Method and system for additive manufacturing using high energy source and hot-wire
A method and system to manufacture workpieces employing a high intensity energy source to create a puddle and at least one resistively heated wire which is heated to at or near its melting temperature and deposited into the puddle as droplets.
1. An additive manufacturing system, comprising:
a high energy device which irradiates a surface of a work piece with a high energy discharge to create a molten puddle on a surface of said work piece; and
a power supply which supplies a heating signal to a consumable wire where said heating signal comprises a plurality of current pulses and where each of said current pulses creates a molten droplet on a distal end of said consumable which is deposited into said puddle;
wherein each of said current pulses reaches a peak current level after said distal end of said consumable contacts said puddle,
wherein said heating signal has no current in between said plurality of said current pulses;
wherein said distal end of said consumable is not in contact with said puddle between subsequent peak current levels of said current pulses;
wherein said power supply controls said heating current such that no arc is created between said wire and said work piece during said current pulses; and
wherein said consumable has each of a sheath portion and a core portion, where said sheath portion has a melting temperature less than a melting temperature of said core portion.
2. The system of claim 1 , wherein said core portion is a solid core.
3. The system of claim 1 , wherein said core portion comprises a plurality of wires, and at least some of said plurality of wires have a melting temperature higher than that of said sheath.
4. The system of claim 1 , wherein said core comprises a plurality of individual wires and a first number of said wires has a melting temperature higher than said melting temperature of said sheath and a second number of said wires has a melting temperature lower than said sheath.
5. The system of claim 1 , wherein said core comprises a flux.
6. The system of claim 1 , wherein said melting temperature of said core is such that at least some of said core does not melt during deposition of said consumable.
7. The system of claim 1 , wherein said melting temperature of said sheath is in the range of 5 to 45% lower than said melting temperature of said core.
8. The system of claim 1 , wherein said melting temperature of said sheath is in the range of 10 to 35% lower than said melting temperature of said core.
9. The system of claim 1 , wherein said consumable does not have a circular cross-section.
10. The system of claim 1 , wherein said sheath does not extend around the entire perimeter of said core.
11. The system of claim 1 , wherein said consumable is asymmetric.
12. The system of claim 1 , wherein said sheath comprises a flux.
13. The system of claim 1 , wherein said sheath has at least a first layer and a second layer, where said first layer is directly adjacent to said core, and said first layer has a different chemistry than said second layer.
14. The system of claim 13 , wherein said second layer comprises tungsten carbide.
15. An additive manufacturing consumable, comprising:
a sheath portion; and
a core portion which is at least partially covered by said sheath portion,
wherein said sheath portion has a melting temperature less than a melting temperature of said core portion.
16. The consumable of claim 15 , wherein one of said sheath portion and said core portion comprise a flux.
17. The consumable of claim 15 , wherein said consumable is asymmetric.
18. The consumable of claim 15 , wherein said sheath portion does not extend around the entire perimeter of said core portion.
19. The consumable of claim 15 , wherein said melting temperature of said sheath portion is in the range of 5 to 45% lower than said melting temperature of said core portion.
20. The consumable of claim 15 , wherein said melting temperature of said sheath portion is in the range of 10 to 35% lower than said melting temperature of said core portion.
21. The consumable of claim 15 , wherein said core portion comprises a plurality of wires, and at least some of said plurality of wires have a melting temperature higher than that of said sheath portion.
22. The consumable of claim 15 , wherein said sheath portion has at least a first layer and a second layer, where said first layer is directly adjacent to said core portion, and said first layer has a different chemistry than said second layer.
23. The system of claim 22 , wherein said second layer comprises tungsten carbide.