Experimental Investigations And Multi Response Optimization In Pulsed Nd Yag Laser Cutting Of Novel Frp Composite Materials

Abstract

In recent years, Kevlar and Basalt fiber-based composites are in increasingly high demand in various sectors particularly in defense, aerospace and automotive industries. Typical applications of these composites in the automobile and aerospace sectors need precise and dimensionally accurate machining. Laser cutting proves its suitability over conventional techniques during the processing of fiber reinforced polymer composites due to its unique characteristics such as material versatility and no tool wear etc. It also offers precise and accurate cutting in term of geometrical characteristics such as widths, deviations and taper of the kerf. In the present thesis, a pulsed Nd:YAG laser system is used for cutting of fabricated Kevlar, Basalt and their hybrid composite laminate. A range of experiments has been performed with varied values of five laser cutting parameters such as lamp current, pulse width, pulse frequency, air pressure and cutting speed. Key geometrical quality characteristics viz. top and bottom kerf widths, kerf deviations and kerf taper have been considered as output performance measures. Experimentally observed data have been used to develop adequate mathematical models and statistical analysis. In order to improve the dimensional accuracy of the proposed composites during laser cutting, three different multi-response optimization techniques such as Teaching-learning based optimization algorithm, Firefly algorithm and Grey relational analysis based genetic algorithm have been employed. Validation experiments show that the proposed optimal range of parameters improved the overall geometrical quality by 15.07 %, 15.97 % and 15.02 % for Kevlar, Basalt and their hybrid composite respectively. From the parametric effect analysis, it has been revealed that the geometry of cut is not only affected by laser cutting parameters but also affected by the specific properties of respective fibers and epoxy resin.