Aggregate abrasive grains for abrading or cutting tools production

Abstract

Aggregate abrasive grains are formed for use in the production of abrading or cutting tools by providing abrasive core particles, coating these particles with adhesive, and separately dropping the adhesive coated core particles onto a layer of abrasive peripheral particles. The method further includes covering the dropped core particles with further peripheral particles, in a way to form aggregate particles, each of which includes a core particle having peripheral particles attached to it. The adhesive includes a binding agent and a solvent for the binding agent. Finally, the aggregate particles are consolidated by causing the solvent to evaporate, i.e. by letting the adhesive set.

1 .- 26 . (canceled) 
     
     
         27 . An apparatus for forming aggregate abrasive grains for use in the production of abrading or cutting tools, each of said aggregate abrasive grains comprising an abrasive core particle and several abrasive peripheral particles disposed around the core particle, wherein said apparatus comprises:
 a first chute for separately dropping core particles coated with adhesive onto the layer of abrasive particles;   at least one spraying nozzle suitably arranged for coating said core particles with adhesive as they drop from said first chute;   a conveyor belt for carrying a layer of peripheral particles under said first chute, so that said core particles may drop onto said layer of peripheral particles;   a second chute suitably arranged with respect to the said first chute for covering the core particles dropped on the layer of peripheral particles with further peripheral particles, in such a way as to form aggregate particles, each of which comprises a core particle having peripheral particles attached to it;   a heating chamber through which said conveyor belt carries said aggregate particles for causing said solvent to evaporate.   
     
     
         28 . An aggregate particle comprising
 a core diamond having a size between 14 mesh and 60 mesh and   a plurality of peripheral diamonds having a size between 25 mesh and 400 mesh,   wherein the ratio of the size of the peripheral diamonds to the size of the core diamond being comprised in the range from 1/2 to 1/31 and wherein the peripheral diamonds are disposed around the core diamond and are attached to the core diamond with diamond-diamond bonds.   
     
     
         29 . The aggregate particle according to  claim 28 , wherein said core diamond is a monocrystalline diamond. 
     
     
         30 . The aggregate particle according to  claim 28 , wherein said peripheral diamonds are monocrystalline diamonds. 
     
     
         31 . The aggregate particle according to  claim 28 , wherein all said peripheral diamonds disposed around said core diamond belong to a specific class among −25/+30 mesh, −30/+35 mesh, −35/+40 mesh, −40/+50 mesh, −50/+60 mesh, −60/+70 mesh, −70/+80 mesh, −80/+100 mesh, −100/+120 mesh, −120/+140 mesh, −140/+170 mesh, −170/+200 mesh, −200/+230 mesh, −230/+270 mesh, −270/+325 mesh and −325/+400 mesh. 
     
     
         32 . Diamond network comprising aggregate particles according to  claim 28 . 
     
     
         33 . PCD cutter comprising aggregate particles according to  claim 28 . 
     
     
         34 . PCD cutter comprising a substrate and a PCD tablet bonded to said substrate, wherein said PCD tablet comprises a diamond network according to  claim 32 . 
     
     
         35 . PCD cutter comprising a substrate and a PCD tablet bonded to said substrate, wherein said substrate contains aggregate particles according to  claim 28 .