Indexable cutting inserts and methods for producing the same

Abstract

A related cutting insert includes a cutting insert body comprising sintering a layer of a superhard material, machining a hole through said sintered layer, brazing said machined layer onto a preformed cemented carbide substrate, and grinding a brazed product to form a cutting insert of predetermined shape.

1 - 10 . (canceled)  
   
   
       11 . A cutting insert comprising a base portion of a superhard material or a cemented carbide, a layer of superhard material attached to said base and a hole through both said base portion and layer, said hole extending generally conically from said layer through said base, wherein said hole is in a cemented carbide body attached to said base portion and said superhard layer.  
   
   
       12 . The cutting insert of claim  1  wherein said base portion is a cemented carbide and said layer of superhard material is attached to said base by sintering.  
   
   
       13 . The cutting insert of claim  2  wherein said cemented carbide body is attached to said base portion and said superhard layer by brazing.  
   
   
       14 . The cutting insert of claim  1  wherein said superhard material is cubic boron nitride or polycrystalline diamond.  
   
   
       15 . The cutting insert of claim  1  wherein said superhard layer includes a chip breaker portion.  
   
   
       16 . A method for making a cutting insert comprising: 
 forming a layer of superhard material;    attaching said layer onto a superhard material or a cemented carbide substrate;    forming a hole through said layers; and    attaching a preformed annular body within said hole.    
   
   
       17 . The method of claim  6  wherein the preformed annular body has a through hole of conical shape.  
   
   
       18 . The method of claim  6  wherein said substrate is a cemented carbide and said layer is attached to said substrate by sintering.  
   
   
       19 . The method of claim  6  wherein said preformed annular body is attached by brazing.  
   
   
       20 . The method of claim  6  wherein said layer and said substrate are both made of a superhard material.