Different types of laser cutting equipment vary in the type of laser they use and the way the laser moves during operation. The primary types of lasers used for cutting are carbon dioxide (CO2) lasers and solid-state lasers using a glass or crystal gain medium doped with neodymium (Nd). The physical configuration of laser cutting machines can be categorized into three categories, called flying optics, moving material, and hybrid systems. The output from the lasers can be either pulsed or continuous. Some laser cutting systems, called laser microjets, incorporate a water jet that assists the cutting process.
CO2 lasers are a type of gas laser that use a gain medium composed of carbon dioxide, nitrogen, and helium and may also contain hydrogen, xenon, or water vapor. The gain medium is excited, or pumped, by electricity to produce a beam of infrared light. They can have very high power, with some industrial CO2 lasers producing outputs of several kilowatts. Laser cutting equipment using CO2 lasers is used on metals such as steel and aluminum as well as other materials, including plastic, fabric, and wood.
Neodymium-doped lasers are lasers that use a solid gain medium doped with the rare earth metal neodymium, pumped with light from a diode laser or flashlamp. The most common medium is neodymium-doped yttrium aluminum garnet (Y3Al5O12), or Nd:YAG. Other neodymiumm-doped materials used in lasers are yttrium orthovanadate (YVO4), yttrium lithium fluoride (LiYF4), and glass composed primarily of silicon dioxide (SiO2). These lasers can also be very powerful and are used primarily for cutting metals and ceramics.
Most laser cutting equipment is configured in one of three ways. In a moving material laser, the material being worked is mobile. In a flying optics laser, the material being worked is stationary while the laser moves over it on both horizontal axes. In a hybrid laser, the workpiece is moved along on one horizontal axis, usually the longer of the two, while the laser is mobile on the other horizontal axis. Similarly, laser cutting equipment that can cut on a greater number of axes, called multiaxis laser cutters, vary in their design according to whether the workpiece or the cutting head is moved on each of its axes.
Each configuration has different advantages. Flying optics machines are faster than the other types. Moving material lasers are the slowest, but have simpler optical systems. Hybrid lasers are faster than moving material lasers, but have better power efficiency and less complex optics than a flying optics machine.
A cutting laser's beam can be pulsed, firing a series of brief but rapid pulses of light. Pulsed lasers are useful for applications requiring high energy output lasting only a brief period. They are also used for heat-sensitive materials that would be at risk of melting if subjected to a continuous beam. Pulsed beams are also used in laser microjets, where the water jet helps to direct the beam and cools off the material being worked.