Method for densifying surface of powder metallurgy article and apparatus for the same

Abstract

A method of densifying a surface of a powder metallurgy article and an apparatus for the same are provided. A powder metallurgy blank is fixed in position in a fixture for being subjected to a surface treatment that employs an actuating member to exert to a pre-selected surface of the powder metallurgy blank simultaneously a spinning force and a vertically pressing force. The pre-selected surface can thus be densified to have sufficient wear resistance due to the application of the bi-directional forces.

1 . A method for densifying surface of a powder metallurgy article, comprising the steps of: 
 fixing in position in a fixture a powder metallurgy blank;    performing a surface treatment to a pre-selected surface of the powder metallurgy blank, wherein the surface treatment is performed by contacting the pre-selected surface of the powder metallurgy blank with an actuating member that allows at least a vertically pressing force and a spinning force to be simultaneously exerted onto the pre-selected surface of the powder metallurgy blank; and    removing the powder metallurgy article thus-obtained from the fixture as soon as the pre-selected surface of the powder metallurgy blank has been densified to a predetermined hardness.    
   
   
       2 . The method of  claim 1 , wherein the powder metallurgy blank is formed by pressurizing and sintering a porous powder metallurgy material.  
   
   
       3 . The method of  claim 1 , wherein the actuating member is made of a material with hardness greater the powder metallurgy blank.  
   
   
       4 . The method of  claim 1 , wherein the actuating member is movable relative to the pre-selected surface of the powder metallurgy blank.  
   
   
       5 . The method of  claim 4 , wherein the moving range of the actuating member is designed to cover the entire pre-selected surface of the powder metallurgy blank.  
   
   
       6 . The method of  claim 1 , wherein the actuating member exerts simultaneously the at least a vertically pressing force and a spinning force to the pre-selected surface of the powder metallurgy blank via a contact surface thereof.  
   
   
       7 . The method of  claim 6 , wherein the contact surface of the actuating member can further provide a friction force to the pre-selected surface of the powder metallurgy blank.  
   
   
       8 . An apparatus for use in the method of  claim 1 , comprising: 
 a fixture for fixing in position a powder metallurgy blank;    a driving unit;    an actuating member driven by the driving unit for exerting at least a vertically pressing force and a spinning force simultaneously onto a pre-selected surface of the powder metallurgy blank;    a control unit for controlling the driving unit to drive the actuating member with predetermined conditions, so as to densify the pre-selected surface of the powder metallurgy blank to reach a desired hardness; and    a power source for supplying power to the driving unit and the control unit.    
   
   
       9 . The apparatus of  claim 8 , wherein the driving unit can further drive the actuating member to move all over the entire pre-selected surface of the powder metallurgy blank.  
   
   
       10 . The apparatus of  claim 8 , wherein the predetermined conditions at least comprise a spinning speed, a moving speed, and the vertically pressing force of the actuating member driven by the driving unit.  
   
   
       11 . The apparatus of  claim 8 , wherein the actuating member exerts simultaneously the at least a vertically pressing force and a spinning force to the pre-selected surface of the powder metallurgy blank via a contact surface thereof.  
   
   
       12 . The apparatus of  claim 11 , wherein the contact surface of the actuating member can further provide a friction force to the pre-selected surface of the powder metallurgy blank.  
   
   
       13 . The apparatus of  claim 8 , wherein the actuating member is made of a material with hardness greater than the powder metallurgy blank.  
   
   
       14 . The apparatus of  claim 8 , wherein the powder metallurgy blank is formed by pressurizing and sintering a porous powder metallurgy material.