JP3038439B2 - Cutting, grinding and polishing tools using composite diamond grains - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to cutting, grinding, grinding, and grinding composite diamond grains obtained by depositing diamond on the surface of heat-resistant granules by a vapor phase method. Related to abrasive tools.

<Prior Art> Conventionally used cutting, grinding and polishing tools using diamond grains include metal bond wheels, resin bond wheels, vitrified bond wheels, and abrasive cloths. However, the diamond grains used are mainly natural or artificial (ultra-high pressure) having a major / short diameter ratio of less than 1.2. They are expensive and have limited field of use. The present applicant has previously invented and filed an application as Japanese Patent Application No. 63-219889, in which heat-resistant granules having a surface coated with vapor phase diamond are coated. However, these had a ratio of major axis to minor axis which was spherical or similar.

<Problems to be Solved by the Invention> The tools using the conventional diamond grains have low cutting, grinding and polishing efficiencies as described below.

That is, the ratio of the major axis to the minor axis is low, and the bonding property is low. For example, in a resin bond system, projections are formed by surface treatment to supplement the bonding property. On the other hand, in the abrasive paper field, those using diamond grains have been very limited due to cost and low bonding properties.

Conventionally, abrasive grains such as Al ₂ O ₃ and SiC are generally used. However, these were not high in both cutting performance and cost performance.

Therefore, practically, there has been a demand for the development of cutting, grinding, and polishing tools having high cutting performance and high cost performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tool capable of performing cutting, grinding and polishing that meets the above-mentioned requirements.

<Means for solving the problem> To achieve the above object, the present inventors have conducted intensive studies and found that the ratio of the longest axis length to the shortest axis length is at least 1.2 on the entire surface of the heat-resistant granular material. A tool with a specific orientation in which the composite diamond grains obtained by depositing fine crystal diamond particles by the vapor phase method are in such a way that the surface to be machined contacts in the vertical direction can be subjected to high-efficiency cutting, grinding and polishing. And completed the present invention.

That is, (a) heat-resistant granules having many active sites obtained by pulverization are sieved and sorted so that the longest axis length and the shortest axis length are at least 1.2, and the entire surface of the selected granules is removed. A composite diamond grain coated with a vapor-phase diamond film and having a ratio of the longest axis length to the shortest axis length of at least 1.2, a cutting, grinding and polishing body made of a binder, and (b) a support. The present invention relates to a cutting, grinding and polishing tool using composite diamond grains, wherein the composite diamond grains are oriented in the longitudinal direction with respect to the surface to be machined.

 Hereinafter, the present invention will be described in detail.

Examples of the heat-resistant particulate used in the present invention include diamond, W, Mo, Ta, WC, SiC, TiC, TaC, Al ₂ O ₃ , ZrO ₂ ,
Heat-resistant metals and ceramics such as Cr ₂ O ₃ , TaN, ZrN, and Si ₃ N ₄ are suitable.

As described above, the shape of the grains needs to have a ratio of the longest axis length to the shortest axis length of at least 1.2, but practically,
It is desirably 1.5 to 10, particularly preferably 5 or around 5. The reason for this is that by giving the orientation, a high bonding force and a long tool life can be achieved.
Also, the shortest axis length needs to be 10 to 700 μm,
In particular, it is preferably in the range of 30 to 400 μm.

The method of preparing the base particles is as follows: (1) Ceramics and heat-resistant metal lump are selected by sifting the crushed particles. That is, it is sufficient to classify the particles by a sieve having a finer mesh than the major axis, classify the material remaining on the sieve with a sieve coarser than the minor axis, and use the material which is below the sieve.

(2) A powder having a large ratio of major axis to minor axis is obtained by powder sintering. For example, a method may be adopted in which the unfired body is formed into a thin plate, crushed to adjust flat grains, and fired in a rotary kiln or the like.

In the diamond composite grains in the cutting, grinding and polishing tools of the present invention, the surface of the heat-resistant granular material is coated with polycrystalline diamond by a gas phase method. The desired thickness of the coating varies depending on the size of the heat-resistant granular material, and is determined in consideration of the application, the time required for coating, and the like.

The size of the particles constituting the diamond coating layer can be selected from fine particles on the order of submicrons to about 20 μm depending on the conditions for the deposition and synthesis.

In order to deposit diamond particles on the surface of the heat-resistant granular material, a known vapor phase diamond synthesis method can be applied. That is, methane, ethane,
Hydrocarbons such as propane, benzene, toluene, and cyclohexane; oxygen-containing organic compounds such as methanol, ethanol, propanol, tertiary butanol, and acetone;
Further, those obtained by adding an oxygen-containing substance such as H ₂ O, CO ₂ , or CO to these can also be used. These gases are used alone or mixed with a carrier gas such as hydrogen or argon. The pressure of the gas can be from about 10 ^-2 Torr to a pressurized state depending on the synthesis method.

In order to precipitate diamond particles on the entire surface of the heat-resistant granular material by these methods, there is a raw material for diamond synthesis,
In addition, the particulate matter is placed in a heat-resistant container in an atmosphere excited to a state where diamond can be generated, and is placed at a position where the granular material becomes a reaction space region, and the particulate matter is intermittently interposed by a vibrator or the like connected to the heat-resistant container. May be reversed.

Although the granular material partially overlaps with the next granular material, the diamond deposition thickness of the longer diameter surface is larger than the shorter diameter surface, and the granular material is film-like,
The entire deposition surface has irregular irregularities.

Since the heat-resistant granular material is made by pulverization or the like, it has many active sites. These active sites act as nuclei for diamond formation, and diamond particles precipitate.

The cutting, grinding and polishing tool of the present invention comprises a cutting, grinding and polishing body obtained by mixing and solidifying the composite diamond grains with a binder, and a support for supporting the cutting, grinding and polishing body.

Next, specific examples of the cutting, grinding and polishing tools of the present invention will be described with reference to the drawings.

FIG. 1 shows an abrasive paper in which composite diamond grains are arranged almost upright on a base paper. In the figure, 1 is a composite diamond grain, 2 is a binder, and 3 is a backing paper. The cutting, grinding, and polishing tool shown in FIG. 1 is obtained by uniformly dispersing the composite diamond particles on, for example, a cloth tape, and placing the composite diamond particles in a charged state. On the other hand, they are arranged vertically, that is, almost vertically in the figure. In order to fix this to the base paper, for example, the base paper coated with a thin binder is turned down, the composite particles are placed below, and when an electric field is applied between the base paper and the composite particles, the binder is stuck in a state where the composite particles stand up Adheres to Thereafter, the fixing agent is solidified to fix the grains.

FIG. 2 relates to a metal bond wheel which is another practical example of the cutting, grinding and polishing tool of the present invention. In the figure,
11 is a diamond composite grain, 12 is a metal bond, and 13 is a base metal.

This metal bond wheel has composite diamond grains,
When a metal bond (eg, copper powder and bronze powder) is mixed and cold pressed onto an annular base, the composite diamond grains are oriented almost perpendicular to the compression direction. This is further subjected to each of the steps of firing, hot pressing, truing, and dressing to form a metal bond wheel. In addition, a support having a shape such as a cylindrical shape or a cup shape can also be used.

 Next, the present invention will be described with reference to Examples and Comparative Examples.

Example 500 mg of alumina particles having an average longest axis length of 650 μm and an average shortest axis length of 80 μm were set in a reaction bucket in a hot filament method diamond synthesizer. A 0.3 mmφ tantalum wire processed into a coil shape was used as the excitation hot filament, and the height was set to 7 mm from the inner bottom surface of the reaction bucket. During the synthesis, the bucket was intermittently vibrated by an electromagnetic vibrator at a rate of 10 seconds every 10 minutes.

The synthesis reaction is performed at a pressure of 100 Torr and a tantalum filament temperature of 2
450 ° C, ethanol and hydrogen as raw material gas, concentration of ethanol 3% by volume, total flow rate 150cc / min 10
Time went on.

After the completion of the reaction, the particles were taken out from the bucket, and the surface condition was observed with an optical microscope. The surface was covered with a film having a dense structure composed of diamond particles of several μm. In particular, in the film having the longest diameter, irregular unevenness with a step of about 10 μm was observed. The measured Raman shift the particle surface by microscopic Raman spectroscopy, a peak due to a sharp diamond bonding to 1334cm ^-1, by an admission low peak with very broad near 1500 cm ^-1, a trace amount of the diamond phase i It was confirmed that the film was a diamond coating film containing a carbon component. Incidentally, the weight of the obtained diamond composite particles was 890 mg.

Next, using these composite grains, a 180 mmφ metal-bonded diamond wheel was prepared as shown below. 174m diameter
Using 600mg of the composite particles and 20g of copper powder as a metal bond, 14g of bronze powder, etc. on an iron base metal of mφ, the metal in which the composite particles were oriented as shown in Fig. 1 by cold pressing, firing, hot press truing, and dressing. Created a bond wheel.

Next, a wet cutting test was performed using this diamond wheel. Work material is marble block (100 × 20 × 35m
m), a 20 × 35 mm surface was cut 10 times by a cutter at 2800 rpm. The initial dynamic power at that time was 270 W, the average power was 310 W, and the average cutting time per operation was 140 seconds. After cutting 10 times,
The surface composed of the composite grains and the metal bond, that is, the abrasive grain surface was observed with an optical microscope. The result is that 70% of the composite grains remain and 20%
% Were crushed and 10% were missing.

Comparative Example A composite diamond particle was manufactured under the same conditions as in the example, using a fused alumina having an average diameter of 300 μm having a length-to-short ratio of 1.1 or less. The production amount was 910 mg. As a result of observation with a microscope, the surface of the composite diamond particles was covered with a dense diamond film of several μm in the same manner as in the example. The results of microscopic Raman spectroscopy were almost the same as those of the composite diamond particles in the examples. A 180 mmφ diamond wheel was prepared from the composite grains of 600 mg under the same conditions, and a wet cutting test was performed in the same manner as in the example. The initial power at that time is 30
0 W, average power was 350 W, and the cutting time per cycle was 150 seconds. 55% observation result by optical microscope after 10 times cutting
Was left intact, 25% crushed and 20% shed.

The fused alumina having an average particle diameter of 300 μm or less having a major axis diameter ratio of 1.1 or less used in the comparative example has almost the same volume as the alumina particles used in the example, but has a surface area of about 56%. I have.

When comparing the cutting test characteristic value of the marble block in the metal bond diamond wheel between the example and the comparative example, the example is superior in all cases.

That is, the initial power and the average power were small, and the average cutting time per cycle was short. Further, in the case of the example, the abrasive grain surface after cutting 10 times showed less crushing and falling off than the comparative example.

Examples and Comparative Examples are examples of a metal bond diamond wheel.For example, diamond was deposited on a heat-resistant granular material having a ratio of the longest axis length to the shortest axis length of at least 1.2 by resin bonding on a base paper. In the cutting, grinding and polishing tools shown in FIG. 1 in which the composite diamond grains are oriented and fixed in a direction substantially perpendicular to the base paper, the polishing efficiency is superior to the case where the composite diamond grains are not oriented. .

The reason is that the composite diamond grains used for the abrasive grain surface, the ones used in the present invention have a slender shape, and when grinding compared to those having a lower ratio of the major axis to the minor axis, the contact between the workpieces is reduced. This is because the resistance is small, the clogging is unlikely due to the spontaneous cutting effect of the composite grains, and the bonding force due to the large anchoring effect is high and long lasting.

<Effect of the Invention> Compared to conventional metal-bonded diamond wheels or abrasive cloth coated with diamond grains, the cutting, grinding and polishing tools of the present invention have excellent cutting, grinding and polishing capabilities, and The value is enormous.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cutting, grinding and polishing tool of the present invention in which diamond composite particles having an elongated particle diameter are fixed to a base paper using a fixing agent. FIG. 2 shows a metal bond wheel of the present invention made using diamond composite particles having an elongated particle diameter. In the figure, 1,11 ... diamond composite grains, 2 ... binder, 3
…… mounting paper, 12… metal bond, 13… mounting metal.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-317111 (JP, A) JP-A-51-60091 (JP, A) JP-A-2-262964 (JP, A) JP-A-59-1984 139875 (JP, A) JP-A-56-155793 (JP, A) JP-A-1-157497 (JP, A) JP-A-59-137311 (JP, A) JP-A-63-283858 (JP, A) JP-A-1-108105 (JP, A) JP-A-63-158764 (JP, U) JP-B-53-35675 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24D 3/00 B24D 3/20

Claims (3)

(57) [Claims] (1) A heat-resistant granular material having many active sites, obtained by pulverization, is sieved and sifted so that the longest axis length and the shortest axis length are at least 1.2. A cutting, grinding, or polishing body comprising a composite diamond particle having a ratio of a longest axis length to a shortest axis length of at least 1.2, the entire surface of which is coated with a vapor-phase diamond film; A cutting, grinding and polishing tool using composite diamond grains, wherein the composite diamond grains are oriented in the longitudinal direction with respect to the surface to be machined. 2. The cutting, grinding and polishing tool according to claim 1, wherein the cutting, grinding and polishing body is fixed to a support of a circular body and forms a wheel. 3. The cutting, grinding and polishing tool according to claim 1, wherein the support is a backing paper and the binder is a resin bond.