Auto adaptable cutting structure

Abstract

A cutter is configured with a diamond table made from a thin hard facing material layer of polycrystalline diamond bonded to a backing layer made from cemented tungsten carbide. The face of the diamond table includes a concavity formed with a curved shape wherein at least a portion of the face in a center of the cutter is recessed with respect to at least some portion of the face about the perimeter of the cutter. This concave curved shape is formed in the diamond table itself such that the diamond table has a varying thickness depending on the implemented concavity. Alternatively, the concave curved shape is formed in the backing layer and a substantially constant thickness diamond table layer is attached thereto.

1 . A cutter, comprising:
 a backing layer; and   a thin hard facing material layer bonded to the backing layer, wherein a thickness of the thin hard facing material layer varies along at least a part of a length of the cutter to define a face of the cutter having a curved surface.   
     
     
         2 . The cutter of  claim 1  wherein the cutter has one of a round, half-round, elliptical and half-elliptical shape. 
     
     
         3 . The cutter of  claim 1  wherein the length of the cutter extends along an orientation axis of the cutter, and the thickness of the thin hard facing material layer in the part of the length varies along that orientation axis. 
     
     
         4 . The cutter of  claim 3  wherein the cutter has a round shape and the orientation axis is a first orientation axis for the round shape, the thickness of the thin hard facing material layer increasing along at least a portion of a length of the first orientation axis. 
     
     
         5 . The cutter of  claim 4  wherein the cutter having the round shape further includes a second orientation axis orthogonal to the first orientation axis, the thickness of the thin hard facing material layer further increasing along at least a portion of a length of the second orientation axis. 
     
     
         6 . The cutter of  claim 3  wherein thickness of the thin hard facing material layer increases in a continuous curved manner along the orientation axis. 
     
     
         7 . The cutter of  claim 3  wherein the cutter has an elliptical shape and the orientation axis is one of a major and minor axis for the elliptical shape, the thickness of the thin hard facing material layer increasing along at least a portion of a length of one of the major and minor axes. 
     
     
         8 . The cutter of  claim 7  wherein the thickness of the thin hard facing material layer increases along at least a portion of a length of both the major and minor axes. 
     
     
         9 . The cutter of  claim 3  wherein the cutter has a half-round shape and the orientation axis is a first orientation axis for the half-round shape, the thickness of the thin hard facing material layer increasing along at least a portion of a length of the first orientation axis. 
     
     
         10 . The cutter of  claim 9  wherein the cutter having the half-round shape further includes a second orientation axis orthogonal to the first orientation axis, the thickness of the thin hard facing material layer further increasing along at least a portion of a length of the second orientation axis. 
     
     
         11 . The cutter of  claim 3  wherein the cutter has a half-elliptical shape and the orientation axis is one of a major and minor axis for the half-elliptical shape, the thickness of the thin hard facing material layer increasing along at least a portion of a length of one of the major and minor axes. 
     
     
         12 . The cutter of  claim 11  wherein the thickness of the thin hard facing material layer increases along at least a portion of a length of both the major and minor axes. 
     
     
         13 . A cutter, comprising:
 a backing layer; and   a thin hard facing material layer bonded to the backing layer, wherein a thickness of the thin hard facing material layer varies to define a paraboloid front surface concavity for the cutter.   
     
     
         14 . The cutter of  claim 13  wherein the paraboloid front surface concavity is defined by a continuously curved surface. 
     
     
         15 . The cutter of  claim 13  wherein the cutter has a round shape and the paraboloid front surface concavity follows a first axis of the cutter round shape. 
     
     
         16 . The cutter of  claim 15  wherein the paraboloid front surface concavity also follows a second axis of the cutter round shape which is perpendicular to the first axis. 
     
     
         17 . The cutter of  claim 15  wherein round cutter shape is a half-round shape. 
     
     
         18 . The cutter of  claim 13  wherein the cutter has an elliptical shape and the paraboloid front surface concavity follows one of a major or minor axis of the elliptical round shape. 
     
     
         19 . The cutter of  claim 18  wherein the elliptical shape is a half-elliptical shape. 
     
     
         20 . The cutter of  claim 13  wherein the cutter has an elliptical shape and the paraboloid front surface concavity follows both of a major and minor axis of the elliptical round shape. 
     
     
         21 . The cutter of  claim 20  wherein the elliptical shape is a half-elliptical shape. 
     
     
         22 . The cutter of  claim 13  wherein the paraboloid front surface concavity comprises a first portion of a face of the cutter, and wherein a thickness of the thin hard facing material layer in a second portion of the face of the cutter is substantially constant. 
     
     
         23 . A cutter, comprising:
 a cylindrical backing layer having a front surface; and   a thin hard facing material layer bonded to the front surface of the backing layer, the thin hard facing material layer having a front surface including a paraboloid concavity.   
     
     
         24 . The cutter of  claim 23  wherein the paraboloid concavity is defined by a continuously curved surface. 
     
     
         25 . The cutter of  claim 23  wherein the paraboloid concavity is a spherical cavity. 
     
     
         26 . The cutter of  claim 23  wherein the paraboloid concavity is an elliptical paraboloid cavity. 
     
     
         27 . The cutter of  claim 23  wherein the paraboloid concavity is a hyperbolic paraboloid cavity. 
     
     
         28 . The cutter of  claim 23  wherein a thickness of the thin hard facing material layer varies across the front surface of the backing layer to define the paraboloid concavity. 
     
     
         29 . The cutter of  claim 23  wherein a thickness of the cylindrical backing layer varies across the front surface of the backing layer, and the thin hard facing material layer has a substantially constant thickness, so as to define the paraboloid concavity. 
     
     
         30 . A drill bit, comprising:
 a bit matrix including a cutter pocket formed therein;   a cutter, comprising:
 a backing layer which is attached by brazing to the cutter pocket; and 
 a thin hard facing material layer bonded to the backing layer, wherein a thickness of the thin hard facing material layer is not constant so as to define curved cutter surface presenting a counter angle. 
   
     
     
         31 . The drill bit of  claim 30  wherein the curved surface of the cutter defines a variable back rake angle as a function of depth of cut. 
     
     
         32 . The drill bit of  claim 30  wherein the cutter has one of a round, half-round, elliptical and half-elliptical shape. 
     
     
         33 . The drill bit of  claim 30  wherein the curved surface of the cutter defines a variable back rake angle as a function of depth of cut extending from a positive angle to a negative angle. 
     
     
         34 . The drill bit of  claim 30  wherein the curved surface defines a concave front surface of the cutter. 
     
     
         35 . The drill bit of  claim 30  wherein the curved surface defines a parabolic front surface of the cutter. 
     
     
         36 . A drill bit, comprising:
 a bit matrix including a cutter pocket formed therein;   a cutter, comprising:
 a cylindrical backing layer which is attached by brazing to the cutter pocket and which defines a relief angle; and 
 a thin hard facing material layer bonded to the front surface of the backing layer, the thin hard facing material layer having a front surface including a paraboloid concavity which defines both a counter angle and back rake angle; 
   wherein the back rake angle and relief angle are not equal to each other.   
     
     
         37 . The drill bit of  claim 36  wherein the back rake angle is a positive back rake angle. 
     
     
         38 . The drill bit of  claim 36  wherein the counter angle of the paraboloid concavity is such that the back rake angle is a positive back rake angle over a range of depth of cut. 
     
     
         39 . The drill bit of  claim 38  wherein the back rake angle varies over that range of depth of cut. 
     
     
         40 . The drill bit of  claim 36  wherein the paraboloid concavity is defined by a continuously curved surface. 
     
     
         41 . The drill bit of  claim 36  wherein the paraboloid concavity is a spherical cavity. 
     
     
         42 . The drill bit of  claim 36  wherein the paraboloid concavity is an elliptical paraboloid cavity. 
     
     
         43 . The drill bit of  claim 36  wherein the paraboloid concavity is a hyperbolic paraboloid cavity. 
     
     
         44 . The drill bit of  claim 36  wherein a thickness of the thin hard facing material layer varies across the front surface of the backing layer to define the paraboloid concavity. 
     
     
         45 . The drill bit of  claim 36  wherein a thickness of the cylindrical backing layer varies across the front surface of the backing layer, and the thin hard facing material layer has a substantially constant thickness, so as to define the paraboloid concavity.