Self-renewing cutting surface, tool and method for making same using powder metallurgy and densification techniques

Abstract

In one embodiment, a self-renewing cutting tool includes a substrate and a layer bonded to the substrate forming a composite cladding. The layer includes a plurality of pieces of a first material having irregular, non-uniform shapes, the irregular, non-uniform shapes forming cutting edges, and a second material in which the plurality of first pieces are embedded. The second material is bonded to both the plurality of pieces of the first material and the substrate by densification of the plurality of pieces of a first material and a powder of the second material. At least some cutting edges of the first material lie beneath a surface of the second material and are exposable by wear of the second material.

What is claimed is: 
     
         1 . A self-renewing cutting tool comprising:
 a substrate; and   a layer bonded to the substrate forming a composite cladding, the layer including
 a plurality of pieces of a first material having irregular, non-uniform shapes, the irregular, non-uniform shapes forming cutting edges, and 
 a second material in which the plurality of pieces of the first material are embedded, the second material bonded to both the plurality of pieces of the first material and the substrate by densification of the plurality of pieces of the first material and a powder of the second material, 
   wherein at least some cutting edges of the plurality of pieces of the first material lie beneath a surface of the second material and are exposable by wear of the second material.   
     
     
         2 . The self-renewing cutting tool of  claim 1 , wherein the cutting edges are randomly oriented. 
     
     
         3 . The self-renewing cutting tool of  claim 1 , wherein the plurality of pieces of the first material are fragments of crushed machine tool inserts. 
     
     
         4 . The self-renewing cutting tool of  claim 1 , wherein the plurality of pieces of the first material have an average shortest diameter, the powder of the second material has an average longest particle diameter, and the average longest particle diameter is less than 0.05 times the average shortest diameter. 
     
     
         5 . The self-renewing cutting tool of  claim 1 , wherein the plurality of pieces of the first material have an average shortest diameter, the powder of the second material has an average longest particle diameter, and the average longest particle diameter is less than 0.005 times the average shortest diameter. 
     
     
         6 . The self-renewing cutting tool of  claim 1 , wherein the plurality of pieces of the first material have an average shortest diameter, the powder of the second material has an average longest particle diameter, and the average longest particle diameter is less than 0.00005 times the average shortest diameter. 
     
     
         7 . The self-renewing cutting tool of  claim 1 , wherein a bonding force between the plurality of pieces of the first material and the second material is greater than a strength of the plurality of pieces of the first material, such that under stress pieces of the first material more readily break than detach from the second material. 
     
     
         8 . The self-renewing cutting tool of  claim 1 , wherein the second material has a hardness that is less than a hardness of the first material. 
     
     
         9 . The self-renewing cutting tool of  claim 1 , wherein the first material comprises tungsten carbide. 
     
     
         10 . The self-renewing cutting tool of  claim 1 , wherein the first material comprises silicon carbide, cubic boron nitride, diamond, zirconium oxide or tool steel. 
     
     
         11 . A self-renewing cutting tool comprising:
 a plurality of pieces of a first material having cutting edges, and   a second material in which the plurality of pieces of the first material are embedded, the second material having a hardness that is less a hardness of the first material, the second material bonded to the plurality of pieces of the first material by densification of the plurality of pieces of the first material and a powder of the second material,   wherein at least some cutting edges of the plurality of pieces of the first material lie beneath a surface of the second material and are exposable by wear of the second material.   
     
     
         12 . The self-renewing cutting tool of  claim 11 , wherein the cutting edges of the plurality of pieces of the first material are randomly oriented. 
     
     
         13 . The self-renewing cutting tool of  claim 11 , wherein the cutting edges of the plurality of pieces of the first material are oriented in predetermined directions. 
     
     
         14 . The self-renewing cutting tool of  claim 11 , wherein the plurality of pieces of the first material each have an irregular, non-uniform shape. 
     
     
         15 . The self-renewing cutting tool of  claim 11 , wherein a bonding force between the plurality of pieces of the first material and the second material is greater than a strength of the plurality of pieces of the first material, such that under stress pieces of the first material more readily break than detach from the second material. 
     
     
         16 . A self-renewing cutting tool comprising:
 a substrate; and   a layer bonded to the substrate, the layer including
 a plurality of pieces of a first material having cutting edges, the plurality of pieces of the first material having an average shortest diameter, and 
 a second material in which the plurality of pieces of the first material are embedded, the second material bonded to both the plurality of pieces of the first material and the substrate by densification of the plurality of pieces of a first material and a powder of the second material, the powder of the second material having an average longest particle diameter, 
   wherein the average longest particle diameter is less than 0.05 times the average shortest diameter.   
     
     
         17 . The self-renewing cutting tool of  claim 16 , wherein the plurality of pieces of the first material each have an irregular, non-uniform shape. 
     
     
         18 . The self-renewing cutting tool of  claim 16 , wherein at least some cutting edges of the plurality of pieces of the first material lie beneath a surface of the second material and are exposable by wear of the second material. 
     
     
         19 . The self-renewing cutting tool of  claim 16 , wherein the average longest particle diameter is less than 0.005 times the average shortest diameter. 
     
     
         20 . The self-renewing cutting tool of  claim 16 , wherein the average longest particle diameter is less than 0.00005 times the average shortest diameter.