Systems and Methods for Dual Plasma Wire Arc Additive Manufacturing

1 .- 20 . (canceled)

21 . A method comprising:

emitting an outer shielding gas from a torch assembly toward a substrate;

emitting an ionizing gas from the torch assembly toward the substrate, wherein the ionizing gas is substantially surrounded by the outer shielding gas;

extending a consumable electrode wire from the torch assembly toward the substrate, wherein the consumable electrode wire is substantially surrounded by the ionizing gas and the outer shielding gas;

retracting the consumable electrode wire away from the substrate;

attempting to establish a second electrical current between a nonconsumable electrode and the substrate, wherein a successful establishment at least partially ionizes the ionizing gas into a plasma;

if the attempting is not successful, then repeating the extending, retracting, and attempting until the attempting is successful; and

if the attempting is successful, then establishing a first electrical current between the consumable electrode wire and the substrate, wherein the first electrical current melts an end of the consumable electrode wire for deposition upon the substrate while the consumable electrode wire is substantially surrounded by the plasma and the outer shielding gas.

22 . The method of claim 21 , wherein the ionizing gas comprises an inner shielding gas and a middle shielding gas.

23 . The method of claim 22 , further comprising mixing the inner shielding gas and the middle shielding gas in a mixing region within the torch assembly to create the ionizing gas.

24 . The method of claim 21 , further comprising determining that the end of the consumable electrode wire is in contact with the substrate, after extending the consumable electrode wire and before retracting the consumable electrode wire.

25 . The method of claim 24 , wherein the determining that the end of the consumable electrode wire is in contact with the substrate is based on an electrical continuity test.

26 . A method comprising:

feeding a feed wire through a main channel of a torch assembly, wherein a distal end of the feed wire is in proximity to a substrate;

supplying an inner shielding gas along the feed wire;

supplying a middle shielding gas, wherein the inner shielding gas mixes with the middle shielding gas near a distal end of the main channel;

applying a second electrical current through an electrode disposed at the distal end of the main channel to the distal end of the feed wire such that the second electrical current is configured to start an arc that is configured to ionize a mixture of the inner and middle shielding gases to form a plasma arc surrounding the feed wire;

retracting the feed wire away from the distal end of the main channel; and

applying a first electrical current through the feed wire, wherein the first electrical current is configured to create an electric arc to melt the feed wire to be deposited onto the substrate.

27 . The method of claim 26 , wherein the electrode is positioned inside the torch assembly.

28 . The method of claim 26 , wherein the electric arc is configured to ionize the inner shielding gas to form a shielding gas arc, wherein the shielding gas arc is positioned within the plasma arc.

29 . The method of claim 28 , wherein the plasma arc and the shielding gas arc surround a molten feed wire annually when the molten feed wire is deposited onto the substrate.

30 . The method of claim 26 , further comprising reducing a velocity of supplying the inner shielding gas along the feed wire when applying the second electrical current through the feed wire.

31 . The method of claim 26 , further comprising applying a third electrical current through the electrode when retracting the feed wire, wherein the third electrical current is greater than the first electrical current.

32 . The method of claim 26 , further comprising supplying an outer shielding gas surrounding the feed wire, wherein the outer shielding gas is not ionized.

33 . The method of claim 26 , further comprising maintaining the plasma arc while retracting the feed wire.

34 . The method of claim 26 , wherein the middle shielding gas has a laminar flow profile.

35 . A method comprising:

supplying an inner shielding gas along a feed wire, wherein the feed wire is fed through a main channel of a torch assembly;

supplying a middle shielding gas, wherein the inner shielding gas mixes with the middle shielding gas near a distal end of the main channel;

positioning a distal end of the feed wire in contact with a substrate;

retracting the feed wire away from the substrate;

applying a second electrical current through an electrode disposed at the distal end of the main channel to the distal end of the feed wire, wherein the second electrical current is configured to ignite an arc;

determining if the arc is ignited:

if not ignited, repeating the positioning, retracting, applying the second electrical current, and determining steps until the arc is ignited; wherein the arc is configured to ionize a mixture of the inner and middle shielding gases to form a plasma arc surrounding the feed wire; and

applying a first electrical current through the feed wire, wherein the first electrical current is configured to create an electric arc to melt the feed wire to be deposited onto the substrate.

36 . The method of claim 35 , wherein the electrode is positioned inside the torch assembly.

37 . The method of claim 35 , wherein the electric arc is configured to ionize the inner shielding gas to form a shielding gas arc, wherein the shielding gas arc is positioned within the plasma arc.

38 . The method of claim 35 , further comprising applying a third electrical current through the electrode when retracting the feed wire, wherein the third electrical current is greater than the first electrical current.

39 . The method of claim 35 , further comprising supplying an outer shielding gas surrounding the feed wire, wherein the outer shielding gas is not ionized.

40 . The method of claim 35 , further comprising maintaining the plasma arc while retracting the feed wire.