Design for Manufacturing: Laser Cutting

Carbon dioxide laser cutting beams are frequently used throughout manufacturing to provide precision cut sheets of material. Laser cutters are exceptionally well suited to intricate details, irregular contours, and tight dimensional tolerances. Laser cutters can provide 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 to achieve maximum radiative power applied to the material. Excessively thick materials (typically greater than 3/8") will tend to diffract the beam and cause coherency problems. Also, molten metal pools will further scatter the beam, resulting in poor cutting performance. Further issues may be caused by the 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 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 that 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 use thermal energy to cut precision edges, that thermal energy must only be directed onto surfaces with a high ignition set point. Engineers must ensure they are utilizing laser CNC machines only on materials not at risk of combustion from the cutting process.