Method and apparatus for controlling dispersion of molten metal in a mold cavity

Abstract

A method and apparatus for controlling the dispersion of molten metal in a mold cavity is disclosed, the control facilitated by a localized densification of foam in a lost foam casting operation for producing metal castings, wherein the filling of regions of the mold cavity which do not lend themselves to castability is maximized, an amount of backfill and casting defects are minimized, and a flow pattern of molten metal and material properties of the resulting casting are optimized.

1 . An apparatus for locally densifying a lost-foam casting pattern for controlling dispersion of molten metal in a mold cavity comprising: 
 a pattern die with a cylinder and a pattern forming cavity formed therein, the cylinder in communication with the pattern forming cavity;    a squeeze pin slidably disposed in the cylinder of said pattern die;    means for applying a force on said squeeze pin, said means for applying a force causing said squeeze pin to slidably move in the cylinder of said pattern die in a direction towards the pattern forming cavity of said pattern die; and    a pattern disposed in the pattern forming cavity of said pattern die, wherein a sliding of said squeeze pin causes a localized densification of said pattern.    
   
   
       2 . The apparatus according to  claim 1 , wherein said means for applying a force is a hydraulic cylinder.  
   
   
       3 . The apparatus according to  claim 1 , wherein said means for applying a force is a spring.  
   
   
       4 . The apparatus according to  claim 1 , wherein said pattern is produced from a foam material.  
   
   
       5 . The apparatus according to  claim 4 , wherein the foam material is an expanded polystyrene foam.  
   
   
       6 . The apparatus according to  claim 1 , wherein when said pattern is embedded in sand to produce a mold cavity therein, the local densification facilitates a diversion of a molten metal introduced into the mold cavity, the diversion promoting a filling of the mold cavity.