JPS59169764A - Solid grindstone - Google Patents

Abstract

PURPOSE:To enale finishing processing of a material, having high hardness, with high precision, by a method wherein, in a solid grindstone consisting of mainly a binding material for precise grinding processing and grinding grain, whisker is used as grinding grain. CONSTITUTION:Silicon carbide whisker 1 having a diameter of 0.05-0.2mum and a length of 10-40mum is dispersed in, for example, phenol resin precondensate water solution so that whisker content is 10vol%, and after molding is effected under a catalyst hydrochloride, a disc solid grindstone is formed by heating so that the porosity of a pore 3 in a binding material 2 is about 50%. Aluminum oxide, silicon nitride, aluminum nitride, etc. may be used as the whisker 1, and polyurethane, hard rubber, melamine resin, etc. may be used as the binding material 2. This enables sharp improvement of finishing precision.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid grindstone that uses metal whiskers as abrasive grains and is particularly suitable for precision polishing. A grindstone is composed of abrasive grains, a binder, and pores. The performance of the whetstone is mainly determined by the hardness, grain size, and content of the abrasive grains. In addition to holding abrasive grains, the binder is required to have elasticity and hardness suitable for polishing.

Furthermore, pores are necessary for absorbing polishing debris, fallen abrasive grains, etc., exposing new abrasive grains, preventing clogging of the abrasive surface, and dissipating frictional heat during polishing. Such solid whetstones are widely used in various fields, but if we look at whetstones that are suitable for precise polishing of highly hard materials such as metal, stone, and glass, The reality is that there is still no book that satisfies me. A grinding wheel that is fully suitable for such uses requires fine abrasive grains, but such abrasive grains are difficult to hold firmly in the binder, and even with advanced technology, they cannot be produced in large quantities. There is a problem that it is difficult to mix.

Therefore, when performing precision polishing on highly hard materials, it is common practice to perform preliminary polishing with a solid grindstone, and then perform puff polishing or lapping polishing, in other words, spraying a slurry of fine abrasive grains onto the surface of the object to be polished. On top of that, non-woven fabric, felt,
A method of polishing in which the surface of the object to be polished is rubbed evenly with a roller of abrasive grains while being pressed with synthetic leather, etc. and sliding.
A two-step process is adopted in which the free abrasive method is used. Although the free abrasive method has good finishing accuracy, it has many drawbacks such as extremely large amounts of abrasive grains used, severe environmental pollution, and the time required to dispose of waste liquid.

In view of the above-mentioned problems, the inventors of the present invention continued their intensive research, and as a result discovered that metal whiskers are excellent as fine abrasive grains, and completed the present invention.

An object of the present invention is to provide a solid grindstone that can finish high-hardness materials with high precision. Another object of the present invention is to provide a human-shaped grindstone that has excellent abrasive grain holding power and is capable of efficient high-precision finishing using a relatively small amount of abrasive grains. Further objects and advantages will become apparent from the description below.

The above object is achieved by a solid grindstone whose main components are a binder and abrasive grains, and which is characterized in that whiskers are used as the abrasive grains.

The solid grindstone of the present invention increases the grinding power by dispersing whiskers as abrasive grains in a binder.

Its greatest feature is improved finishing accuracy. Examples of whiskers applicable to the present invention include elemental metals such as iron and silicon, metal oxides such as aluminum oxide, beryllum oxide, molybdenum oxide, copper oxide, nickel oxide, and magnesium oxide, metal carbonates such as silicon carbide, and Examples include whiskers of metal nitrides such as silicon nitride, aluminum nitride, etc., among which whiskers of aluminum oxide, silicon carbide, silicon nitride, and aluminum nitride are preferred. The characteristics required for abrasive grains vary depending on the material of the material to be polished.It is difficult to generalize, but it is necessary that they have excellent abrasive power and good adhesion retention with the bonding material.In general, whiskers have a high hardness. It has a high and fine shape, but from the above points, the Mohs hardness is 7.
In addition to the above, it is preferable that the abrasive grains have good adhesion and retention properties with the binder used. For example, polyvinyl alcohol-based synthetic resin (PVA-based synthetic resin) is used as a binding material.
When using metal whiskers such as silicon carbide or aluminum oxide as abrasive grains, the polishing power,
Favorable results can be obtained in terms of adhesion retention and the like. The whiskers used in the present invention are finer and have greater abrasive power than commonly used abrasive grains. It has excellent polishing power and can perform high-precision finishing even on highly hard materials.

In fact, as is clear from the examples described below, even with the solid grindstone according to the present invention containing only 10% of whiskers, precision finishing processing equivalent to that when the free abrasive method is applied can be achieved. It's something you get. The amount of whiskers is
Although it varies depending on the material of the object to be polished and the required precision, it is preferable to mix it in at most 60% by volume. It goes without saying that in wood cutting, whiskers and commonly used abrasive grains may be used in combination. These whiskers can be easily produced by selecting an appropriate method from known methods such as a plating substrate method, a vapor phase method, a reduction reaction method, a solution electrolysis method, etc., and may be used by appropriately selecting from existing whiskers.

Various binding materials can be used, such as polyurethane, hard rubber, porous polyvinyl alcohol synthetic resin, phenol resin, melamine resin, and ceramic, but this is not suitable for applications that require high-precision finishing. The most preferred material is a polyvinyl alcohol-based synthetic resin porous material that has high porosity, appropriate elasticity, and excellent bonding strength with whiskers. Such a polyvinyl alcohol-based synthetic resin porous body is produced by adding a pore-forming agent such as starch to an aqueous polyvinyl alcohol solution obtained by partially or completely saponifying vinyl acetate, for example.
Products obtained by reacting aldehydes in the presence of an acid catalyst such as sulfuric acid, removing the pore-forming agent, and impregnating and curing with a thermosetting resin such as melamine, elia, or phenol as necessary. It is. At this time, a thermosetting resin initial condensate or thermosetting resin powder such as a phenol resin initial condensate, a melamine resin initial condensate, a urea resin initial condensate, an area resin initial condensate, etc., or a thermosetting resin powder is added to the reaction stock solution to initiate the reaction. This can reduce hardness loss under wet conditions.

The solid grindstone of the present invention using whiskers as abrasive grains can be easily manufactured by the same method as ordinary resinoid grindstones and PVA-based grindstones. For example, if it is a resinoid type, it may be done by kneading toxic whiskers and a powdered or liquid phenol resin, etc., molded, then heated and baked, or if it is a PVA type, it can be done by kneading it with a polyvinyl alcohol aqueous solution. If necessary, whiskers are dispersed in an aqueous solution containing a thermosetting resin initial condensate and a thermosetting resin powder, reacted with aldehydes in the presence of a pore-forming agent and a catalyst, and then heated. is obtained by performing a curing treatment with a thermosetting resin. At this time, the reaction stock solution is allowed to react while flowing in a certain direction, or the whiskers are press-fitted in the direction of the fiber axis, etc., so that the polishing surface of the whetstone and the fibrous cross section of the whiskers match as much as possible. The polishing power is further improved.

When performing high-precision finishing on high-hardness materials, there is an advantage in that preliminary polishing using an LTL grindstone and precision finishing using free abrasive grains can be omitted using the free abrasive method, which is disadvantageous in terms of man-hours.

Furthermore, since whiskers have excellent abrasive power, only a small amount of abrasive grains need to be added, which greatly improves the JII of the whetstone. The present invention will be specifically explained with reference to the following examples.The abrasive grain count in the examples is Japanese Industrial Standard JII? 16001-56.

Further, the abrasive grain ratio and whisker content ratio in the examples are values calculated according to the following.

Example 1 Straight @ 0.05 to α2μ, length 1 so that the whisker content in the aqueous solution of phenolic resin initial condensate was 10% by volume.
Silicon carbide whiskers (Mohs hardness: 23) of 0 to 40μ are dispersed, and malt is formed in the presence of a hydrochloric acid catalyst at 170°C.
was heated for 10 hours to produce a disk-shaped solid grindstone (the grindstone of the present invention) with a porosity of 50%. Instead of silicon carbide whiskers, use silicon carbide abrasive grains No. 4000 (average grain size 4μ) at an abrasive ratio of 30.
A chromium-plated metal roll was polished using a wet method using a disc-shaped solid grindstone with a porosity of 50% in the same manner as above, except that the blending was performed so that the grinding wheel of the present invention had a porosity of 50%. The finishing accuracy of the control product was 0.2 microns, while that of the control product was 0.1 microns.

Further, it can be seen that the specific gravity of the grindstone of the present invention is 0.611/-, whereas the specific gravity of the control product is 1.2 g/.

Example 2 A 10% aqueous solution of polyvinyl alcohol with a polymerization degree of 1700 obtained by completely saponifying vinyl acetate had a whisker content of 9.
Diameter (LO5~0.2μ, length 10~
40μ silicon carbide whiskers (Mohs hardness 9.3) are dispersed, wheat starch is used as a pore generator and 37μ as a crosslinking agent.
% formaldehyde aqueous solution and hydrochloric acid as a catalyst, and then a water-soluble melamine resin was added and kneaded, then cast into a disc-shaped container and given a vortex to give directionality to the whiskers, followed by a solidification reaction at 60°C for 10 hours. I went there. After the reaction was completed, unreacted hydrochloric acid, formaldehyde, and starch were removed by washing with water, and then 13
The solid grindstone obtained after heat treatment at 0° C. for 5 hours had a porosity of 65% and #≠ whiskers were oriented in the direction of the vortex flow.

This was molded into a one-story whetstone so that the surface perpendicular to the axis in which the whiskers were oriented was the polishing surface.

When this was placed on a lapping surface plate and used for wet final polishing of an aluminum plate, a finishing accuracy of 0.05 micron was obtained.

Example 3 Polyvinyl alcohol with a degree of polymerization of 1700, obtained by completely saponifying vinyl acetate, and polyvinyl alcohol with a degree of polymerization of 500 were mixed at a weight ratio of 1:1. A whisker content of 3% by volume was added to a 10% aqueous solution of polyvinyl alcohol. Silicon carbide whiskers (Mohs hardness: 93) with a diameter of α5 to 1.0 μ and a length of 2 to 10 ffB were dispersed, and wheat starch was added as a pore-forming agent, 375A polmarchite aqueous solution as a crosslinking agent, and hydrochloric acid as a catalyst. After thorough kneading, the mixture was cast and reacted at 60° C. for 15 hours to solidify. After assimilation, unreacted hydrochloric acid, formalin, and starch were removed by washing with water, and then heat-pressed at 110°C using a press machine to achieve a porosity of 70.
% solid grindstone (the grindstone of the present invention) was obtained.

Use silicon carbide abrasive grains No. 400 instead of silicon carbide whiskers (
A solid whetstone with a porosity of 70% (
A control product) was manufactured.

These whetstones were placed in a grinder, and a -C stainless steel watch case was dry-polished using the outer periphery while applying wax. The required final finishing accuracy for the watch case is α1 micron, but the whetstone of the present invention Although this required accuracy was achieved for final polishing, the limit of the control product was rLs microns, and in order to achieve the required accuracy, a puff finishing process using a cotton puff and chromium oxide free abrasive grains was necessary.

Furthermore, the specific gravity of the grindstone of the present invention is 0.31/cd, whereas the specific gravity is 1!
etc.

The weight of the grindstone was 0.5 g/cr4, and the grindstone of the present invention was about 405/cm lighter than the control item.

Example 4 100 parts by weight of polyvinyl alcohol with a degree of polymerization of 1700 obtained by completely saponifying vinyl acetate and phenol resin initial condensate 1
0 parts by weight were dissolved in water to prepare a 10% aqueous solution. Silicon carbide whiskers with a diameter of 0.05 to 0.2 μm and a length of 10 to 40 μm were dispersed in the aqueous solution so that the whisker content was 8%, starch was used as a pore-forming agent, and 37% was used as a crosslinking agent. After adding formaldehyde aqueous solution and hydrochloric acid as a catalyst and thoroughly kneading, the mixture was reacted and assimilated at 60°C for 15 hours.
After washing with water, a porous body was obtained. The porous body was further heated to 13
Heating at 0℃ for 5 hours 1. A solid grindstone C (invention grindstone) having a porosity of 65% and having a hardened phenol resin was obtained.

Silicon carbide abrasive grains 00400 instead of silicon carbide whiskers
A solid grindstone (control product) was produced in the same manner as above except that No. 0 (average particle size 4 μm) was blended so that the abrasive grain ratio was 25% by volume.

When these grindstones were attached to a fixed grinder and a ferrite alloy was polished by a wet method using the outer circumference, the polishing accuracy was 0.08μ when using the grindstone of the present invention, while that of the control product was 0.3μ. . It can be seen that the grindstone of the present invention has an abrasive grain ratio of approximately ■ compared to the control product, and exhibits the same or higher effect.

Furthermore, the specific gravity of the grindstone of the present invention was 1.1 g/cd, while that of the control product was 0.611/d.

Example 5 Aluminum oxide whiskers (Mohs hardness: A8 ) was added, wheat starch was added as a pore-generating agent, 37% formaldehyde was added as a cross-linking agent, and sulfuric acid was added as a catalyst, and the mixture was poured into a mold and reacted at 60°C for 10 hours and then at 130°C for 5 hours. completed. When the obtained product was used for polishing a stainless steel plate, a finish with a finishing accuracy of 0.6 microns could be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the synthetic whetstone of Example 1, Fig. 2 is an explanatory diagram of the synthetic whetstone of Example 2, and Fig. g6 is an explanatory diagram of the synthetic whetstone of Example 4. In the drawings, 1 is a whisker; 2 represents the combined feathers, and 3 represents the stomata. 15- Figure 1 Figure 2

Claims (1)

[Scope of Claims] (1) A solid γ grindstone whose main components are a binder and abrasive grains, characterized in that whiskers are used as the abrasive grains. (2) B according to claim (1), wherein the whisker is made of an elemental metal, a metal oxide, a metal carbide, or a metal nitride! Grindstone (6) Solid grindstone (4) according to claim (2), in which the metal oxide is aluminum oxide Solid grindstone (4), according to claim (2), in which the metal carbide is silicon carbide Grinding wheel (5) Solid grinding wheel (6) according to claim 2, wherein the metal nitride is silicon nitride or aluminum nitride Claim 6, wherein the metal whisker has a Mohs hardness of 7 or more The solid grindstone (7) according to the falling crab according to claims 1) to (5). A solid whetstone as described in any of the above