Die-casting apparatus for fabricating vehicle part casing and method of fabricating vehicle part casing using the same

Abstract

A method of fabricating a vehicle part casing using a die-casting apparatus includes preparing a molten aluminum (AL) alloy by heating an Al alloy. A die-casting mold is preheated, and then, the vehicle part casing is molded by pouring the molten Al alloy into the die-casting mold. The vehicle part casing is removed from the die-casting mold and a surface of the vehicle part casing is trimmed. Burs on the vehicle part casing are removed.

What is claimed is: 
     
         1 . A method of fabricating a vehicle part casing using a die-casting apparatus, comprising:
 preparing a molten aluminum (Al) alloy by heating an Al alloy;   preheating a die-casting mold;   molding the vehicle part casing by pouring the molten Al alloy into the die-casting mold;   removing the vehicle part casing from the die-casting mold and trimming a surface of the vehicle part casing; and   removing burs on the vehicle part casing.   
     
     
         2 . The method according to  claim 1 , wherein the step of preparing the molten Al alloy comprises heating the Al alloy at a temperature ranging from 645° C. to 665° C. 
     
     
         3 . The method according to  claim 1 , wherein the step of preheating the die-casting mold comprises preheating the die-casting mold at a temperature ranging from 220° C. to 250° C. 
     
     
         4 . The method according to  claim 1 , wherein the step of molding the vehicle part casing comprises pouring the molten Al alloy to a lower part of the die-casting mold. 
     
     
         5 . The method according to  claim 4 , wherein the step of pouring the molten Al alloy into the die-casting mold comprises pouring the molten Al alloy at a pressure ranging from 90 MPa to 110 MPa while maintaining an internal vacuum pressure of a cavity in the die-casting mold in a range from 140 mbar to 160 mbar. 
     
     
         6 . The method according to  claim 1 , wherein a composition of the Al alloy comprises 88.2% to 80.3% Al, 9.6% to 12.0% Si, 1.5% to 3.5% Cu, 0.1% to 0.5% Mn, 0.1% to 0.3% Mg, 0.1% to 0.5% Ni, 0.1% to 0.9% Fe, 0.1% to 0.5% Ti, 0.1% to 1.0% Zn, 0.1% to 0.3% Sn, 0.0% to 0.1% Pb, 0.0% to 0.1% Cr, and inevitable impurities, based on 100% by weight of the alloy composition. 
     
     
         7 . The method according to  claim 1 , wherein the step of molding the vehicle part casing comprises molding the vehicle part casing while exhausting gas from the molten Al alloy using vacuum. 
     
     
         8 . The method according to  claim 1 , wherein the die-casting mold includes a fixed mold and a movable mold, in which the fixed mold has a negative shape so that one side of the vehicle part casing is carved thereinto and the movable mold has a positive shape so that another side of the vehicle part casing is carved thereinto. 
     
     
         9 . A die-casting apparatus for fabricating a vehicle part casing comprising:
 a fixed mold having a negative shape so that one side of the vehicle part casing is carved thereinto;   a movable mold disposed movable in a direction towards the fixed mold, the movable mold having a positive shape so that another side of the vehicle part casing is carved thereinto, in which the movable mold is engaged with the fixed mold between which a cavity having a shape of the vehicle part casing is formed; and   an exhausting part connected to the cavity and decreasing an internal pressure of the cavity, in which the exhausting part exhausts gas contained in a molten Al alloy which is inserted into the cavity.   
     
     
         10 . The die-casting apparatus according to  claim 9 , wherein the movable mold comprises:
 a molten metal path connected to a lower part of the cavity, so that a molten metal enters the cavity through the molten metal path;   a plurality of first gas outlets formed in an upper part of the cavity, in which the gas is contained in the plurality of first gas outlets; and   a plurality of second gas outlets connected to the exhausting part to form a vacuum in an interior of the cavity.   
     
     
         11 . The die-casting apparatus according to  claim 10 , wherein the movable mold has: first gas paths; and second gas paths connecting the plurality of first gas outlets and the plurality of second gas outlets to the cavity, and
 wherein a diameter of each of the second gas paths is smaller than that of each of the first gas paths.   
     
     
         12 . The die-casting apparatus according to  claim 10 , further comprising a pressure sensor connected to one first gas outlet among the plurality of first gas outlets to measure the internal pressure of the cavity. 
     
     
         13 . The die-casting apparatus according to  claim 10 , further comprising a sleeve part connected to the molten metal path through which the molten metal is poured, wherein the sleeve part has a gas outlet in an upper part to exhaust the gas therefrom.