MAGNET FABRICATION BY ADDITIVE MANUFACTURING

1 . A method of layer-by-layer fabrication of a magnetic object upon a baseplate, the method comprising:

(a) positioning a tip of a wire over a top surface of the baseplate, the wire comprising one or more ferromagnetic materials;

(b) melting the tip of the wire to form a molten segment over the top surface of the baseplate, whereby the molten segment subsequently solidifies over the top surface of the baseplate;

(c) generating a magnetic field encompassing the top surface of the baseplate proximate the molten segment, whereby a magnetic moment of the segment is substantially aligned with the magnetic field after solidification;

(d) translating the wire relative to the baseplate; and

(e) repeating steps (b)-(d) one or more times to form the magnetic object, each segment being formed over the baseplate or one or more previously formed and solidified segments.

2 . The method of claim 1 , wherein step (b) comprises:

contacting the top surface of the baseplate or one or more previously formed and solidified segments with the tip of the wire; and

passing an electrical current between the wire and the baseplate, whereby the tip of the wire melts due to contact resistance at the tip of the wire.

3 . The method of claim 1 , wherein steps (b), (c), and (d) are performed substantially simultaneously, the molten and solidified segment forming at least a portion of a layer of the magnetic object.

4 . The method of claim 1 , wherein step (b) comprises applying energy from a high-energy source to the tip of the wire.

5 . The method of claim 4 , wherein the high-energy source comprises a laser beam or an electron beam.

6 . The method of claim 1 , further comprising altering an orientation of the magnetic field during formation of at least two of the segments.

7 . The method of claim 1 , wherein no magnetic field is generated over the top surface of the baseplate during step (a).

8 . The method of claim 1 , wherein no magnetic field is generated over the top surface of the baseplate during at least a portion of step (d).

9 . The method of claim 1 , wherein the wire comprises at least one of iron, cobalt, nickel, gadolinium, or neodymium.

10 . The method of claim 1 , further comprising flowing a gas over a tip of the wire during at least step (b), the gas (i) reducing or substantially preventing oxidation of the segments during deposition and/or (ii) increasing a cooling rate of the molten segment.

11 . An apparatus for the layer-by-layer fabrication of a three-dimensional magnetic object from segments formed by melting a ferromagnetic wire, the apparatus comprising:

a baseplate for supporting the object during fabrication;

a wire-feeding mechanism for dispensing the ferromagnetic wire over the baseplate;

a magnetic field generator for generating a magnetic field encompassing a build area disposed over a top surface of the baseplate;

an energy source for applying energy to a tip of the ferromagnetic wire sufficient to cause the ferromagnetic wire to form a molten ferromagnetic segment within the build area, a magnetic moment of the ferromagnetic segment being substantially aligned with an orientation of the magnetic field during solidification;

one or more mechanical actuators for controlling a relative position of the base and the wire-feeding mechanism; and

circuitry for controlling the one or more actuators and the energy source to create the three-dimensional magnetic object in the build area from successively formed ferromagnetic segments.

12 . The apparatus of claim 11 , wherein:

the baseplate is electrically conductive; and

the energy source comprises a power supply for applying a current between the ferromagnetic wire and the baseplate, the ferromagnetic segment being formed in response to contact resistance at the tip of the ferromagnetic wire.

13 . The apparatus of claim 11 , wherein the magnetic field generator comprises at least one of an electromagnet or a permanent magnet.

14 . The apparatus of claim 11 , further comprising one or more second actuators for controlling the orientation of the magnetic field relative to the top surface of the baseplate.

15 . The apparatus of claim 11 , wherein the energy source comprises at least one of a laser beam or an electron beam for melting the tip of the ferromagnetic wire.

16 . The apparatus of claim 11 , wherein the circuitry comprises a computer-based controller for controlling at least one of the energy source or the one or more mechanical actuators.

17 . The apparatus of claim 11 , further comprising ferromagnetic wire within the wire-feeding mechanism.

18 . The apparatus of claim 17 , wherein the ferromagnetic wire comprises at least one of iron, cobalt, nickel, gadolinium, or neodymium.