LASER CUTTING WITH CONTROLLED FRACTURE

[B][COLOR="Red"]LASER CUTTING WITH CONTROLLED FRACTURE[/COLOR][/B]

[B]Abstract:[/B]

In the increasing and vast field of manufacturing in less time we have to go at a speed of supersonic jet. In this paper we will understand fracture mechanism using laser cutting with controlled fracture. Laser cutting using the controlled fracture technique has great potential to be used for the machining of brittle materials. In this technique, the applied laser energy produces a mechanical stress that causes the material to separate along the moving path of laser beam .The material separation is similar to a crack extension and the fracture growth is controllable. The laser heat first induces compressive stress around the laser spot. After the passage of the laser beam, the compressive stress is relaxed, and then a residual tensile stress is induced. The stable separation of the brittle material is due to the local residual tensile stress. The experimental material in this study are alumina ceramic and the laser source is CO2 laser. The relationship between the laser power, cutting speed, diameter of the laser spot, and specimen geometry are obtained from the experimental analysis, and the phenomenon are also explained from the result of the stress analysis. This method is a single step process and no mechanical snapping is required. Because the cutting edges are free of chipping and micro cracks, the edge need no further cleaning or grinding. The paper discusses the use of lower power laser to separate glass without melting the material. An additional water jet coolant is applied to produce tensile stress along the cutting path. This improvement of the controlled fracture method has been recognized as having good prospects of fracture use. We investigate the fracture mechanism of laser cutting with controlled fracture when the moving laser beam is focused on material surface; a shallow groove is formed by evaporative removal of material. The heat generation by laser induces a transient temperature distribution and a time dependent stress field. The fracture grows in a stable fashion along the moving path of the laser spot . It is clear by the study that mechanism has wide prospects in the future and will be amongst the leading manufacturing technique.

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