Why Laser Air Assist is Essential for Laser Cutting

Recently, there has been a significant increase in the number of users that are embracing air assist for laser cutting and engraving. The reason for this is not far-fetched; laser air assist systems are incredibly effective and efficient for all laser cutters and engravers, preventing burns and chars, and saving money in the long term.

What is Laser Air Assist?

Basically, laser air assist is the act of blowing high-pressure air onto your workpiece during laser cutting or engraving. Interestingly, there are several ways to go about this; you could adopt pure nitrogen gas, oxygen gas, or pressurized air. While nitrogen and oxygen are the most commonly used assist gases; pressurized air is a cost-effective alternative to these gases. Hence, this article aims to shed more light on air-assisted laser engraving and its many advantages in your laser workshop.

• Enhanced Edge Finish: The air assist helps to create cleaner and smoother cut edges. As the laser beam cuts through the material, the air stream blows away molten debris and slag, preventing it from re-solidifying on the edges and resulting in a more refined finish.
• Reduced Hazing and Discoloration: It minimizes the occurrence of hazy or discolored edges, which can be a problem without proper air assistance. This is particularly crucial when cutting materials that are sensitive to heat, such as plastics or thin metals.

• Efficient Removal of Material: The air stream aids in the rapid removal of the melted and vaporized material from the cutting zone. This allows the laser to progress more quickly through the material, significantly increasing the cutting speed.
• Optimal Laser Focus: By constantly clearing the area around the laser beam, air assist helps maintain a stable and optimal laser focus, further enhancing the cutting efficiency.

• Protection from Debris: The air assist helps protect the laser cutting system’s lenses and mirrors from damage caused by flying debris. Without air assistance, the debris generated during cutting can accumulate on these critical components, reducing their effectiveness and shortening their lifespan.
• Cooling Effect: In addition to removing debris, the air stream also provides a cooling effect on the lenses and mirrors, reducing the risk of overheating and prolonging their durability.

• Compatibility with Different Materials: Laser air assist can be adjusted to suit various materials and thicknesses.
• For example, different air pressures and flow rates can be used for cutting thin metals versus thicker plastics, ensuring optimal cutting performance across a wide range of materials.
• Handling of Reflective Materials: In the case of reflective materials like copper or aluminum, the air assist helps manage the reflection of the laser beam and reduces the risk of damage to the laser source.

• Reduced Post-Processing: With better cutting quality and less debris, there is less need for extensive post-processing operations such as grinding or polishing. This saves time and labor costs.
• Longer Equipment Lifespan: By protecting the laser cutting system components, air assist reduces the frequency of replacements and maintenance, resulting in cost savings over the long term.

How does Laser Air Assist Work? 

Although relatively new to some, machine tool manufacturers started researching and developing the process as early as 1998. It was found that CO2 laser engravers need more than just a light beam to successfully engrave. They also require the injection of an assist gas nozzle at the laser head to complement the operations. This convergence initiates an exothermic reaction. An exothermic reaction is a chemical reaction that releases energy through light or heat. The application of nitrogen, oxygen, or pressurized air helps transfer heat more efficiently than the beam alone. With this, you get your job done faster, cleaner, and smoother.

For years, oxygen was the most commonly used gas with air assist for laser engraving. It was later succeeded by nitrogen, which was found to produce a cooler engraving with cleaner edges. This was a perfect option for industries where aesthetics and edge quality were vital. However, it has been discovered that pressurized air is a more economical option with equivalent efficiency to nitrogen and oxygen.

This is not to say that pressurized air is a total replacement for nitrogen or oxygen. After all, air is made up of 80% nitrogen, with the remainder mainly consisting of oxygen. Air-assist laser cutting aims to use this high nitrogen concentration while exploiting the advantage of a much more diluted gas simultaneously.

Possible Risks for Not Using an Air Assist 

When your laser engraver is running, it generates some debris as well as smoke from heat. This can be very dangerous as debris can cause flare-ups creating a fire risk. The smoke produced by heat has the following negative effects:

• Smoke can interact with the energy of the beam in the direction of your laser, decreasing the total strength and creating inconsistencies.
• A lot of smoke will create residue around the laser engraver on the laser optics and everywhere else.
• Smoke produces discoloration, residue, and chemicals that can reach your workpiece, making it less pleasing to the eyes and your respiratory system.
• Risk of flammability depending on the materials e.g wood and certain acrylics.