AWS-C7 4-C7 4M pdf free download

AWS-C7 4-C7 4M pdf free download.Process Specification and Operator Qualification for Laser Beam Welding.
diode laser. A type of laser in which the active medium is a semiconductor with polished end facets forming mirror surfaces. Also called semiconductor laser. Diode lasers used for alignment emit in the visible:
other diode lasers emitting in the infrared are used for material processing.
excitation. Process of transferring energy from the energy source to the active medium.
fiber laser. A solid-state laser design in which the active medium is a doped optical fiber.
F-number. The ratio of the focal length of a lens or focusing mirror to the diameter of the beam incident on the lens or mirror. Note the definition is somewhat different than that for photographic systems.
focal length. In a lens or lens system, the distance from the principal plane, the surface at which the projections of an entering and exiting ray intersect, to the focal point. In a thick lens or system of lenses, the principal plane is often inside the lens itself; for set-up purposes, operators often use the back focal length. which is the distance from the front surface of a focusing lens or mirror system to the focal point.
hermetic. The rating of a seal that prevents the exchange of fluids (gases or liquids) between a contained voltime and an exterior environment.
infrared (I R). Electromagnetic radiation possessing wavelengths between those of visible light and microwaves.
laser. A device that produces a concentrated coherent light beam by stimulated electronic or molecular transitions to lower energy levels. Laser is an acronym for light amplification by stimulated emission of radiation.
laser beam. The output radiation of a laser that can be steered and focused by mirrors, lenses, or both, to do useful work.
laser generator. See laser.
laser system. A machine or fabrication tool consisting of a laser, a workpiece holder, and a means of delivering the beam to the workpiece and deflecting it over the workpiece in a controlled manner. The most common type of controller is a computer numerical controller. orCNC.
lens. A transparent optical element with curved surfaces. used to converge or diverge light rays via refraction.
mirror. An optical element which reflects nearly 100% of the laser beam.
mode. A stable condition of oscillation in a laser. There are transverse modes and longitudinal modes. Longitudinal modes occur at slightly different frequencies; most lasers operate on a large number of longitudinal modes simultaneously. Transverse modes describe the distribution of energy in a plane perpendicular to the direction of propagation. A laser can operate in one transverse mode (single mode) or in many modes simultaneously (called multi-mode or mixed mode operation).
Nd:Glass. Neodymium-doped glass which is utilized as the lasing material in some solid-state lasers. The neodymium atoms form the active medium.
Nd:YAG. Neodymium-doped yttrium aluminum garnet (YAG) crystal which is utilized as the lasing material in a common type of solid-state laser. The neodymium atoms form the active medium. See YAG.
nozzle. A device projecting from the focusing head with an outlet to direct gas into the laser beam processing area.AWS-C7 4-C7 4M  pdf download.