System and method for formation and processing of high pressure die cast metal articles

Abstract

A system and method for formation and processing of pressurized die cast metal articles or components includes an injection or casting station in which a series of cast metal articles are formed within a series of dies by the introduction of a metal material into the dies. The dies are then moved to a retention area where the metal material is permitted to solidify to form the castings, after which the dies are opened and the castings removed therefrom, and subsequently are transferred to a short cycle solution heat treatment station. The castings are conveyed through the short cycle solution heat treatment station with the castings maintained within a series of fixtures to dimensionally support and stabilize the castings during solution heat treatment thereof. The castings thereafter are moved through a quenching chamber or station, with the castings further being held or retained in a fixtured, dimensionally stabilized alignment and/or orientation as the castings are subjected to a quenching operation to quench and cool the castings to a normalized or substantially cooled state.

1 . A method of processing pressurized die cast metal articles, comprising:
 inserting a molten metal material into a die at a casting station;   moving the die to a retention area and retaining the metal within the die for a time sufficient for the metal to solidify to form a casting;   moving the casting from the retention area into a furnace chamber of a short cycle solution heat treatment station;   fixturing the casting for movement through the furnace chamber of the short cycle solution heat treatment station with the casting dimensionally stabilized in a defined, indexed position; and   subjecting the casting to solution heat treatment including exposing the casting to heat at a temperature above a solution heat treatment temperature for the metal of the casting for an initial heat-up period, and thereafter maintaining the casting in the furnace chamber at a temperature sufficient to enable solution heat treatment of the casting within a reduced heat treatment cycle time.   
     
     
         2 . The method of  claim 1 , wherein the pouring station includes a molten metal holding area, and further comprising capturing heat from the holding area and redirecting the captured heat into the heat treatment furnace chamber. 
     
     
         3 . The method of  claim 1 , wherein the pouring station includes a molten metal holding area, and further comprising capturing heat from the holding area and redirecting the captured heat to a retention area along the transfer path of the castings prior to entry of the castings into the furnace chamber of the heat treatment station. 
     
     
         4 . The method of  claim 1 , wherein the die includes a core about which the casting is formed, and wherein placing the casting within the heat treatment furnace comprises aligning at least a portion of the casting and/or a core opening of the casting with a series of applicators that apply heated fluid flows toward at least a portion of the casting and/or the core opening to heat treat the casting and remove the core from the casting. 
     
     
         5 . The method of  claim 1 , wherein placing the casting within the heat treatment furnace in an indexed position comprises positioning the casting in a first position with X, Y and Z axes of the casting oriented in a known first orientation, with respect to a first plurality of applicators. 
     
     
         6 . The method of  claim 5 , and further comprising moving the casting to a second position with the casting oriented in a known, second orientation, different from the first orientation so that at least a portion of the die and/or a core opening are in alignment with a second plurality of nozzles; and directing fluid pressure from the second plurality of nozzles at the die and/or core opening for heat treating the casting. 
     
     
         7 . The method of  claim 5 , wherein the fluid flows are applied at the casting at a velocity of at least about 50 ft/sec. 
     
     
         8 . The method of  claim 1 , wherein the heat treatment station further comprises an entry chamber defining a retention area for receiving the casting after removal of the casting from its die and prior to entry into the furnace chamber, and a quench chamber downstream from the furnace chamber for quenching the casting. 
     
     
         9 . The method of  claim 1 , further comprising moving the casting from the furnace chamber and into a quench chamber upon completion of solution heat treatment of the casting, and quenching the casting. 
     
     
         10 . The method of  claim 9 , wherein moving the casting into the quench chamber comprises engaging the casting within a casting fixture configured to hold the casting in a stabilized arrangement to substantially ensure dimensional accuracy of the casting and limit casting distortion during quenching of the casting. 
     
     
         11 . The method of  claim 9 , further comprising removing a core from the casting during quenching. 
     
     
         12 . The method of  claim 9 , wherein quenching the casting comprises applying water, air, mist, fluid, oil or a combination of fluids and/or air. 
     
     
         13 . The method of  claim 12 , wherein quenching the casting further comprises applying a fluid media under high pressure or dunking the casting in a tank. 
     
     
         14 . The method of  claim 1 , wherein inserting the molten metal material into the die comprises injecting the molten metal into the die through a gate passage. 
     
     
         15 . The method of  claim 14 , further comprising removing a gating formed along the casting prior to placing the casting within the heat treatment furnace. 
     
     
         16 . The method of  claim 14 , wherein the molten metal is injected into the die in a high pressure die casting process by a piston wherein the piston is moved at an injection speed of at least about 3 to 10 m/sec and a flow velocity of the molten metal through the gate passage is at least about 25 to 80 m/sec. 
     
     
         17 . The method of  claim 14 , wherein the molten metal is injected into the die in a low pressure casting process at pressures of about 2-20 psi. 
     
     
         18 . The method of  claim 1 , further comprising removing a gating formed with the casting, and moderating and arresting cooling of the casting during removing of the gating. 
     
     
         19 . The method of  claim 1 , wherein moving the casting from the retention area comprises engaging a gating formed along the casting with a transfer mechanism and moving the casting with the casting held by its gating. 
     
     
         20 . The method of  claim 1 , wherein fixturing the casting within the heat treatment furnace further comprises locating the casting in a fixture for movement through the furnace chamber and/or for quenching to limit the casting distortion and promote geometric casting accuracy as the casting moves through the heat treatment station, and/or during quenching. 
     
     
         21 . The method of  claim 20 , further comprising placing the fixture with the casting received therein on a conveyance system, moving the casting through the heat treatment station, and transferring the fixture with the casting therein to a quench chamber for quenching the casting. 
     
     
         22 . The method of  claim 20 , further comprising applying heat to the casting and/or to the fixture in which the casting is received prior to entry of the casting into the heat treatment furnace to maintain or increase the temperature of the casting up to or above the short cycle solution heat treatment temperature prior to heat treatment. 
     
     
         23 . The method of  claim 20 , wherein the fixture comprises a loose-toleranced carrier, configured to engage and hold the casting at selected positions thereof to facilitate geometric accuracy as the casting moves through the heat treatment station, and/or during quenching. 
     
     
         24 . The method of  claim 20 , wherein the fixture comprises a carrier configured to substantially match a configuration of the casting to maintain the casting in a dimensionally stabilized position during solution heat treatment and/or quenching of the casting. 
     
     
         25 . The method of  claim 1 , further comprising engaging the castings with a transfer mechanism, moving the casting from the heat treatment station to a quenching station, and locating the casting within a fixture in the quenching station to limit distortion as the casting is quenched. 
     
     
         26 . The method of  claim 26 , further comprising applying an age treatment to the casting after quenching. 
     
     
         27 . The method of  claim 1 , wherein the shortened heat treatment cycle time is less than about 35 minutes. 
     
     
         28 . The method of  claim 1 , further comprising exposing the casting to quenching after solution heat treating the casting. 
     
     
         29 . The method of  claim 28 , further comprising removing an internal core from the casting during quenching. 
     
     
         30 . The method of  claim 28 , and wherein exposing the casting to quenching comprises placing the casting in an indexed position within a quench chamber for quenching the casting with X, Y and Z axes of the casting oriented in a known first orientation, and wherein a core opening of the casting is located in alignment with at least one of a plurality of applicators. 
     
     
         31 . The method of  claim 1 , further comprising after formation of the casting, while the die and casting are retained in the retention area, removing the casting from the die and monitoring a temperature of the casting and applying heat to the casting as needed to arrest cooling of the casting at a temperature at or above a furnace introduction temperature prior to solution heat treatment of the casting. 
     
     
         32 . The method of  claim 31 , wherein if the casting has not reached the pre-determined furnace introduction temperature, the casting is either rejected or is placed in a casting holding location and heat is applied to the casting until the casting reaches the pre-determined furnace introduction temperature. 
     
     
         33 . The method of  claim 1 , wherein the furnace chamber of the short cycle solution heat treatment station comprises multiple conveyors extending therethrough, each of the conveyors including a series of fixtures for receiving a casting therein, and wherein placing the casting within the heat treatment furnace comprises selectively positioning the casting within an open fixture of one of the conveyors. 
     
     
         34 . The method of  claim 1 , wherein fixturing the casting within the heat treatment furnace chamber comprises locating the casting within a first fixture for moving the casting through the heat treatment furnace chamber, and engaging the casting with a secondary casting fixture inside the heat treatment furnace chamber to limit casting distortion and to promote geometric casting accuracy during heat treatment of the casting. 
     
     
         35 . The method of  claim 1 , wherein subjecting the casting to solution heat treatment comprises:
 heating the casting at the temperature above the solution heat treatment temperature to raise a temperature of the metal of the casting to a part process stabilization temperature therefor; and   moving the casting to a soak area wherein the casting is exposed to a heated environment at a temperature less than the solution heat treatment temperature for the metal of the casting.