Method and system for surface densification

Abstract

A method for densifying a surface of a powder metal part, includes blending a plurality of powdered metals to form a powder metal blend, actuating an upper punch and a lower punch to apply pressure to the powder metal blend to compact the powder metal blend, sintering the compacted powder metal blend in an oven, forming the compacted powdered metal blend into the powder metal part, heating a portion of the surface of the powder metal part, and densifying the portion of the surface of the powder metal part for a predetermined period of time after the portion of the powder metal part is heated to a predetermined temperature.

What is claimed is: 
     
         1 . A method for densifying a surface of a powder metal part, the method comprising:
 blending a plurality of powdered metals to form a powder metal blend;   forming the powdered metal blend into the powder metal part;   actuating an upper punch and a lower punch to apply pressure to the powder metal blend to compact the powder metal blend;   sintering the compacted powder metal blend in an oven;   heating a portion of the surface of the powder metal part; and   densifying the portion of the surface of the powder metal part for a predetermined period of time after the portion of the powder metal part is heated to a predetermined temperature.   
     
     
         2 . The method of  claim 1  wherein heating the portion of the surface of the powder metal part includes heating the portion of the surface of the powder metal part to a temperature between 300° C. and 700° C. 
     
     
         3 . The method of  claim 2  wherein the predetermined temperature is maintained using a temperature control feedback system. 
     
     
         4 . The method of  claim 3  wherein the temperature control feedback system uses closed loop temperature control with infrared monitoring or the like for heating the portion of the surface of the powder metal part to a temperature between 300° C. and 700° C. 
     
     
         5 . The method of  claim 1  wherein densifying a surface of the powder metal part includes applying a point load on the portion of the surface of the powder metal part using a conical shaped tool. 
     
     
         6 . The method of  claim 1  wherein heating a portion of the surface of the powder metal part includes heating a linear portion of the powder metal part. 
     
     
         7 . The method of  claim 6  wherein densifying the portion of the surface of the powder metal part includes applying a line load on the heated linear portion using at least one roller. 
     
     
         8 . The method of  claim 1  wherein the powder metal part comprises a gear having gear teeth and densifying the portion of the surface for the powder metal part includes applying a gear meshing load to the gear teeth. 
     
     
         9 . The method of  claim 1  wherein heating the portion of the surface of the powder metal part includes applying an induction heat with an induction heating device. 
     
     
         10 . The method of  claim 1  wherein heating the portion of the surface of the powder metal part includes applying microwave radiation with a microwave device. 
     
     
         11 . The method of  claim 1  wherein heating the portion of the surface of the powder metal part includes applying a laser to the portion of the surface of the powder metal part. 
     
     
         12 . A method for densifying a surface of a powder metal part, the method comprising:
 blending a plurality of powdered metals to form a powder metal blend;   forming the powdered metal blend into the powder metal part;   actuating an upper punch and a lower punch to apply pressure to the powder metal blend to compact the powder metal blend;   sintering the compacted powder metal blend in an oven;   heating a portion of the surface of the powder metal part; and   densifying the portion of the surface of the powder metal part, wherein densifying the portion of the surface of the powder metal part includes applying a point load on the portion of the surface of the powder metal part using a conical shaped tool for a predetermined period of time after the portion of the powder metal part is heated to a predetermined temperature.   
     
     
         13 . The method of  claim 12  wherein applying a point load on the portion of the surface of the powder metal part includes moving the conical shaped tool axially along the powder metal part. 
     
     
         14 . The method of  claim 13  wherein applying a point load on the portion of the surface of the powder metal part includes rotating the conical shaped tool about an axis of rotation. 
     
     
         15 . The method of  claim 12  wherein applying a point load on the portion of the surface of the powder metal part includes rotating the powder metal part about an axis of rotation. 
     
     
         16 . The method of  claim 12  wherein the heating the portion of the surface of the powder metal part includes heating the portion of the surface of the powder metal part to a temperature between 300° C. and 700° C. 
     
     
         17 . The method of  claim 16  wherein heating the portion of the surface of the powder metal part includes applying an induction heat with an induction heating device. 
     
     
         18 . The method of  claim 16  wherein heating the portion of the surface of the powder metal part includes applying microwave radiation with a microwave device. 
     
     
         19 . The method of  claim 16  wherein heating the portion of the surface of the powder metal part includes applying a laser to the portion of the surface of the powder metal part. 
     
     
         20 . A system for densifying a surface of a powder metal part comprising:
 a workstation, wherein the powder metal part is disposed in or on the workstation;   a heating element adjacent the powder metal part and configured to heat a portion of the surface of the powder metal part to between 300° C. and 700° C.;   a tool adjacent the part and configured to apply a point load to a portion of the surface of the powder metal part after the portion of the surface of the powder metal part has been heated; and   a controller configured to control the heating element, the workstation, and the tool, wherein the controller is configured to control a rate at which the heating element heats the portion of the surface of the powder metal part, and a rate of movement of the tool relative to the surface of the powder metal part.