Chapter 2 Laser (Light Amplification by Stimulated Emission of Radiation) PDF
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This chapter introduces lasers, focusing on light amplification by stimulated emission of radiation, and specifically different types of laser cutting machines such as CO2, Nd, and Nd:YAG lasers. It also details various laser cutting methods and how they apply to different materials, such as metals and plastics.
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Chapter 2 LASER (Light Amplification by Stimulated Emission of Radiation) Part 1 INTRODUCTION A LASER (Light Amplification by Stimulated Emission of Radiation) is a non- conventional source of energy which...
Chapter 2 LASER (Light Amplification by Stimulated Emission of Radiation) Part 1 INTRODUCTION A LASER (Light Amplification by Stimulated Emission of Radiation) is a non- conventional source of energy which is being increasingly implemented in industrial machining due to the high precision and quality products which can be obtained. Laser-machined work- pieces have superior dimensional tolerances and accuracy and minimal heat-affected-zone. Most laser- cutting machines are equipped with CNC capabilities for ensuring quality and timely outputs. By varying the intensity of the laser beam, we can cut/engrave a variety of materials. Engraving using CNC-controlled lasers is different from traditional engraving processes as there is no requirement for a resistive mask. The path of the laser tool, and consequently the laser beam, is controlled precisely by the CNC system. 1.1 Types Of Laser Cutting Machines There are three main types of lasers used in laser cutting: Ø The CO2 laser is suited for cutting, boring, and engraving. Ø The Nd laser is used for boring and where high energy but low repetition is required. Ø The Nd:YAG laser is used where very high power is needed and for boring andengraving. The neodymium (Nd) and neodymium yttrium-aluminum-garnet (Nd:YAG) lasers are identicalin style and differ only in application.Both CO2 and Nd/Nd:YAG lasers can be used for welding. 1.1.1 CO2 Lasers Since the discovery of lasers, CO2 lasers have been the most employ in the material processing industry. The emission of carbon dioxide lasers results form an electric discharge maintained in agas mixture of carbon dioxide, nitrogen and helium. The classic wavelength of emission is in the infrared, around 10.6 μm, but lower wavelengths are now being used for processing specific polymers.CO2 lasers offer a high average power output; from a few Watts up to 50 kW. CO2 lasers are currently used in automotive industry or other steel parts manufacturing activities. The CO2 laser is also an ideal tool for industrial marking, annealing, engrave or weld metals, plastics or wood if applicable. While providing excellent beam quality, they offer a much lower electrical-to-optical conversion efficiency (
