JPH0532196B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a superabrasive cutter, and in particular, superabrasive grains such as fine diamond powder or cubic boron nitride are added to the outer periphery of a cutter substrate on a disc. This invention relates to a diamond cutter or a CBSN cutter which is obtained by sintering a compact containing powder.

(Prior Art) Examples of this type of diamond cutter include the following.

As the first diamond cutter, the 10A
As shown in the figure, put half of the powder 1a containing diamond fine particles into a mold, level it evenly, then place the iron plate that will become the cutter base 2, and then put the remaining half of the powder 1b. There are products that are sintered while being pressed with a press.

As the second diamond cutter, No. 10B
As shown in the figure, powder containing fine diamond particles is compacted to form a green compact 3a into a predetermined shape.
After molding two pieces, an iron plate serving as the cutter substrate 4 is placed in a mold and sintered. In the case of this diamond cutter, the seam between the green compacts 3a and 3a is planar, and a sintered body whose outer surface is also substantially planar is formed.

As the third diamond cutter, the 10th C
As shown in the figure, a single green compact 5 made of powder containing fine diamond particles is molded into a predetermined shape in advance, and is positioned on the radial extension line of the cutter base plate 6 together with the cutter base plate. put it in,
By sintering the powder compact 5 and causing the cutter substrate 6 to bite into the sintered body 7 formed by sintering the powder compact 5 due to the thermal expansion of the cutter substrate 6, the powder compact 5 is sintered as shown in FIG. 10D. There is one in which the sintered body 7 is fused to the cutter substrate 6 at the same time as the cutter substrate 6 is fused.

(Problems to be solved by the invention) Among the conventional diamond cutters, the first
Diamond cutters are used as molds for sintering powder compacts, and the number of combinations increases, making the structure complex. Moreover, it is not suitable for mass production because it cannot be efficiently produced in each separate process.

Compared to this first diamond cutter,
The second diamond cutter can be mass-produced relatively easily because the manufacturing process can be separated. but,
When molding a powder compact, a disk-shaped powder compact with a flat surface is preformed, and the flat surfaces are joined to form a diamond layer by sintering the two compacts. As a result, there is a part where no diamond fine powder particles are present at the boundary between two facing green compacts.

Therefore, a third diamond cutter was created that could eliminate the defects of the second diamond cutter by forming one sheet of compacted powder in advance, but this third diamond cutter
The amount that the cutter substrate digs into the sintered body due to thermal expansion increases as the diameter increases and also as the temperature increases, so when making relatively small cutters or using powder with a low sintering temperature. It is not suitable when using.

Furthermore, the adhesive strength between the diamond sintered body and the cutter substrate is relatively weak, making it unsuitable for use as a cutter under harsh conditions.

Therefore, the main object of this invention is that superabrasive grains are present in every part of the sintered body, there is no localized uneven wear, it always shows good sharpness, and the number of molds is relatively small. Super abrasive grains that can simplify the manufacturing equipment, separate manufacturing processes and mass-produce, make relatively small cutters, and use powder with a low sintering temperature. It is to provide cutters.

(Means for Solving the Problems) This invention provides a cutter substrate in which concave portions are formed at appropriate intervals on the outer periphery, and a compacted powder body in which powder containing superabrasive grains is divided into two parts. The two green compacts are heated and sintered while being pressurized.
a sintered body fixed to the outer periphery of the cutter substrate, the sintered body is fixed so that grooves and protrusions formed on the two powder bodies face each other at the seam of the two compacts, This is a superabrasive cutter whose boundary meanders in the thickness direction of the cutter substrate.

(Operations and Effects of the Invention) According to the present invention, since the sintered body is meandering in the thickness direction of the cutter substrate at the boundary between the two green compacts, diamonds are not present in any part of the sintered body. Super abrasive grains such as fine powder particles are present, so there is no uneven wear and always shows good sharpness.

Moreover, according to the present invention, since the green compact can be manufactured by preforming the green compact divided into two pieces using powder containing superabrasive grains such as fine diamond particles, the manufacturing process can be separated. This makes it possible to mass-produce superabrasive cutters such as diamond cutters. In addition, since it can be manufactured by preforming two compacts, the number of molds used during sintering can be relatively small.
It is possible to prevent the manufacturing mold from becoming complicated.

Moreover, since two preformed compacts are made, the cutter substrate is sandwiched between them in the mold, the compacts are bonded together and sintered, and they are also bonded to the cutter substrate. Unlike conventional diamond cutters, which fuse with the sintered body through expansion, it does not depend on the coefficient of thermal expansion of the cutter substrate, so relatively small cutters can be made, and the sintering temperature can be adjusted. It is also possible to use powder with a low

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Example) Fig. 1 is a perspective view of a diamond cutter which is an embodiment of the present invention, Fig. 2 is a plan view of the main part thereof, and Fig. 3 is a longitudinal sectional view thereof.

4 to 8 are diagrams showing an example of the manufacturing method of the embodiment.

This diamond cutter 10 includes a sintered body 14 containing superabrasive grains such as fine diamond particles 12, and a disk-shaped cutter substrate 16 that supports the sintered body 14.

The sintered body 14 containing the diamond fine powder particles 12 is
A concave line 18a and a convex line 18b are continuously formed in the inside thereof, and the whole is formed in a wavy shape. The concave line 18a and the convex line 18b are
Although they are formed radially substantially parallel to the radial direction of the cutter base plate 16, they may be formed obliquely to the radial direction.

In the cutter substrate 16, cooling through holes 20 are formed near the inner peripheral edge of the sintered body 14 at appropriate intervals.

Next, a method for manufacturing the diamond cutter 10 will be described, and its structure, particularly the structure of the sintered body 14, will be explained in detail.

First, it contains 1 to 50% by volume of diamond fine powder particles 12 of 20 to 400 meshes, 30 to 50% of copper, and 30 to 50% of iron.
Prepare metal powder such as 30-50% tin and 5-10% tin,
The powder is injected into the green compact manufacturing apparatus 24 (see FIG. 4).

This green compact manufacturing apparatus 24 has inner and outer cylinders 28 and 30 that are in close contact with the inner and outer walls of an annular trapezoid 26 and protrude in a stepwise manner from the upper surface of the trapezoid 26. A large-diameter cylindrical portion 28a is formed on the outer cylinder 30, and a long cylindrical portion 30a is formed on the outer cylinder 30, and the diamond fine powder particles, which have been measured in accordance with a predetermined calculation, are placed on the trapezoid 26. A green compact 34 is injected with various types of powder 22 containing the powder, and is pressed and tightened upwardly by an annular mold 32 to harden it to a density that is about 1 to 30% lower than the density of what will later become the sintered alloy, as shown in FIG. to form. Annular trapezoid 26
As shown in Fig. 5, the top surface of the
7a and grooves 27b are formed.

As shown in FIG. 6, this preformed compact 34 has an annular disk shape, one main surface of which is substantially flat, and the other main surface of which is a convex portion of the trapezoid 26. A grooved line 18a and a convex line 18b are formed corresponding to the line 27a and the grooved line 27b.

In addition to the above-mentioned examples, the material of this green compact 34 is 30 to 50% nickel and 10 to 70% cobalt.
%, molybdenum 5-10%, tungsten 5-10%
One or more of these may be added.

Also, instead of the metal powder described above, for example,
Synthetic resin powders such as phenol resin, epoxy resin, or polyimide resin may also be selectively employed.

The powder forming the green compact 34 is uniformly distributed and filled into the mold by the green compact manufacturing device 24 described above, and is compressed from above and below by a press at 1 ton/cm ^{2 .}
After compression bonding and preforming at a pressure of 5 ton/cm ² to 5 tons/cm 2 , the mold is removed from the mold.

On the other hand, the cutter board 16 is made of a thin disc made of iron, copper, titanium, or an alloy such as steel or an alloy of copper and beryllium. is formed with a notch. Note that the gear-shaped portion of the cutter base plate 16 formed by the concave portions 36 corresponds to each convex portion 38.
The adjacent convex portions 38 and the cutter substrate 16
The shape may be slightly bent in opposite directions in the direction in which the two main surfaces intersect.

Further, in this embodiment, the convex portion 38 is made slightly thinner than the main body of the cutter substrate 16 to form a step, thereby maintaining the strength of the cutter substrate 16 and reducing the thickness of the sintered body 14. ing.

Then, the powder compact 34 and the cutter substrate 16 are placed in a separately prepared press sintering device 40 (see FIG. 6).

This press sintering device 40 has a trapezoidal shape 46 having a cylindrical upward concave step 42 with a depth approximately equal to half the height of the powder compact 34, and a convex shaft 44 in the center.
and an upper mold 50 having a downward recessed step 48 symmetrical to the recessed step 42 of the trapezoid 46 .

Then, the recessed step portion 42 of the mold, that is, the trapezoid 46
The press table mold 54 and the press table mold 5 are connected to each other by the recessed step portions 48 of the upper mold 50 to form a space which is a part for accommodating the powder compact 34.
A press upper die 54 facing the press die 2 is attached to the outer peripheral wall surface portions of the trapezoid 46 and the upper die 50, respectively. Moreover, a cylindrical mold 56 is attached to the outer peripheral wall surface portions of the press table mold 52 and the press upper mold 54.

Then, the cutter base plate 16 is fitted into the convex shaft 44 protruding from the center of the trapezoid 46, and the powder compact 34 and the cutter base plate 16 housed in the accommodating portion formed in advance by the recessed step portion 42 are inserted into the cutter base plate 16. An upper mold 50 containing another powder compact 34 is loaded at a predetermined location of the recessed step 52 so as to sandwich the periphery thereof.

Then, a press device (not shown) is used to press with a predetermined pressure from the lower surface of the press table mold 52 and from the upper surface of the press upper mold 54, and press the green compact 34 housed on the press table mold 52 side. It is also brought into close contact with the powder compact 34 housed in the upper die 54.

Then, in this pressed state,
For example, in an electric furnace, the cutter substrate 16 and the powder compact 3 are heated in a hydrogen stream or a similar atmosphere.
4 and sintered together.

Therefore, the two sintered powder compacts 34 are fixed to each other, and are also fixed to the cutter substrate 16.
A sintered body 14 is fixed to the outer peripheral edge of the sintered body 14 .

In addition, the grooves 18a and 18b formed on the upper surface of one sintered body 34 and the grooves 18a and 18b formed on the lower surface of the other sintered body 34 are arranged so as to correspond to the shapes of the grooves 18a and 18b. As shown in Figure 8, the seam 34a of the two completed compacts 34 is
The cutter substrate 16 meanders in the thickness direction along the above-described shape.

Therefore, when the diamond cutter 10 is rotated to cut the material to be cut, the seam of the powder compact 34 is not a straight line, so the seam is always in contact with the material to be cut. Since fine diamond particles are present in all parts, uneven wear does not occur locally, and parts other than the joints are always in contact with the material to be cut.

Moreover, the concave portion 36 and the convex portion 3 of the cutter board 16
Due to the unevenness formed by 8 and 8, the sintered body 14
The adhesive area increases and the adhesive strength increases. Moreover, in this embodiment, since the through holes 20 are formed continuously near the sintered body 14,
Even when the sintered body part is not used while being cooled by water cooling, for example, when it is used dry by attaching it to an electric grinder, the through hole 20 performs air agitation to dissipate the heat generated during cutting into the air. This cooling effect has the effect of slowing down the transfer of heat to the core of the cutter substrate 16.

Note that the mold 46 in the press sintering device 40
and 50 are molded from carbon, conductive ceramic, ferrite, tungsten carbide, or the like.

Further, in the example of the diamond cutter, the through hole 20 is formed along the inner peripheral edge of the sintered body 14, but instead of such a through hole 20, for example, a through hole 20 is formed along the outer peripheral edge of the cutter substrate 16. Of course, the shape of the formed recess 36 can be changed as appropriate, as shown in FIGS. 9A to 9J.

Further, on both main surfaces of the sintered body 14, a waveform in which grooves and protrusions are continuous may be formed radially substantially parallel to the radial direction or obliquely to the radial direction.

Note that superabrasive grains such as cubic boron nitride (CBN) may be selected instead of the diamond fine powder grains.

[Brief explanation of the drawing]

1 and 3 are diagrams showing a diamond cutter which is an embodiment of the present invention. FIG. 1 is a perspective view thereof, FIG. 2 is a plan view of the main part thereof, and FIG. The figure is a longitudinal cross-sectional view. FIG. 4 and FIG. 5 are illustrative views showing an example of a green compact manufacturing apparatus. FIG. 6 is an illustrative view showing an example of a powder compact. FIG. 7 is a sectional view showing an example of a press sintering apparatus. FIG. 8 is an illustrative view showing the mold of the press sintering device and the main parts of the green compact. Figure 9 shows
FIG. 7 is an illustrative view showing another example of the recessed portion of the cutter substrate.
FIGS. 10A to 10D are illustrative views showing a conventional method for manufacturing a diamond cutter. In the figure, 10 is a diamond cutter, 1
2 is a diamond fine powder grain, 14 is a sintered body, 16 is a cutter substrate, 18a is a concave strip, 18b is a convex strip, 2
0 is a through hole, 22 is a powder, 24 is a green compact production device, 26 is a trapezoid, 27a is a convex strip of the sintered body, 27b
28 is an inner cylinder, 30 is an outer cylinder, 32 is a concave strip of the sintered body,
34 is a pressing mold, 34 is a powder compact, 36 is a recessed part, 38 is a convex part, 40 is a press sintering device, 42 is a concave stepped part, 4
4 is a convex shaft, 46 is a trapezoid, 48 is a concave step, 50 is an upper mold, 52 is a press table mold, and 54 is a press upper mold.

Claims (1)

[Scope of Claims] 1. A cutter substrate having concave portions formed at appropriate intervals on its outer periphery, and a powder containing superabrasive grains are molded as a compact into two parts, and the two compacts are The powder is heated and sintered while being pressurized, and the sintered body is fixed to the outer periphery of the cutter substrate, and the sintered body is formed between the two green compacts at the joint thereof. A super abrasive cutter in which concave lines and convex lines are fixed facing each other, and the boundaries meander in the thickness direction of the cutter substrate. 2. The superabrasive cutter according to claim 1, wherein the seams of the powder compact are formed in a waveform in which concave lines and convex lines are continuous. 3. The sintered body is compacted into a disk shape with a powder compact containing 20 to 400 meshes of diamond fine powder particles in a volume ratio of 1 to 50%. The superabrasive cutter according to item 2. 4. The cutter board is made of steel material,
Claims 1 to 3, wherein a U-shaped recess is formed on the outer periphery to which the powder compact is joined.
The superabrasive cutter described in any of the above.