2013年2月22日星期五

FAQs about Laser Engraving & Cutting


  • How does a laser work?
  • The term "Laser" 

    "LASER" stands for "Light Amplification by Stimulated Emission of Radiation". Lasers amplify light by absorbing and radiating energy. The laser radiation is generated by a laser source. For this, concentrated energy is supplied to a crystal rod (solid state laser) or a special gas mixture (gas laser). This energy can be supplied in the form of light (flash lamps or diode laser) or by electric discharge (comparable to a fluorescent lamp). The crystal rod or the laser active gas is arranged between two mirrors. This generates a light resonator that directs the laser light into a specific direction and amplifies it in this manner. A defined percentage of the laser light is emitted through the partially transmissive mirrors and is available for working the material.
  • Laser beam characteristics 

    Laser light can be highly collimated by means of a focus lens. An extremely high energy density is generated in the focus of the laser beam, which can be used for melting or evaporating the material. In addition, using suitable optics (mirrors), laser light can be directed and reflected, and this completely without any losses even over large distances. Positioning systems (laser plotters) or galvanometer scanners are used as movement systems. The result is a universal and wear-free tool as the laser beam will never become blunt.
  • Different laser types for different applications 

    Common laser types include "sealed-off" gas lasers (CO2 lasers) and fiber lasers. Both operate economically and feature a long service life. CO2 lasers are especially suited for laser engraving and laser cutting. Fiber lasers are mainly used for laser marking. In addition, with the Speedy 300 flexx, Trotec is the only laser system manufacturer to offer a product that combines both technologies and thus supports all applications (engraving, cutting and marking) equally effectively.

    How safe is a laser?

    • Laser safety classes 

      Laser machines are classified according to different safety classes based on the injury risk for the user and the laser power and wavelength.
      Laser systems of class 1 are considered safe for the eyes. Extended exposure to radiation will not be harmful to health. In addition, class 1 laser machines are housed in a completely sealed enclosure so that no radiation can escape from the machines.
      Laser systems of class 2 comprise visible lasers that are only safe for the eyes if exposure is short.
      Laser systems of class 3 are not associated with any risk in the event of short-term, accidental exposure. However, there might be a risk of injury if these laser systems are used incorrectly by unqualified users. Users should be particularly mindful of reflections (e. g. caused by reflective material surfaces).
      Laser systems of class 4 may cause damage to eyes and skin or ignite a fire within the danger area of the machine. Users working with machines of this laser class are compelled to strictly observe the safety regulations.
    • Closed concept of triumph laser machines 

      Thanks to the closed design of triumph lasers, your operating staff is optimally protected. In addition, this concept allows for quick and efficient extraction of dust and gas.
      The enclosed triumph flatbed laser machines fall under laser safety class 2. Why only laser class 2? triumph machines include a laser pointer that indicates the user where the laser hits the material. According to the internationally valid standard, laser pointers fall under laser safety class 2. 
    • Triumph laser machines - special cases with laser class 4 

      However, two exceptions must be mentioned here: If a Triumph laser plotter is equipped with a pass-through, the closed concept is opened and the laser machine will then fall under laser safety class 4. The situation is similar for Triumph galvo marking lasers. The laser falls under laser safety class 4 if no appropriate enclosure is provided.
      Laser machines of safety class 4 may only be operated when special protective equipment is provided (protective glass, shields, safety goggles). Naturally, we will be happy to provide you with information and advise you personally on the topic laser safety.

      What types of lasers exist and what are their differences?

      • ommon laser types available in the market 

        The laser machines available in the market mainly differ by the laser source they use. We mainly talk about COlasers, fiber lasers and vanadate lasers. Each laser type has its own advantages and disadvantages and is suited for use on different materials.
      • CO2 lasers (gas lasers) 

        COlaser are gas lasers that are based on a carbon dioxide gas mixture, which is stimulated electrically. With a wavelength of 10.6 micrometers, they are mainly suited for working on non-metallic materials and on most plastics. COlasers have a relatively high efficiency and feature a very good beam quality. They are therefore the most widely used laser types.
        Suited for the following materials: Woodacrylicglasspapertextilesplasticsfoils & filmsleather,stone
      • Fiber lasers 

        Fiber lasers belong to the solid state laser group. They generate a laser beam by means of the so-called seed laser and amplify it in specially designed glass fibers, which are supplied with energy via pump diodes. With a wavelength of 1.064 micrometers, fiber lasers produce an extremely small focal diameter; as a result their intensity is up to 100 times higher than that of COlasers with the same emitted average power.
        Fiber lasers are optimally suited for metal marking by way of annealing, for metal engraving, and for high-contrast plastic markings. Fiber lasers are generally maintenance-free and feature a long service life of at least 25,000 laser hours.
        Suited for the following materials: Metalscoated metalsplastics
      • Nd:YAG, Nd:YVO (crystal lasers) 

        Like fiber lasers, crystal lasers belong to the solid-state lasers. Nowadays, lasers for marking applications are pumped by diodes (in the past by flash lamps). The most common laser types in this category areNd:YAG (neodymium-doped yttrium aluminum garnet) and Nd:YVO (neodymium-doped yttrium ortho-vanadate), named after the doping element neodymium and the carrier crystal. With 1.064 micrometers, crystal lasers have the same wavelength as fiber lasers and are thus also suited for marking metals and plastics.
        Unlike fiber lasers, these laser types include the relatively expensive pump diodes, which are wearing parts. They must be replaced after approx. 8,000 to max. 15,000 laser hours. The crystal itself also has a shorter service life than a fiber laser.