The type of laser suitable for laser cutting applications largely depends on the material being cut. However, when selecting and setting up a metal laser cutters for a specific application, other factors should be considered, such as machine configuration, laser power, wavelength, time mode, space mode, and focus size.
The laser power or wattage can increase or decrease the total processing time of the cutting application. The reason for this is that as the laser power increases, the intensity of the beam also increases (power density (intensity) = P /πr2).
The price of laser metal cutting machines usually depends on the power of the laser. The greater the laser power, the more expensive the equipment. Therefore, laser cutting machine manufacturer and workshops must find a balance between processing costs and equipment costs when selecting laser machines based on laser power.
The wavelength of a laser beam is the spatial length of a complete cycle of photons in the beam. The specific wavelength of the laser beam determines the radiation absorption rate of the material, which allows the material to be heated, melted, and vaporized to create the necessary cuts.
Beam mode: This mode refers to how the intensity of the laser beam is distributed across the cross-section of the beam. This mode will affect the size and intensity of the beam focus, which in turn affects the cutting quality. Generally, the best mode has a Gaussian intensity distribution (TEM00).
The light beam is guided through a lens or special mirror and focused on a small spot with high intensity. The point with the smallest beam diameter is called the focal point. The best focus position for laser cutting applications depends on several factors, including the characteristics and thickness of the material, the beam shape and mode, the type of assist gas, and the state of the focusing lens.
Laser cutting is suitable for various metal and non-metal materials, including plastic, wood, gems, glass, and paper. As mentioned in the previous sections, the type of material to be cut and its properties largely determine the best cutting mechanism, cutting gas and cutting gas pressure, and the laser machine used for laser cutting applications.
In addition to the reactivity or non-reactivity of the material being cut, another material consideration that manufacturers and workshops may also consider when deciding whether laser cutting is suitable for their cutting application is reflectivity. The greater the reflectivity of the material, the greater the percentage of radiation that is reflected rather than absorbed by it. The lower absorption rate slows down the cutting process and prolongs the turnaround time, and increases the laser power required to cut the material. Highly reflective materials (such as copper and aluminum) can also cause damage to the laser machine because the beam may be reflected back to the components of the laser cutting machine.