Laser Beam Machining Fig : Schematic illustration of the laser-beam machining process. ( Examples of holes produced in nonmetallic parts by LBM.)

Laser Beam Machining Schematic diagram of a laser beam machine1

3d) Laser Beam Machining (LBM) Generally used for: drilling, slitting, slotting, scribing, and marking operations Holes can be made down to 0.025 mm Generally used on thin stock material

Laser Beam Machining LBM is a process in which removal of work material takes place by an Intense monochromatic beam of light ( Coherent beam ) called the Laser. 2. Here solid state laser i.e. ruby Crystal rod is used , which is doped With a small amount of chromium oxide. Initially the atoms of a medium are at ground state.

Laser Beam Machining Laser Concept Photon Emission Model Nucleus Electron Ground State Excited State Orbits Photon Electron is energized to the excited state Electron relaxes to ground state and photon is produced Photon Emission Model Proton and neutron are in the nucleus. Electron revolve around the nucleus in a circular orbit 3. When a mass of energy from a light source( xenon flash lamp ) is made to fall on this medium ( ruby crystal rod ), it causes absorption of radiation by the atoms of the medium. 4.This results in electron of the atoms of the medium to jump to upper energy level which is excited state. From excited state, the atoms immediately begins to drop to their ground state. 5.This chain reaction results in the emission of photon which is extremely rapid

Laser Beam Machining More precise 6. When this light ( photon ) is focused through ordinary lenses at spot on the work piece, High energy density is obtained which removes metal Advantages : More precise Useful with a variety of materials: metals, composites, plastics, and ceramics Smooth, clean cuts Faster process Decreased heat-affected zone

Laser Beam Machining 1.The process is limited to thin sheet plates. Disadvantages : 1.The process is limited to thin sheet plates. 2. Low rate of metal removal 3. Life of flash lamp is short. 4.Cost of equipment is high 5.The machined holes are not round and straight