JP2998160B2 - Artificial whetstone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is to grow diamond grains or CBN (cubic boron nitride) grains of a controlled size at a predetermined position on a substrate by vapor phase growth. It is related to artificial whetstones.

[Conventional technology]

When precision processing is performed on hard and brittle materials such as cemented carbides and ceramics, processing such as grinding and polishing using a grindstone using superabrasive grains such as diamond and CBN is required. As a conventional superabrasive grindstone, for example, a vitrified bond grindstone using a feldspar-based bond as a binder of diamond, which is a superabrasive, a resinoid bond grindstone using a thermosetting resin or a hard thermoplastic resin as a binder, a metal And an electrodeposition whetstone in which the abrasive grains are mechanically fixed by nickel plating while holding the abrasive grains on the surface of the base.

On the other hand, while these conventional general diamond grinding wheels all use natural or artificial diamond grains for the abrasive grains, a diamond grinding wheel composed of precipitation-generated artificial diamond grains is disclosed in Japanese Patent Application Laid-Open No. 60-201878. And Japanese Patent Application Laid-Open No. 60-201879. In this conventional example, at least a polishing action surface of a whetstone substrate is formed of a vapor-deposited layer (or a sintered alloy) having a structure in which at least one of W, Mo, and Nb, and an alloy thereof is present as a dispersed phase. And a diamond polishing wheel having a structure in which artificial diamond grains formed by an artificial diamond precipitation generation method are in close contact with the dispersed phase.

[Problems to be solved by the invention]

Generally, the following performance is required for a superabrasive grindstone that performs grinding and polishing on a hard and brittle material.

Easy or unnecessary truing or dressing.

Have appropriate chip pockets based on appropriate abrasive grain spacing, degree of concentration and amount of abrasive grain protrusion.

It has strong abrasive grain holding power and can prevent the deterioration of the forming accuracy of the work surface due to the abrasive grains falling off.

Abrasive grains of uniform shape and size, uniform initial performance, average wear of abrasive grains, high accuracy and long life.

However, the vitrified bond grindstone, the resinoid bond grindstone, and the metal bond grindstone all require forming of a grindstone shape by truing and dressing forming at the time of clogging, and the work is troublesome. In addition, at this time, cleavage and crushing of the abrasive grains are apt to occur, and there is a problem that the grinding accuracy is easily deteriorated due to a reduction in the molding accuracy, a reduction in the surface roughness of the workpiece, and a reduction in the life of the grinding wheel. there were.

Furthermore, in the conventional metal bond whetstone, electrolytic dressing or the like must be performed in order to obtain an appropriate amount of protruding abrasive grains, and there is a problem that it takes more time and effort.

On the other hand, truing and dressing are not required for electrodeposited whetstones, but the grain spacing and concentration cannot be controlled as expected in the manufacture of whetstones. Can not. For this reason, the chips are not properly discharged, and the grinding / polishing resistance is increased due to clogging of the grindstone, and the surface roughness of the product such as scratches and burns is likely to deteriorate. In particular, in the case of a diamond whetstone, there are problems that the heat radiation of the grinding heat is suppressed, the temperature rises, and the consumption of diamond abrasive grains that are chemically unstable at high temperatures is easily promoted.

On the other hand, in the conventional example composed of precipitation-produced artificial diamond grains, it is possible to control the grain size distribution of the abrasive grains to be narrow and relatively uniform, but still expect the grain spacing and the degree of concentration. It is difficult to control the value. Therefore,
As in the case of the conventional electrodeposition whetstone, a chip pocket which is indispensable for the whetstone cannot be appropriately formed. Therefore, it is difficult to discharge cutting chips and it is easy to cause clogging of the grindstone, and it is easy for the machining resistance to increase and scratches and burns to occur, resulting in deterioration of the product surface roughness. The same problem as in the above-mentioned electrodeposition whetstone, which is liable to be consumed, remains unsolved.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and aims at eliminating the need for truing and dressing, and arbitrarily adjusting the abrasive grain spacing, the degree of concentration, and the abrasive grain protrusion amount. Controllable and optimal tip pockets can be configured, and if necessary, extremely strong abrasive holding power can be provided.In addition, artificial abrasives with uniform shapes and sizes of abrasives, high accuracy and long life can be provided. Then, it is in solving the said conventional problem.

[Means for solving the problem]

In order to achieve the above object, the invention according to claim 1 is:
An artificial grindstone formed by artificially forming abrasive grains on the surface of a grindstone base material, wherein the base material is a finely processed metal or ceramic surface, or a nitride film selectively formed on the base material surface; One of the surfaces of the intermediate layer made of any one of a carbonized film and an oxide film is used as an abrasive grain forming nucleus surface, and diamond particles or CBN particles are formed on the nucleus surface by a vapor phase generation method. In the artificial grindstone, the crystal direction of diamond grains or CBN grains formed by the vapor phase generation method is characterized by being at least one of (111) and (100) as a mirror index with respect to the grindstone grinding surface.

The invention according to claim 2 is the artificial grinding wheel according to claim 1, wherein the diamond grains or
The concentration of abrasive grains on the grinding surface of CBN grains is 50 to 200 (2.2 to 8.8
ct / cm ³ ).

[Action]

The grindstone according to the present invention has a single layer of diamond grains or CBN grains that are vapor-phase grown on a metal or ceramic base material that has been formed with high precision in advance according to the shape of the workpiece. Therefore, it is not necessary to perform truing.

Since the nucleus generation position of the abrasive grains to be vapor-phase grown can be precisely set in advance using a photofabrication method or a mask formed with high precision, the abrasive grain spacing can be arbitrarily controlled. In addition, the particle size of the abrasive grains can be freely adjusted by controlling the conditions for forming the abrasive grains, so that the degree of concentration can be arbitrarily controlled. Therefore, the optimum chip pocket can be formed by setting the abrasive grain interval and the degree of concentration according to the properties of the workpiece, and the chips can be easily discharged, and the clogging of the abrasive grains is suppressed. Therefore, no dressing is required.

Also, if necessary, by forming a metal plating layer with an arbitrarily controlled thickness between the abrasive grains formed by vapor phase growth, it is also possible to obtain an appropriate amount of abrasive grain protrusion, whereby the grinding stone can be obtained. Is further promoted, and each abrasive grain can be extremely firmly held on the substrate.

In addition, the abrasive grains formed by the vapor phase growth method can have uniform crystal direction, shape and size, the wear of the abrasive grains is averaged, the initial performance is uniform without variation, and as a result, high precision and A long life grinding wheel can be obtained.

 Hereinafter, this will be described in more detail.

The grindstone of the present invention uses metal or ceramic as a base material. As the base material, there can be used one in which diamond (or CBN; hereinafter the same) is directly vapor-phase-synthesized on the surface thereof, and one in which diamond is not formed. The former includes, for example, W (tungsten), Ta (tantalum), Mo (molybdenum), Si (silicon), Nb (niobium), Au (gold), Ag (silver), Cu
(Copper), Al (aluminum) and alloys containing them.

Examples of ceramics on which diamond can be directly vapor-phase synthesized on the surface include Al ₂ O ₃ (alumina), Si ₃ N ₄
(Silicon nitride) and WC (tungsten carbide). Alloys containing these are also available.

On the other hand, Fe (iron) -based metals such as stainless steel, Co
For (cobalt), Ni (nickel), etc., graphite or the like is generated, and it is not possible to directly vapor-phase synthesize diamond on its surface.

The base material of the grindstone of the present invention formed using these materials can be preliminarily formed with high dimensional accuracy in accordance with the shape of the processed portion to be ground or polished. If abrasive grains are formed in a single layer by vapor phase growth on the surface of a base material formed into a predetermined shape, a grindstone having extremely high shape accuracy can be obtained, and truing becomes unnecessary.

In the present invention, when a substrate on which diamond cannot be directly vapor-phase synthesized is used, an intermediate layer is formed on the surface of the substrate, and diamond is vapor-grown through the intermediate layer. To synthesize. As the intermediate layer, for example, Al ₂ O ₃ , SiO ₂
(Silicon oxide), metal oxide films such as MgO (magnesium oxide), carbide films such as SiC (silicon carbide), TiC (titanium carbide), B ₄ C (boron carbide), TiCN (titanium carbonitride), and TiN (nitride) A nitride film such as titanium), Si ₃ N ₄ , BN (boron nitride), or a cermet film in which the various oxides, carbides, and nitrides are combined with a metal such as Mo or Cr, such as a TiC-based cermet film, is preferable. It is.

The diamond abrasive grains of the present invention are formed by vapor phase growth on the base material surface via the intermediate film or directly without the intermediate film. For example, CO (carbon monoxide), H ₂ (hydrogen ),
CVD (chemical vapor deposition) by decomposition of a compound such as CH ₄ (methane) can be suitably used.

The crystal direction of the diamond abrasive grains of the present invention can be arbitrarily formed by controlling the component gas concentration in CVD and the substrate temperature. For example, when the substrate temperature is high, the Miller index (11
1) When the carbon concentration is high and the substrate temperature is low, crystals of (100) can be obtained. Incidentally, those with a Miller index (111) are useful as grinding stones because they are triangular pyramid-shaped abrasive grains, and those with a Miller index (100) are useful as abrasive wheels for polishing because they are flat-type abrasive grains. It becomes something.

The positions of the abrasive grains of the grindstone of the present invention are preliminarily finely set on the base material surface by using a photofabrication technique or a masking technique. Thus, the abrasive grain spacing and the degree of concentration are controlled on the order of microns. Here, the degree of concentration refers to the weight percentage of the diamond abrasive grains, and a concentration of 100 ct / cm ^{3 is} defined as 100. In terms of calculation, the lower limit is 0 (0 ct / cm ³ ) and the upper limit is 400 (17.6 ct / cm ³ ), but the general range of use as a superabrasive is 50 to 200. . In general, the greater the degree of concentration, the longer the life of the grindstone, the better the accuracy of roughness of the workpiece, and the smaller the size of the grindstone, but on the other hand, it is expensive and makes truing and dressing difficult.

The control of the degree of concentration of the abrasive grains also depends on the size of the formed abrasive grains. Thus, the size of the abrasive grains can be freely set by controlling the synthesis time of the abrasive grains, which is the synthesis condition in vapor phase growth.

According to the present invention, the abrasive grains formed with the controlled abrasive grain spacing and concentration as described above can be more firmly fixed with a plated metal layer such as nickel or copper. This provides a strong abrasive holding power.

Further, the thickness of the plating layer can be finely controlled by controlling the plating time, whereby the protrusion amount of the abrasive grains can be freely adjusted. Thus, in the present invention, the amount of protrusion of the abrasive grains is controlled in combination with the interval between the abrasive grains and the degree of concentration, and an optimum chip pocket is set. As a result, a grindstone that is hard to clog is obtained, and dressing is not required.

Next, embodiments of the present invention will be specifically described with reference to the drawings.

(First Embodiment) This embodiment is an example in which a substrate on which diamond cannot be directly vapor-phase synthesized is used on the surface.

1 to IX schematically show the manufacturing process. The substrate 1 is a disk made of stainless steel SUS304 having a diameter of 100 mm. First, in step I, the surface 1a is finished by surface grinding.

In step II, a Si ₃ N ₄ film 2 of about 1 μm was formed on the surface 1a by chemical vapor deposition. The film forming conditions are as follows.

Reaction gas: SiH ₄ (monosilane) 100 ccm NH ₃ 25 ccm Base material temperature: about 300 ° C. Synthesis time: about 30 minutes In the process III, first, the base material 1 on which the Si ₃ N ₄ film 2 is formed is a diamond of # 2000. The powder was immersed in an alcohol solution in which the powder was dispersed, and ultrasonic waves were applied for 10 minutes. This is Si
₃ N ₄ with a surface fine flaws of the membrane 2, allowed increasing the nucleation density of the diamond crystals to be vapor-deposited, in order to produce a reliable crystal at a predetermined position.

Thereafter, the substrate 1 is taken out and washed, and the Si ₃ N
₄ Approximately 1 positive resist (OFPR800, Tokyo Ohkasha) on film 2
It was applied to a thickness of μm and covered with a photoresist film 3.

In the process IV, a glass pattern 4 (20 μm
A dot 4D having a diameter of 5 μm was formed on the grid of the interval, and the photoresist film 3 was brought into close contact with the photoresist film 3, and the photoresist film 3 other than the dots 4D was exposed with a mercury lamp.

In step V, development was performed using a predetermined developing solution according to a standard method, and the remaining photoresist film 3 was removed except for the portion of the photoresist film 3 where dots 4D had not been exposed.

In step VI, etching was performed on the Si ₃ N ₄ film 2 partially protected by the regularly arranged residual photoresist film 3. In this embodiment, the exposed Si ₃ N ₄ film 2 was removed by sending CF ₄ gas at a flow rate of 100 ccm and performing plasma etching for about 30 minutes. Incidentally, when the intermediate layer is formed of not a Si ₃ N ₄ film but an SiO ₂ film, wet etching using an etchant may be used.

In step VII, the remaining photoresist film 3 is stripped. Thereby, on the surface 1a of the substrate 1, corresponding to the dots 4D of the glass pattern, Si ₃ N ₄ lands 2 having a diameter of 5 μm and a height of 1 μm 2
D is exposed in an array with a spacing of 20 μm.

In Step VIII, diamond was synthesized on the surface 1a of the substrate 1 having the pattern of the Si ₃ N ₄ lands 2D by a vapor phase growth method. The diamond synthesis conditions are as follows.

Apparatus: Microwave plasma CVD equipment Microwave power 1000 W Reactant gas: CO 5 ccm H ₂ 95 ccm Base material temperature: about 900 ° C. Synthesis time: about 20 hours Pressure: 40 Torr Thus, the particle size is 5 μm, Miller index (111) ) Diamond grains 5 were formed on each Si ₃ N ₄ land 2D.

In step IX, electroless nickel plating was performed on the grindstone surface of the substrate 1 on which the diamond particles 5 having a particle size of 5 μm were regularly arranged at intervals of 20 μm under the following conditions.

Plating solution: SUMER S-790 (manufactured by Nippon Kanigen) Solution temperature: 70 ° C Plating time: 20 minutes As a result, a nickel metal layer 6 having a thickness of about 2 μm is formed, and the diamond grains 5 are firmly fixed. A grindstone having a shape as shown in (a) was obtained.

The shape of the grindstone is determined by the shape of the base material 1 that is formed in advance in accordance with the shape and dimensions of the portion to be ground or polished. FIGS. 2 (b), (c), (d), and (e) illustrate other grinding stone shapes formed in the above embodiment.

(Second Embodiment) This embodiment is an example in which a base material capable of directly synthesizing diamond in a vapor phase is used.

3A to 3I schematically show the manufacturing process. The base material 11 is a cemented carbide alloy formed into a cylindrical shape with a shaft shown in FIG. 2 (b) (however, only a half section is shown).
Consists of the classification K10.

In step I, the surface 11a is first finished by grinding.

In step II, the base material 11 was immersed in an alcohol solution in which # 2000 diamond powder was dispersed, and ultrasonic waves were applied for 10 minutes in order to increase the nucleation density of diamond crystals.

Thereafter, a separately manufactured stainless steel pattern 12 having a thickness of 50 μm (having holes 13 having a diameter of 10 μm punched in a grid at intervals of 40 μm) was tightly wound around the surface 11a of the base material and masked.

In step III, diamod was synthesized by vapor phase epitaxy on the surface 11a of the base material 11 not masked by the stainless steel pattern 12 while rotating the base material 11. The diamond synthesis conditions are as follows.

Equipment: Hot filament CVD equipment Distance between tungsten filament and substrate surface 11a 10mm Reaction gas: CH ₄ 3 ccm H ₂ 97 ccm Filament temperature: about 2000 ℃ Base material temperature: about 600 ℃ Filament radiation only, no cooling Synthetic time : 20 hours Pressure: 100 Torr Thus, the particle size is 10μm, height is about 6μm, Miller index (10
Diamond grains 15 of 0) were formed at the locations of the holes 13 of the stainless steel pattern 12, respectively.

In step IV, the stainless steel pattern 12 is
_{Using the three} solutions, wet etching was performed by a shower method for about 10 minutes.

In step V, a 4 μm-thick electrolytic copper plating is applied to the grindstone surface of the base material 11 on which diamond particles 15 having a particle size of 1 μm are regularly arranged at regular intervals of 40 μm according to a conventional method.
The diamond grains 15 were firmly fixed by using. As a result, the protrusion amount of the diamond grains 15 became about 2 μm.

〔The invention's effect〕

As described above, according to the present invention, the abrasive grains are uniformly formed at predetermined intervals, shapes, and sizes set in advance, and an optimum chip pocket is formed, so that truing and dressing can be performed. There is an effect that a grindstone that is unnecessary, has a very strong abrasive grain holding force, is suitable for high-precision grinding or polishing, and has a long life can be obtained relatively easily.

In particular, diamond grains formed by vapor deposition or
The crystal direction of CBN grains is mirror index (1
In the invention according to claim 1, which comprises at least one of 11) and (100), the Miller index (11
When 1) is used, it becomes a triangular pyramid-shaped abrasive grain and is suitable for grinding wheels, and when the mirror index (111) is used, it becomes a flat abrasive grain and is suitable for a grinding wheel. The effect is that the most suitable whetstone can be provided.

According to the invention of claim 2, wherein the degree of concentration of diamond grains or CBN grains on the grinding wheel grinding surface is 50 to 200, the life of the grinding wheel as a super-abrasive grinding wheel and the accuracy of the roughness of the workpiece are set. , The cost can be reduced, and the truing and dressing properties can also be kept good.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of the manufacturing process of the present invention, FIG. 2 is a perspective view illustrating the shape of a grindstone formed by the manufacturing method of the present invention, and FIG. 3 is another example of the manufacturing process of the present invention. FIG. In the figure, 1,11 is a substrate, 2 is an intermediate layer, 5 and 15 are diamond abrasive grains, and 6 and 16 are metal layers.

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C30B 29/04 C30B 29/04 S (56) References JP-A-2-15976 (JP, A) JP-A-60-76965 ( JP, A) JP-A-2-279278 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24D 3/00 310 B24D 3/00 320 B24D 3/06 C30B 29/04

Claims (2)

(57) [Claims] An artificial whetstone obtained by artificially forming abrasive grains on the surface of a base material of a whetstone, wherein said whetstone is selectively applied to a finely processed metal or ceramic surface of said base material or a surface of said base material. One of the surfaces of the formed intermediate layer composed of any one of nitride film, carbon film and oxide film is used as the abrasive grain forming nucleus surface, and diamond or CBN particles are formed on the nucleus surface by vapor phase production. In the artificial whetstone formed by the method, the diamond particles or CBN formed by the vapor phase generation method
The crystal direction of the grains is mirror index (11
An artificial whetstone comprising at least one of (1) and (100). 2. The artificial grinding wheel according to claim 1, wherein the degree of concentration of the diamond grains or CBN grains on the grinding wheel grinding surface is 50 to 200 (2.2 to 8.8 ct / cm ³ ).