Powder injection molded metal product and process

Abstract

A powder injection molding process for making hard to make parts having internal cavities and hard to make parts made by the process. Metal powders having a variety of shapes and sizes are mixed with binder to make a feedstock. The feedstock is molded into at least two raw molded parts which are then sintered to join the parts together to form the hard to make part. This process eliminates all secondary operations in parts having internal cavities where core withdrawal is not possible. In preferred embodiment two raw parts are joined together during the sintering step without adding any materials to assist the bonding. This methodology can be used to make assemblies that have complex internal cavities such as filter sections and wave-guide components that are a low cost critical solution for the communications industry.

What is claimed is:  
     
         1 . A powder injection molding process for making hard-to-make parts having internal cavities comprising the following steps: 
 A) metal powders having a variety of shapes and sizes are mixed with binder to make a feedstock,    B) the feedstock is molded into at least two raw molded parts,    C) the at least two molded parts are then sintered to join the parts together to form the hard-to-make part.    
     
     
         2 . A process as in  claim 1  wherein said metal powders comprise copper.  
     
     
         3 . A process as in  claim 1  wherein no material is added between the at least two parts to assist in the bonding.  
     
     
         4 . A process as in  claim 1  wherein said at least two parts are two parts.  
     
     
         5 . A process as in  claim 1  wherein said hard-to-make part is a wave guide component.  
     
     
         6 . A process as in  claim 4  wherein said hard-to-make part is a filter section.  
     
     
         7 . A process as in  claim 1  wherein said process is a part of a mass production process for making said hard-to-make parts.  
     
     
         8 . A process as in  claim 1  wherein said raw molded parts taken together are about 15 percent to 35 percent larger than the hard-to-make part.  
     
     
         9 . A process as in  claim 1  wherein said raw molded parts taken together are about 28 to 30 percent larger than the hard-to-make part.  
     
     
         10 . A process as in  claim 1  wherein said metal powders of various sizes are prepared using a water atomization process.  
     
     
         11 . A process as in  claim 1  wherein each of said raw molded parts comprise at least one location pin or pin hole for assuring proper positioning of the parts.  
     
     
         12 . A process as in  claim 1  wherein a compressive force is applied to press the at least two parts together during the sintering process.  
     
     
         13 . A process as in  claim 11  wherein one of the at least two parts is on top of another part and said compressive force is applied by adding a weight on top of the top part.  
     
     
         14 . A process as in  claim 1  wherein said sintering takes place in a sintering furnace and a strong reducing gas is added to the sintering furnace during the sintering process.  
     
     
         15 . A process as in  claim 13  wherein said strong reducing gas is hydrogen.  
     
     
         16 . A process as in  claim 2  wherein said molded parts are sintered at temperatures about 2 to 10 degrees C. below a melt point for the metal powders.  
     
     
         17 . A process as in  claim 16  wherein said powders are copper powders and said melt point is about 1083 C.  
     
     
         18 . A hard-to-make part having an internal cavity comprising: 
 A) a first sintered part,    B) a second sintered part solidly bound to said first sintered part at an interface forming said internal cavity with no added material at said interface.    
     
     
         19 . A hard-to-make part as in  claim 18  wherein said hard-to-make part is a copper part.  
     
     
         20 . A hard-to-make part as in  claim 18  wherein said hard-to-make part is a wave guide component.  
     
     
         21 . A hard-to-make part as in  claim 20  wherein said hard-to-make part is a filter section.