JPS61219575A - Resin bond wheel - Google Patents

Abstract

PURPOSE:To avoid concentration of stress in a resin mold of bond and lengthen the life of a resin bond wheel by forming a metal covering applied to a diamond grinding grain in spherical outward shape, the surface of which is smooth and little rugged. CONSTITUTION:The periphery of a diamond grinding grain 3 attached on the flange of a base metal by means of bond is covered nearly spherically by a covering metal (for example, nickel) 4. Said diamond grinding grains 3 are mixed with material powder of bond made of resin and filler, and this mixture is filled in a mold and heated and further pressurized to form a wheel. At this time, stress in a resin mold of bond is evenly dispersed and not concentrated partially.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resin bond wheel using metal-coated diamond or CBN abrasive grains.

[Conventional technology]

Resin-bonded wheels with diamond abrasive grains are preferred because they cut better than metal-bond wheels, but they have the disadvantage of a short lifespan. The main cause of short life is the shedding of diamond abrasive grains. The main cause of wheel wear is that abrasive grains on the wheel surface separate from the bond during the grinding operation. It has often been pointed out that in resin bonded wheels, the diamond abrasive grains effectively exert a grinding action and wear out very little, and most of the diamond abrasive grains are lost by falling off.

Metal-coated diamond is well known as an improvement in this respect. Diamond abrasive grains are coated with a metal such as nickel, and even if the diamond breaks, it is supported by the metal shell to prevent it from falling off, and the coated metal has a particularly great effect in holding it firmly in the bond. has been done.

Since the adhesion between the coated metal and the bond is weak and retention is primarily due to mechanical gripping, it is desirable that the surface of the coat be irregular. Diamond abrasive grains for resin bonding have irregular grain shapes, so the surface of the coating will be irregular, but on top of that, the process of forming the coating will naturally or artificially promote undulations on the surface. In extreme cases, there are coatings with many thorn-like protrusions.

[Problem that the invention seeks to solve]

As mentioned above, the metal coating has the effect of suppressing the diamond abrasive grains from falling off in the resin bonded wheel, but even so, the service life of the wheel is not necessarily long enough.

The principle of preventing falling off as described above as an effect of the metal coating is based on the assumption that the bond containing the abrasive grains, that is, the resin molded body, is homogeneous. In reality, stress is distributed in the resin molded body, and the distribution is complicated around metal-coated abrasive grains that are irregular in shape and have many undulations, and there are particularly localized areas where stress is concentrated.

The molded body is likely to break in areas where stress is locally concentrated. That is, the bond disintegrates, which causes wear on the wheel and therefore shortens its life.

[Means to solve the problem]

It is an object of the present invention to provide a long-life resin bonded diamond wheel.

To this end, the metal coating applied to the diamond abrasive grains has a smooth surface with few undulations and a simple outer shape ideally spherical to avoid stress concentration in the resin molded body of the bond.

〔composition〕

Generally, when forming a metal coating on diamond, electroless plating is performed to initially make the surface of the diamond conductive, but electroplating is used to deposit the metal to a predetermined thickness. In electroplating, plating metal is preferentially deposited on protrusions on the surface to be plated, which tends to promote undulations. As mentioned above, this tendency was conventionally considered to be favorable.

However, there are techniques to curb this tendency. The plating metal precipitates to fill the recesses on the surface to be plated, so the undulations on the surface of the diamond abrasive grains are smoothed out and the surface is smooth.
The outline will be simple.

The wheel of the present invention uses metal-coated diamond abrasive grains of the type B, which are surface-treated with a silane coupling agent. Organosilicon compounds having a reactive group that binds to an inorganic substance such as a metal and a reactive group that binds to an organic substance such as a resin are known as silane coupling agents.

A surface treatment method is also known in which a monomolecular layer of this type of compound is formed on the surface of a metal or the like.

The diamond abrasive grains subjected to the above treatment are mixed with bond material powder consisting of resin and filler, filled into a mold, heated,
The process of pressurizing and forming the wheel is similar to the conventional method of manufacturing resin-bonded wheels.

〔Example〕

In the figure, reference numeral 1 denotes a base metal, and diamond abrasive grains 3 are attached to the periphery of the base metal using a bond 2. As shown in Fig. 2, the diamond abrasive grains 3 are surrounded by metal (for example, nickel).
4 is used to cover it in an approximately spherical shape.

[For production]

In wheel manufacturing, the diamond abrasive grains of the present invention have a simple external shape and a smooth surface, so they are used in the powder mixing process.
Very good mixability.

This point is not only advantageous in the mixing process, but also ultimately results in a more sound resin molded product.

In the resin molded body, that is, the bond, the abrasive grains contained therein have a simple shape and have no undulations on the surface, so that stress is evenly distributed and is not locally concentrated. Bond rupture and collapse that occur when conventional metal-coated abrasive grains are used are significantly suppressed, resulting in improved wheel life.

Although mechanical engagement has little effect on retaining abrasive grains, the adhesive effect of the silane coupling agent compensates for this point.

〔effect〕

Conventional resin-bonded wheels that use metal-coated diamond abrasive grains have focused on strengthening the retention of abrasive grains through mechanical engagement, but have overlooked the effect this structure has on the strength and other properties of the resin molded object that serves as the bond. . The present invention focuses on this point and adopts a metal-coated bag shape that does not impair the bonding properties, which has a remarkable effect of improving the life of the wheel and increasing the effective utilization rate of expensive diamond abrasive grains. The profits are large.

The above explanation has been made regarding diamond wheels, but it goes without saying that the same holds true for CBN wheels.

[Brief explanation of drawings]

The drawings show an embodiment of the resin bond wheel according to the present invention, and FIG. 1 is a side view, and FIG. 2 is an enlarged sectional view of abrasive grains used in the resin bond wheel of the present invention. 1...Base metal 2...Bond 3.Diamond abrasive grain 4...Coating metal No.: i-Figure 2

Claims (1)

[Claims] Countless diamonds or diamonds coated with a coated metal with a smooth surface and few undulations in a simple shape as close to a sphere as possible.
A resin bond wheel with a grinding wheel containing BN abrasive grains attached to the periphery of the base metal.