JPH02262963A - Diamond-impregnated tool and its manufacture - Google Patents

Abstract

PURPOSE:To make cutting and grinding properties extremely favorable by burying all the cutting blades of diamond particles so that they may stand opposite and upright to the substance to be processed. CONSTITUTION:Diamond particles are placed on a plate inside a DC electric circuit which has a high pressure generator, and is erected with the cutting blade vertical. Adhesives are applied on one end of this diamond particles and then metallic powder or metallic carbide power same or in the same line as binders are applied. The diamond particles, on which this metallic powder or metallic carbide powder is applied, are mixed with the binders and then those are let fall freely into a carbon mold. By sintering the diamond particles and the binders charged in this carbon mold, a desired diamond-impregnated tool can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a diamond-impregnated tool and a method for manufacturing the same, and in particular, the present invention relates to a diamond-impregnated tool and a method for manufacturing the same, and in particular, the present invention relates to a diamond impregnated tool and a method for manufacturing the same. The present invention relates to a buried diamond impregnated tool and its manufacturing method, and is used in the field of manufacturing tools such as diamond drill bits and diamond wheels for rock drilling.

[Prior Art] Diamond drill bits for rock drilling, diamond wheels for cutting hard materials, and the like are used for various uses and purposes depending on how diamonds are planted.

For example, in diamond drill bits.

Bits with diamond grains set only on the tip surface of the bit are called surface-set diamond drill bits, and bits in which diamond grains are mixed with hard metal or metal carbide and soft metal powder, molded and sintered are called impregnated drill bits. It is called a diamond drill bit.

There are various types of industrial crystalline diamond grains currently in use, but most of them are shown in Figure 1 (A).
For the octahedron and dodecahedron shown in (B), the intersection angle of the edges of the octahedron is 90 degrees, and that of the dodecahedron is approximately 130 degrees. However, impregnated tools typically use synthetic diamond grains, most of which are octahedral and tetradecahedral, with the edges of the tetradecahedron having an intersection angle of 135 degrees.

In either case, the intersection of the edges is called the cutting edge,
When the cutting edge is upright facing the workpiece, cutting stress is concentrated and the cutting quality is maximized. Figures 2 (A) and (B) are
This is a schematic diagram in which all diamond cutting edges are buried facing the workpiece, and the cutting edge angle is O in this case, as shown in FIG. 2(B). FIGS. 3(A) and 3(B) are schematic diagrams showing the state of cutting edges of diamond grains in conventional impregnated tools.
) shows the case where the cutting edge is inclined at 22.5 degrees with respect to the cutting direction.

The degree of stress concentration in the case shown in Fig. 2 (B) above and in the case shown in Fig. 3 (B) is 131:100, respectively, and the cutting edge stands upright facing the workpiece. In that case, 30
This results in an improvement in cutting force of more than %.

As a result, with surface-set diamond drill bits, countermeasures have been taken to improve the cutting force even under the same drilling conditions by planting the cutting edge of the diamond grains one by one so that they are precisely facing the workpiece. Ta. However, it requires a lot of labor to plant the diamond grains with the tip of the crystal facing the workpiece, and it is inevitable that the cost will be higher than that of an impregnated diamond drill.On the other hand, surface set diamond drills Although the initial cutting quality is excellent, the diamond grains in the surface set may wear out with use.
In contrast, with an impregnated diamond drill, although the initial cutting quality is poor, even if the diamond grains on the surface wear out or fall off, the cutting force will decrease rapidly. It also has the advantage of being very durable because the next layer of diamond grains that are randomly mixed inside appear on the surface.

[Problem to be solved by the invention]

It is an object of the present invention to provide an impregnated diamond tool that combines the advantages of conventional surface-set diamond tools with the advantages of impregnated diamond tools.

In other words, the surface layer of the diamond grains embedded in the bond metal has its tip cutting edge facing the direction of the workpiece, and the diamond grains embedded in the bond metal also have the same surface layer as the surface layer. By arranging the cutting edge to face the workpiece, the diamond impreg has excellent machinability at the initial stage of use, and can withstand long-term use without deteriorating in machinability during subsequent use. The aim is to provide integrated tools.

[Means and operations for solving the problems] The gist of the diamond impregnated tool according to the present invention is as follows.

That is, in a diamond impregnated tool comprising diamond grains, a hard metal or a metal carbide, and a soft metal that bind the diamond grains, all of the cutting edges of the diamond grains face the workpiece. This diamond impregnated tool is characterized by being buried upright.

The diamond impregnated tool according to the present invention can be manufactured by the following two methods, and the gist of each method is as follows.

That is, the step of placing a diamond grain on an electrode plate in a DC electric circuit having a high-pressure generator and standing it upright with the cutting edge up and down; a step of applying metal powder or metal carbide powder; a step of mixing the diamond grains coated with the metal powder or metal carbide powder with a binder and then allowing them to fall freely into a carbon mold; and a step of freely falling into a carbon mold. 1. A method of manufacturing a diamond impregnated tool, comprising the step of sintering grains and a binder.

and a step of magnetizing the surface of the diamond grains, a step of placing the diamond grains on an anode or a cathode which face each other to form a magnetic field, and standing upright with the cutting blades up and down, and adhering to one end of the diamond grains. After applying the agent,
a step of applying metal powder or metal carbide powder that is the same as or similar to the binder; a step of mixing diamond grains coated with the metal powder or metal carbide powder with the binder and then allowing them to fall freely into a carbon mold; A method for manufacturing a diamond impregnated tool, comprising the step of sintering diamond grains and a binder filled in a mold.

In the diamond impregnated tool according to the present invention, the cutting edges, which are the tips of the buried diamond crystals, are all upright facing the workpiece.
This is a major feature.

Next, the details of the manufacturing method will be explained.1 The method for making diamond grains stand upright according to the present invention is the method for automatically planting diamond grains in a diamond drill bit according to Japanese Patent Publication No. 52-10749, and the method for automatic planting of diamond grains in a diamond drill bit is published in Japanese Patent Publication No. 52-95.
This is an application of the diamond drill bit manufacturing method according to No. 23.

That is, when a diamond grain is placed in a high-voltage DC electric circuit, the circuit is closed, and the voltage is gradually increased, an electric field is generated and an electrostatic charge is generated on the bipolar plates. For example, the distance between the two poles is 10 to 20
In the case of m, when the voltage exceeds 10 kV, a strong electric field is formed between the two poles, and due to dielectric polarization, the tip of the diamond grain in contact with the electrode plate has a charge of the opposite sign, and the opposite tip has a charge of the same sign. The diamond grains are concentrated and stand upright, and are finally attracted to the opposite electrode of the opposite sign, so the tip of the cutting blade is attracted to the opposite electrode and becomes upright.

At this time, it is convenient to attach paper coated with an adhesive to the counter electrode in order to stabilize the diamond grains in an upright state.

The diamond grains on the paper coated with adhesive are all upright, so after applying adhesive to the cutting edge of the crystal at one end, metal powder or metal carbide powder of the same or similar type as the binding material is applied. Apply. The binding material may be alloy powders such as Fe, Ne, Go, etc. used in conventional tools, or in the case of drill bits, it may be a mixed powder of cemented carbide metal carbide and binding metal or alloy, depending on the type of tool. An appropriate bonding material can be selected depending on the application. In the above-treated diamond grains, bonded metal powder is attached to one cutting edge via an adhesive, so the center of gravity of the diamond particles is unevenly distributed toward the one cutting edge to which bonded metal powder is attached. It happens.

The diamond particles subjected to these treatments are removed, and a certain amount of a predetermined bonded metal powder or metal carbide powder is mixed therein.

Thereafter, the mixed diamond grains and binder powder are simultaneously allowed to freely fall into the recesses of the sintering carbon mold. When free-falling into the carbon mold, the binder powder falls randomly, but the diamond grains fall on one cutting edge where the same or similar metal powder or metal carbide powder as the binder powder is bonded via an adhesive. Since the center of gravity is unevenly distributed in the diamond grains, all the diamond grains freely fall vertically with their parts facing down, and are buried vertically in the binding powder.

The diamond impregnated tool according to the present invention can be obtained by taking out the carbon mold that has been buried upright during the bonding powder and sintering it.

The second manufacturing method according to the present invention is disclosed in Japanese Patent Publication No. 52-9523
This is an application of the method, and the following method is used to make the diamond grains stand upright.

That is, the surface of the diamond grain is first subjected to magnetization treatment.

The magnetization treatment is performed by a known method, and a magnetic metal film of iron, nickel, cobalt, etc. is coated. Magnetized diamond grains are placed on the plate of an electromagnet that has an anode or a cathode above and below. When the power supply is closed and the entire device is gently vibrated,
The diamond grains are magnetized, and the cutting edge portion at the tip is most strongly magnetized, so the diamond grains stand upright with the cutting edge portion at the tip facing the direction of the magnetic field lines, and are attracted to the opposite pole. In this case as well, similarly to the first method of the present invention,
In order to stabilize the upright state, it is preferable to attach a paper coated with an adhesive to the counter electrode.After the diamond grains are upright, the same steps as in the first method are used to prepare the diamond impregnated grains according to the present invention. You can get tools.

[Example] A usage test was conducted to confirm the effectiveness of the tool according to the present invention in actual use. That is, a diamond drill bit 46TC with an outer diameter of 46 m and an inner diameter of 32 nn was manufactured by the method for manufacturing a diamond impregnated tool according to the present invention, and the rotation speed was 500 rpI11 and the supply pressure was 300 to 10 m.
When we conducted a drilling test on granite with a -axial compressive strength of approximately 1500 kg/aJ and a conventional diamond impregnated drill bit, the drilling speed was 3 to 4.
cm/min, whereas the diamond impregnated drill bit according to the present invention has a drill bit of 4 to 5 cm/w.
It was found that it is possible to improve the excavation speed by about 30%. With a diamond surface set drill bit of the same size, the drilling speed under the same conditions is approximately 51/2
It has been found that the diamond impregnated drill bit according to the present invention can be compared to a surface-set product of approximately the same dimensions.

〔Effect of the invention〕

The diamond-impregnated tool according to the present invention has extremely good cutting and grinding properties because all the cutting edges at the tips of the diamond grains are buried upright facing the workpiece, contrary to conventional wisdom. According to the example, the cutting speed could be improved by about 30%.

In addition, the tool of the present invention not only has improved machinability, but also the diamond grains embedded in the binder have an upright cutting edge just like the diamond grains in the surface layer, resulting in long-term machinability and It can maintain excavability and has good durability.

However, in the manufacturing method,
49 and Japanese Patent Publication No. 52-9523, it is a new and effective method, and it is cheaper than the manufacturing cost of conventional surface-set diamond tools, and it has a surface-set diamond tool in terms of performance. It has become possible to manufacture tools that are comparable to set products.

Although the embodiments of the present invention have been described with respect to diamond-impregnated drill bits, it is clear that the technical idea of the present invention is applicable not only to diamond-impregnated drill bits but also to other tools. .

[Brief explanation of drawings]

Figures 1 (A) and (B) are both perspective views showing diamond crystals; (A) is an octahedron, (B) is a dodecahedron, and Figures 2 (A) and (B) are diamond crystals. This shows how diamond grains are buried in the diamond impregnated tool according to the invention, (A) is a schematic front view showing how diamond grains are upright in the binder, and (B) is a schematic front view showing how one diamond grain is buried in a workpiece. The front view showing the opposing angle of 0 degrees, and FIGS. 3(A) and 3(B) show the state of embedding diamond grains in a conventional diamond impregnated tool.
A) is a schematic front view showing the scattering state of the opposing angles of diamond grains in the binder, and (B) is a front view showing an example in which the opposing angles are inclined at 22.5 degrees.

Claims (3)

[Claims] (1) A diamond impregnated tool comprising diamond grains, a hard metal or metal carbide, and a soft metal that bind the diamond grains,
A diamond impregnated tool characterized in that all of the cutting edges of the diamond grains are embedded vertically facing the workpiece. (2) The step of placing diamond grains on the electrode plate in a DC electric circuit having a high pressure generator and standing upright with the cutting blades up and down, and applying an adhesive to one end of the diamond grains, which is the same as or similar to the bonding material. a step of applying metal powder or metal carbide powder, a step of mixing the diamond grains coated with the metal powder or metal carbide powder with a binder and then allowing them to fall freely into a carbon mold; A method for manufacturing a diamond impregnated tool, comprising the step of sintering diamond grains and a binder. (3) applying magnetization treatment to the surface of the diamond grains;
The diamond grains are placed on an anode or a cathode that faces each other to form a magnetic field, and are made to stand upright with the cutting blades up and down, and after applying an adhesive to one end of the diamond grains, a metal of the same or similar type as the bonding material is applied. a step of applying powder or metal carbide powder; a step of mixing the diamond grains coated with the metal powder or metal carbide powder with a binder and then allowing them to fall freely into a carbon mold; and a step of allowing the diamond grains coated with the metal powder or metal carbide powder to fall freely into a carbon mold. and sintering a bonding material.