JPH11277442A - Sharp-edged grinding tool and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sharp-edged grinding tool which exhibits a high cutting quality for a difficult-to-grinding material, and which is excellent in heat- resistance. SOLUTION: A sharp-edged grinding tool incorporates a planar abrasive grain layer 1 having a sintered first metal binding phase 2 and grindstone grains 4 dispersed in the first metal bonding phase 2. Each of the grindstone grains 4 is composed of a sintered second metal binding phase 6 and super abrasive grains 8 dispersed in the phase 6. The averaged particle size of the grindstone grains 4 is 0.05 to 0.5 mm, and the porosity of the first metal binding phase 2 is not less than 5 vol.%, and the porosity of the second metal binding phase 6 less than 5 vol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin blade grindstone capable of obtaining excellent sharpness even on difficult-to-cut materials such as hard ceramics, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, ceramic materials such as alumina and silicon nitride have been increasingly used as precision parts for electronic devices and the like, and demand for high-precision processing of such materials has been increasing.

[0003]

However, since this kind of ceramics is extremely hard, cutting using a so-called metal-bonded grindstone in which superabrasive grains such as diamond are dispersed in a metal bonding phase is difficult. The sharpness of the superabrasive grains is quickly rounded due to the loss of hardness, and the sharpness is reduced quickly. Even if the tip of the superabrasive grain becomes dull, if the superabrasive grain drops off in sequence, new superabrasive grains will be exposed and the sharpness can be prevented from lowering. Since the metal binder phase supporting the grains is hard, the superabrasive grains are not allowed to easily fall off, and the self-sharpening action is poor. Therefore, the sharpness is significantly reduced.

On the other hand, a resin-bonded or vitrified bond wheel made of resin or glass as a binder phase supporting a superabrasive grain has a softer or more brittle binder phase than a metal bond wheel, so When the tip becomes dull, the superabrasive grains fall off, and the self-sharpening action is excellent and good sharpness lasts for a long time. However, resin-bonded or vitrified bond wheels have lower strength and heat resistance than metal-bonded wheels, and cannot withstand high-speed cutting of difficult-to-cut materials that require strength and heat resistance. was there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thin blade whetstone which can obtain a good sharpness even for difficult-to-cut materials, and has excellent strength and heat resistance, and a method for producing the same. It is an issue.

[0006]

In order to solve the above-mentioned problems, a thin blade grindstone according to the present invention is a thin blade grindstone having a flat abrasive layer, and the abrasive layer is formed by sintering. A first metal binder phase and abrasive grains dispersed in the first metal binder phase, wherein the abrasive grains are respectively a sintered second metal binder phase and an ultra-fine grain dispersed in the second metal binder phase. And abrasive grains.

Further, a method of manufacturing a thin blade grindstone according to the present invention comprises a step of preparing a first slurry in which a metal binder powder and superabrasive grains are dispersed in a resin binder solution, and using the first slurry. A step of preparing granules; a step of drying and firing the granules to prepare grinding stones; and a second step of dispersing the metal binder powder and the grinding stones in a resin binder solution.
A step of preparing a slurry, a step of applying the second slurry on a substrate, and a step of solidifying the applied second slurry and then separating and sintering the substrate from the substrate. I do.

[0008]

FIG. 1 is an enlarged sectional view showing a thin blade grindstone according to a first embodiment of the present invention. This thin blade grindstone has a flat-shaped abrasive grain layer 1, and this abrasive grain layer may be in the shape of an annular plate or a plate having another shape. Further, the thin blade grindstone may be constituted only by the abrasive grain layer 1, or the abrasive grain layer 1 may be fixed to various grindstone bases (not shown).

The abrasive layer 1 in this embodiment has a sintered first metal binding phase 2 and a large number of grinding stones 4 substantially uniformly dispersed in the first metal binding phase 2. I have. In addition, each of the grindstone grains 4 has a sintered second metal bonding phase 6.
And superabrasive grains 8 dispersed in the second metal bonding phase 6. FIG. 1 schematically shows the structure of the abrasive grain layer 1, and the distribution of the abrasive grains 4 is not limited to the illustrated state.

Although the average particle size of the grinding stones 4 is not limited, a typical thin blade for precision cutting is 0.05 to 0.5.
mm is preferred, and more preferably 0.1 to 0.3 mm
It is. In the former range, the frequency at which the grindstone grains 4 drop off from the first metal bonding phase 2 with cutting is appropriate, and
The surface roughness of the abrasive layer 1 is not significantly increased as compared with a normal metal-bonded grinding wheel in which superabrasive particles are dispersed in a metal bonding phase, and the surface roughness of the cut surface is not impaired.

As the superabrasive grains 8 in the grindstone grains 4, diamond and / or CBN are preferable. The average particle size of the superabrasive grains 8 is not limited, but 3 to 60 μm is preferable and more preferably 5 to 30 μm as a thin blade whetstone for precision cutting of general difficult-to-cut materials. In terms of the relationship with the average particle size of the grindstone 4, the average particle size of the superabrasive 8 is preferably about 5 to 20% of the average particle size of the grindstone 4.

The second metal bonding phase 6 may be one sintered at a temperature lower than the melting point of the superabrasive grains 8, for example, tin,
Lead, nickel, copper, cobalt, chromium, iron, silver, etc. alone or alloys or mixtures thereof can be used. Particularly preferred materials for the second metal binding phase 6 include copper, tin, cobalt and alloys thereof.
The second metal bonding phase 6 is preferably sintered relatively densely in order to hold the superabrasive grains 8 reliably, and is not limited, but its porosity is preferably less than 5 vol%, more preferably 2 vol. %. This kind of porosity can be measured by a well-known mercury porosimeter or the like.

The first metal bonding phase 2 may also be one that is sintered at a temperature equal to or lower than the melting point of the superabrasive grains 8.
Lead, nickel, copper, cobalt, chromium, iron, silver, etc. alone or alloys or mixtures thereof can be used. Particularly preferred materials for the first metal binding phase 2 include copper, tin, and alloys thereof. The first metal binding phase 2 is preferably, but not limited to, a more porous material than the second metal binding phase 6, and has a porosity of preferably 5 vol% or more, more preferably 5 to 15 vol.
%.

The hardness relationship between the first metal bonding phase 2 and the second metal bonding phase 6 is not particularly limited, but the following combinations are possible. The first combination is the first metal binding phase 2
Is smaller than the hardness of the second metal binding phase 6. In this case, while the support force of the superabrasive grains 8 by the second metal bonding phase 6 increases, the wear rate of the first metal bonding phase 2 increases, so that the abrasive grains 4 exposed on the surface of the abrasive grain layer 1 are removed. The speed at which the first metal bonding phase 2 wears is higher than the speed at which it wears. Therefore, the wear mark concave portion P1 is easily formed as shown in FIG. 2, and as a result, the grindstone grains 4 are easily dropped as shown in FIG. 3 (P2 is a drop mark concave portion).

The second combination is a case where the hardness of the first metal binding phase 2 is larger than the hardness of the second metal binding phase 6. In this case, while the supporting force of the superabrasive grains 8 by the second metal bonding phase 6 decreases, the wear rate of the first metal bonding phase 2 decreases, so that the dispersion density of the superabrasive grains 8 in the grindstone 4 In the case where the wear of the grinding stone 4 is high and the wear of the grinding stone 4 is poor, the compensation can be made, and the balance between the wearing of the grinding stone 4 and the falling off of the grinding stone 4 can be improved.

The third combination is a case where the hardness of the first metal binding phase 2 is substantially equal to the hardness of the second metal binding phase 6. By selecting any one of the above first to third combinations according to the particle size and the degree of dispersion of the superabrasive particles 8, the average particle size of the grindstones 4, etc., the wear rate of the grindstones 4 and the grindstones 4
The balance with the dropout frequency can be adjusted appropriately.

A filler may be added to the first two layers of the metal binding phase, if necessary. Examples of the filler include solid lubricant particles such as molybdenum disulfide and graphite, hard particles such as silicon carbide and silicon nitride, and whiskers, but are not limited thereto. The amount of the filler added to the first metal binding phase 2 is not limited, but is generally preferably about 0.1 to 5 wt% of the first metal binding phase 2. When the solid lubricant particles are added, the strength of the first metal binding phase 2 is reduced.
Of the grinding wheel can be reduced by the solid lubricant released from the first metal binding phase 2 while promoting the wear of the grinding wheel. If hard particles are added, the wear rate of the first metal bonding phase 2 can be adjusted to adjust the balance with the wear rate of the grindstone grains 4.

As shown in FIG. 4, second superabrasive grains 50 may be added to the first two metal bonding phases as needed. The second superabrasive grains 50 may be the same as the superabrasive grains 8 or may have an average particle diameter different from that of the superabrasive grains 8. As the average particle size of the second superabrasive grains 50 increases, the wear rate of the first metal binding phase 2 decreases, and as the average particle size decreases, the wear rate of the first metal binding phase 2 increases. Also,
As the content of the second superabrasive grains 50 increases, the first metal bonding phase 2 increases.
The wear rate of the first metal binding phase 2 increases as the content decreases. The amount of the second superabrasive grains 50 to be added to the first metal bonding phase 2 is not limited, but is generally preferably about 0.1 to 5% by weight of the first metal bonding phase 2.

A filler may be added to the second metal binding phase 6 as needed. Examples of the filler include solid lubricant particles such as molybdenum disulfide and graphite, hard particles such as silicon carbide and silicon nitride, and whiskers, but are not limited thereto. The amount of the filler added to the second metal binding phase 6 is not limited, but is preferably about 0.1 to 5 wt% of the second metal binding phase 6. When the solid lubricant particles are added, the second metal bonding phase 6
Therefore, the wear of the second metal bonding phase 6 is promoted, and the solid lubricant released from the second metal bonding phase 6 can reduce the grinding resistance of the grindstone. If hard particles are added, the wear rate of the second metal bonding phase 6 can be adjusted without changing the content of the superabrasive grains, and the balance with the wear rate of the first metal bonding phase 2 can be adjusted.

The content of the abrasive grains 4 in the abrasive grain layer 1 is as follows:
It should be appropriately determined according to the use, and is not particularly limited, but is generally preferably 5 to 35 vol%, more preferably 10 to 25 vol%. If it is too small, sufficient cutting performance cannot be obtained, and if it is too large, the effect of the present invention is weakened.

The shape of the grindstone grains 4 can be variously deformed as described later, and is not limited in the present invention. FIG.
In this embodiment, the shape is almost spherical, but it may be cylindrical, prismatic as shown in FIG. 5, or flat (disc) as shown in FIG. Good. Surface area/
As the shape has a larger volume, the holding power of the grindstone grains 4 by the first metal bonding phase 2 increases.

Next, a method of manufacturing the grinding wheel of each of the above embodiments will be described. In one embodiment of the method for manufacturing a thin blade grindstone according to the present invention, first, grindstone grains 4 are manufactured using a granulating device 60 as shown in FIG. The granulating apparatus 60 includes a hollow main body 66 having a large number of openings 64 formed at one end;
And a screw feeder 62 accommodated coaxially in the inside of the main body 66. The raw material slurry is supplied from an introduction portion 68 formed in the main body 66, and the screw 4 is rotated to rotate the screw feeder 62, whereby the particles 4A are successively formed from the opening portion 64. Extrude. Since the size of the grain 4A is determined by the size of the opening 64, if the size of the opening 64 is constant, the grain 4A
The particle size of A also becomes constant. The main body 6 using the scraping member
The particles 4A may be scraped off one after another by rubbing the ends of the opening 6 at regular intervals. However, if the viscosity of the raw material slurry is appropriately adjusted without such trouble, the opening 6
When the protrusion length of the slurry from No. 4 reaches a certain value,
The particles 4 </ b> A having a certain particle size fall from the main body 66.

By changing the shape of the opening 64,
The cross-sectional shape of the grain 4A can be changed as appropriate. The opening diameter of the opening 64 needs to be sufficiently larger than the diameter of the superabrasive grains 8, and is generally preferably about 0.1 to 1.0 mm, more preferably 0.2 to 0.5 mm. , But is not necessarily limited to this range. By appropriately agitating the granules 4A immediately after granulation, the granules 4A can be rounded to approximate a spherical shape.

The raw material slurry is prepared by mixing the superabrasive grains 8, the metal binder powder constituting the second metal binder phase 6, the resin binder, the solvent, and other necessary components into a slurry (or clay) having a certain viscosity. Is mixed. The content of the superabrasive grains 8 in the raw slurry is preferably about 2.5 to 6.0% by weight, and more preferably 3.0 to 5.5% by weight.

The metal binder powder is the above-mentioned material of the second metal binder phase 6 alone or as a mixture. The particle size of the metal binder powder is not limited, but is preferably 500 μm or less in average particle size, more preferably 0.5 to 100 μm.
m. If the average particle size is less than 0.5 μm, the reactivity with water is too strong. If the average particle size is more than 500 μm, sufficient strength cannot be obtained after sintering. The content of the metal binder in the slurry is 79.0 to 92.5 wt%, more preferably 84.5 to 90.0 wt%.

The resin binder not only maintains the structure of the dried particles 4A but also functions to adjust the viscosity of the slurry.
As the resin binder, an aqueous resin binder such as methylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, ethylcellulose, or polyvinyl alcohol is suitable, and if necessary, an oily resin binder dissolved in an organic solvent. May also be used. The content of the resin binder in the slurry is 5.0 to 15.0% by weight, particularly 7.0 to 1%.
It is preferably 0 wt%. If the amount is less than 5.0 wt% or more than 15.0 wt%, it is difficult to form the particles 4A.

The particles 4A formed by the granulator 60 are:
It is placed in a suitable container such as a tray, heated in a vacuum or under an inert atmosphere, dried, and decomposed to remove the resin binder. Subsequently, sintering is performed in a vacuum or in an inert atmosphere to form the grindstone grains 4. The drying conditions and the sintering conditions are different depending on the composition of the grains 4A, and cannot be said unconditionally. However, as a general value, the heat treatment conditions for degassing are heating at 400 to 550 ° C. for 30 to 120 minutes. Preferably, the sintering conditions are as follows: under an inert atmosphere, under a reducing atmosphere, or under reduced pressure;
It is preferable that the heating time is about 900 ° C. and the heating time is about 10 to 60 minutes.

The thus-sintered grindstone grains 4 are again formed into a slurry (or clay) having a constant viscosity together with the metal binder powder, resin binder, solvent and other necessary components constituting the first metal binder phase 2. The slurry is applied to a flat substrate surface with a constant thickness to obtain a plate serving as a grindstone prototype.

FIG. 8 shows an example of an apparatus for manufacturing a plate. In the figure, reference numeral 10 denotes an endless belt stretched horizontally. The endless belt 10 is driven by a pair of rolls 12 and 14. Endless belt 1
A base layer coating device 16, a base layer drying device 18, a slurry coating device 20, and a drying device 24 are disposed at positions facing the upper surface of the belt 0 in order from the upstream side to the downstream side in the belt traveling direction.

The underlayer drying device 16 is disposed near the upper surface of the endless belt 10 in the vicinity of the roll 12, and continuously transfers the undercoating 28 filled therein from the lower end opening thereof to the upper surface of the endless belt 10. Supply. As the base paint 28, for example, resin paints such as urethane resin, epoxy resin, thermosetting polyester, heat-resistant thermoplastic resin, acrylic resin, polypropylene resin, and ethylene vinyl acetate resin can be used. The side wall on the downstream side of the belt of the underlayer drying device 16 is the doctor blade 2.
A base paint having a thickness corresponding to the gap between the doctor blade 26 and the endless belt 10 is applied to the upper surface of the endless belt 10 as the endless belt 10 travels to form a coating film 30. Note that the coating film 30 may not be formed depending on the material of the endless belt.

The underlayer drying device 18 is for drying the coating film 30 formed on the endless belt 10.
For example, it is constituted by a hot air dryer, a far infrared dryer, or the like. The coating film 30 is solidified by being dried by the underlayer drying device 18, and becomes a carrier tape that supports a slurry layer 36 described later. This carrier tape needs to be decomposed and lost during sintering described later. Although the thickness of the carrier tape is not limited, it is preferably about 2 to 50 μm so that sufficient strength can be obtained and moreover, it can be removed without leaving any residue. If the slurry layer 36B after solidification is not too brittle, it is also possible not to form a carrier tape,
In that case, the underlayer coating device 16 and the underlayer drying device 18 become unnecessary.

The slurry applying device 20 is for applying a slurry 34 as a grindstone raw material on the upper surface of the carrier tape formed on the endless belt 10. The slurry coating device 20 has a box shape having an opening at a lower end, and has a downstream side wall provided with a doctor blade 32 (coating thickness regulating member). As a result, the grindstone raw material slurry 34 filled in the slurry coating device 20 is transferred to the doctor blade 3 as the endless belt 10 travels.
The slurry 2 is applied to a predetermined thickness on the carrier tape by the step 2 to form a slurry layer 36.

The doctor blade 32 of this embodiment is
As shown in FIG. 9, a first blade 32A and a second blade 32B are provided, and a gap amount from the first blade 32A to the endless belt 10 is made larger than a gap amount from the second blade 32B to the endless belt 10. ing. Any gap amount can be adjusted by adjusting means (not shown) in accordance with a desired thickness of the grindstone and the viscosity of the slurry. Generally, the gap from the first blade 34A to the endless belt 10 is about 5 to 20 mm. The gap between the second blade 34B and the endless belt 10 is preferably about 0.1 to 2 mm. However, it is not limited to this range.

Thus, the two-stage blades 32A, 32
By using B, bubbles contained in the slurry 34 can be removed to some extent in the gap between the blades 32A and 32B, and the amount of bubbles contained in the slurry layer 36 pushed out from the gap between the second blades 32B is reduced. be able to. In addition, there is an advantage that even if the liquid level of the original slurry 34 fluctuates, the applied thickness of the slurry layer 36 is hardly affected.

A mixing tank 38 for supplying slurry to the slurry coating device 20 is provided above the slurry coating device 20.
The mixing tank 38 is connected to a kneader 42 having a plurality of hoppers 40 each containing a slurry raw material. In the present invention, the doctor blade 32
Instead of this, it is also possible to adopt a structure using an application roll as the application thickness regulating member.

The drying device 24 heats the slurry layer 36, volatilizes the solvent, and solidifies the slurry.
It is for obtaining. As the drying device 24, far-infrared drying is suitable from the point of quick drying, but other known heating methods such as hot air drying and heat transfer heating can be applied. However, since the slurry contains metal powder, microwave drying is not suitable in principle. The heating condition of the slurry layer 36 by the drying device 24 is not limited, but generally the ambient temperature is 40 to 80 ° C. and the drying time is about 20 to 120 minutes.

The plate 36B separates from the endless belt 10 at a position where the endless belt 10 bends downward. A cutting device (or punching device) 46 is provided in the traveling direction of the plate 36B, and a rectangular or disk-shaped plate S is obtained by the cutting device 46. The plate S is composed of a thin underlayer made of a resin and a porous grindstone raw material formed on the underlayer.

Next, an embodiment of a method for manufacturing a thin blade whetstone using the above apparatus will be described. First, the grindstone particles 4, the metal binder powder to be the first metal binding phase 2, the resin binder, the solvent, and other necessary components are put into the hopper 40, and are mixed into a slurry by the kneader 42. If you want to mix the slurry,
Uniform mixing can be achieved more easily than mixing only powdered raw materials.

The content of the grindstone particles 4 in the slurry 34 is not limited, but is generally preferably about 0.3 to 3.5 wt%, more preferably 0.8 to 2.5 wt%.

The metal binder powder is a single material or a mixture forming the first metal binder phase 2 described above, and the particle diameter of the metal binder powder is preferably 500 μm or less, more preferably 500 μm or less. Is set to about 0.5 to 100 μm. If the average particle size is less than 0.5 μm, the reactivity with water is too strong. If the average particle size is more than 500 μm, sufficient strength cannot be obtained after sintering. The content of the metal binder in the slurry is 9.7 to 46.5% by weight, and more preferably 19.
It is set to 2-32.5 wt%.

The resin binder maintains the structure of the plate after the slurry is dried, and also functions to adjust the viscosity of the slurry. The type of the resin binder may be the same as that used in the granulation process. The content of the resin binder in the slurry is not limited, but is 50 to 90 wt%, particularly 65 to 90 wt%.
Preferably it is 80 wt%. If it is less than 50 wt%, the strength of the plate 36B after drying becomes insufficient, and 90 wt%.
If it is larger, the viscosity is too high and shaping becomes difficult.

In the present invention, if the viscosity of the slurry is appropriate, the settling of the grindstone particles 4 in the slurry applied in a flat plate shape is small. Therefore, it is also possible to shape the dried plate body 36B into a grindstone shape, dry and sinter it, and use it as the abrasive layer 1 as it is. in this case,
Since the bonding is not performed, there is an advantage that the manufacturing cost is low and the thickness of the abrasive layer 1 can be reduced.

On the other hand, by adjusting the viscosity of the slurry, the abrasive grains 4 are allowed to slightly settle in the slurry layer, and after obtaining two plate bodies 36B having different densities of the abrasive grains 4 on the upper surface and the lower surface, As shown in FIG. 10, the upper surfaces of the plate bodies 36 </ b> B having less distribution of the grindstones 4 are joined to each other and dried and sintered, so that the grindstones are disposed on both sides than the center in the thickness direction as shown in FIG. 11. It is also possible to produce a thin blade whetstone with a large number of 4's.

Although not essential for each slurry,
In addition to the above components, a surfactant, a plasticizer, a combustor for promoting pore formation, and the like can be added. The surfactant has an effect of improving the dispersibility of the abrasive grains and the metal binder powder in the slurry, and specifically, an alkylbenzene sulfonate, an α-olefin sulfonate, an alkyl sulfate, Alkyl ether sulfates, anionic surfactants such as alkane sulfonates,
Examples include nonionic surfactants such as polyethylene glycol derivatives and polyhydric alcohol derivatives.
Surfactant content in slurry is 0.05-5wt
%, Particularly preferably in the range of 0.5 to 3 wt%. 0.05
If the content is lower than 5 wt%, the above effect cannot be obtained, and if the content is more than 5 wt%, the effect is hard to increase any more.

The plasticizer is used to add plasticity to the plate 36B, and includes polyhydric alcohols such as ethylene glycol, polyethylene glycol, and glycerin, oils and fats such as sardine oil, rapeseed oil, and olive oil, and ethers such as petroleum ether. , Diethyl phthalate, di-n-phthalate
Esters such as butyl, diethylhexyl phthalate, dioctyl phthalate, sorbitan monooleate, sorbitan triolate, sorbitan palmitate, and sotubitan stearate can be exemplified. The content of the plasticizer is preferably in the range of 0.1 to 15 wt%, particularly preferably 2 to 10 wt%. If the amount is less than 0.1 wt%, the plasticizing action may be insufficient, and if the amount is more than 15 wt%, the strength of the plate body 36B may decrease.

The combustible agent for forming pores is used to promote the formation of pores by being eliminated during sintering of the plate 36B, and is made of a combustible material such as pulp, cotton, lint, corn starch, carboxymethyl cellulose. , Water-insoluble cellulose fibers, polyvinyl butyral resin, polyvinyl resin, acrylic resin, polyethylene resin and the like. Although the shape of the pore-forming combustible is not limited,
Specifically, a powdery substance of about 0.1 to 200 μm,
A fibrous material having a length of 200 μm or less, preferably about 30 to 120 μm is suitable.

The viscosity of the slurry to be applied is 20,000 to 70,000 cps at 20 ° C., especially 30,000 to 70,000 cps.
A range of 55000 cps is preferred. 20,000 cps
If it is less than 7, the porous structure may collapse at the time of drying.
If the viscosity is higher than 0000 cps, the doctor blade 32
Molding may be difficult.

In order to manufacture a thin blade whetstone, the endless belt 10 is run after the base coater 16 is filled with the base coat 28 and the slurry coater 20 is filled with the slurry 34. Then, first, the base paint layer 30 is formed on the endless belt 10 while being regulated by the gap amount between the doctor blade 26 and the endless belt 10.
0 indicates that the underlayer drying device 18 is dried by the underlayer drying device 18. Further, the slurry coating device 20
Thereby, the slurry layer 36 having a thickness corresponding to the gap between the doctor blade 32 and the endless belt 10 is applied. The slurry layer 36 is dried by being heated by the drying device 24 to form a plate 36B, which is separated from the endless belt 10 at the position of the roll 14 and formed into a short plate 36B by a cutting device (or a punching device) 46. . The plate 36B has the same diameter as the thin blade grindstone to be manufactured, or has a circular or rectangular shape larger than the thin blade grindstone. If necessary, the carrier tape is peeled from the plate 36B.

When the plate 36B is obtained, the plate 36B is punched into a grindstone shape to prepare a grindstone prototype. Next, the grindstone prototype is placed in a heating furnace having an inert atmosphere, a reducing atmosphere, or a vacuum atmosphere inside, and a heat treatment is performed to decompose and volatilize and remove the resin binder contained in the grindstone prototype. Although the heat treatment conditions for this degassing are not limited,
It is preferable to heat at 550 ° C. for 30 to 120 minutes.

After the degassing process is completed, the grindstone prototype is taken out of the heating furnace and sintered by ordinary sintering or hot pressing. The sintering conditions are not limited because they differ depending on the type of the metal binder used, but generally, the heating temperature is about 600 to 900 ° C. and the heating time is
６０60 minutes. When performing hot pressing,
Further, the pressing pressure is preferably about 100 to 1000 kgf / cm ² .

By performing such sintering, the metal binder particles are mutually bonded. The grindstone may be non-porous, but if it is necessary to make the grindstone porous, non-pressurized sintering may be performed or hot pressing pressure may be reduced to form the required amount of pores. When the pores are formed, the pores opened on the surface of the grindstone can hold the grinding fluid to achieve lubrication and cooling, and the pores serve as chip pockets to enhance chip dischargeability, thereby improving cutting performance or grinding performance.

On the other hand, as shown in FIG.
If the grinding plate is formed by laminating B, it is not essential, but the first plate body 36B and the second plate body 36B having the same thickness are formed so that the respective slurry development directions A and B are substantially orthogonal to each other. It is preferable that the layers are stacked in such a way that The slurry development directions A and B do not have to be completely orthogonal to each other.
It is sufficient if the direction is close to a right angle of about ゜. By intersecting the slurry developing directions in this way, it is possible to reduce the variation in the characteristics of the grindstone in the circumferential direction due to the slurry developing direction. Therefore, since the grinding performance is uniform over the entire circumference of the grindstone, it is possible to reduce the possibility that vibration of the grindstone occurs during cutting and chipping of the workpiece due to uneven grinding performance. In order to bond the two plates 36B, they need only be stacked, pressed if necessary, and then sintered. By sintering, the plate 3
At the interface between the 6Bs, the bonding proceeds and the two are integrated.
Plate 3 using an adhesive which is decomposed and removed during sintering
6B may be laminated.

According to the thin blade grindstone of the above embodiment, as shown in FIG. 1, the grindstone grains 4 are dispersed in the first metal bonding phase 2, and the superabrasive grains 8 are contained inside each of the grindstone grains 4. Due to the dispersed structure, when the work material is ground with the thin blade grindstone, the first metal bonding phase 2 exposed on the surface of the abrasive grain layer 1 is worn at a higher speed than the grindstone grain 4 as shown in FIG. And then
Eventually, the grindstone grains 4 themselves fall off the first metal bonding phase 2. As a result, even if the self-sharpening action of the superabrasive grains 8 in the grindstones 4 is poor, the grindstones 4 themselves are renewed, so that good sharpness is maintained for a long time. Further, since the superabrasive grains 8 protruding to the surface of the abrasive grain layer 1 are uniformly distributed and have a low distribution density, the cutting pressure of each superabrasive grain 8 is large,
From this point, the sharpness can be improved.

According to the manufacturing method of the above embodiment,
Since the abrasive layer 1 is formed by applying the slurry containing the abrasive grains 4, the production cost of the abrasive layer 1 is low and the structure can be homogenized.

It should be noted that the present invention is not limited to only the above-described embodiments, and it is needless to say that the configurations of the embodiments may be appropriately combined or other known configurations may be added.

[0056]

Next, the effects of the present invention will be demonstrated with reference to examples. [Example] 20/3 of the trade name "IMM" manufactured by Tomei Diamond Co., Ltd.
40 g of 0 μm diamond abrasive grains, Cu-10 wt% S
880 g of n-5 wt% Ag-5 wt% Fe mixed powder and 80 g of an organic binder having the following composition were kneaded using a kneader. Organic binder composition: methyl cellulose 14 g polyethylene glycol 30 g "Span 80" manufactured by Kanto Chemical Co., Ltd. 5 g water 600 ml

The kneaded material was extruded by a granulator 60 as shown in FIG. 7 to form columnar grains 4A having a diameter of 0.5 mm and a length of 1 mm. These grains 4A are placed in a vacuum at 450
Degassing was performed at 30 ° C. for 30 minutes to remove the resin binder. Furthermore, sintering was performed at 750 ° C. for 1 hour in a vacuum to obtain grinding stones 4. The porosity of these grinding stones 4 was measured by a mercury infiltration type density measuring device (“Mercury / Non-mercury porosimeter” manufactured by PMI) and found to be 2 vol%.

2.0 g of grinding stone 4 and 15 wt% of Cu
25 g of the Sn-5 wt% Ag mixed powder and 73 g of the organic binder having the above composition were kneaded using a kneader. This slurry is stretched in a thin plate shape on a flat sheet by a doctor blade device as shown in FIG.
A plate of mx 500 mm length x 2 mm thickness was obtained. The plate was dried to form a green molded body, and an annular body having an outer diameter of 100 mm and an inner diameter of 40 mm was punched from the green molded body by a hand press. In addition, this green molded body can be used again as a raw material by adding the amount of hot water calculated by the above ratio and returning the slurry to a slurry.

The green compact was heated at 450 ° C. for 30
Heating was performed in a nitrogen atmosphere for a minute to remove the binder. Next, it is sintered at 700 ° C. for 1 hour in a nitrogen atmosphere,
A grindstone prototype was manufactured. The thickness of the obtained grindstone prototype is 1.5
mm. The porosity of the grindstone prototype was measured by the density measuring instrument, and was found to be 10 vol%. This grindstone prototype is formed by lapping, and the outer diameter is 100 mm and the inner diameter is 40
A thin blade of 0.5 mm × 0.5 mm in thickness was obtained.

[Comparative Example] Trade name "IM" manufactured by Tomei Diamond Co., Ltd.
2.0 g of 20/30 μm diamond abrasive grains of “M”, C
u-10 wt% Sn-5 wt% Ag-5 wt% Fe mixed powder 25 g and organic binder 73 g having the following composition
Was kneaded using a kneader to obtain a slurry. Organic binder composition: methyl cellulose 14 g polyethylene glycol 30 g "Span 80" manufactured by Kanto Chemical Co., Ltd. 5 g water 600 ml

This slurry was stretched into a thin plate on a flat sheet by a doctor blade device as shown in FIG. 8 to obtain a plate having a width of 150 mm, a length of 500 mm and a thickness of 2 mm. The plate was dried to form a green molded body, and an annular body having an outer diameter of 100 mm and an inner diameter of 40 mm was punched from the green molded body by a hand press. In addition, this green molded body can be used again as a raw material by adding the amount of hot water calculated by the above ratio and returning the slurry to a slurry.

The green compact was heated at 450 ° C. for 30
Heating was performed in a nitrogen atmosphere for a minute to remove the binder. Next, it is sintered at 700 ° C. for 1 hour in a nitrogen atmosphere,
A grindstone prototype was manufactured. The thickness of the obtained grindstone prototype is 1.0
mm. When the porosity of the grindstone prototype was measured by the above-mentioned density measuring device, it was 1 vol%. This grindstone prototype is formed by lapping and has an outer diameter of 100 mm x an inner diameter of 40 m.
A thin blade whetstone of mx 0.5 mm in thickness was obtained.

[Comparative Experiment 1] Using the grindstones of the examples and comparative examples, cutting of 96 wt% Al ₂ O ₃ (water absorption rate 0%) was performed. The cutting conditions are as follows. Cutting tester: "Slicer USM-20A" manufactured by Toshiba Corporation Revolution: 15000 rpm Cutting depth: 1.2 mm Feeding speed: 50 mm / min Feeding pitch: 5 mm Cutting method: Down cut Coolant: Emulsion 10% diluent Work material dimensions: Width 50mm x length 50mm x thickness 1.0mm

A large number of lines were cut under the above conditions, and the cutting resistance in the normal direction at this time was measured every 10 cutting lines using a dynamic strain meter manufactured by Kistler. Table 1 shows the results.

[0065]

[Table 1]

As is clear from the results shown in Table 1, the thin blade grindstone of the example did not increase the cutting resistance even after cutting alumina, which was a difficult-to-cut material, many times, and did not break during the cutting.

[0067]

As described above, the thin blade grindstone according to the present invention has a structure in which the grindstone grains are dispersed in the first metal bonding phase and the superabrasive grains are dispersed in each of the grindstone grains. When the work material is ground with this thin blade grindstone, the first metal bonding phase exposed on the surface of the abrasive grain layer wears at a faster speed than the grindstone grains, and the grindstone grains themselves eventually fall off from the first metal bonding phase. I do. As a result, even if the spontaneous cutting action of the superabrasive grains in the grindstone grains is poor, the sharpness of the grindstones is maintained for a long time because the grindstone grains themselves are replaced. In addition, since the superabrasive grains protruding to the surface of the abrasive layer are uniformly distributed and have a low distribution density, the cutting pressure of each superabrasive grain is large, and from this point, sharpness can be improved.

Further, according to the production method of the present invention, since the slurry containing abrasive grains is applied to form the abrasive layer, the production cost of the abrasive layer is low and the structure can be homogenized.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of one embodiment of a thin blade grindstone according to the present invention.

FIG. 2 is an enlarged sectional view showing the operation of the embodiment.

FIG. 3 is an enlarged sectional view showing the operation of the embodiment.

FIG. 4 is an enlarged sectional view showing another embodiment of the present invention.

FIG. 5 is an enlarged sectional view showing still another embodiment of the present invention.

FIG. 6 is an enlarged sectional view showing still another embodiment of the present invention.

FIG. 7 is a schematic view showing a granulation step of the grinding wheel manufacturing method of the present invention.

FIG. 8 is a front view of a molding apparatus used in the manufacturing method.

FIG. 9 is an enlarged sectional view of a main part of the molding apparatus.

FIG. 10 is a perspective view showing another embodiment of the grinding wheel manufacturing method of the present invention.

FIG. 11 is a perspective view showing another embodiment of the grinding wheel manufacturing method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 abrasive layer 2 first metal binding phase 4 grinding stone 6 second metal binding phase 8 superabrasive P1, P2 recess (tip pocket) 10 endless belt (substrate) 16 underlayer coating device 20 slurry coating device 32 doctor blade ( Coating thickness regulating member) 34 Raw material slurry 36 Coating layer 36B plate body 60 Granulator

Claims (4)

[Claims] 1. A thin blade whetstone comprising a flat abrasive layer, wherein the abrasive layer comprises a sintered first metal binder phase and abrasive grains dispersed in the first metal binder phase. A thin blade grindstone, wherein each of the grindstone grains includes a sintered second metal binder phase and superabrasive grains dispersed in the second metal binder phase. 2. The grinding stone according to claim 1, wherein the average particle diameter of the grinding stone is 0.05 to 0.1.
5. The thin blade grinding wheel according to claim 1, wherein the porosity of the first metal binding phase is 5 vol% or more, and the porosity of the second metal binding phase is less than 5 vol%. Forming a first slurry in which a metal binder powder and superabrasives are dispersed in a resin binder solution;
A step of preparing granules using the first slurry; a step of drying and firing the granules to form grinding stones; and dispersing the metal binder powder and the grinding stones in a resin binder solution. A step of preparing a second slurry, a step of applying the second slurry on a substrate, and a step of solidifying the applied second slurry and then separating the second slurry from the substrate and sintering. Characteristic method of manufacturing thin blade whetstone. 4. A step of solidifying the applied second slurry, peeling the second slurry from the substrate to obtain two plate bodies, joining the separated surfaces of these plate bodies, and sintering. The method for producing a thin blade grindstone according to claim 3, wherein: