Of the three main thermal cutting methods – oxyfuel, plasma and laser – there is no question laser offers the best cut quality, especially for fine features and holes. This is what makes laser the most appropriate method for stringent precision cutting in any industry.
Within the laser category, there are two main technologies: gas laser (CO2) and solid-state laser (YAG, disc and fiber). This article focuses on solid-state laser, and specifically within the solid-state category, fiber laser. Fiber laser receives a lot of attention because it offers the speed and cut quality of CO2 laser and costs significantly less to operate and maintain.
Defining fiber
Fiber laser cutting systems are similar to CO2 laser systems in that they use a laser light to cut metal. However, the systems differ in the intensity of the light produced and in how the light is moved (beam transmission) from the power source to the cutting head.
Fiber laser systems rely on multiple solid-state pump diodes to generate a laser beam with a very short wavelength – 1-micron wavelength compared to 10-micron wavelength for CO2 laser systems. The beam is then moved through a flexible fiber optic cable to the laser cutting head. A CO2 system, on the other hand, relies on mirrors, installed a set distance apart, to transfer the light beam.
Fiber lasers are similar to CO2 lasers in that they use a laser light to cut metal. However, they differ in the intensity of the light produced and in how the light is moved from the power source to the cutting head.
Benefits of fiber laser
The use of a fiber optic cable rather than mirrors offers a number of benefits to the end user: greater flexibility when it comes to table size and configuration, less money spent for electricity and cooling, the ability to cut non-conductive metals, and significantly lower maintenance frequency and costs.
There is no practical limit to a solid-state laser’s table size. A larger cutting table merely requires a longer delivery fiber. In fact, it is even possible to install a fiber laser cutting head right next to a plasma cutting head on a plasma cutting table, something that is not an option for CO2 laser. At the same time, the ability to bend or coil fiber optics means the fiber laser systems are relatively compact compared to CO2 systems of similar power. This is especially beneficial to shops with limited floor space.
Another significant benefit of fiber laser is its energy efficiency. Because fiber laser is a completely solid-state digital, monolithic design, it has higher wall-plug efficiency. For every unit of power that passes through a CO2 laser system, only 8 to 10 percent is actually used. With a fiber laser system, users can expect power efficiency figures of about 31 percent.
In other words, a fiber laser system consumes about three to five times less energy making it roughly 86 percent more energy efficient. The benefit of this is not only lower energy consumption compared to a CO2 system, but also lower cooling requirements.
The third benefit is an ability to cut non-conductive metals. Fiber lasers feature positive light properties, such as a shorter wavelength, which improves beam absorption into the material being cut and enables the cutting of non-conductive metals such as brass and copper.
A more concentrated light source creates a smaller spot and longer depth of focus so fiber lasers can cut thin materials fast and medium thickness materials more efficiently. With stainless steel and thinner mild steel, up to 6 mm (1/4 in.), a 1.5-kW fiber laser can cut just as quickly as a 3-kW CO2 laser. This very high power density translates to increased output, yet operating costs for fiber laser cutting systems are lower than those of traditional CO2 systems.
A final benefit of fiber laser is maintenance. Traditional CO2 laser systems require regular maintenance. Mirrors need to be maintained and calibrated. Resonators and turbines that move the gas need to be replaced. And, the lasing gas needs to be cleaned out regularly because of its tendency to collect impurities.
All of this maintenance can add up, and a CO2 system could cost up to $40,000 per year to maintain. Fiber laser systems, on the other hand, require little to no maintenance because they don’t rely on mirrors or turbines.
The HyIntensity Fiber Laser HFL015 system includes the power source, cutting head, gas supply, operator interface consoles, motion controls and software.
Fiber considerations
There are a few important things to take into account when adopting fiber laser. The material to be cut is the first. While fiber laser is excellent at cutting most materials, because of the shorter wavelength it cannot cut acrylic or polycarbonate and can only cut wood or fabric in limited applications.
Another consideration is the thickness of material to be cut. Thicker materials, specifically mild steel, require more power to cut, and in those instances, laser cutting may be a less attractive option. This is where the ability to install a fiber laser cutting head right next to a plasma cutting head may be well utilized. In this scenario, operators can cut thinner material requiring tight tolerances very quickly with the fiber laser cutting head before easily switching to plasma.
It’s even possible to cut the same part with two different cutting methods. For example, operators can choose to cut the inside holes, shapes and fine features of a part with fiber laser and the outside profile of the part with plasma.
Another thing to know about fiber laser is that the shorter 1-micron wavelength produced by fiber laser systems transmits through the cornea of the eye to the retina. This eye safety is an easy issue to address with safety enclosures and glasses.
In summary, fiber laser cutting systems offer many benefits over traditional CO2 laser systems. They are more efficient, cost less to maintain and are easily integrated into existing metal cutting tables and solutions. However, fiber may not be right for everyone. The type and thickness of material most often cut, as well as the required cut quality, are among the considerations one must make before choosing a solution.
