JPS6334073A - Metal bond grindstone - Google Patents

Abstract

PURPOSE:To reduce the grinding resistance and increase the strength of the grindstone and improve the discharge performance by dispersing carbon fibers which are applied with metal covering and have a prescribed size into an abrasive grain layer formed by dispersing superfine abrasive grains into a metal bonding agent phase. CONSTITUTION:A metal layer made of Ni, etc. is formed onto the surface of a carbon fiber having a length of 0.01-1.00mm by using the electroless plating method with the body thickness corresponding to the size, etc. of the carbon fiber so that the specific gravity of the carbon fiber is made close to that of a metal bonding agent. Then, the carbon fiber which is metal-covered is added by 2-30vol% and the superfine abrasive grains made of diamond, etc. are added by a prescribed quantity into the powdery metal bonding agent such as Cu, Sn, Fe, Ni, etc., and these materials are mixed sufficiently, and molded, and cold press and baking are carried out to obtain a grindstone form. Therefore, the dispersion performance and wettability of the carbon fiber are improved, and the strength of the grindstone is improved. Further, since the carbon fiber is exposed onto the surface of the metal bonding agent, grinding resistance is reduced, and the discharge performance for the grinding chips is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a metal bond grindstone used for cutting concrete and stone, grinding ferrite and glass, and the like.

``Prior art'' This type of metal bonded grinding wheel has diamond or C in a metal binder phase made of an alloy of copper, tin, iron, nickel, etc.
A type that has an abrasive grain layer made of dispersed superabrasive grains such as BN, and this abrasive grain layer is formed on a whetstone base metal, and an all type that does not have a whetstone base metal and consists only of an abrasive grain layer. There is a blade type.

``Problems to be Solved by the Invention'' By the way, in such a metal bonded grindstone, the coefficient of friction between the metal binder phase and the material to be ground is large, so the grinding resistance is large, and chipping and sluggishness are large. , there was a risk that the grinding wheel would overheat due to frictional heat. In addition, because the metal binder phase is densely formed, the superabrasive grains are difficult to fall off, and chip pockets on the surface of the low grain layer are difficult to form.
There was a drawback that the discharge of grinding debris was insufficient.

Therefore, in order to reduce the grinding resistance and facilitate the formation of chip pockets, metal-bond grinding wheels have been prototyped in which graphite powder is added to the metal binder phase. A new problem arises in that the strength of the grinding material decreases and the abrasive grain layer is easily damaged by the grinding load. It is also possible to obtain the same effect by mixing carbon fiber instead of graphite powder, but the specific gravity of carbon fiber is smaller than that of metal powder, and it is difficult to mix the two uniformly. Moreover, the surface of the carbon fiber has poor wettability with the metal binder, and sufficient bonding strength cannot be obtained at the interface between the two, making it impossible to obtain a satisfactory effect of improving the strength of the grindstone.

``Object of the present invention'' The present invention has been made in view of the above circumstances, and an object thereof is to provide a metal bonded grindstone that has low grinding resistance, high grindstone strength, and has good drainage of grinding debris. .

"Means for Solving the Problems" The metal bonded grindstone of the present invention is characterized in that metal-coated carbon fibers are dispersed in the abrasive grain layer.

"Example" Hereinafter, one embodiment of the present invention will be described in detail.

The metal bonded grindstone of this example has an abrasive layer formed by dispersing superabrasive grains such as diamond or CBS and metal-coated carbon fibers in a metal binder phase such as copper, tin, iron, or nickel. It has the following. The grindstone of the present invention may be one in which the abrasive grain layer is formed on the grindstone base metal, or may be an all-blade type whetstone consisting of only an abrasive grain layer. The amount of dispersion of the metal-coated carbon fibers is preferably 2 to 30 vol%. If the amount of this dispersion is less than 2 vol%, a sufficient effect of improving the strength of the whetstone will not be obtained, and if it is more than 30v○1%, the amount of carbon fiber exposed from the surface of the abrasive grain layer will increase, making the sharpness of the whetstone difficult. descend.

The length of the metal-coated carbon fiber is 0.01=1.
It is desirable that the temperature is about 100 oz. If the carbon fibers are shorter than this value, the aspect ratio of the carbon fibers will be small, and the effect of improving the strength of the grinding wheel will be reduced.

Additionally, if carbon fibers longer than the above value are used, it will be difficult to uniformly disperse the carbon fibers into the metal bond opening, making the abrasive grain layer non-uniform and causing local abnormalities in the abrasive grain layer. Risk of wear.

As the metal for coating the carbon fibers, copper, nickel, or an alloy thereof, which can be easily deposited by electroless plating or electroplating and has good bonding properties with a metal binder, is suitable.

Further, the thickness of the metal coating is desirably determined in accordance with the thickness of the carbon fibers so that the specific gravity of the metal-coated carbon fibers is as close as possible to the specific gravity of the metal binder.

Next, a method for manufacturing such a metal bond grindstone will be explained.

First, a metal coating having a predetermined thickness is formed on the surface of a carbon fiber having a predetermined size using an electroless plating method.

Next, a predetermined amount of the metal-coated carbon fibers and superabrasive grains are added to the powdered metal binder, thoroughly mixed, and then placed in a mold and cold pressed, followed by hot pressing or sintering to form a grindstone. Form into shape. Then, the obtained molded body is subjected to shaping and dressing to obtain a metal bond grindstone.

For metal bond grindstones with such a configuration,
Since it is manufactured by mixing carbon fibers whose specific gravity is approximately equal to that of the metal binder by applying a metal coating to the metal binder, the carbon fibers have good dispersibility in the metal binder phase. At the same time, the metal coating increases the wettability between the carbon fibers and the metal binder, so that the bonding strength at the interface between the carbon fibers and the metal binder can be increased. Therefore, with this grindstone, it is possible to significantly increase the strength of metal bond opening, and improve the grindstone strength and grinding ratio.

In addition, according to this metal bond grindstone, during grinding,
Since the carbon fibers are exposed on the metal binder surface, the coefficient of friction between the metal binder surface and the material to be ground can be significantly lowered, and the grinding resistance of the grindstone can be reduced. Therefore, it is possible to prevent the material to be ground from chipping or sluggishness, and it is possible to prevent the grindstone from overheating.

In addition, the carbon fibers exposed on the metal bond surface partially peel off from the metal bond opening during grinding, forming groove-shaped chip pockets in the traces, which improves the drainage of grinding debris. The grindstone is less likely to become clogged.

Although ordinary carbon fibers were used in the above embodiments, similar effects can be obtained by using silicon carbide fibers, silicon carbide whiskers, or the like.

Experimental Example J Next, an experimental example will be given to demonstrate the effect of the metal bonded grindstone of the present invention.

First, nickel was deposited on the surface of a carbon fiber of a predetermined size using an electroless plating method to form a metal coating.

Next, this carbon fiber was bonded to a metal binder (Cu; 85 vol%, Sn; 15 vol%) together with diamond superabrasive grains.
ol% (also common to the following grindstones) was added in a predetermined amount to the powder, thoroughly mixed, and then molded and fixed to the outer periphery of a disc-shaped base metal.

Furthermore, the obtained molded body was hot-pressed and sintered, shaped into a grindstone, and subjected to treatments such as dressing to obtain a disc-shaped metal bonded grinding wheel of Experimental Example 1.

On the other hand, a disc-shaped metal bonded grinding wheel of Comparative Example 1 was manufactured in the same manner as above except that carbon fiber was not added.

Next, grinding was performed using the above two metal bond grinding wheels under the following grinding conditions (wet type).

Grinding conditions Material to be ground: 96% alumina grinding wheel peripheral speed +
1500x/min.

Feed speed: 10 i/min.

Cross feed " 2u Depth of cut: 0.01'RM In addition, an all-blade type (thin disc-shaped) cutting whetstone without a whetstone base metal was manufactured using substantially the same process as in Experimental Example 1 and Comparative Example 1. , and the metal bond grindstones of Experimental Example 2 and Comparative Example 2.

Next, grinding and cutting were performed using the metal bond grindstones of Experimental Example 2 and Comparative Example 2 under the following conditions (wet type).

Grinding conditions Material to be ground: Ferrite Grinding wheel peripheral speed: l 500 i/min.

Feed speed: l 50 Ri/min.

Depth of cut: 20xx Cutting edge protrusion: 25zx The following table shows the compositions of the four types of metal bond grinding wheels and the grinding results for each.

As is clear from the above table, the metal bonded grindstones of Experimental Examples 1 and 2 were confirmed to have reduced grinding resistance, reduced chipping width, and improved grinding 1 fl ratio compared to each comparative example.

"Effects of the Invention" According to the metal bonded grindstone of the present invention, the following excellent effects can be obtained.

(2) Carbon fibers whose specific gravity is approximately equal to that of the metal binder by being coated with a metal are mixed with the metal binder to produce the carbon fibers, so that the carbon fibers have good dispersibility in the metal binder phase.

At the same time, the metal coating increases the wettability between the carbon fibers and the metal binder, so that the bonding strength at the interface between the carbon fibers and the metal binder can be increased. therefore,
The strength of the metal bond is extremely high, and the strength of the grinding wheel is greatly improved.

■During grinding, carbon fibers are sequentially exposed on the surface of the metal binder tank, so the coefficient of friction between the surface of the metal binder tank and the material to be ground can be significantly lowered, and the grinding resistance of the grindstone can be reduced. Therefore, it is possible to prevent the material to be ground from becoming chipped or sloppy, and the grindstone can be prevented from overheating.

■The carbon fibers exposed on the surface of the metal binder phase partially peel off from the metal bond opening during grinding, and easily fall off while sweeping away the grinding debris from the ground area, forming chip pockets in the traces. Easily removes grinding debris and prevents clogging of the grindstone.

Claims (3)

[Claims] (1) A metal bonded grindstone having an abrasive layer formed by dispersing superabrasive grains in a metal binder phase, characterized in that metal-coated carbon fibers are dispersed in the abrasive layer. Metal bond whetstone. (2) The amount of dispersion of the carbon fibers forming the metal coating is 2 to 2.
The metal bond grindstone according to claim 1, wherein the metal bond grindstone is 30 vol%. (3) The length of the carbon fiber is 0.01 to 1.0 mm, as claimed in claim 1 or 2.
Metal bond whetstone described in section.