How Does a CO2 Laser Engraver Work?

co2 laser engraving

When shopping for a laser engraver, you have a number of options including fiber lasers, semiconductor lasers, Nd: YAG laser, excimer laser, and CO2 lasers. Of all these types, the CO2 laser is arguably the most popular. One reason why the CO2 is more popular is that it can be used on almost any material that supports laser engraving.

So, how does a CO2 laser engraver work? The laser engraver consists of a gas-filled tube with mirrors on either end. One is reflective and the other one only lets a considerable amount of light to pass through. To produce light, electric power is passed through the gas tube which comprises nitrogen, carbon dioxide, helium, and hydrogen. The beam generated travels through the machine with the help of the mirrors until it reaches the laser head where it is magnified and focused on a single point. The result is a very powerful laser beam that can cut through a wide range of materials including paper, wood, glass, rubber, plexiglass, plastic, leather, ceramic, and cloth.

CO2 laser engraver explained in more detail

When an electric current is passed through the gas tube, it stimulates the nitrogen molecules causing them to be excited thereby releasing energy. Once both nitrogen and carbon dioxide molecules are excited, the laser machine reaches a state of population inversion. This means that the excited particles in the system are more than non-excited ones.

To produce a light beam, the nitrogen atoms must lose their excitement by releasing energy as protons. This can only take place if the nitrogen atoms come in contact with extremely cold helium atoms. This contact causes the nitrogen molecules to release light. Nitrogen gas is preferred over other gases because it can become excited for long periods of time without really giving off its energy in the form of light or protons.  

The laser produced by a CO2 laser is very powerful when compared to normal light. This is because the mirrors surrounding the gas tube reflect most of the light traveling via the tube. It is this reflection that causes the nitrogen light to build intensity as it travels back and forth in the tube. Even though the light from a CO2 laser can engrave many materials, you need a powerful machine to cut through steel and other materials.

The common ones used in machining fall in the range of 25 Watt and 100W while the high-powered can be as high as 1,000W (See our buying guide for a list of the engravers we recommend). The light produced is infrared and therefore invisible to the human eye. the light also has a long wavelength (approximately 10.6 micrometers).

History of the CO2 laser engraver

The laser technology has come a long way from the days of giant machines with massive radiations. The current lasers are smaller, cleaner, and precise. Historically, the first-ever laser called the “maser” was invented by Arthur Schawlow and Charles Townes in 1954. The name is an acronym for microwave amplification by stimulated emission radiation. The maser basically used microwave radiation and ammonia gas rather than visible light to engrave on objects. It wasn’t long before the pair advanced their technology to utilize infrared light – a project that paved a way for a multi-billion dollar industry.

In 1950, Theodore Maiman made the ruby laser which was considered to the first viable optical laser. Although Maiman made the invention, it was actually Gordon Gould who introduced the word laser in the industry after making his first light laser in 1958. Unfortunately, he failed to patent his invention in time and many people beat him to the punch. He, however, did receive a patent in 1977.

1963 marked the breakthrough of the laser engraver as it was the year when Kumar Patel invented the first CO2 laser engraver. He began his research when he joined Bell Labs in 1961. The CO2 laser had a higher frequency and a considerably lower cost compared to the ruby laser. These factors made it one of the most popular inventions for over half a century. His invention would engrave on a number of materials including plywood, cardboard, acrylic, and MDF.

In 1965, Western Electric developed the first laser specifically used for manufacturing purposes such as drilling holes in diamond dies. Two years later, Boeing researchers introduced a focused CO2 laser beam for engraving which led to the manufacture of the modern CO2 engraver in 1975. By this time, the laser technology had powers exceeding 1,000 watts and had penetrated to the aerospace industry. It was also around the early 1970s that the gas laser was used to cut through different heavy materials including metal. Somewhere in the 1980s, around 20,000 commercial lasers had been utilized in different industries.

Advantages of a CO2 lasers

CO2 laser engravers are high-power machines that fit perfectly in the personalization industry. Check out some of their advantages.

  • Precision

The CO2 laser beam technology has a reputation for creating high precision laser engravings. With a general hole center deviation of between 0.1 and 0.4 mm and a contour deviation of 0.1 – 0.5 mm, you are guaranteed a perfect cut and a smooth surface finish. This high precision allows for the engraving of detailed images.

  • Perfect for thicker materials

When you want to laser engrave on thick materials (above 5mm), both a fiber laser and a CO2 will get you home. However, the latter will ensure you get a smoother, high-quality finish.CO2 lasers will deliver a faster initial piercing time and quicker cutting, especially on a straight line.

  • High production efficiency

Compared to other laser engraving technologies, CO2 lasers have a high production efficiency. High-speed engraving and etching can be done immediately and resembling the pattern output from the computer software.

  • Safe and reliable

CO2 laser technology is a non-contact process meaning the light beam doesn’t touch the material it is engraving on. Instead, it allows the material to melt on its own through intense heat. This way, your material is exposed to minimal mechanical stress. Additionally, you will have zero “knife marks” and hence no damage to the workpiece surface and no deformation of the material.

  • Eco-friendly

CO2 laser engravers don’t use chemicals or UV light during the process of engraving. They only need a small amount of carbon dioxide and water to function. This means there is limited emission and wastes. When working with a CO2 laser, the working environment of the operator is greatly improved. As a matter of fact, the only time you have emissions is when working with plastic.

  • Lower cost

If you have a smaller batch of processing, a CO2 laser is the most affordable option since it’s not limited by the amount of processing. Compared to other laser technologies like fiber, CO2 lasers are reasonably priced. Ultimately, the power of the individual machine determines the cost but they are generally cheaper.

Disadvantages of CO2 lasers

  • Material limitation

Although CO2 lasers are ideal for thicker materials, they are primarily limited to non-metallic materials. Luckily, high-powered machines are available in the market today and these can laser engrave on metal products.

  • High sensitivity

Secondly, CO2 lasers require careful alignment which cannot be knocked out place. If you accidentally mess with the alignment, you will need to ask an expert to fix it. In a world where time is money, this kind of downtime is no good news for anyone.

  • High maintenance costs

CO2 lasers are high-energy consumption machines, resulting in a significantly higher cost of operation. You should carefully plan your projects to avoid high electricity bills.

A CO2 laser is undoubtedly one of the best laser engraving machines. Even though it has a couple of drawbacks, it still stands tall as the most preferred laser engraver for both hobbyists and entrepreneurs. It comes with a ton of benefits such as precision, affordability, reliability, high production efficiency, and eco-friendliness. But what makes this engraver unique is its adaptability to a wide array of materials. As long as the material is non-metallic and is suitable for laser engraving, the CO2 laser engraver will get the job done.