Laser Beam Machining (LBM):
LASER stands for “Light Amplification using Stimulated Emission of Radiation”.
This process utilizes the energy of coherent photons. Light energy (by flash lamp or energy source) of a particular frequency is thrown on to the laser tube (Ruby rod) to excite the atoms of the inside media. The electrons from laser tube are reflected and made to strike on work piece to be machined, with the help of optical lens. This light energy is converted to thermal energy upon striking the work material because energy of photon is absorbed by the material which leads to rise in local temperature. This results in melting and vaporization of work material and finally material removal.
The wavelength of Laser Beam varies from half micron to 70 microns so it can easily be focused on work piece by using optical lenses placed in the path of beam of light.
Figure shows the set up of Laser Beam Machining. The Laser beam is focused towards the material to be machined with the help of lens. The work piece is placed near the focal point of lens.
Any material can be machined by this process.
There is no contact between the tool and work piece so Tool wear is non-existent.
The laser beam machining can be used for cutting, drilling (up to 0.005 mm dia.), welding, cladding and alloying.
It is a very costly method so it should be used only when it is not feasible to machine a work piece by any other method.