharge grooves 3 are formed in the diamond cutting blade 6 at a predetermined interval. Next, when the dressing work of the diamond cutting edge 6 is performed, as shown in FIG.
Are uniformly set, and the diamond core bit 9 is completed.

FIG. 7 shows a second embodiment of the present invention.
The diamond cutting edge 6 is melted and removed halfway to form the chip discharge groove 3, and then the diamond cutting edge 6 is joined to the tip of the body 1. The core bit 9 improves the bonding strength of the diamond cutting edge 6 and is particularly effective against the temperature rise of the diamond cutting edge 6 and the bonding portion 4 due to the cutting heat during the dry drilling operation.

FIG. 8 shows that the chip discharge groove 3 is formed by extending to the body 1 in the first embodiment, and there is an effect that chips can be easily discharged.

FIG. 9 shows a third embodiment of the present invention.
The diamond cutting edge 6 is formed into a ring shape by firing and is directly joined to the body 1. That is, since the body 1 is firmly fixed to the fixing base 21, the body outer die 22, and the body inner die 23, and the ring-shaped diamond cutting blade 6 is fired and molded, the outer die 24 for the cutting blade and the cutting die Set the inner mold 25. After that, a mixed powder of metal powder containing diamond abrasive grains is filled and pressed by the pressing die 26. At this time, the diamond cutting blade 6 is heated to a predetermined temperature by a high-frequency heating coil (not shown) set on the outer periphery of the cutting blade outer mold 24.

The surface of the body 1 should be polished or
Alternatively, if the bondability between the diamond cutting edge 6 and the body 1 is enhanced by providing a coating layer such as copper plating or nickel plating on the surface of the body 1, the diamond cutting edge 6 can be reliably bonded to the body 1. . According to this embodiment, the cutting blade outer mold 24 and the cutting blade inner mold 25 having high circularity are provided.
Therefore, the diamond cutting edge 6 with high roundness can be manufactured.

Next, after firing and forming the diamond cutting edge 6,
The one integrated with the body 1 is released. FIG. 10 shows the integrated product after mold release. If the body 1 is tapered in order to facilitate the mold release, the body outer mold 22 and the body inner mold 23 are easily separated. The formation and setting of the chip discharge groove 3 thereafter are performed by the same steps as those in the first embodiment described above.

[0019]

As described above, according to the method for producing a diamond core bit of the present invention, since the diamond cutting edge is formed in a ring shape, the roundness is high and chipping and cracks are not generated, so that the productivity is improved. It improves and leads to cost reduction. Since the chip discharge groove is melted and removed by using a local heating source such as electron beam machining, laser machining, or electric discharge machining, it is possible to sufficiently secure the high circularity of the diamond cutting edge, and thus damage the diamond abrasive grains. It is possible to easily set the diamond abrasive grains without doing so. Furthermore,
Since the diamond abrasive grains can be sharpened without damage to the diamond abrasive grains, the cutting performance of the original diamond core bit can be fully brought out.

[Brief description of drawings]

FIG. 1 is a front view showing a diamond cutting edge obtained by a first step of a first embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a side view showing a core bit obtained by the second step of the first embodiment.

FIG. 4 is a front view showing a core bit obtained by the third step of the first embodiment.

5 is a side view of FIG.

FIG. 6 is a side view showing a core bit obtained by the fourth step of the first embodiment.

FIG. 7 is a side view showing a core bit obtained according to the second embodiment.

FIG. 8 is a side view showing another embodiment of FIG.

FIG. 9 is a sectional view showing a first step of the third embodiment.

FIG. 10 is a side view showing a core bit obtained by the first step of the third embodiment.

FIG. 11 is a side view showing an example of a conventional core bit.

FIG. 12 is a front view of FIG.

FIG. 13 is a perspective view showing an arcuate diamond cutting blade used in FIG. 11.

14 is a cross-sectional view taken along the line A-A ′ of FIG.

[Explanation of symbols]

1 is a body, 3 is a chip discharge groove, 6 is a diamond cutting edge,
9 is a diamond core bit and 10 is a diamond abrasive grain.

Claims (4)

[Claims] 1. A first step of forming (a) a diamond cutting edge containing diamond abrasive grains in a ring shape, and (b) the ring-shaped diamond cutting edge obtained in the first step is attached to the tip of a cylindrical body. A second step of joining, (c) a third step of melting and removing the ring-shaped diamond cutting edge obtained in the second step at a predetermined interval to form a chip discharge groove, (d) a diamond on the diamond cutting edge A fourth step of dressing for dressing abrasive grains, and a diamond core bit manufacturing method characterized by: 2. A first step of (a) forming a diamond cutting edge containing diamond abrasive grains in a ring shape, and (b) melting and removing the ring-shaped diamond cutting edge obtained in the first step at predetermined intervals. A second step of forming a chip discharge groove by means of (c) a third step of joining the ring-shaped diamond cutting blade having the chip discharge groove obtained in the second step to the tip of a cylindrical body, (d) A fourth step of dressing the diamond cutting blade to sharpen the diamond abrasive grains, and a diamond core bit manufacturing method. 3. A first step in which (a) a diamond cutting edge containing diamond abrasive grains is fired and formed into a ring shape, and at the same time, is joined to the tip of a cylindrical body, and (b) a ring shape obtained in the first step. A second step of melting and removing the diamond cutting edge at a predetermined interval to form a chip discharge groove, (c) a dressing process for sharpening diamond abrasive grains on the diamond cutting edge obtained in the second step A method for manufacturing a diamond core bit, which is characterized by being manufactured by the following steps: 4. The step of melting and removing a diamond cutting edge to form the chip discharge groove is performed by using a local heating source such as an electron beam, a laser beam, or electric discharge machining. The method for manufacturing a diamond core bit according to claim 1, claim 2 or claim 3.