How to Prevent Fires

June 14, 2024

Laser machines can potentially cause fires due to improper material handling or parameter settings, which can damage materials and machine components. Before installing flame detectors, we experienced a fire that lasted six minutes, causing significant damage to our machines.

Now, flame detectors are standard on all Thunder Laser Machines. These heat sensors stop operation when they detect a fire. However, we can still take several precautions to prevent fires.

Materials

Many materials used in laser processing are flammable, including but not limited to: plywood, various solid wood boards, acrylic, ABS plastics, foam, paper, fabrics, leather, etc. When processing these flammable materials, closely monitor the machine and do not leave it unattended.

Power

Setting the power too high can cause materials to catch fire. Higher power delivers more energy in the same time, increasing material temperature to the ignition point. To ensure good cutting results, choose the lowest power setting possible.

Speed

Setting the speed too low can cause materials to catch fire. Lower speeds increase laser exposure time, leading to localized energy build-up and higher material temperatures, reaching the ignition point. To ensure good cutting results, choose the highest speed setting possible.

A good set of cutting parameters should balance power and speed: power not too high, speed not too low, while achieving smooth and sharp material edges and the desired cut quality.

Some very thick or special materials may require unique speeds. For example, cutting wood close to 20mm thick may require single-digit speeds. However, setting the speed to 1mm/s is not recommended because the extended laser exposure time can cause materials to catch fire rather than be cut through. During a fire, materials strongly carbonize, and the produced carbon black absorbs laser energy, preventing the laser from cutting through at very low speeds.

Air Assist

Setting the air assist too low can cause materials to catch fire. Air assist cools and prevents combustion; insufficient air assist may lead to fires. Generally, we choose strong air assist for cutting, but sometimes we reduce or turn off air assist for special effects. In such cases, monitor the material closely and address any fires immediately.

When cutting thick materials, the laser head’s air assist alone may not cool the cut line effectively. A feasible method is to elevate the thick material and continuously blow air at the material’s bottom with an air gun during cutting until the process is complete.

Handling Fires

If flames are observed while operating the laser machine, immediately press the emergency stop button to halt processing. If flames persist after stopping, promptly use a fire extinguisher to spray at the base of the flames. After extinguishing the fire, inspect the machine and replace any damaged parts promptly.