Disc Cutter for an Earth Boring System

Abstract

In one aspect of the present invention a disc cutter for an earth boring system includes an axle and a sintered polycrystalline ceramic disc disposed about and forming a continuous perimeter around the axle. The disc cutter may be attached to a drill bit comprising a body, working face and plurality of blades. Another aspect of the present invention comprises a method of forming a disc cutter including providing a can of a generally cylindrical shape with a central axis, positioning a column of disposable material, carbide, and crystalline grains in such a manner so when put under high temperature and high pressure a compact in the shape of a disc cutter may be formed and a column from the center axis may be removed. Another method for forming a disc cutter comprises forming a plurality of compacts and bonding the compacts together in a generally toroidal shape.

1 . A disc cutter for an earth boring system, comprising:
 an axle;   a sintered polycrystalline ceramic disc disposed about the axle; and   the ceramic disc forming a continuous perimeter around the axle.   
     
     
         2 . The disc cutter of  claim 1 , wherein the axle comprises a polycrystalline ceramic layer disposed on an exterior surface of the axle. 
     
     
         3 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc is composed of a uniform polycrystalline ceramic material. 
     
     
         4 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc comprises a carbide core proximate the axle and a sintered polycrystalline ceramic external layer bonded to the carbide core. 
     
     
         5 . The disc cutter of  claim 4 , wherein the carbide core comprises a polycrystalline ceramic interior layer proximate the axle. 
     
     
         6 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc is freely rotatable about the axle 
     
     
         7 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc is fixed to the axle. 
     
     
         8 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc comprises grooves. 
     
     
         9 . The disc cutter of  claim 8 , wherein the grooves originate from a rim of the sintered polycrystalline ceramic disc and terminate at the axle. 
     
     
         10 . The disc cutter of  claim 8 , wherein the grooves are continuous around the axle. 
     
     
         11 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc comprises protrusions extending from and adding texture to the ceramic disc. 
     
     
         12 . The disc cutter of  claim 1 , wherein the sintered polycrystalline ceramic disc comprises two parallel cutting edges comprising supplemental internal angles. 
     
     
         13 . The disc cutter of  claim 1 , wherein the disc comprises a rim comprising an internal angle measuring 80 to 140 degrees between two parallel cutting edges each comprising an internal angle greater than 90 degrees. 
     
     
         14 . The disc cutter of  claim 13 , wherein the sintered polycrystalline ceramic disc comprises a carbide core and a distance from at least one cutting edge to the carbide core is equal to a distance from the rim to the carbide core. 
     
     
         15 . The disc cutter of  claim 1 , further comprising a plurality of sintered polycrystalline ceramic discs. 
     
     
         16 . A drill bit for penetrating earthen formations, comprising:
 a body comprising a working face;   the working face comprising a plurality of blades converging toward a center of the working face and diverging toward a gauge of the working face;   an axle bonded to one of the plurality of blades; and   a sintered polycrystalline ceramic disc disposed about the axle and the disc forming a continuous perimeter around the axle.   
     
     
         17 . The drill bit of  claim 16 , further comprising at least one shear cutter disposed on one of the plurality of blades. 
     
     
         18 . The drill bit of  claim 16 , wherein the axle is bonded to one of the plurality of blades at the gauge of the working face. 
     
     
         19 . The drill bit of  claim 16 , wherein the sintered polycrystalline ceramic disc is aligned tangent to a periphery of the working face. 
     
     
         20 . The drill bit of  claim 16 , wherein the sintered polycrystalline ceramic disc is aligned perpendicular to the working face.