Brazed diamond dressing tool

Abstract

A dressing blade for finishing and reconditioning new and used abrasive grinding and cutting tools has a slab-shaped shank with an extension protruding longitudinally from the shank. Superabrasive grains are disposed on the surface of the extension and held in place by a brazed metal composition. This composition is formed by brazing a powdered mixture of brazing metal components and active metal components. Specific extension configurations are provided which allow aligning the superabrasive grains in single layer arrangement for precise dressing and simple fabrication of the tool. The novel dressing tool exhibits excellent wear characteristics.

1 . A dressing blade for conditioning abrasive tools comprising (i) a slab-shaped metal shank defining a flat base and a flat top parallel to the base and having an extension protruding longitudinally from an end of the shank, (ii) superabrasive grains and (iii) a brazed metal composition operative to chemically bond the superabrasive grains to the extension, wherein the brazed metal composition is a thermally densified mass comprising a brazing metal component and an active metal component, and wherein the superabrasive grains are uniformly dispersed within the brazed metal composition and are in a single layer in contact with each adjacent grain.  
   
   
       2 . The dressing blade of  claim 1  wherein the superabrasive grains are selected from the group consisting of diamond grains, cubic boron nitride grains and mixtures thereof.  
   
   
       3 . The dressing blade of  claim 2  wherein the superabrasive grains are diamond grains.  
   
   
       4 . The dressing blade of  claim 1  wherein the active metal component is selected from the group consisting of titanium, zirconium, chromium, hafnium, and their hydrides, and alloys and combinations thereof.  
   
   
       5 . The dressing blade of  claim 4  wherein the active metal component is titanium or a hydride thereof.  
   
   
       6 . The dressing blade of  claim 1  wherein the brazing metal component comprises metals selected from the group consisting of copper, silver, tin, zirconium, silicon and iron.  
   
   
       7 . The dressing blade of  claim 1  wherein the brazing metal component comprises copper and tin.  
   
   
       8 . The dressing blade of  claim 5  wherein the brazing metal component comprises copper and tin.  
   
   
       9 . The dressing blade of  claim 5  wherein the brazed metal composition comprises about 50-90 wt. % copper, about 5-35 wt. % tin and about 5-15 wt. % of titanium or a hydride thereof.  
   
   
       10 . The dressing blade of  claim 9  wherein the brazed metal composition comprises about 50-80 wt. % copper, about 15-25 wt. % tin and about 5-15 wt. % of titanium or a hydride thereof.  
   
   
       11 . The dressing blade of  claim 1  wherein the brazed metal composition comprises about 70 wt. % copper, about 21 wt. % tin and about 9 wt. % titanium or a hydride thereof.  
   
   
       12 . A dressing blade for conditioning abrasive tools comprising (i) a slab-shaped metal shank defining a flat base and a flat top parallel to the base and having a metal extension protruding longitudinally from an end of the shank, (ii) and an abrasive portion comprising superabrasive grains and a brazed metal composition operative to bond the superabrasive grains to the extension, wherein the extension is a flat sheet having one side flush with the base and the opposite side defining a flat face, and in which the superabrasive grains are uniformly dispersed within the brazed metal composition, positioned adjacent to the flat face and are in a single layer such that each grain is in lateral contact with each adjacent grain.  
   
   
       13 . The dressing blade of  claim 12  wherein all the superabrasive grains are about the same size having a characteristic diameter, and the superabrasive grains and brazed metal composition define an abrasive layer having a thickness of less than two characteristic diameters.  
   
   
       14 . The dressing tool of  claim 12  wherein the blade further comprises a pair of side panels each of which panels is positioned at opposite lateral sides of the extension to define a single channel therebetween adapted to contain the superabrasive grains and the brazed metal composition.  
   
   
       15 . The dressing blade of  claim 14  wherein the side panels have a height extending from the base to the top of the shank along their full lengths.  
   
   
       16 . The dressing blade of  claim 14  wherein the side panels have a height extending from the base to below the top of the shank along a portion of their lengths.  
   
   
       17 . The dressing blade of  claim 16  wherein the extension further comprises an end panel positioned at an extremity of the extension longitudinally distant from the shank such that the end panel, the side panels and shank define a single tray therebetween adapted to contain the superabrasive grains and brazed metal composition.  
   
   
       18 . A dressing blade for conditioning abrasive tools comprising (i) a slab-shaped metal shank defining a flat base and a flat top parallel to the base and having a metal extension protruding longitudinally from an end of the shank, (ii) and an abrasive portion comprising superabrasive grains and a brazed metal composition operative to bond the superabrasive grains to the extension, wherein the superabrasive grains are uniformly dispersed within the brazed metal composition and are in a single layer in contact with each adjacent grain and wherein the extension comprises a plurality of elongated flat walls parallel to each other and perpendicular to the base of the shank to form elongated alleys between consecutive walls, and in which the superabrasive grains and brazed metal composition are positioned in the alleys.  
   
   
       19 . The dressing blade of  claim 18  wherein all the superabrasive grains are about the same size defined by a characteristic diameter and the walls have a height less than two characteristic diameters.  
   
   
       20 . The dressing blade of  claim 19  wherein the walls are laterally spaced apart by a distance less than two characteristic diameters and the superabrasive grains within each alley are aligned in a single row extending longitudinally from the shank.  
   
   
       21 . The dressing blade of  claim 18  wherein the extension further comprises a flat sheet having one side flush with the base and in which the walls extend from the opposite side of the flat sheet.  
   
   
       22 . The dressing blade of  claim 18  wherein the extension further comprises a plurality of flat sheets extending longitudinally from the shank, the sheets being alternately aligned flush with the top and the base and extending between pairs of walls to form an orthogonal serpentine lateral cross section, thereby enclosing the superabrasive grains and brazed metal composition of laterally successive alleys alternately at planes flush with the base and with the top of the shank.  
   
   
       23 . The dressing blade of  claim 1  wherein the brazed metal composition further comprises a plurality of particles of a hard component other than diamond and having a Rockwell C hardness of at least about 1000 Knoop.  
   
   
       24 . The dressing blade of  claim 23  wherein the hard component is a compound selected from the group consisting of tungsten carbide, titanium boride, silicon carbide, aluminum oxide, chromium boride, chromium carbide and combinations thereof.  
   
   
       25 . The dressing blade of  claim 1  wherein the brazed metal composition further comprises an infiltrant component operative to eliminate all porosity of the brazed metal composition.  
   
   
       26 . The dressing blade of  claim 1  wherein the extension is a flat sheet having one side flush with the base and the opposite side defining a flat face, and in which the superabrasive grains are positioned adjacent to the flat face, and wherein the brazed metal composition comprises about 50-90 wt. % copper, about 5-35 wt. % tin and about 5-15 wt. % of titanium or a hydride thereof.  
   
   
       27 . The dressing blade of  claim 26  wherein the extension further comprises a pair of side panels each of which panels is positioned at opposite lateral sides of the extension to define a single channel therebetween adapted to contain the superabrasive grains and the brazed metal composition, and wherein the brazed metal composition comprises about 50-90 wt. % copper, about 5-35 wt. % tin and about 5-15 wt. % of titanium or a hydride thereof.  
   
   
       28 . The dressing blade of  claim 1  wherein the extension comprises a plurality of flat walls parallel to each other and perpendicular to the base of the shank to form elongated alleys between consecutive walls, wherein the superabrasive grains and brazed metal composition are positioned in the alleys, and wherein the brazed metal composition comprises about 50-90 wt. % copper, about 5-35 wt. % tin and about 5-15 wt. % of titanium or a hydride thereof.  
   
   
       29 . A method for preparing a dressing blade for conditioning abrasive tools comprising: 
 a) providing a slab-shaped metal shank defining a flat base and a flat top parallel to the base and having an extension protruding longitudinally from an end of the shank;    b) applying to the extension a layer of brazing metal composition comprising a brazing metal component and an active metal component;    c) pressing superabrasive grains into the paste to form a single layer of superabrasive grains in lateral contact with each other to obtain a blade precursor; and    d) heating the blade precursor to liquefy the brazing metal composition and create a bond between the components of the brazing metal composition and the superabrasive grains.    
   
   
       30 . The method of  claim 29  wherein the extension comprises a flat sheet having one side flush with the base and the opposite side defining a flat face.  
   
   
       31 . The method of  claim 30  wherein the extension further comprises a pair of side panels each of which panels is positioned at opposite lateral sides of the extension to define a single channel therebetween adapted to contain the superabrasive grains and the brazed metal composition.  
   
   
       32 . The method of  claim 31  wherein the extension further comprises an end panel positioned at an extremity of the blade longitudinally distant from the shank such that the end panel, the side panels and shank define a single tray therebetween adapted to contain the superabrasive grains and brazed metal composition.  
   
   
       33 . The method of  claim 29  wherein the extension comprises a plurality of flat walls parallel to each other and perpendicular to the base of the shank to form elongated alleys between consecutive walls, and in which the superabrasive grains and brazed metal composition are positioned in the alleys.  
   
   
       34 . The method of  claim 33  wherein the extension further comprises a flat sheet having one side flush with the base and in which the walls extend from the opposite side of the flat sheet.  
   
   
       35 . The method of  claim 33  wherein the extension further comprises a plurality of flat sheets extending longitudinally from the shank, the sheets being alternately aligned flush with the top and the base and extending between pairs of walls to form an orthogonal serpentine lateral cross section, thereby enclosing the superabrasive grains and brazed metal composition of laterally successive alleys alternately at planes flush with the base and with the top of the shank.  
   
   
       36 . The dressing blade of  claim 18  in which a plurality of superabrasive grains are in each alley.