JPH10309670A - Structure of porous diamond cutting blade and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out working by making the most of characteristics of diamond by constituting a diamond cutting blade of diamond grains, a connecting member to connect the diamond grains and a support base plate to support the diamond grains connected by the connecting member and forming the connecting member by connecting the adjacent diamond grains at a small contact point. SOLUTION: In case of constituting a porous diamond cutting blade by using diamond grains 1, the diamond grains 1 of a specified grain size are soaked in a viscous solution 2 formed in a paste type by mixing solvent and active wax and the viscous solution 2 is uniformly attached in an periphery of the diamond grains 1. The porous diamond cutting blade 4 of large porosity making the viscous solution 2 a small contact point 3 is constituted by providing the viscous solution 2 around the diamond grains 1 in uniform thickness, filling it around a metal base plate provided in a heat resistant mold and sintering it at high temperature. Consequently, it is possible to properly work by preventing production of cementite at the time of working a steel product and to carry out favourable working of steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond cutting tool provided with a diamond cutting blade for cutting, polishing, cutting, drilling or drilling various kinds of workpieces such as stones and pipes. The present invention relates to a structure of a porous diamond cutting blade capable of cutting a material and a method of manufacturing the same.

[Prior art]

Conventionally, when a diamond tool is manufactured, a sintering method and an electrodeposition bonding method are known as shown in FIGS. 5 (a) and 5 (b). As shown in FIG.
In the sintering means, for example, the diamond particles 51 are mixed with cobalt powder or a mixed powder of cobalt, copper, and tin, and then mixed with nitrogen, hydrogen, or hydrogen and nitrogen, or 900 to 1000 ° in an atmosphere such as vacuum. By the hot press method that presses hot while maintaining the temperature of C,
The metal powder is compacted and sintered to form a sintered tip 52 having diamond particles fixed thereon, and the sintered tip is attached to a steel substrate by brazing or laser welding or the like.

[0003] In the electrodeposition bonding method, for example, a steel base material is used as a material to be plated, and a non-plated portion is masked with a plating resist or the like, and then nickel plating is applied to a base, and then a surface active agent is used. Electroplating is performed using a nickel plating solution prepared by mixing a dispersion in which a fixed amount of diamond particles 61 are dispersed, and the eutectoid diamond particles are fixed by electrodeposited nickel 62.

In the sintering means, as shown in FIG. 5 (a), the retention of the diamond particles 51 depends on the embracing force due to the shrinkage of the surrounding sintered metal and the internal strain, so that the diamond particles 61 are sintered. It will be in the state covered with the binding metal.
Further, as shown in FIG. 5B, in the electrodeposition bonding method, the electrodeposited metal 62 shows a swelling, and the diamond particles 61 are held in a state of being embraced by the electrodeposited metal 62.

Therefore, when cutting or grinding a steel material using the diamond particles 51, 61 in the above-described state, the heat generated in the diamond particles 51, 61 cannot be dissipated, and the diamond cutting edge becomes graphitized. If the temperature exceeds a certain high temperature during the operation, it reacts with iron in the presence of oxygen to generate cementite (Fe ₃ C), which is graphitized and becomes brittle, and the diamond cutting edge becomes extremely worn, making cutting impossible.

[0006] Therefore, cutting and grinding of iron and steel has conventionally been performed with a grindstone. As the grindstone, a resin grindstone (using a phenol resin or the like), a vitrified grindstone (using a vitreous or porcelain binder), or a metal grindstone is used.

[0007]

However, when cutting steel with the above-mentioned grindstone, the following problems exist.

[0008] Resin whetstones have good grindability and the like with respect to steel, but have a high wear rate and a short working life. Although the metal-based bond grindstone has a longer working life than the resin grindstone, the grindability and the like were not so good.

[0009] The vitrifying grindstone has an intermediate performance between the resin grindstone and the metal-based bond grindstone, but has a disadvantage that the bond forming the grindstone is fragile and easily broken during operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an advantage in that the characteristics of diamond, such as high heat dissipation, high thermal conductivity, and high heat capacity, of diamond are achieved by optimizing a connecting member for bonding diamond grains. It is an object of the present invention to provide a porous diamond cutting tool capable of performing operations such as cutting and grinding of steel by utilizing the above, and a method of manufacturing the same.

[0011]

In order to achieve the above-mentioned object, the present invention provides a method comprising the steps of: combining diamond grains; a joining member for joining the diamond grains; and a support substrate for supporting the diamond grains joined by the joining member. The joining member had a structure of a porous diamond cutting blade formed by connecting adjacent diamond grains with small contacts.

A method for producing a porous diamond cutting blade for providing a binding force between the diamond grains by providing an active brazing layer around the diamond grains by means of peripheral means and sintering at 750 to 950 degrees. did.

A method for producing a porous diamond cutting blade, wherein an active brazing layer is provided around diamond grains by a peripheral means, and sintering is performed for a predetermined time in a range of 750 ° to 950 °. And a method for producing a porous diamond cutting blade which determines the porosity between diamond grains based on the particle size of the active wax layer and the coating thickness of the active brazing layer.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 is a principle diagram showing a bonding state of a porous diamond, FIG. 2 is a principle diagram comparing a ratio of a diamond using a porous diamond cutting blade and a resin bond, and FIG. 3 is a diagram showing application of a porous diamond to a cutting tool. It is a perspective view of the state which carried out.

As shown in FIGS. 1 (a) and 1 (b), when a porous diamond cutting blade is formed using diamond grains 1, first, diamond grains 1 having a predetermined grain size are mixed with a solvent and an active wax. The silver wax is mixed and immersed in the viscous liquid 2 formed into a paste, and the viscous liquid 2 is uniformly attached around the diamond grains 1 (active wax layer).

Note that a viscous liquid 2
A viscous liquid coating device may be used as an attaching means for attaching the liquid uniformly. That is, the viscous liquid coating device, the diamond particles into a fluidized state by jetting air in a predetermined range of the casing, from the supply nozzle having an opening in the casing of the diamond particles in the fluidized state, alcohol and bond and. A viscous liquid (slurry liquid) in which silver wax or the like is dissolved is sprayed in a mist state. When the viscous liquid 2 is sprayed, it can be adjusted so that the diamond grains have a desired thickness.

Next, as shown in FIGS. 1C and 1D,
When the viscous liquid 2 is provided with a uniform thickness around the diamond grains 1, the viscous liquid 2 is filled around the metal substrate provided in the heat-resistant mold and sintered at a temperature between 750 degrees and 950 degrees. The liquid 2 becomes a small contact 3 to form a porous diamond cutting blade 4 having a high porosity.

As shown in FIG. 4, the viscous liquid 2 which comes into contact with the diamond particles (solid S) 1 at a contact angle θ by the balance between the surface tension, the cohesive force and the tension to become the small contact 3 of the viscous liquid 2. It is determined from the relationship between (L) and the surrounding gas A, γ × A / L (surface tension), γ × L / S (cohesion), and γ × A / S. Note that γ ×
A / S ≦ or ≧ γ × L / S + cos θγ × A / L.

Further, depending on the type of the tool, when sintering the diamond grains 1, the diamond grains 1 are sintered in a state where they are arranged at predetermined positions on the substrate to be mounted, and then the diamond cutting blade is fixed to the substrate by laser welding. In some cases,

It is to be noted that the sintering temperature is increased from 750 degrees to 950 degrees.
In the range of the degree, when the angle is 750 degrees or less, the contact angle θ of the viscous liquid 2 provided around the diamond particle 1 becomes too large to be a small contact, and when the angle is 950 degrees or more,
This is because the contact angle θ between the diamond particles 1 and the viscous liquid 2 becomes too small, and the bonding strength is impaired when sintered.

As shown in FIG. 2, when the bonding state of the diamond grains 1 of the porous diamond cutting blade 10 is compared with the diamond cutting blade 15 of a conventional resin bond in principle, the following is obtained. Porous diamond cutting blade 1
0 means that the volume occupied by diamonds is 75% when the diamond particles 1 are closest packed assuming that they are spherical.

On the other hand, the concentration 10 of the maximum diamond concentration of the diamond
At 0% (4.4 ct / cm ³ ), assuming that the specific gravity of diamond is 3.5, 4.4 × 0.2 / 3.5 = 0.25, that is, this value is The ratio occupied by diamonds is shown, indicating that it is 25%.

Now, assuming that the concentration of diamond in the resin bond is 100% (25% × 4) and the diamond grain size is 50 mesh (290 μm), the weight of one diamond is 0.5236 × 0.029. ³ × 3.5 = 0.00004
47 g, the number of grains per ct (carat) is 0.2 / 0.0000447 = 4474 grains / ct. Since it is assumed that the concentration of diamond is 100%, 4.4 × 4474 = 19686 grains / ct. cm ³ .

On the other hand, when the porous diamond cutting blade is 300%
(75% × 4) and 19,686 grains / cm ³ , the diamond grain size is calculated as: 4.4 × 300% × 0.2 / 19686 = 0.0001
34 g 0.000134 / 3.5 = 0.0000383 cm ³ 0.5236 × d ³ = 0.0000383 d = 0.04183 cm = 0.418 mm = 418 μm It can be seen that this is a conversion of diamond particle size of almost 40 mesh.

Therefore, when the diamond grain size of the resin bond is 50 mesh and the diamond grain size of the porous diamond cutting edge is 40 mesh, the number of cutting edges in contact with the workpiece is almost the same and the diamond grain size is different. In addition, it is possible to make the cutability and the finished surface roughness the same.

Further, since the strength of diamond is proportional to the particle size, the strength of one grain is 50: 40 = 290 ³ : 420 ³ 50 × 420 ³ = 40 × 290 ³ ≒ 3: 1, and the porous diamond is cut. The blade configuration has high strength.

Further, since the heat dissipation of porous diamond is proportional to the surface area of diamond, 50 mesh and 4
When the diamond grain size of 0 mesh is compared, 50: 40 = 290 ² : 420 ² 50 × 420 ² = 40 × 290 ² ≒ 2.6: 1, and the heat dissipation of 50 mesh is 260% better than that of 40 mesh diamond. I understand.

The diamond has a particle size of 50 m.
Although a comparison was made between esh and 40 mesh, it goes without saying that the present invention can be applied to a state of other granularity. Table 1 shows the relationship between the mesh number of diamond grains, the grain size of diamond grains, and the number of grains per ct (carat).

[0029]

[Table 1]

Next, the case where the porosity of the porous diamond cutting blade is determined will be described. 29 diamond grain size
When a material having a diameter of 0 μm to 420 μm is used, the specific gravity of the artificial diamond is 3.5, and the specific gravity of the silver wax containing 2% titanium (Ti) as a viscous liquid is 8.0. is there. At this time, the filling ratio of diamond was set to approximately 50% (the theoretical packing density was 75%,
(In the case of diamond, it is not a sphere, so the experimental value was averaged.) The average particle size of diamond was 355
μm and the shape is assumed to be spherical.

The weight of diamond per 1 cm ³ is
3.5 / 2 = 1.75 g. Therefore. The weight per diamond is 0.5236 × 0.0355 ³ × 3.5 = 0.0000
82 g. Then, the number of diamond grains in 1 cm ³ is 1.75 / 0.000082 = 21.341 grains.

The surface area of one diamond is π × 0.0
355 ² = 0.00396 cm ² . And 1c
The total surface area of the diamond grains contained in m ³ is 0.00396 × 21.341 = 84.5 cm ² .

On the other hand, when the thickness of the viscous liquid coated on the diamond surface is 0.1 mm, the volume of the active wax is 84.5 × 0.01 = 0.845 cm ³ . The density of the viscous liquid at the time of coating is approximately 30%
Therefore, the actual volume is 0.845 × 30% = 0.
25 cm ³ , and the weight of the active wax is 0.25 × 8.0 = 2 g.

Accordingly, the porosity is 100% − (volume of diamond + volume of active wax), and 100− (50 + 25) = 25%. That is, it is understood that the porosity (heat dissipation) can be determined by the value of the calculation planned in advance.

Therefore, when forming a tool that handles a heavy-cut or difficult-to-machine workpiece, the porosity is increased and the heat dissipation is increased, so that a light-cut or easy-to-machine workpiece is formed. It is convenient for a tool such as that described above to reduce the porosity and obtain the strength of the porous diamond cutting blade.

[0036]

Next, as shown in FIG. 3, a porous diamond grindstone 22 having a porous diamond cutting blade 20 having a cutting edge thickness T of 5 mm and a porous diamond cutting blade 20 on a peripheral edge of a support substrate 21 having a diameter of 4 inches, On the other hand, a comparison is made with the configuration of an alumina-based vitrified grinding stone (not shown) having a 4-inch diameter and a cutting blade thickness of 5 mm.

The working condition is that the work W is made of mild steel.
With a peripheral speed R of 350 m / min and a cutting depth D of 2 m
When the cutting operation was performed at a feed rate of 100 mm / min at m, the following measurement results were obtained.

Immediately after the operation, the temperature of the working surface of the porous diamond grindstone 22 is 50 degrees (cutting depths of 2 mm and 3 mm).
mm). On the other hand, the temperature of the working surface immediately after the operation of the alumina-based vitrified grinding wheel is 2 m in the cutting depth.
m, 85 degrees, and 3 mm depth of cut, 13
It was 0 degrees.

The specific cutting resistance and the cutting resistance were such that the porous diamond grindstone 22 was 62% of the alumina vitrified grindstone.

Also, with a 50-mesh (290 μm) diamond grindstone, the degree of concentration = 100% (4.4 ct / cm)
³ ) Resin bond diamond wheel and 40m
porosity of 3 with porous diamond (420 μm)
Using a 0% porous diamond wheel, tungsten carbide (WC) -cobalt (Co) based cemented carbide,
JIS in H-5501 cemented carbide standard, by grinding G species -2 No. of (G _2), and measure the time to finish below 3S. As a result, the porous diamond wheel could be finished in 60% of the time of the resin-bonded diamond wheel.

[0041]

The present invention has the following advantages because it is configured as described above. (1) Since diamond grains are joined together at small contact points to form a diamond cutting blade, cementite can be prevented from occurring even when processing steel products, making it possible to work properly. Therefore, only the control in the plane direction (X and Y directions) needs to be performed, and good processing of steel or the like can be performed without performing control in the vertical direction (Z direction).

(2) The porous diamond cutting blade has a machinability and a finished surface roughness of, for example, 40 mesh even when compared with a diamond tool using a conventional resin bond or the like.
Since the work performed with a conventional diamond tool using a diamond grain size of 50 mech can be performed in the same state using a diamond grain size of 50 mech, and has excellent heat dissipation and heat conductivity, the steel member It is possible to carry out machining such as cutting without generating cementite.

(3) In the case of manufacturing a porous diamond cutting blade, the peripheral edge of the diamond grain is coated with an active brazing material,
Since it is configured to be sintered at 50 to 950 degrees, the strength of the bonding force between adjacent diamond grains can be improved,
By increasing the exposure rate of diamond grains, it is possible to maximize the large thermal conductivity, heat capacity and heat dissipation of diamond, and to process steel parts without generating cementite Becomes

(4) When manufacturing a porous diamond cutting blade, it is possible to determine the porosity of adjacent diamond grains, so that it is possible to manufacture a porous diamond cutting blade corresponding to a workpiece. Become.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b), 1 (c), and 1 (d) are principle diagrams showing a bonded state of a porous diamond of the present invention.

FIG. 2 is a principle diagram comparing the ratio of diamond using a porous diamond cutting blade of the present invention and a resin bond.

FIG. 3 is a perspective view showing a state in which the porous diamond of the present invention is applied to a cutting tool.

FIG. 4 is a principle diagram showing a contact angle of a small contact point to which the porous diamond of the present invention connects.

FIG. 5 is a principle view showing a configuration of a diamond tool showing a conventional configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diamond particle 2 Viscous liquid 3 Small contact point 4 Porous diamond cutting blade 10 Porous diamond cutting blade 20 Porous diamond cutting blade 21 Support substrate 22 Porous diamond grindstone

Claims (3)

[Claims] The present invention comprises a diamond grain, a joining member for joining the diamond grain, and a support substrate for supporting the diamond grain joined by the joining member, wherein the joining member connects adjacent diamond grains with small contacts. A structure of a porous diamond cutting blade formed by being connected. 2. An active brazing layer is provided around the diamond grains by a peripheral means, and sintering is performed in a range of 750 ° to 950 ° to impart a cohesive force between the diamond grains. Manufacturing method of porous diamond cutting blade. 3. A method for producing a porous diamond cutting blade, wherein an active brazing layer is provided around diamond grains by a peripheral means, and sintering is performed for a predetermined time in a range of 750 ° to 950 °. A method for producing a porous diamond cutting blade, wherein the porosity between diamond particles is determined from the size of the diamond particles and the coating thickness of the active brazing layer.