CO2 vs Fiber Laser Laser Cutting

CO2 vs. Fiber Laser, which is better? This has been a common discussion in manufacturing circles for many years now as some insist CO2 was the better technology and others say the new innovations of Fiber Lasers are in fact better.

Who is right? Which technology is better and what exactly is the difference?

Before we start here are some terms for further understanding the processes of Laser Cutting:

A gain medium (also active laser medium): A gain medium is the main differentiating factor among the various kinds of laser beams. In our case, a fiber laser uses a solid-state gain medium, and a CO2 laser uses a gas-state gain medium. This medium determines the different properties of the laser beams that are produced.

An optical resonator: This is an arrangement of a highly reflective set of mirrors that further amplifies the laser beam. The light beam repeatedly bounces between the mirrors through the gain medium before it exits the system. This enables the laser to possess as much energy as possible before exiting the cavity.

Light (radiation) from the source is stimulated in a medium, which is further amplified using an optical resonator. These are just the basics of how a laser system works. Just by understanding the basics will be enough to grasp the differences between Fiber and CO2 lasers.

Now, Let’s start by differentiating what is a CO2 Laser and What is a Fibre Laser.

CO2Laser

The use of CO2 gas as a gain medium in the laser system characterizes CO2 lasers. A sealed gas tube with reflectors at both ends forms the backbone of any CO2-based laser machine. The tube is filled with a mixture of nitrogen, carbon dioxide, hydrogen, helium, and xenon gases. A high-voltage electrical discharge is passed through the tube, which starts a chain reaction in the gas mixture, creating a high-energy laser beam.

Fiber Laser

In contrast to the gas-based CO2 lasers, a fiber laser comprises a solid optical fiber (fiber-optic) cable as its gain medium. The fiber-optic cable is laced with rare earth metals like erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium, and holmium. The energy source used for these lasers is a solid fiber-coupled laser diode, which provides light to the optical cable. Naturally, there are some significant differences between these two types of lasers. Here are some of the key distinctions.

Laser Source

The CO2 laser uses a flashlamp or an RF generator as its energy source and a gas mixture in a tube to generate and amplify the laser beams. The Bigger the CO2 tube, the more powerful the laser beam.

A fiber laser uses an optical fiber doped in rare earth metals to amplify the laser beam. The intensity of the laser beam depends on the energy source, the doping process, and the length of the optical fiber.

Power Consumption

CO2 lasers can achieve a photoelectric conversion of around 10-15%. Thus, for a 50-W laser, you’d need to have a power source of at least 500 W. This translates to an overall increase in the operation cost for the machines. CO2 tubes also need additional cooling equipment to cool down the tubes, which results in further increases in the power consumption of the machines.

Fiber lasers can achieve a 35-50% power efficiency. So, a 50-W fiber laser system would need only a 100-150-W power supply. This drastically reduces the overall cost of operation and results in huge energy savings. Also, low-powered fiber laser machines can operate well with little to no additional cooling.

Wave Length

A CO2 laser has a wavelength of approximately 10 μm. This limits the materials it can work with, and highly reflective materials can’t be processed with CO2 lasers because they cannot absorb this wavelength of light and are therefore unaffected by it. Thus, shiny metals like aluminum, steel, copper, and brass can’t be readily cut using low-powered CO2 lasers.

Fiber laser has a much shorter wavelength at 1.04 μm, which allows it to penetrate through most of the materials; these can readily absorb this laser beam. Thus, a fiber laser can be used on a wide variety of materials.

Speeds

Overall, CO2 lasers have slower cutting speeds. Below 4 mm thickness, a similarly powered CO2 laser would be three times slower compared to a fiber laser. This is because of the wavelength characteristics and because of a wider focus area of the laser beam. The overall energy of the CO2 laser beam is spread over a larger area and the laser is also limited by the absorptivity of the material.

Fiber lasers, in contrast, have a much more focused laser beam as a result of their lower wavelengths. This allows for rapid heating of the material on the focus area and higher cutting speeds can be achieved. However, the thicker the material, beyond 8-mm thickness, both the lasers have similar cutting speeds.

Conclusion

Both CO2 lasers and fiber lasers have their pros and cons with the fiber technology being a newer technology on the market.

CO2 lasers are readily available, initial costs are cheap, and they can be used with many materials, mainly non-metals, for etching, engraving, and cutting fiber laser technology is an improvement over CO2 technology in certain aspects. It can easily etch metals, it has a tighter focus area, and it’s coupled with lower operating costs, but only after a higher upfront investment.

We hope this gives you more information with regards to CO2 laser cutting vs fiber Laser cutting and its differences.

Please feel free to send us your design and allow us to give you the suitable advice on whether Laser Cutting is the best service for your needs and how we can assist you.

Starlaser Team

Email: info@starlaser.co.za or Chris@starlaser.co.za or rory@starlaser.co.za