Earth-boring tools having pockets for receiving cutting elements therein and methods of forming such pockets and earth-boring tools

Abstract

Methods of forming cutting element pockets in earth-boring tools include machining at least one recess to define at least one surface of a cutting element pocket using a cutter oriented at an angle to a longitudinal axis of the cutting element pocket. Methods of forming earth-boring tools include forming a bit body and forming at least one cutting element pocket therein using a rotating cutter oriented at an angle relative to a longitudinal axis of the cutting element pocket being formed. Earth-boring tools have a bit body comprising a first surface defining a lateral sidewall of a cutting element pocket, a second surface defining an end wall of the cutting element pocket, and another surface defining a groove located between the first and second surfaces that extends into the body to enable a cutting element to abut against an area of the lateral sidewall and end wall of the pocket.

1 . A method of forming a cutting element pocket in an earth-boring tool, the method comprising:
 machining a first recess in an earth-boring tool and defining a lateral sidewall surface of a cutting element pocket using a rotating cutter oriented at an angle relative to a longitudinal axis of the cutting element pocket;   machining a second recess in the earth-boring tool and defining at least a portion of an end surface of the cutting element pocket; and   forming the lateral sidewall surface and the end surface of the cutting element pocket to enable a generally cylindrical cutting element to simultaneously abut against an area of each of the lateral sidewall surface and the end surface of the cutting element pocket.   
   
   
       2 . The method of  claim 1 , wherein using a rotating cutter comprises using an endmill cutter. 
   
   
       3 . The method of  claim 2 , wherein using an endmill cutter comprises using a ballnose endmill cutter. 
   
   
       4 . The method of  claim 1 , wherein machining a second recess further comprises machining the second recess after machining the first recess. 
   
   
       5 . The method of  claim 1 , wherein machining a second recess further comprises machining the second recess prior to machining the first recess. 
   
   
       6 . The method of  claim 1 , wherein machining a second recess further comprises using the same rotating cutter used to machine the first recess to machine the second recess. 
   
   
       7 . The method of  claim 6 , wherein using the same rotating cutter used to machine the first recess to machine the second recess further comprises orienting the rotating cutter at an angle relative to the longitudinal axis of the cutting element pocket while machining the second recess. 
   
   
       8 . The method of  claim 1 , wherein machining a second recess in the drill bit comprises machining a groove in a surface of the drill bit exposed within the first recess. 
   
   
       9 . The method of  claim 8 , wherein machining a groove comprises machining a groove, at least a portion of the groove having a generally annular shape. 
   
   
       10 . The method of  claim 1 , wherein machining a second recess in the drill bit comprises machining a generally planar recess in the drill bit oriented substantially transverse to the longitudinal axis of the cutting element pocket. 
   
   
       11 . The method of  claim 10 , wherein machining the first recess further comprises causing the first recess to intersect the generally planar recess. 
   
   
       12 . The method of  claim 1 , wherein forming the lateral sidewall surface and the end surface of the cutting element pocket to enable a generally cylindrical cutting element to simultaneously abut against each of the lateral sidewall surface and the end surface of the cutting element pocket comprises causing at least a portion of the second recess to extend in a generally radially outward direction from the longitudinal axis of the cutting element pocket beyond at least a portion of the lateral sidewall surface of the cutting element pocket. 
   
   
       13 . A method of forming an earth-boring tool, the method comprising: forming a bit body; and
 forming at least one cutting element pocket in the bit body, comprising:
 machining a first recess in a surface of the bit body and defining a lateral sidewall surface of a cutting element pocket using a rotating cutter oriented at an angle relative to a longitudinal axis of the cutting element pocket; 
 machining a second recess in the bit body and defining at least a portion of an end surface of the cutting element pocket; and 
 forming the lateral sidewall surface and the end surface of the cutting element pocket to enable a generally cylindrical cutting element to simultaneously abut against an area of each of the lateral sidewall surface and the end surface of the cutting element pocket. 
   
   
   
       14 . The method of  claim 13 , wherein forming a bit body comprises:
 providing a powder mixture; and   pressing the powder mixture to form a green bit body.   
   
   
       15 . The method of  claim 14 , wherein at least one of machining a first recess and machining a second recess comprises machining the green bit body. 
   
   
       16 . The method of  claim 14 , wherein forming a bit body further comprises partially sintering the green bit body to form a brown bit body. 
   
   
       17 . The method of  claim 16 , wherein at least one of machining a first recess and machining a second recess comprises machining the brown bit body. 
   
   
       18 . The method of  claim 17 , wherein forming a bit body further comprising sintering the brown bit body to a desired final density. 
   
   
       19 . The method of  claim 14 , wherein forming a bit body further comprises sintering the green bit body to a desired final density. 
   
   
       20 . The method of  claim 19 , wherein at least one of machining a first recess and machining a second recess comprises machining the bit body after sintering the green bit body to a desired final density. 
   
   
       21 . The method of  claim 14 , wherein forming a bit body comprises forming a bit body comprising a particle-matrix composite material. 
   
   
       22 . The method of  claim 13 , wherein forming a bit body comprises forming a bit body predominantly comprised of a metal or metal alloy. 
   
   
       23 . The method of  claim 22 , wherein forming a bit body comprises forming a steel bit body. 
   
   
       24 . The method of  claim 13 , wherein using a rotating cutter comprises using an endmill cutter. 
   
   
       25 . The method of  claim 24 , wherein using an endmill cutter comprises using a ballnose endmill cutter. 
   
   
       26 . The method of  claim 13 , wherein machining a second recess further comprises machining the second recess after machining the first recess. 
   
   
       27 . The method of  claim 13 , wherein machining a second recess further comprises machining the second recess prior to machining the first recess. 
   
   
       28 . The method of  claim 13 , wherein machining a second recess further comprises using the same rotating cutter used to machine the first recess to machine the second recess. 
   
   
       29 . The method of  claim 28 , wherein using the same rotating cutter used to machine the first recess to machine the second recess further comprises orienting the rotating cutter at an angle relative to the longitudinal axis of the cutting element pocket while machining the second recess. 
   
   
       30 . The method of  claim 13 , wherein machining a second recess in the bit body comprises machining a groove in a surface of the bit body exposed within the first recess. 
   
   
       31 . The method of  claim 30 , wherein machining a groove comprises machining a groove, at least a portion of the groove having a generally annular shape. 
   
   
       32 . The method of  claim 13 , wherein machining a second recess in the bit body comprises machining a generally planar recess in the bit body oriented substantially transverse to the longitudinal axis of the cutting element pocket. 
   
   
       33 . The method of  claim 32 , wherein machining the first recess further comprises causing the first recess to intersect the generally planar recess. 
   
   
       34 . The method of  claim 13 , further comprising:
 securing a cutting element within the at least one cutting element pocket; and   filling at least a portion of a void within at least one of the first recess and the second recess around the cutting element with a filler material.   
   
   
       35 . The method of  claim 34 , wherein filling at least a portion of a void within at least one of the first recess and the second recess around the cutting element with a filler material comprises filling the at least a portion of the void with at least one of a brazing alloy, a soldering alloy, a welding alloy, and a hardfacing material. 
   
   
       36 . The method of  claim 34 , wherein filling at least a portion of a void within at least one of the first recess and the second recess around the cutting element with a filler material comprises filling the at least a portion of the void with a preformed solid structure. 
   
   
       37 . The method of  claim 36 , wherein filling the at least a portion of the void with a preformed solid structure comprises at least one of brazing, welding, and flamespraying the preformed solid structure to the bit body. 
   
   
       38 . The method of  claim 36 , wherein filling the at least a portion of the void with a preformed solid structure further comprises forming the preformed solid structure to comprise a particle-matrix composite material. 
   
   
       39 . An earth-boring tool having a bit body comprising:
 a first surface defining a lateral sidewall surface of a cutting element pocket, at least a portion of the first surface having a generally cylindrical shape centered about a longitudinal axis of the cutting element pocket;   a substantially planar second surface defining a back end surface of the cutting element pocket; and   at least one additional surface defining a groove located between the first surface and the second surface and extending into the bit body in a generally radially outward direction from the longitudinal axis of the cutting element pocket beyond the at least a portion of the first surface.   
   
   
       40 . The earth-boring tool of  claim 39 , wherein the bit body is predominantly comprised of steel. 
   
   
       41 . The earth-boring tool of  claim 39 , wherein the bit body is predominantly comprised of a particle-matrix composite material. 
   
   
       42 . The earth-boring tool of  claim 39 , further comprising a cutting element secured within the at least one cutting element pocket. 
   
   
       43 . The earth-boring tool of  claim 42 , further comprising a filler material disposed within at least a portion of the at least one cutting element pocket around the cutting element. 
   
   
       44 . The earth-boring tool of  claim 43 , wherein the filler material comprises at least one of a brazing alloy, a soldering alloy, a welding alloy, and a hardfacing material. 
   
   
       45 . The earth-boring tool of  claim 43 , wherein the filler material comprises a preformed solid structure. 
   
   
       46 . The earth-boring tool of  claim 45 , wherein the preformed solid structure is at least one of brazed, welded, and flamesprayed to the bit body. 
   
   
       47 . The earth-boring tool of  claim 45 , wherein the preformed solid structure comprises a particle-matrix composite material. 
   
   
       48 . A method of forming an earth-boring tool, the method comprising:
 forming a bit body; and   forming at least one cutting element pocket in the bit body, comprising:
 forming a first surface in the bit body defining a lateral sidewall surface of the at least one cutting element pocket and causing at least a portion of the first surface to have a generally cylindrical shape centered about a longitudinal axis of the cutting element pocket; 
 forming a substantially planar second surface defining a back end surface of the cutting element pocket; and 
 forming at least one additional surface defining a groove located between the first surface and the second surface and causing the at least one additional surface to extend into the bit body in a generally radially outward direction from the longitudinal axis of the cutting element pocket beyond the at least a portion of the first surface. 
   
   
   
       49 . The method of  claim 48 , wherein at least one of forming a first surface, forming a substantially planar second surface, and forming at least one additional surface comprises machining a recess in the bit body using a rotating cutter oriented at an angle relative to the longitudinal axis of the at least one cutting element pocket. 
   
   
       50 . The method of  claim 49 , wherein forming a first surface comprises machining a recess in the bit body using the rotating cutter oriented at an angle relative to the longitudinal axis of the at least one cutting element pocket. 
   
   
       51 . The method of  claim 49 , wherein using a rotating cutter comprises using an endmill cutter. 
   
   
       52 . The method of  claim 51 , wherein using an endmill cutter comprises using a ballnose endmill cutter. 
   
   
       53 . The method of  claim 48 , wherein forming a substantially planar second surface further comprises forming the substantially planar second surface after forming the first surface in the bit body.