Chapter 2: Laser (Light Amplification by Stimulated Emission of Radiation) - PDF

**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 prec...

**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. Types Of Laser Cutting Machines =============================== There are three main types of lasers used in laser cutting: - The CO~2~ laser is suited for cutting, boring, and engraving. - The Nd laser is used for boring and where high energy but low repetition is required. - The Nd:YAG laser is used where very high power is needed and for boring and engraving. ### CO~2~ Lasers #### Since the discovery of lasers, CO~2~ lasers have been the most employ in the material processing industry. The emission of carbon dioxide lasers results form an electric discharge maintained in a gas 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.CO~2~ lasers offer a high average power output; from a few Watts up to 50 kW. CO~2~ lasers are currently used in automotive industry or other steel parts manufacturing activities. #### The CO~2~ 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 (\