Semi-solid casting apparatus and method

• US 6,640,879 B2
• Filed: 09/10/2002
• Issued: 11/04/2003
• Est. Priority Date: 07/24/1998
• Status: Expired due to Fees

• Current Assignee: Gibbs Die Casting Aluminum Company, Semi-Solid Technologies, Inc.
• Original Assignee: Gibbs Die Casting Aluminum Company, Semi-Solid Technologies, Inc.
• Inventors: Myojin, Shinya, Mendez, Patricio F., OʼDaniels, John F., Neill, Richard I. Jr., Barron, Charles E., Gage, Timothy B., Rice, Christopher S., Richard, Kevin L.
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): LIN, ING HOUR
• Application Number:
  US10/238,199
• Publication Number:
  US 20030006020A1
• Time in Patent Office: 420 Days
• Field of Search: 164/113, 164/312, 164/309, 164/900, 164/133, 164/136, 164/71.1, 164/335, 164/337, 222/595, 222/593, 266/239
• US Class Current: 164/309
• CPC Class Codes: B22D 1/00 Treatment of fused masses in the ladle or the supply runners before casting for continuous casting B22D11/10; metallurgical processing, e.g. refining of iron or other metal C21, C22, C25C
• CPC Class Codes: B22D 17/007 Semi-solid pressure die casting
• CPC Class Codes: B22D 17/06 Air injection machines
• CPC Class Codes: B22D 17/10 with horizontal press motion
• CPC Class Codes: B22D 17/30 Accessories for supplying molten metal, e.g. in rations supplying molten metal in ration in general B22D39/00
• CPC Class Codes: Y10S 164/90 Rheo-casting

Abstract

A die casting system includes a vessel defining a reservoir with a controlled heater and an agitator for maintaining the bath of semi-solid metal in a homogeneous isothermal state, a transfer system capable of transferring a known quantity of metal in its semi-solid state to a mold cavity in a die casting machine, the transfer system including a heated suction tube, a vacuum source for vacuum ladling semi-solid metal from the bath to a die, and a plunger tip providing a path for free air flow to allow evacuation of the suction tube during casting and a metal replacement system for replacing the known quantity of transferred metal with a similar amount of liquid metal so that a stable homogeneous isothermal bath of semi-solid metal is controllably maintained to be available for die casting operations.

Claims

1. An apparatus for delivering heated metal to a die casting device for the manufacture of molded metal castings, the die casting device comprising dies forming at least one cavity having a vacuum gate and a metal feed gate, the apparatus comprising:

a source of molten metal wherein the temperature of the molten metal is maintained at a predetermined temperature range above the temperature at which it will begin to solidify;

a temperature controlled vessel maintaining the metal in a semi-solid state wherein up to about 45% of the metal is suspended as particles in a fluid fraction of the metal;

a heated suction tube;

a shot sleeve in a metal flow communication with the vessel through the heated suction tube, the shot sleeve communicating with the cavity through the metal feed gate and having a plunger reciprocally disposed in the sleeve to force semi-solid metal in the sleeve under pressure into the cavity;

a vacuum source communicating with the vacuum gate, cavity, feed gate and shot sleeve to draw semi-solid metal from the temperature controlled vessel through the heated suction tube into the sleeve in a position to be forced by the plunger into the cavity, wherein the vessel comprising a bottom, a side wall, and a top, and further comprising an agitator disposed in the vessel and a heater positioned to deliver heat to semi-solid metal in the vessel through the bottom of the vessel and the bottom of the vessel includes an independently dimensioned heating chamber in metal flow communication with the semi-solid metal in the vessel through the bottom of the vessel and the heater is positioned to heat metal in the heating chamber.

2. The apparatus of claim 1 wherein the heater is an induction heater.

3. The apparatus of claim 1 wherein the agitator is positioned in the vessel to promote mixing of metal in the heating chamber with the semi-solid metal in the vessel.

4. The apparatus of claim 1 wherein the shot sleeve is jacketed and a fluid is circulated through the jacket.

5. The apparatus of claim 4 wherein the bottom of the vessel includes an independently dimensioned heating chamber in metal flow communication with the semi-solid metal in the vessel through the bottom of the vessel and the heater is positioned to heat metal in the heating chamber.

6. The apparatus of claim 1 further comprising a delivery means for delivering predetermined volumes of molten metal from the source of molten metal to the vessel.

7. The apparatus of claim 1 wherein the suction tube for delivering the semi-solid metal to the heated shot sleeve extends upwardly from the surface of semi-solid metal in the vessel.

8. An improved vessel for holding and maintaining a semi-solid metal, wherein the vessel having a bottom and a side wall, and top, an agitator, and a heater, the improvement wherein the heater is located to deliver heat to the semi-solid metal in the vessel only through the bottom of the vessel and the bottom of the vessel includes an independently dimensioned heating chamber in metal flow communication with semi-solid metal in the vessel through the bottom of the vessel and the heater is positioned to heat metal in the heater chamber.

9. The improved vessel of claim 8 wherein the heater is an induction heater.

10. The improved vessel of claim 8 and further comprising an agitator in the vessel, the agitator being positioned to promote mixing of metal in the heating chamber with the stirred semi-solid metal in the vessel.