Cutting element and methods of making same

Abstract

A cutting element includes a substrate having a peripheral side edge, the peripheral side edge having an associated radius of curvature; and a body of superhard polycrystalline material bonded to the substrate along an interface, the body of superhard polycrystalline material having a peripheral side edge and a longitudinal axis. The body of superhard polycrystalline material has a working surface; and a plurality of spaced apart cutting edges extending to the working surface through respective chamfer portions, the cutting edges being spaced around the working surface by a further region. The cutting edges have an associated radius of curvature, the radius of curvature of one or more of the cutting edges being less than the radius of curvature of the substrate. A method of making such a cutting element is also disclosed.

1 . A cutting element comprising:
 a substrate having a peripheral side edge, the peripheral side edge having an associated radius of curvature; and   a body of superhard polycrystalline material bonded to the substrate along an interface, the body of superhard polycrystalline material having a peripheral side edge and a longitudinal axis; wherein:   the body of superhard polycrystalline material comprises:   a working surface; and   a plurality of spaced apart cutting edges extending to the working surface through respective chamfer portions, the cutting edges being spaced around the working surface by a further region; wherein   the cutting edges have an associated radius of curvature, the radius of curvature of one or more of the cutting edges being less than the radius of curvature of the substrate.   
     
     
         2 . A cutting element according to  claim 1 , further comprising a protrusion or recessed region extending from the working surface about a central longitudinal axis of the cutting element. 
     
     
         3 . The cutting element of  claim 1 , wherein the body of superhard polycrystalline material comprises any one or more of polycrystalline diamond, diamond-like carbon, or cubic boron nitride of natural and/or synthetic origin. 
     
     
         4 . The cutting element of  claim 1 , comprising three or more cutting edges. 
     
     
         5 . The cutting element of  claim 1 , wherein the working surface comprises an undulating topology. 
     
     
         6 . The cutting element of  claim 1 , wherein the working surface comprises a recessed region extending to a position between around 0.5 mm to around 2 mm above the interface between the body of superhard polycrystalline material and the substrate. 
     
     
         7 . The cutting element of  claim 1 , wherein the chamfers extend at an inclined angle to the plane along which the longitudinal axis of the cutting element extends. 
     
     
         8 . The cutting element of  claim 1 , wherein the body of superhard polycrystalline material comprises polycrystalline diamond material having inter-bonded diamond grains with interstitial spaces between the inter-bonded diamond grains, at least a portion of the interstitial spaces being substantially free of metal solvent catalyst material. 
     
     
         9 . The cutting element of  claim 1 , wherein the radius of curvature of one or more of the cutting edges is between around 2 mm to around 16 mm. 
     
     
         10 . The cutting element of  claim 1 , wherein the working surface has a central recess therein having a depth in a plane parallel to the longitudinal axis of the cutting element measured from the highest point on the working surface to the bottom of the recess of between around 0.5 mm to around 2.5 mm; and/or the distance along said axis from the bottom of the central recess to the interface with the substrate is between around 1 to around 2 mm. 
     
     
         11 . The cutting element of  claim 1 , wherein the further region between the plurality of spaced apart cutting edges extends between the working surface and the peripheral side edge of the body of superhard polycrystalline material, the further region being arcuate in a plane parallel to the longitudinal axis. 
     
     
         12 . The cutting element of  claim 11 , wherein the further region is concave in a plane parallel to the longitudinal axis. 
     
     
         13 . An earth-boring tool, comprising:
 a body; and   at least one cutting element according to  claim 1  attached to the body.   
     
     
         14 . A method of making the cutting element of  claim 1  comprising:
 providing a mass of particles or grains of superhard material to form a pre-sinter assembly; and 
 treating the pre-sinter assembly in the presence of a catalyst/solvent material for the superhard grains at an ultra-high pressure of around 5.5 GPa or greater and a temperature at which the superhard material is more thermodynamically stable than graphite to sinter together the grains of superhard material to form the cutting element. 
 
     
     
         15 . A method according to  claim 14 , wherein the step of providing a mass of grains of superhard material comprises providing a mass of diamond grains to form a body of polycrystalline diamond material. 
     
     
         16 . A method according to  claim 14 , wherein the step of treating the pre-sinter assembly comprises treating the pre-sinter assembly in a canister that is shaped to create any one or more of the plurality of spaced apart cutting edges extending to the working surface through respective chamfer portions, the topology of the working surface, or the topology of the peripheral side surface. 
     
     
         17 . A method according to  claim 14 , further comprising processing the cutting element after the step of treating the pre-sinter assembly to create any one or more of the plurality of spaced apart cutting edges extending to the working surface through respective chamfer portions, the topology of the working surface, or the topology of the peripheral side surface, wherein the step of processing comprises using any one or more of laser ablation or EDM machining. 
     
     
         18 . A drill bit or a component therefor comprising the cutting element according to  claim 1 .