Carbon dioxide laser cutting beams are frequently used throughout manufacturing to provide precision cut sheets of material. Laser cutters are extremely well suited to intricate details, irregular contours, and tight dimensional tolerances. Laser cutters are capable of providing cuts to an accuracy of +/- 0.004”.
Despite these benefits, laser cutting does come with a few restrictions. Lasers are typically applied perpendicular to the cutting surface in order to achieve maximum radiative power applied to the material. Materials which are excessively thick (typically greater than 3/8”) will tend to diffract the beam and cause coherency problems. Additionally, molten metal pools will scatter the beam further resulting in poor cutting performance. Further problems may be caused by reflection of the beam either from loss of cutting power or damage to the laser optics.
Beam reflection results from two sources: reflective surfaces or molten metal pools. Some particularly reflective metals such as copper or silver are poor choices for use of laser cutting. Aluminum, a less reflective metal, may be used if anti-reflective coatings are utilized. Aluminum alloys may reduce the risk of reflection. Alternatively, special laser cutting systems certified for aluminum cutting may be used. These special laser cutters have reflection sensing systems which safely shut down the cutter in the event of beam reflection back into the laser optics system. Engineers must take special care to ensure that the design accounts for these risks to be mitigated.
A final concern is material flammability. As lasers make use of thermal energy to cut precision edges, that thermal energy must only be directed onto surfaces that have a high ignition set point. Engineers must ensure that they are utilizing laser CNC machines only on materials which are not at risk of combustion from the cutting process.