JPH05184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method suitable for manufacturing a grinding wheel using superabrasive grains such as diamond and CBN (cubic boron nitride).

(Prior art and problems) Conventional superabrasive grindstones include microwave bonded grindstones that use microwave as a bonding material, metal bonded grindstones that use metal as a bonding material, and vitrified bonded grindstones that use glassy bond as a bonding material. Both of these grindstones are manufactured by filling a mold with superabrasive grains and a binder, then heating and compressing them to solidify them, or by compressing them at room temperature to solidify them, and then sintering or firing them. There is.

Therefore, these manufacturing methods require a compressor and a mold, resulting in high manufacturing costs.Moreover, in addition to using molds, the grindstones manufactured from the viewpoint of mold release are difficult to shape, wall thickness, and size. There were problems such as significant restrictions on the quality of the product.

In addition to the above-mentioned whetstones, there is also an electroplated whetstone in which super-abrasive grains are bonded to the surface of the base material using metal plating. The layers are easy to peel off, and
There were also problems such as the inability to correct misalignment between the base material and the abrasive grain layer.

(Object of the invention) The present invention was made to solve the above problems, and it does not require a compressor or a mold, and is not subject to restrictions on shape, wall thickness, or size. The purpose of the present invention is to provide a method for manufacturing a superabrasive grinding wheel with a long life.

(Means for Solving the Problems) The method for manufacturing a superabrasive grindstone according to the present invention involves coating the surface of a base material with a slurry-like mixture containing superabrasive grains and metal powder, and then drying and hardening the mixture. forming a porous abrasive layer skeleton on the surface of the material, sintering the abrasive layer skeleton at the sintering temperature of the metal powder, and infiltrating molten metal into the porous portions of the abrasive layer skeleton;
This method is characterized in that the bond between the superabrasive grains and the metal powder is strengthened by solidifying the molten metal.

By the way, in the present invention, diamond and CBN are used as superabrasive grains, and the grain size of these grains is 5 to 200μ.
It is m. Further, as the metal powder, cobalt powder, nickel and nickel alloy powder, copper and copper alloy powder, iron and iron alloy powder, aluminum and aluminum alloy powder, etc. are used. Their particle size is between 1 and 200 μm. The blending ratio of superabrasive grains and metal powder is appropriately set depending on the type of grindstone to be manufactured. Furthermore, grindstones of various strengths are used depending on the physical properties of the object to be ground. Therefore, the mixture of superabrasive grains and metal powder contains inorganic fibers and metal fibers to improve the hardness of the grinding wheel, and known fillers (silicon carbide powder, alumina powder, glass) to improve the grinding performance of the grinding wheel. powder, cemented carbide powder, etc.) are added as appropriate.

In addition, water or an organic solvent is used as the liquid for turning the mixture into a slurry state.
A binder is used to positively adhere the slurry mixture to the surface of the substrate depending on the shape of the substrate.
As the binder, a mixed solution of a hydrolyzate of ethyl silicate and an acid curing agent, water glass, sodium alginate, PVA, etc. are diluted as necessary and used.

Any material may be used as the base material as long as it has appropriate strength and has a melting point higher than that of the metal powder and the infiltrant material described below.

Methods for coating the surface of the substrate with the slurry mixture include dipping, brushing, scraping, and
There is pouring etc. Dipping is a method of moving a substrate into and out of a slurry mixture, and is suitable for coating the mixture in a relatively thin layer. Scraping molding is a method in which a mixture is applied to a desired part of a base material and shaped using a spatula, etc. By increasing the viscosity of the mixture, a fairly thick abrasive grain layer can be molded. Pouring is a method in which a weir is provided at the peripheral edge of the substrate to form a recess, and the slurry mixture is poured into the recess, and is suitable when the surface of the substrate to be coated is flat.

As a method for curing the mixture coated on the surface of the substrate, there is a method of removing the liquid by natural drying or forced drying using a dryer. Further, the abrasive grain layer skeleton is sintered by heating the abrasive grain layer skeleton in a sintering furnace at a sintering temperature of the metal powder. Note that the sintering of the abrasive layer skeleton can also be performed simultaneously with the infiltration step.

As the metal that is melted and infiltrated into the pores of the abrasive layer skeleton, iron alloy, nickel alloy, cobalt alloy, copper, copper alloy, silver solder, aluminum alloy, solder, etc. are used.

Examples of the method of melting the infiltrant and infiltrating it into the pores of the abrasive layer aggregate, that is, the infiltration method, are as follows. Specifically, the abrasive layer skeleton is heated together with the base material to a temperature higher than the melting point of the infiltrant, and then the abrasive layer skeleton is brought into contact with the infiltrant. keep it in contact with the surface,
There is a method in which the entire structure is heated to a temperature higher than the melting point of the infiltrant, or a method in which the abrasive layer skeleton and the base material are immersed in the molten infiltrant. Although infiltration can be carried out at normal pressure, the infiltration effect can be improved by applying increased or reduced pressure during infiltration.

The amount of pores can also be varied by controlling the amount of infiltrant.

Next, to explain the process of manufacturing a grinding wheel using the aforementioned superabrasive grains, metal powder, base material, etc., first, the superabrasive grains and metal powder are mixed in a mixer at the required mixing ratio, and the required amount of liquid is mixed. and mix these to form a slurry mixture.

Next, the slurry mixture is coated on the surface of a predetermined base material and cured to form an abrasive grain layer skeleton made of a porous mixture on the base material surface, and then the abrasive grain layer skeleton is sintered. At the same time, the surface of the base material is infiltrated with an infiltrating material. Thereafter, by truing and dressing the surface of the abrasive grain layer, a superabrasive grindstone is obtained in which the bond between the superabrasive grains and the metal powder is strengthened by the infiltration material.

Example 1 To a mixture consisting of 40 parts by weight of diamond abrasive grains (#170/200) and 60 parts by weight of cobalt powder (#350), 35 parts by weight of a water glass aqueous solution diluted 6 times was added and mixed. , make a slurry-like mixture. Next, the slurry mixture was coated on the surface of a tapered disk-shaped base material with a diameter of 150 mm to a thickness of 2 mm by scraping and molding, and then these were dried in a dryer at a temperature of 90° C. for 3 hours. The mixture is hardened to form a porous abrasive layer skeleton made of a mixture of diamond abrasive grains and cobalt powder on the surface of the substrate. Next, after coating the surface of the abrasive grain layer skeleton with bronze powder, it is heated at a temperature of 1000 in a sintering furnace in a reducing atmosphere.
℃ for 30 minutes to sinter the cobalt powder and infiltrate it into the abrasive layer skeleton, and then
The surface of the abrasive grain layer was trued and dressed to form a specified diamond grindstone. When this grinding wheel was used to grind carbide (JIS, P-30) and atmospheric silicon nitride, the lifespan was three times longer than that of a commercially available microwave bonded grinding wheel, and that of a commercially available vitrified bonded grinding wheel.
It was 10 times more effective and equivalent to commercially available metal bonded grindstones.

Example 2 30 parts by weight of an ethyl silicate hydrolyzate and an acid curing agent were added to a mixture of 30 parts by weight of CBN abrasive grains (#325/400) and 70 parts by weight of carbonyl nickel powder.
Add the mixed solution with 0.3 weight and mix to make a slurry-like mixture. Next, the slurry-like mixture was coated to a thickness of 3 mm by a dipping method on the base material (diameter 30 mm), which was shaped like a round bar and had a concave part formed on its circumference, using a dipping method. After leaving it for a while, place it in the dryer at a temperature of 90℃.
The mixture is dried for 2 hours to harden the mixture, and a porous abrasive layer skeleton made of a mixture of CBN abrasive grains and carbonyl nickel powder is formed at a predetermined position on the surface of the base material. Next, this was sintered in a sintering furnace in a reducing atmosphere at a temperature of 800℃ for 30 minutes, and then the abrasive layer skeleton was immersed in molten silver solder (JIS, BAg-7). Silver solder is infiltrated into the abrasive layer skeleton. Next, after taking them out of the molten silver solder, the surface of the abrasive grain layer was trued and dressed to form a CBN irregularly shaped grindstone with a shaft. This grindstone also had the same physical properties as the first example.

Example 3 5 parts by weight of water glass and 25 parts by weight of water were added to a mixture consisting of 40 parts by weight of diamond abrasive grains (#170/200) and 60 parts by weight of bronze powder (#270) and mixed to form a slurry. Make a mixture of. Then,
Apply the mixture to the circumference of a round bar-shaped iron base material with a diameter of 300 mm and a length of 200 mm, and shape it with a spatula to the desired thickness.
20mm coated and then heated to 90℃ in a dryer.
The mixture is cured by drying for 3 hours to form a porous abrasive layer skeleton made of a mixture of diamond abrasive grains and bronze powder on the surface of the substrate. Next, silver solder (JIS, BAg) with a diameter of 1 mm is applied to the surface of the abrasive grain layer.
-8), and then held at a temperature of 820° C. for 30 minutes in a sintering furnace in a reducing atmosphere to simultaneously sinter the bronze powder and infiltrate the silver solder. Thereafter, the surface of the abrasive layer was trued and dressed to obtain a centerless diamond grindstone.

(Effects of the Invention) As is clear from the above description, the present invention provides a method of coating a substrate surface with a mixture containing superabrasive grains and metal powder after forming it into a slurry state, and curing the coated mixture. After that, the metal powder is sintered and the molten metal is infiltrated into the porous parts of the abrasive layer skeleton, and the solidification of the molten metal strengthens the bond between the superabrasive grains and the metal powder. Superabrasive grindstones can be manufactured accurately without using molds or molds. Therefore, manufacturing costs are reduced, and there are no restrictions on shape, wall thickness, size, etc. In addition, the abrasive grain layer of the resulting abrasive wheel is composed of sintered metal powder, so it has a long life and has excellent effects such as being able to partially modify the base material with superabrasive grains, etc.

Claims (1)

[Claims] 1. After coating the surface of a base material with a slurry-like mixture containing superabrasive grains and metal powder, the mixture is dried and hardened to form a porous abrasive layer skeleton on the surface of the base material. It is characterized by sintering at the sintering temperature of the metal powder and infiltrating molten metal into the porous portions of the abrasive layer skeleton, and solidifying the molten metal to strengthen the bond between the superabrasive grains and the metal powder. Method for manufacturing super-abrasive grinding wheels.