Low-velocity die-casting

Abstract

The casting process of this invention focuses on the existing die-casting applications while offering benefits heretofore not available in die-casting. The benefits that the users receive from this process include longer tool life (up to 5 times). The other major benefit is better part quality (i.e., less internal porosity and better dimensional capability). The process utilizes molten metal 20 at the die cast machine 10. This invention is distinguishable from semi-solid molding or forming due in large part to the use of molten or fully liquid metal 20. The ladle 22 operation that delivers the molten metal 20 to the injection chamber 34 is another primary feature of this invention. A controller 28 is utilized that communicates with the furnace 30 and the ladle delivery system 22 to regulate the temperature of the molten metal 20 and the pour speed.

I claim:  
     
         1 . A method of die-casting metal parts comprising: 
 providing molten metal to a die-cast machine;    delivering the molten metal to an injection chamber of the die-cast machine;    controlling the temperature of the molten metal during the delivering to the injection chamber;    introducing the molten metal to the injection chamber at a controlled temperature;    injecting the molten metal into a die; and    allowing the molten metal to cool in the die to form a die-cast metal part.    
     
     
         2 . The method of  claim 1  wherein the controlling further comprises: 
 communicating the temperature of the molten metal during the delivering step via a furnace thermocouple.  
 
     
     
         3 . The method of  claim 2  further comprising: 
 controlling a pour rate at which the molten metal is introduced to the injection chamber to minimize a temperature loss.  
 
     
     
         4 . The method of  claim 3  further comprising: 
 controlling an injection rate at which the molten metal is injected into the die.  
 
     
     
         5 . The method of  claim 4  wherein the injection rate is about 10 to about 30 inches/second.  
     
     
         6 . The method of  claim 5  wherein the injection rate is initially about 10 inches/second and subsequently increases to about 15 to about 30 inches/second.  
     
     
         7 . The method of  claim 1  wherein the controlling of the temperature of the molten metal is within a +/−1 degree F. range.  
     
     
         8 . The method of  claim 1  wherein the controlling of the temperature of the molten metal is a function of a pour rate at which the molten metal is introduced to the injection chamber.  
     
     
         9 . A method of die-casting metal parts comprising: 
 providing molten metal to a die-cast machine;    delivering the molten metal to an injection chamber of the die-cast machine at a temperature;    introducing the molten metal to the injection chamber;    controlling a pour rate of the molten metal into the injection chamber as a function of the temperature of the molten metal;    injecting the molten metal into a die; and    allowing the molten metal to cool in the die to form a die-cast metal part.    
     
     
         10 . The method of  claim 9  further comprising: 
 controlling the temperature of the molten metal during the delivering to the injection chamber.  
 
     
     
         11 . The method of  claim 10  wherein the controlling of the pour rate is a function of the temperature of the molten metal.  
     
     
         12 . The method of  claim 9  further comprising: 
 controlling an injection rate at which the molten metal is injected into the die.  
 
     
     
         13 . The method of  claim 12  wherein the injection rate is a function of the temperature of the molten metal.  
     
     
         14 . The method of  claim 12  wherein the injection rate is about 10 to about 30 inches/second.  
     
     
         15 . The method of  claim 14  wherein the injection rate is initially about 10 inches/second and subsequently increases to about 15 to about 30 inches/second.  
     
     
         16 . The method of  claim 10  wherein the controlling of the temperature of the molten metal is within a +/−1 degree F. range.  
     
     
         17 . A method of die-casting metal parts comprising: 
 providing molten metal to a die-cast machine;    delivering the molten metal to an injection chamber of the die-cast machine;    controlling the temperature of the molten metal during the delivering to the injection chamber;    introducing the molten metal to the injection chamber at a controlled temperature;    controlling a pour rate at which the molten metal is introduced to the injection chamber to minimize temperature loss;    injecting the molten metal into a die;    controlling an injection rate at which the molten metal is injected into the die; and    allowing the molten metal to cool in the die to form a die-cast metal part;    wherein the controlling of the injection rate and of the pour rate of the molten metal is a function of the temperature at which the molten metal is introduced to the injection chamber.    
     
     
         18 . The method of  claim 17  wherein the injection rate is about 10 to about 30 inches/second.  
     
     
         19 . The method of  claim 18  wherein the injection rate is initially about 10 inches/second and subsequently increases to about 15 to about 30 inches/second.  
     
     
         20 . The method of  claim 17  wherein the controlling of the temperature of the molten metal is within a +/−1 degree F. range.