Application of LBM in Aerospace Industry

Application of LBM in Aerospace Industry INTRODUCTION: Requirement of precision components, complicated design, stringent standards and testing, unusual size of workpiece, restrictions in conventional machining processes has lead to development of advanced machining processes shortly AMP. In past few years, there were several AMP’s developed such as electric discharge machining (EDM), electron beam machining, electrochemical machining, chemical machining processes (CMP), ultrasonic machining (USM), and jet machining processes abrasive jet machining, water jet machining, laser beam machining etc. Each of these AMP’s has its limitations in workpiece material, shape etc. But LBM is the one of the AMP’s where almost all material can be processed. One of major advantage of LBM is its ability to machine both conductive and non-conductive materials. Laser beam machining (LBM) is one of the most widely used thermal energy based non-contact type advance machining process which can be applied for almost whole ra nge of materials. Laser beam is focused for melting and vaporizing the unwanted material from the parent material. As of now the major application on LBM is profile cutting of geometrically complex part and making miniature holes in sheetmetal. HISTORY OF LASER: In 1917, it was Albert Einstein who first told the world about the process called â€Å"Stimulated Emission† which makes the laser possible. In 1957, Gordon Gould, a Columbia University student designed the first laser device in his laboratory. However the first working laser (ruby laser) was found on 16th of May, 1960 by Dr. Theodore Maiman. This demonstration of ruby laser acted as entry door to this field. Till then lots and lots of researches have been done and various lasers were found. Some of major contributions and highlights are â€Å"Gas laser† which used helium and neon gases by Ali Javan during 1960, semi conductor laser by Gunther Fenner in 1962, CO2 laser by Kumar Patel on 1964, Nd-YAG laser by Ge usic in 1964 etc. The first excimer laser was demonstrated in 1970 by Basov et ah and it was liquid xenon which was excited with a pulsed electron beam. The first commercial application of continuous wave CO2 lasers was made during 1967 by Western Electric and the first successful industrial application of laser cutting was die-board slotting. Whereas now, lasers have been into many areas such as aerospace, die and mold manufacturing, biomechanical devices, automotive, electric, and electronic industries etc. Likewise many studies have been made to find many such lasers and also studies were done to improve / optimize the working parameters of the lasers. FUNDAMENTALS OF LASER: Light Amplification by Stimulated Emission of Radiation – LASER is a device which produces a monochromatic light beam where all the waves are coherent. LASER consists of four primary components: Active medium : It contains atoms whose electrons are excited to higher energy levels by an energy source. They are solid crystals such as ruby or Nd:YAG, liquid dyes, gases like CO2 or Helium/Neon, or semiconductors such as GaAs. Excitation Mechanism: Excitation mechanisms pump energy into the active medium. Three basic method of excitation are optical, electrical or chemical. High Reflectance Mirror Partially Transmissive Mirror The major principles of Laser are stimulation, amplification and population inversion.