Stepped polycrystalline diamond compact insert

Abstract

The present invention addresses this need in the art by providing a cutter insert comprising a plug section and a cutter pedestal. The cutter insert in preferably formed of tungsten carbide, except for two exterior surfaces covered with PDC. The plug section may be circular or oval in cross section perpendicular to the axis of the insert. The plug section and the pedestal each defines a shoulder which is coated with a PDC layer. In this way, two cutting surfaces are applied to the formation, enhancing the cutting ability of the insert.

1 . A PDC cutter comprising: 
 a plug;    a pedestal atop the plug;    the pedestal having a side wall and a substantially flat top;    a step between the plug and the pedestal; and    the step and the pedestal top being substantially parallel.    
     
     
         2 . The PDC cutter of  claim 1 , further comprising: 
 a pedestal shoulder connecting the top and the side wall.    
     
     
         3 . The PDC cutter of  claim 1 , further comprising: 
 a plug shoulder connecting the plug and the step.    
     
     
         4 . The PDC cutter of  claim 1 , further comprising: 
 a fillet between the step and the pedestal.    
     
     
         5 . The PDC cutter of  claim 1 , further comprising: 
 wherein the side wall is slanted.    
     
     
         6 . The PDC cutter of  claim 1 , further comprising: 
 a pedestal shoulder connecting the top and the side wall; and,    a plug shoulder connecting the plug and the step.    
     
     
         7 . The PDC cutter of  claim 6 , further comprising: 
 wherein the cutter defines an axis and the cutter defines a back rake angle; and,    wherein the plug shoulder and pedestal shoulders define angles to the axis approximately equal to the back rake angle.