Apparatus for jet application of molten metal droplets for manufacture of metal parts

• US 6,202,734 B1
• Filed: 08/03/1998
• Issued: 03/20/2001
• Est. Priority Date: 08/03/1998
• Status: Expired due to Fees

• Current Assignee: Sandia Corporation (Martin Marietta Corporation)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Essien, Marcelino, Peebles, Henry C., Sackinger, Philip A., Schlienger, Eric M.
• Primary Examiner(s): BATTEN JR, J REED
• Application Number:
  US09/128,346
• Time in Patent Office: 960 Days
• Field of Search: 164/271, 164/258, 164/46, 266/202, 118/623
• US Class Current: 164/271
• CPC Class Codes: B22F 10/22 Direct deposition of molten metal
• CPC Class Codes: B22F 2202/05 Use of magnetic field
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/115 by spraying molten metal, i.e. spray sintering, spray casting
• CPC Class Codes: B22F 9/14 using electric discharge
• CPC Class Codes: B23K 3/0607 Solder feeding devices
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

The apparatus comprises a device for supplying molten metal, a device for heating molten metal such that it remains fluid while within the apparatus, a device for applying a magnetic field in a direction perpendicular to the device for supplying molten metal, a device for transmitting electric current directly through molten metal to exert a force in a first direction on molten metal, where the device for transmitting can reverse the direction of the current to a second direction, opposite of the first direction, to form a droplet of molten metal, and a receiver for the droplet where the accumulation of a multitude of droplets upon the receiver results in the formation of the desired metal part. The mixing chamber can include a rotary electrode arrangement which mixes the molten metal by movement. In order to customize the metal composition of various areas of the metal part being produced, the apparatus can have a first and second feed stream input, each feed stream being of a different composition, and each input with port electrodes, where the supply of electric current to the port electrodes is separably controlled, such that variation in the amount of current supplied to each port electrode results in variation in the amount of molten metal that is moved through the first and second input into the annular chamber.

Claims

1. An apparatus for the direct formation of metal parts from molten metal, comprising:

a) means for supplying said molten metal;

b) means for heating said molten metal such that it remains fluid while within said apparatus;

c) means for applying a magnetic field in a direction perpendicular to said means for supplying said molten metal;

d) means for transmitting electric current directly through said molten metal to exert a force in a first direction on said molten metal, where said means for transmitting can reverse the direction of said current to a second direction, opposite of said first direction, to form a droplet of said molten metal;

e) receiving means for said droplet where the accumulation of a multitude of said droplets upon said receiving means results in the formation of the desired metal part.

2. The apparatus of claim 1 wherein said means for supplying is a mixing chamber comprising at least two feed stream inputs having port electrodes, where said inputs are oriented normal to the applied magnetic field, an optional disposal reservoir, a rotary electrode arrangement within the annular chamber of said mixing chamber, and a feed stream output having port electrodes, where said output is oriented normal to the applied magnetic field.

3. The apparatus of claim 2 wherein said rotary electrode arrangement comprises two sets of electrodes having opposite polarity, where each set comprises at least one electrode, where one set of electrodes is attached to the interior wall of the annular chamber and the other set of electrodes is attached to the outer wall of the annular chamber, where the passing of current through said two sets of electrodes causes molten metal present in said annular chamber to move, thus mixing said metal.

4. The apparatus of claim 2 which comprises a first and second feed stream input, each feed stream being of a different composition, and each input with port electrodes, where the supply of electric current to said port electrodes is separably controlled, such that variation in the amount of current supplied to each port electrode results in variation in the amount of molten metal that is moved through said first and second input into the annular chamber, and said variation in amount of molten metal moved through said first and second input results in variation of the composition of the droplet produced which, in turn results in variation in the composition of the metal within said desired metal part.

5. The apparatus of claim 1 wherein said means for transmitting comprises:

a) a programmable electric current source capable of outputting alternating electric current of a predetermined duration; and

b) a drive chamber comprising an electrode means, in contact with said molten metal, for passing said electric current through said molten metal.

6. The apparatus of claim 1 wherein all parts in contact with said molten metal are made from or coated with materials which do not react with molten tin at a temperature of about 500°

C.

7. The apparatus of claim 1 wherein said means for heating are copper heating blocks, wherein the heat supplied by said blocks to the molten metal is regulated by a temperature controller.

8. The apparatus of claim 7 wherein said temperature controller insures that the temperature differential of the molten metal from the molten metal reservoir to the jetter orifice is no greater than about 3°

C.

9. The apparatus of claim 1 wherein said means for applying a magnetic force is a samarium-cobalt permanent magnet.

10. The apparatus of claim 1 wherein said receiving means is a thermal sink mounted on a multi-axial movable stage.

11. The apparatus of claim 10 wherein said multi-axial movable stage has a movement precision of about 35 μ

m.