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Laser beam machining
- 1. LASER BEAM MACHINING SHAIKH MOHAMMEDNURHULHAQ (537ME13043) Under The Guidance Of:
- 2. Shri. CHANNABASAVA Sir CONTENTS Abstract Laser Beam Machining Laser Types of Laser Laser Application Parameters Affecting LBM Advantages Dis-Advantages Conclusion Reference
- 3. Abstract An overview isgiven of the state of the art of laser beam machining in general with special emphasis on application of short and ultra short laser. In Laser welding the trend is to apply optical sensor for process control Laser surface treatment is mostly used to apply corrosion and wear resistant layers, but also for repair of engine and machine parts. In micro-machining, shorter pulse reduce heat affected damage of material and opens new ways for nanometer accuracy. Even 40years after the development of the development of the laser there is a lot of effort in developing new and better performing lasers. What is Laser LASER is the acronym for Light Amplified Stimulated Emission of Radiation Laser is a device which generates or amplifies light Stimulated emission of electromagnetic radiation Coherent, monochromatic, directional and high power laser beam is used
- 4. Elements of Laser Lasing Medium (Gas, liquid, solid) Pumping process Optical feedback element
- 5. Laser Beam Machining Used light energy from a laser to remove material by vaporization and ablation Energy is concentrated optically Laser emits either continuous or pulsed light beam
- 6. Effect of LaserBeam on Material
- 8. Gas Laser Electriccurrent is discharged through a gas to produce a coherent light Operate on the principle of converting electric energy into laser light output Gas acts as pumping medium to attain the necessary population inversion Types of Laser Gas Laser Solid State Laser Excimer Laser
- 9. Common gaslaser are CO2 Gas Laser, He-Ne Gas Laser Solid State Laser Constructed by doping a rare earth element into a variety of host materials Pumped optically by arc lamps or flash lamps Respond well to Q-switching Ruby or Nd:YAG is the most common host material Ruby Laser
- 10. Excimer Laser Usesa combination of an inert gas and reactive gas Excimer is form of Ultraviolet Chemical Laser Excimer is short for ‘excited dimmer’
- 11. Dye & SemiconductorLaser Dye Laser use complex organic dyes, such as rhodamine 6G Semiconductor Laser sometimes called diode lasers Very small and use low power.
- 12. Operation: Laser Cutting Cutting starts by drilling a hole by moving beam Cutting speed depends on material and thickness Both pulsed and continuous laser is used Thickness ranges from 0.5-1 inch Used for cutting complex geometry and for clean cutting operation
- 13. Laser Welding For weldingceramics and dissimilar materials like steel and aluminum Produces maximum penetration and minimum distortion in materials Beam can be easily shaped, focused and directed Application Razor Blade Electronic Circuit Laser Cladding Used to improve surface quality by applying a corrosion resistant layer on product Laser Beam is used to create a shallow melt pool Metal powder is supply using an inert gas flow Application Chemical industry Mining and marine application
- 14. Laser Application Heavy Manufacturing Seam &spot welding Cladding & drilling Light Manufacturing Engraving Drilling Electronics Skiving of circuits Wire stripping Medical Cosmetic Surgery Hair removal
- 15. Parameter Affecting LBM •Working Material • AssistGases • Focusing Lenses • Laser Beam • Environment Laser Beam Machining
- 16. Advantages Non Contact No solvent chemical Selective material removal Flexibility Fully automated Disadvantages Requires specially trained operators Not for mass metal removal processes Requires greater control of joint tolerances Expensive equipment Consumes much energy
- 17. Conclusion When optimalfocus positioning is centred in the work piece, there is an optimal interaction between the number of required scans, the diameteron the LASER beam input as well as on the output side, and the associatedflank angle. The further off-centredthe focus positionis, the more scans are required for a full cut. The diameter on the LASER beam output side wanes, the deeper the focus is positionedin the work piece The optimal feed rate obtained after conducting various experiment, amount to 8mm/s. This results in a pulse overlap of 97.7%. Even if higher pulse overlap values reduce the required number of scans, they are not usable. By analyzing the influence of the pulse overlap to the diameter on the LASER beam output as well as on the input side, there was no dependency discovered. The investigating of the track overlap found that the best values for the track overlap amount to 14.3%. To enlarge the kerf width the number of tracks need to be increased. The more nested circles into each other, the less number of scans required. However, it is essential here to take into account the increasing required manufacturing time. The optimal value of concentric circles is two. More than two circles are not an efficient operation. If a closed configuration on the LASER beam output side is required only low wobbing frequencies are usable
- 18. References http://www.google.com http://www.sciencedirect.com http://en.wikipedia.org/wiki/laser_cutting http://www.gobookee.org/powerpoint-of-laser-beam-machining/ Laser beam machining (LBM), state of the art and new opportunities/Johan Meijer http://science.howstuffworks.com/laser.htm
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