Manifold with film heater

Abstract

The present invention provides improved heated manifolds, heaters and nozzles for injection molding, having a high strength metal skeleton infiltrated with a second phase metal having higher thermal conductivity. Also disclosed is method of forming a manifold, heater or nozzle preform and infiltrating the preform with a highly thermally conductive material. The invention also provides a method of simultaneously infiltrating and brazing injection molding components of similar or dissimilar materials together.

We claim:  
     
         7 . A hot runner injection molding apparatus, comprising: 
 (a) a melt conveying system having 
 (i) a melt distribution manifold having at least one melt passage for transferring melt from a source of pressurized melt, and  
 (ii) at least one injection nozzle having a nozzle melt passage therethrough, said nozzle melt passage in fluid communication with said at least one manifold melt passage;  
   (b) at least one mold cavity adjacent said at least one injection nozzle, said mold cavity in fluid communication with said nozzle melt passage of said at least one injection nozzle,    (c) wherein at least one of said melt distribution manifold and said injection nozzle comprises a body and a heating element capable of heating at least a portion of said body;    wherein at least a portion of said body is made of a parent metal, said parent metal being at least partially infiltrated with a second metal having a different thermal conductivity than said parent metal.    
     
     
         8 . A melt distribution manifold for an injection molding apparatus, the manifold having at least one melt passage for transferring melt from a source of pressurized melt to an injection nozzle, and comprising a body and a heating element capable of heating at least a portion of said body, 
 wherein at least a portion of said body is made of a parent metal at least partially infiltrated with a second metal having a different thermal conductivity than said parent metal.    
     
     
         9 . An injection nozzle for an injection molding apparatus, the injection nozzle having a melt bore therethrough and comprising a body and a heating element capable of heating at least a portion of said body, wherein at least a portion of said body is made of a parent metal at least partially infiltrated with a second metal having a different thermal conductivity than said parent metal.  
     
     
         10 . A process for fabricating an injection molding component having an electrical heating element attached thereto, the process comprising the steps of: 
 (a) contacting said electrical heating element with a powdered metal preform having at least partial open porosity, said powdered metal preform being composed of a first metal;    (b) contacting said preform adjacent a region of said open porosity with a mass of a second metal, said second metal having a different thermal conductivity than said first metal;    (c) heating said preform, said heating element and said mass so as to cause said second metal to at least partially infiltrate said open porosity of said preform and at least partially join said heating element to said preform when cooled.    
     
     
         11 . A process for fabricating a metal part having at least two components, the process comprising the steps of: 
 (a) making a powdered preform of a first component, said preform having at least partial open porosity;    (b) contacting a second component with said preform of said first component; and    (c) infiltrating said open porosity of preform with a second metal wherein said second component is brazed to said first component by said second metal substantially contemporaneously with said infiltration step.    
     
     
         12 . A process for fabricating a metal part having at least two components, the process comprising the steps of: 
 (a) making a powdered preform of a first component, said preform having at least partial open porosity;    (b) contacting a second component with said preform of said first component to form an assembly thereof;    (c) contacting said preform first component with a mass of a metal infiltrant;    (d) controllably heating said assembly and said metal infiltrant to melt said metal infiltrant;    (e) holding said assembly and said metal infiltrant at temperature until said open porosity of said preform of said first component is at least partially infiltrated by said metal infiltrant and said second component is at least partially brazed to said first component by said metal infiltrant; and    (f) controllably cooling said assembly to solidify the metal infiltrant.    
     
     
         13 . The process of  claim 12  further comprising the steps of: 
 (a) providing said first component by: 
 (i) mixing a metal powder with a binder to form an admixture;  
 (ii) injection molding said admixture into a preform;  
 (iii) heating said preform to extract said binder from said binder, thereby leaving said preform with open porosity; and  
 (iv) partially sintering said preform to partially reduce said open porosity.  
 
 
     
     
         14 . The process of  claim 12  wherein said second component is substantially impermeable to said metal infiltrant.  
     
     
         15 . The process of  claim 14  wherein said second component is a resistance heater element.  
     
     
         16 . The process of  claim 12  wherein said second component is a green powder preform having at least partial open porosity, such that said second component is capable of being infiltrated by said metal infiltrant.  
     
     
         17 . The process of  claim 16  wherein said first and second components are matable heater plates for a manifold heater.  
     
     
         18 . The process of  claim 12  wherein said metal infiltrant is a material having different thermal conductivity than said preform.  
     
     
         19 . The process of  claim 12  wherein said metal infiltrant is substantially copper.  
     
     
         20 . The process of  claim 12  wherein said first component is made of a high strength metal alloy.  
     
     
         21 . The process of  claim 20  wherein said first component is made of a tool steel.  
     
     
         22 . The process of  claim 13  wherein said first component is made of a tool steel.  
     
     
         23 . The process of  claim 22  wherein the binder is extracted at a temperature not exceeding 500° C.  
     
     
         24 . The process of  claim 22 , wherein the preform is partially sintered at a temperature between 1150° C. and 1260° C.  
     
     
         25 . The process of  claim 22 , wherein said first component porosity comprises between 40 to 10% volume of said first component prior to infiltration.  
     
     
         26 . The process of  claim 12  wherein said infiltration is localized over a region of said first component.  
     
     
         27 . A process for fabricating an injection molding component, the process comprising the steps of: 
 (a) mixing a powdered tool steel with a binder to form an admixture;    (b) injecting said admixture into a preform;    (c) debinderizing said preform;    (d) partially sintering said preform to achieve 40% to 10% volume open porosity therein;    (e) contacting said preform with a metal infiltrant, said metal infiltrant having a different thermal conductivity than said preform;    (f) controllably heating said preform and said metal infiltrant to at least the melting temperature of said metal infiltrant;    (g) holding said preform and said metal infiltrant at temperature until said porosity of said first component is at least partially infiltrated by said metal infiltrant; and    (h) cooling said preform to solidify the metal infiltrant and yield said injection molding component.    
     
     
         28 . The process of  claim 27  wherein steps (a)-(d) are repeated prior to step (e) to form a second preform and wherein said second preform is contacted with the first preform in step (e) such that said second preform is at least partially infiltrated by said metal infiltrant in steps (f)-(h) to yield a second manifold heater plate.  
     
     
         29 . The process of  claim 28  wherein said manifold heater plate and said second manifold heater plate are also brazed together by the performance of steps (e)-(h).  
     
     
         30 . The process of  claim 29  wherein step (e) further comprises providing a heater element and contacting said heater element to said preform and said second preform.  
     
     
         31 . The process of  claim 30  wherein said heater element is brazed to at least said manifold heater plate by the performance of steps (e)-(h).