Modelling and Analysis of Laser Micro- machining of Light Metal Alloys

Abstract

Due to high specific strength & durability, light metal alloys act as real security to light-weight components due to their low density, durability, etc. Laser processing of light metal alloys is an emerging area of research work. Keeping in view the outcomes of past research work and the present needs of material processing industry, present research is planned. The thesis consists of 7 chapters. Chapter 1 includes discussions about light metal alloys, laser micro-machining of light metal alloys, fundamental of laser material processing, feature of laser micro-drilling and characteristic features of micro-channeling. Chapter 2 includes exclusive study of past research work done on laser beam machining of different engineering materials and objective & scope of present research. Chapter 3 covers detail of experimental investigation on micro-machining of Al 7075 alloy by Nd:YVO4 pulsed laser following L9 OA of Taguchi's methodology. ANOVA is performed to identify significance of each input parameter on output following confirmation test to check adequacy to model and verify optimum parametric combination. Three responses are then optimized simultaneously using grey relational analysis which shows better result. Further confirmation test is conducted to justify this model, it shows very closeness between two. Micro-drilling operation by Nd:YVO4 laser on copper sheet with detail experimental observation including design of experiment by L9 OA of Taguchi's methodology, optimization both individual and simultaneous, confirmation test and prediction have been discussed in Chapter 4. In chapter 5, in-depth study and analysis on micro-channeling of Al 7075 alloy by diode-pumped fiber laser has been presented. Experiments are performed following response surface methodology based central composite design. Response surface plots and ANOVA are carried out for every response and then optimized individually as well as simultaneously. Surface characteristics analysis and scanning electron microscope photographs are discussed elaborately in Chapter 6. After performing the optimization of processing parameters, ANOVA as well as confirmation test are performed. SEM photographs are also studied critically. Chapter 7 outlines the derived general conclusions out of the present work. It is expected that outcome of this present research will be helpful to open up new insights for developing process controlled laser micro-machining applications.