Enginering (metallurgy and material)

Sunday, 1 May 2011

Laser Welding (LW)

Laser Welding (LW)



Laser Welding (LW) is a welding process, in which heat is generated by a high energy laser beam targeted on the work piece. The laser beam heats and melts the work pieces edges, forming a joint.

Energy of narrow laser beam is highly concentrated: 108-1011 W/in2 (108-1010 W/cm2), therefore diminutive weld pool forms very fast (for about 10-6 sec.).
Solidification of the weld pool surrounded by the cold metal is as fast as melting. Since the time when the molten metal is in contact with the atmosphere is short, no contamination occurs and therefore no shields (neutral gas, flux) are required.

The joint in Laser Welding (Laser Beam Welding) is formed either as a sequence of overlapped spot welds or as a continuous weld.

Laser Welding is used in electronics, communication and aerospace industry, for manufacture of medical and scientific instruments, for joining miniature components.

Advantages of Laser Welding:

  • Easily automated process;
  • Controllable process parameters;
  • Very narrow weld may be obtained;
  • High quality of the weld structure;
  • Very small heat affected zone;
  • Dissimilar materials may be welded;
  • Very small delicate work pieces may be welded;
  • Vacuum is not required;
  • Low distortion of work piece.

Disadvantages of Carbon Arc Welding:
  • Low welding speed;
  • High cost equipment;
  • Weld depth is limited.

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