Welding or additive manufacturing dual wire drive system

1. A welding or additive manufacturing wire drive system, comprising:

a welding wire spool;

a first drive roll;

a second drive roll, wherein one or both of the first drive roll and the second drive roll has a circumferential groove;

a first welding wire, drawn from the welding wire spool, and located between the first drive roll and the second drive roll in the circumferential groove; and

a second welding wire, drawn from the welding wire spool, and located between the first drive roll and the second drive roll in the circumferential groove,

wherein the first welding wire contacts the second welding wire between the first drive roll and the second drive roll, and the first welding wire further contacts a first sidewall portion of the circumferential groove, and the second welding wire further contacts a second sidewall portion of the circumferential groove, and

wherein both of the first welding wire and the second welding wire are radially offset from a central portion of the circumferential groove, and the first welding wire is clamped by the first sidewall portion of the circumferential groove against the second welding wire so as to be clamped offset from the central portion of the circumferential groove, and the second welding wire is clamped by the second sidewall portion of the circumferential groove against the first welding wire so as to be clamped offset from the central portion of the circumferential groove.

2. The welding or additive manufacturing wire drive system of claim 1 , wherein the first welding wire and the second welding wire have different diameters.

3. The welding or additive manufacturing wire drive system of claim 1 , wherein the first welding wire and the second welding wire have different compositions.

4. The welding or additive manufacturing wire drive system of claim 1 , wherein the first welding wire is a solid welding wire and the second welding wire is a flux-cored welding wire.

5. The welding or additive manufacturing wire drive system of claim 1 , wherein the first welding wire is a solid welding wire and the second welding wire is a metal-cored welding wire.

6. The welding or additive manufacturing wire drive system of claim 1 , wherein the central portion of the circumferential groove is concave.

7. The welding or additive manufacturing wire drive system of claim 1 , wherein the welding wire spool includes a central barrel located between first and second end flanges, and an annular divider located along the central barrel between the first welding wire and the second welding wire.

8. A welding or additive manufacturing wire drive system, comprising:

a welding wire spool comprising a first welding wire wound on the welding wire spool and a second welding wire wound on the welding wire spool;

a first drive roll having a first circumferential groove comprising a first inner sidewall, a first outer sidewall, and a first concave groove base extending between the first inner sidewall and the first outer sidewall;

a second drive roll having a second circumferential groove comprising a second inner sidewall, a second outer sidewall, and a second concave groove base extending between the second inner sidewall and the second outer sidewall, wherein the second circumferential groove is aligned with the first circumferential groove, and wherein the first welding wire and the second welding wire are drawn from the welding wire spool between the first drive roll and the second drive roll through both of the first circumferential groove and the second circumferential groove; and

a biasing member that biases the first drive roll toward the second drive roll to force the first welding wire to contact the second welding wire, wherein:

the first welding wire contacts each of the first inner sidewall, the second inner sidewall, and the second welding wire,

the second welding wire contacts each of the first outer sidewall, the second outer sidewall, and the first welding wire,

the first welding wire is clamped by the first inner sidewall, the second inner sidewall, and the second welding wire so as to be clamped offset from both of the first concave groove base and the second concave groove base, and

the second welding wire is clamped by the first outer sidewall, the second outer sidewall, and the first welding wire so as to be clamped offset from both of the first concave groove base and the second concave groove base.

9. The welding or additive manufacturing wire drive system of claim 8 , wherein the first welding wire and the second welding wire have different diameters.

10. The welding or additive manufacturing wire drive system of claim 8 , wherein the first welding wire and the second welding wire have different compositions.

11. The welding or additive manufacturing wire drive system of claim 8 , wherein one of the first welding wire and the second welding wire is a solid welding wire and another one of the first welding wire and the second welding wire is a flux-cored welding wire.

12. The welding or additive manufacturing wire drive system of claim 8 , wherein one of the first welding wire and the second welding wire is a solid welding wire and another one of the first welding wire and the second welding wire is a metal-cored welding wire.

13. The welding or additive manufacturing wire drive system of claim 8 , wherein the welding wire spool includes a central barrel located between first and second end flanges, and an annular divider located along the central barrel between the first welding wire and the second welding wire.