High-density molding device and high-density molding method for mixed powder

Abstract

A first die is filled with a mixed powder including a lubricant. A first pressure is applied to the mixed powder to form a mixed powder intermediate compressed body having a density ratio of 85 to 96%, provided that the maximum density of the mixed powder intermediate compressed body that can be molded by applying the first pressure is 100%. The mixed powder intermediate compressed body is heated to the melting point of the lubricant powder. The mixed powder intermediate compressed body is placed in a second die that is pre-heated to the melting point. A second pressure is applied to the mixed powder intermediate compressed body in the second die to form a high-density mixed powder final compressed body.

1 . A mixed powder high-density molding method comprising:
 filling a first die with a mixed powder prepared by mixing a low-melting-point lubricant powder into a basic metal powder;   applying a first pressure to the mixed powder in the first die to form a mixed powder intermediate compressed body having a density ratio of 85 to 96%, provided that a maximum density of the mixed powder intermediate compressed body that can be molded by applying the first pressure is 100%;   heating the mixed powder intermediate compressed body removed from the first die to a melting point of the lubricant powder;   placing the heated mixed powder intermediate compressed body in a second die; and   applying a second pressure to the mixed powder intermediate compressed body in the second die to form a high-density mixed powder final compressed body.   
     
     
         2 . The mixed powder high-density molding method as defined in  claim 1 ,
 wherein the lubricant powder has a low melting point within a range of 90 to 190° C.   
     
     
         3 . The mixed powder high-density molding method as defined in  claim 1 ,
 wherein the second die is pre-heated to the melting point before the mixed powder intermediate compressed body is placed in the second die.   
     
     
         4 . The mixed powder high-density molding method as defined in  claim 1 ,
 wherein the second pressure is selected to be equal to the first pressure.   
     
     
         5 . A mixed powder high-density molding system comprising:
 a mixed powder feeding device that can externally feed a mixed powder prepared by mixing a low-melting-point lubricant powder into a basic metal powder;   a first press molding device that applies a first pressure to the mixed powder, with which a first die has been filled using the mixed powder feeding device, to form a mixed powder intermediate compressed body;   a heating device that heats the mixed powder intermediate compressed body removed from the first die to a melting point of the lubricant powder; and   a second press molding device that applies a second pressure to the mixed powder intermediate compressed body that is placed in a second die to form a high-density mixed powder final compressed body,   the first press molding device applying the first pressure to the mixed powder in the first die to form the mixed powder intermediate compressed body having a density ratio of 85 to 96%, provided that a maximum density of the mixed powder intermediate compressed body that can be molded by applying the first pressure is 100%.   
     
     
         6 . The mixed powder high-density molding system as defined in  claim 5 ,
 wherein the heating device and the second press molding device are formed by a heating/press molding device that functions as the heating device and the second press molding device, the heating/press molding device includes a plurality of heating/press molding sub-devices, and each of the plurality of heating/press molding sub-devices can be selectively and sequentially operated in each cycle.   
     
     
         7 . The mixed powder high-density molding system as defined in  claim 5 , further comprising:
 a pre-heating device that pre-heats the second die.   
     
     
         8 . The mixed powder high-density molding system as defined in  claim 5 , further comprising:
 a workpiece transfer device that transfers the mixed powder intermediate compressed body formed by the first press molding device to the heating device, transfers the mixed powder intermediate compressed body heated by the heating device to the second press molding device, and transfers the mixed powder final compressed body formed by the second press molding device to a discharge section.