Abrasive article and method for making the same

Abstract

An abrasive article comprising a plurality of abrasive grains that are precisely arranged in accordance with a predetermined pattern and are chemically bonded with a matrix material, and a method for the making thereof are disclosed. A coating layer on each of the abrasive grains functions as a bridge to form chemical bonding between the abrasive grains and the matrix material. In addition to a plated material, the matrix material can include a braze, a solder, a sintered material, an infiltrant, an organic material, and a vitrified material. The method for making the abrasive article comprises the steps of: coating abrasive grains with a coating layer that chemically bonds to each of the abrasive grains; arranging the coated abrasive grains in accordance with a predetermined pattern; and chemically bonding the coated abrasive grains with a matrix material.

Description

TECHNICAL FIELD[0001]The present invention relates generally to abrasive articles and processes for producing the same. More particularly, the present invention relates to an abrasive tool which comprises abrasive grains chemically bonded and precisely arranged in accordance with a predetermined pattern. Accordingly, the present invention involves the fields of materials science, mechanical engineering, and physics.BACKGROUND ART[0002]Diamond, the hardest abrasive currently known, is widely used on saws, drills, and other devices to cut, form, or polish materials such as aluminum, copper, carbide alloy, stone, concrete, asphalt, glass, ceramics, gem stone, semiconductor materials, rubber and resin, while the other super abrasive tool, cubic boron nitride (CBN) tool, is suitable to process steels including common steels and various tough alloy steels. According to their manufacturing methods or bond types, abrasive tools can be categorized into several types, such as metal-bonded (i....

AI Technical Summary

Benefits of technology

The present invention provides a way to increase the service life of expensive abrasive particles and minimize costs by reducing the amount of abrasive particles needed in a customized particle pattern while maximizing efficiency and performance characteristics by using previously coated abrasive grains that enable chemical bonding and precise arrangement of grains in abrasive products. This results in a non-uniform pattern that compensates for uneven wear and includes reinforced areas with higher concentration of grains, more abrasive type of grains, higher quality of grains, harder matrix, smaller size of grains, lower protrusion height of grains, less apex-oriented and more face-oriented grains towards the workpiece, or combinations thereof.

Problems solved by technology

Despite their practical use in industries, a number of issues continue to hamper the performance and usable life of abrasive tools.

For example, grain retention remains problematic.

As a result, grains are often pulled out prematurely, or the height of protrusion of grains is compromised, e.g. less than ⅓ to ½ of the average diameter of the particles, resulting in a limited cutting ability.

Another limitation associated with the conventional abrasive tools is that the grains are not arranged to maximize efficiency for cutting, drilling, grinding, polishing, etc.

Though abrasive tools with abrasive chemically bonded and regularly arranged have been successfully developed by brazing (WO2012 / 162430, WO2010 / 141464, U.S. Pat. No. 6,416,560, U.S. Pat. No. 6,679,243 and U.S. Pat. No. 8,104,464), the bonding strength between grains and brazed material is limited because of thermal residual stress induced during cooling period from high brazing temperature; degradation of grain surface (e.g. graphitization of diamond) because of high brazing temperature; and compromises made when selecting material, temperature and equipment for the brazing process.

In addition, it is difficult for brazing method to achieve accurate grain positioning pattern and protruding height because of further movement of placed particles following melting of the brazing material.

It is also difficult or even impossible for the brazing technique to obtain products with thin blade, high precision and complex shape by means of lower cost.

But no chemical bonding is reported in these tools probably due to the use of naked abrasive grains which have unique surface characteristics (e.g. bad wettability and non-platability of diamond).

In addition, spaces are left among the abrasive grains and pores are fully uniformly dispersed in the electrodeposited abrasive layer (U.S. Pat. No. 4,547,998), which markedly decreases the abrasive retention.

But, the abrasive retention is compromised.

Further, a vitreous bond tool wherein the grains are arranged in a predetermined pattern is reported in U.S. Pat. No. 6,755,720, but no chemical bonding is achieved.

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