Recently, there has been a significant increase in the number of users that are embracing air-assisted laser engraving. The reason for this is not far-fetched; it is incredibly effective and efficient for all laser engravers, preventing burns and saving money in the long term.
Basically, air assist is the act of blowing high-pressure air onto your workpiece during laser engraving or cutting. 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.
How does an 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 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-assisted laser engraving aims to use this high nitrogen concentration while exploiting the advantage of a much more diluted gas simultaneously.
Specific Purpose of an Air Assist
Generally, it helps to achieve the best engraving or cutting by minimizing heat around the laser head and preventing the workpiece from burning.
Benefits of an Air Assist
Air assist has been in vogue for nearly 20 years. Ever since then, the use of an air assist has continually grown in popularity among CO2 laser engravers. Initially, mode quality was a major setback when compressed air was used for CO2 lasers, but this limitation has been minimized with time. In these modern days, air assist has improved the capability of laser engraving some tough materials, including stainless steel and aluminum. Some of the benefits of air-assisted laser engraving include:
Using pressurized air for an air assist comes with a substantial return on investment for businesses that utilize CO2 laser engravers.
In conjunction with injected air, the extreme heat of fiber lasers produces engravings without oxide formation, greatly decreasing or eliminating secondary clean-up operations.
Lower Production Cost
Compared to nitrogen and oxygen, pressurized air is far less costly. In some cases, the cost of using nitrogen or oxygen gas alone could make up 90% of the overall operating cost.
Air assist can speed up your whole engraving operation. This is proven by laser engraving experiments on the complete spectrum of materials and thickness. According to a publication in The Fabricator (January 2017), tests have shown that nitrogen creates quicker engraving for materials thicker than ten gauge, but pressurized air is approximately 3% faster than nitrogen in the mild steel range of 0.135 inches and thinner. In addition, it is around 22% quicker for stainless steel from 0.750 to 0.036 inches, and 14% faster for aluminum in the range of 0.190 to 0.032 inches.
High Edge Quality
Although pressurized air is not the best gas for all engraving purposes, it does help enhance laser-cut edge quality. Air-assisted laser engraving produces an edge quality more than satisfactory for most powder coatings.
The risk of debris causing a fire is greatly reduced, as possibly combustible materials are quickly blown away from the laser beam and the excess heat it produces.
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.
In conclusion, air assist is a crucial component for your CO2 laser engraver. It provides an effective and smooth workflow without compromising the safety of the work environment. We hope this article has exposed you to the importance of air-assisted laser engraving. OMTech has adequate provision for various types of laser engravers equipped with air assist, along with other game-changing features. Do keep us in mind and reach out to us as you commence your engraving journey.