Methods and systems for welding copper using blue laser

1. A method of forming a perfect weld in copper based materials, the method comprising:

a. placing a work piece in a laser system; wherein the work piece comprises placing a first piece of copper based material in contact with a second piece of copper material;

b. directing a blue laser beam at the work piece, whereby a weld is formed between the first piece of copper based material and the second piece of copper based material; wherein the weld comprises a HAZ and a resolidification zone; and,

c. wherein a microstructure of the copper based material, the HAZ and the resolidification zone are identical.

2. The method of claim 1 , wherein the identical microstructures shows no discernable difference in the weld that would indicate a weakness in the weld.

3. The method of claim 1 , wherein the identical microstructure comprises crystal growth regions of similar size.

4. The method of claim 1 , wherein the weld is formed by conduction mode welding.

5. The method of claim 1 , wherein the first and second pieces have a thickness of from about 10 μm to about 500 μm.

6. The method of claim 1 , wherein the first piece comprises a plurality of layers of copper foil.

7. The method of claim 1 , wherein the first piece is copper metal.

8. The method of claim 1 , wherein the first piece is a copper alloy, having from about 10 to about 95 weight percent copper.

9. The method of claim 1 , wherein the laser beam is directed to the work piece as a focused spot having power density is less than 800 kW/cm 2 .

10. The method of claim 1 , wherein the laser beam is directed to the work piece as a focused spot having power density of is less than 500 kW/cm 2 .

11. The method of claim 1 , wherein the laser beam is directed to the work piece as a focused spot having power density from about 100 kW/cm 2 to about 800 kW/cm 2 .

12. The method of claim 1 , wherein the laser beam is directed to the work piece as a focused spot having power density from about 800 kW/cm 2 to about 5 MW/cm 2 .

13. The method of claim 1 , wherein the laser beam is directed to the work piece as a focused spot having power density is greater than 100 kW/cm 2 .

14. The method of claim 1 , wherein the laser beam has a power of less than 500 W.

15. The method of claim 1 , wherein the laser beam has a power of less than 275 W.

16. The method of claim 1 , wherein the laser beam has a power of less than 150 W.

17. The method of claim 1 , wherein the laser beam has a power in the range of 150 W to about 750 W.

18. The method of claim 1 , wherein the laser beam has a power in the range of about 200 W to about 500 W.

19. The method of claim 1 , wherein the laser beam is directed to the work piece as a focused spot having spot size of from about 50 μm to about 250 μm.

20. The method of claim 1 , wherein the laser beam has a wavelength from about 405 nm to about 500 nm.

21. The method of claim 1 , wherein the weld is formed is splatter free.

22. The method of claim 1 , wherein the laser does not vaporize the work piece.

23. A method of forming a perfect weld in copper based materials, the method comprising:

a. placing a work piece in a laser system; wherein the work piece comprises placing a first piece of copper based material in contact with a second piece of copper material;

b. directing a blue laser beam at the work piece, whereby a weld is formed between the first piece of copper based material and the second piece of copper based material; wherein the weld comprises a HAZ and a resolidification zone; and,

c. wherein a range of hardness for the HAZ is within a range of hardness for the copper based material.

24. The method of claim 23 , wherein the range of hardness for the resolidification zone is within a range of hardness for the copper based material.

25. The method of claim 23 , wherein a microstructure of the copper based material, the HAZ and the resolidification zone are identical.

26. The method of claim 25 , wherein the identical microstructures show no discernable difference in the weld that would indicate a weakness in the weld.

27. The method of claim 26 , wherein the identical microstructures shows no discernable difference in the weld that would indicate a weakness in the weld.

28. The method of claim 26 , wherein the identical microstructure comprises crystal growth regions of similar size.

29. The method of claim 23 , wherein the weld is formed by conduction mode welding.

30. The method of claim 23 , wherein the first and second pieces have a thickness of from about 10 μm to about 500 μm.

31. The method of claim 23 , wherein the first piece comprises a plurality of layers of copper foil.

32. The method of claim 23 , wherein the first piece is copper metal.

33. The method of claim 23 , wherein the first piece is a copper alloy, having from about 10 to about 95 weight percent copper.

34. The method of claim 23 , wherein the laser beam is directed to the work piece as a focused spot having power density is less than 2000 kW/cm 2 .

35. The method of claim 23 , wherein the laser beam is directed to the work piece as a focused spot having power density of is less than 500 kW/cm 2 .

36. The method of claim 23 , wherein the laser beam is directed to the work piece as a focused spot having power density from about 100 kW/cm 2 to about 4500 kW/cm 2 .

37. The method of claim 23 , wherein the laser beam is directed to the work piece as a focused spot having power density is greater than 100 kW/cm 2 .

38. The method of claim 23 , wherein the laser beam has a power of less than 500 W.

39. The method of claim 23 , wherein the laser beam has a power of less than 275 W.

40. The method of claim 23 , wherein the laser beam has a power of less than 150 W.

41. The method of claim 23 , wherein the laser beam has a power in the range of 150 W to about 750 W.

42. The method of claim 23 , wherein the laser beam has a power in the range of about 200 W to about 500 W.

43. The method of claim 23 , wherein the laser beam is directed to the work piece as a focused spot having spot size of from about 50 μm to about 250 μm.

44. The method of claim 23 , wherein the laser beam is directed to the work piece as a focused spot having spot size of from about 100 μm to about 500 μm.

45. The method of claim 23 , wherein the laser beam has a wavelength from about 405 nm to about 500 nm.

46. The method of claim 23 , wherein the weld is formed is splatter free.

47. The method of claim 23 , wherein the laser does not vaporize the workpiece.

48. A method of forming a perfect weld in copper based materials, the method comprising:

a. placing a work piece in a laser system; wherein the work piece comprises placing a first piece of copper based material in contact with a second piece of copper material;

b. directing a blue laser beam at the work piece, whereby a weld is formed between the first piece of copper based material and the second piece of copper based material; wherein the weld comprises a HAZ and a resolidification zone;

c. wherein a range of hardness for the resolidification zone is within a range of hardness for the cooper based material; and,

d. wherein a microstructure of the copper based material, the HAZ and the resolidification zone are identical.

49. The method of claim 48 , wherein the identical microstructures show no discernable difference in the weld that would indicate a weakness in the weld.

50. The method of claim 48 , wherein the identical microstructures shows no discernable difference in the weld that would indicate a weakness in the weld.

51. The method of claim 48 , wherein the identical microstructure comprises crystal growth regions of similar size.

52. The method of claim 48 , wherein the weld is formed by conduction mode welding.

53. The method of claim 48 , wherein the first and second pieces have a thickness of from about 10 μm to about 500 μm.

54. The method of claim 48 , wherein the first piece comprises a plurality of layers of copper foil.

55. The method of claim 48 , wherein the first piece is copper metal.

56. The method of claim 48 , wherein the first piece is a copper alloy, having from about 10 to about 95 weight percent copper.

57. The method of claim 48 , wherein the laser beam is directed to the work piece as a focused spot having power density is less than 800 kW/cm 2 .

58. The method of claim 48 , wherein the laser beam is directed to the work piece as a focused spot having power density of is less than 500 kW/cm 2 .

59. The method of claim 48 , wherein the laser beam is directed to the work piece as a focused spot having power density from about 100 kW/cm 2 to about 3000 kW/cm 2 .

60. The method of claim 48 , wherein the laser beam is directed to the work piece as a focused spot having power density is greater than 100 kW/cm 2 .

61. The method of claim 48 , wherein the laser beam has a power of less than 500 W.

62. The method of claim 48 , wherein the laser beam has a power of less than 275 W.

63. The method of claim 48 , wherein the laser beam has a power of less than 150 W.

64. The method of claim 48 , wherein the laser beam has a power in the range of 150 W to about 750 W.

65. The method of claim 48 , wherein the laser beam has a power in the range of about 200 W to about 500 W.

66. The method of claim 48 , wherein the laser beam is directed to the work piece as a focused spot having spot size of from about 50 μm to about 250 μm.

67. The method of claim 48 , wherein the laser beam has a wavelength from about 405 nm to about 500 nm.

68. The method of claim 48 , wherein the weld is formed is splatter free.

69. The method of claim 48 , wherein the laser does not vaporize the work piece.

70. A method of forming a keyhole weld in copper based materials, the method comprising:

a. placing a work piece in a laser system; wherein the work piece comprises placing a first piece of copper based material in contact with a second piece of copper material; and,

b. directing a blue laser beam at the work piece, whereby a keyhole mode weld is formed between the first piece of copper based material and the second piece of copper based material; wherein the weld comprises a HAZ and a resolidification zone.

71. The method of claim 70 , wherein the laser power is less than 1000 kW.

72. The method of claim 70 , wherein the laser power is less than 500 kW.

73. The method of claim 70 , wherein the laser power is less than 300 kW.

74. The method of claim 70 , comprising elongating the laser beam to suppress spatter from the keyhole.

75. The method of claim 70 , comprising modulating the laser power to suppress spatter from the keyhole.

76. The method of claim 70 , comprising rapidly scanning the beam to suppress spatter during the keyhole mode of welding.

77. The method of claim 70 , comprising rapidly decreasing the laser power after the weld is initiated, wherein the method of reducing can be automatically or manually.

78. The methods of claim 1 , 23 , or 70 , comprising using a low atmospheric pressure to reduce entrapped gases and spatter during the welding process.

79. The methods of claim 1 , 23 , or 70 , comprising applying a shielding gas.

80. The methods of claim 1 , 23 , or 70 , comprising applying a shielding gas selected from the group consisting of He, Ar, N 2 .

81. The methods of claim 1 , 23 , or 70 , comprising applying a shielding gas mixture selected from the group consisting of Ar—H 2 , N 2 , N 2 —H 2 .

82. The methods of claim 1 , 23 , or 70 , comprising applying a shielding gas and adding hydrogen to the shielding gas to remove oxide layers and promote wetting of the weld.

83. The methods of claim 1 , 23 , or 70 , comprising directing a second laser beam to the same area as the laser beam to form the weld.