Laser Beam Machining (LBM)

Laser Beam Machining (LBM), Principle of Laser Beam Machining, Working of Laser Beam Machining, Advantages of Laser Beam Machining, Limitations of Laser Beam Machining, Applications of Laser Beam Machining

Principle of Laser Beam Machining (LBM):

              Laser beam Machining [LBM] utilises the energy from the coherent light beams called laser. Laser stands for Light Amplification by Stimulated Emission of Radiation.

          LBM is based on the conversion of electrical energy to light energy and then into thermal energy. Laser beam is a narrow beam of coherent, monochromatic light amplified by stimulated emission of radiation. In LBM, a laser beam is focused on the workpiece by lens to give extremely high energy density to melt and vapourise the metal.

Working of Laser Beam Machining:

             In LBM, under proper conditions, electrical energy stored in capacitor is discharged through gas filled flash lamp to produce an intense flash of white light.

             This light falls over the ruby crystal and reflected back to the reflective mirrors. This laser beam is focussed by an optical lens to amplify and emit as highly collimated coherent beam of small intense spot of light on the work surface. Optical energy is converted into heat energy and impact over the workpiece to melt and vapourise the material.

Advantages, Limitations & Applications of Laser Beam Machining

Advantages of Laser Beam Machining:

• There is direct contact between tool [laser] and workpiece.

• Machining of any material including non-metals is possible, irrespective of their hardness and brittleness.

• Dissimilar metals can be welded easily.

• No distortion of work.

• There is no tool wear problem.

• Easy control of beam configuration and size of exposed area.

• Soft materials like rubber, and plastic can be machined.

Limitations of Laser Beam Machining:

• Overall efficiency is low [10 - 15%].

• Limited to thin sheet plates.

• Low material removal rate.

• Machined holes are not round and straight.

• Life of the flash lamp is short.

• Effective safety procedures are required.

• Cost is high.

Applications of Laser Beam Machining:

• Machining very small holes.

• Cutting complex profiles in thin, hard materials like ceramics.

• Used in partial cutting or engraving.

• Sheet metal trimming, blanking and resistor trimming.

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