Laser Processing Of Metals

by Thomas Scott - Date: 2010-10-19 - Word Count: 455 Share This!

You may have known that lasers produce very powerful and exact beams of light. As a result, they can be used as very useful tools in ordinary to the most sophisticated metal processing.

The cutting process: The laser cutting of the materials is a common application of the laser systems. As the laser beam is focuses on the metal piece the energy is absorbed and transformed into heat. The power density required to cut a metal piece or metal sheet is ranges from 100kw - 100 mw/ cm2. The heat locally provokes to a quick increase of the temperature of the piece; the fusion and/or the vaporization of the interaction zone determine the formation of a cut. Laser cutting leaves with an edge having a high-quality surface finish.

The Welding process: When a low power density (106 W/cm2), however, involve the direct ionization mechanism to melt the metal piece. The laser beam can be transmitted through air rather than requiring a vacuum, the process is easily automated with robotic machinery, x-rays are not generated, and LBW result in higher quality welds.

The drilling process: Like other metal processing operations, drilling is accomplished by melting and/or vaporization (ablation) of metal piece through absorption of energy from a focused laser beam. As the energy required to melt the metal piece is very low compared to in vaporization process, melting is generally favored. The pulse duration and power density determines whether melting or vaporization will take place. Vaporization of a metal takes place when pulse duration is too small (e.g., when Q-switched Nd:YAG laser is used), however, melting takes place when pulse duration is larger e.g., when a flash-lamp pumped Nd:YAG laser is used. A Q-switched Nd:YAG laser normally has pulse duration in the order of nanoseconds, peak power on the order of ten to hundreds of MW/cm2, and a material removal rate of a few micrometres per pulse. While a flash lamp pumped Nd:YAG laser normally has a pulse duration on the order of hundreds of microseconds to a millisecond, peak power in the order of sub MW/cm2, and material removal rate of ten to hundreds of micrometers per pulse.

The Surface Treatments: Lasers offer unparallel control on the surface to obtain various structural effects compared to other surface etching processes. However, the technique is complex and often a computer system is employed to drive the movements of the laser head. Despite this complexity, very precise and clean microstructures and engravings can be achieved at a high rate. The process requires the shorter wavelength of laser beam than the traditional 10,640 nm wavelength CO2 laser. The ytterbium fiber laser is usually employed with a lasing medium of Nd:YVO4 or Nd:YAG at 1,064 nm wavelength, or its harmonics at 532 and 355 nm.

Related Tags: laser cutting, laser energy, laser processing of metals, sophisticated metal processing, laser beam

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