CUTTING HIGHLY REFLECTIVE MATERIALS

Aluminum, copper, brass, and stainless steel are popular metals used to make a variety of different products that customers like for their sleek appearance and mirror-like finish. But it’s this very reflectivity that presents challenges to fabricators who use carbon dioxide (CO2) lasers to process these metals. In short, highly reflective materials can lead to serious issues with cut quality and even laser system damage.

Because the wavelength of a gas laser beam is not within the ideal absorption range of these materials, much of the energy is reflected. Consider aluminum—it redirects about 92% of visible light and up to 98% of medium- and far-infrared radiation. Most laser cutting machines use a laser beam aligned to a flat sheet of material. This means that should the laser beam be reflected by the flat sheet, it can be transmitted back through the beam delivery optics, and into the laser itself, potentially causing significant damage. While some fabricators have sought to solve the reflectivity problem by placing a non-reflective coating on the material, the molten metal created during the laser cutting process is also reflective, which only increases the risk of laser damage.

According to the Welding Institute, the more reflective the material, the higher the chance that damage can occur. So, aluminum, which is more reflective than [carbon manganese] (C-Mn) steel or stainless steel, has a higher potential for causing laser damage.

This isn’t to say that gas lasers can’t work with highly reflective materials because steps can be taken to minimize the risk of damage. Also, modern lasers feature a failsafe that shuts down the laser system if it detects excessive heat caused by reflection. Despite these advancements in gas laser technology, it is still not the most efficient cutting method, and it will still put you at risk of incurring damages.

WHY USE FIBER LASERS FOR CUTTING REFLECTIVE MATERIALS?

While all reflective material can cause laser bounce back, the way the beam is generated and delivered makes a difference. When it comes to cutting reflective material, many experts consider fiber lasers to be a better choice than CO2 lasers. These lasers use resonators that send the laser beam by a series of mirrors and deliver the energy to a single spot. Fiber optics uses a resonator to excite electrons and deliver a beam through a fiber optic cable to the cutting head. With CO2 lasers, mirrors can reflect the laser back to the resonators, lens, and other components, but a fiber laser is a solid-state system that eliminates any such risk. With fiber laser systems, there are no mechanical components to maintain and no misaligned components that can lead to costly downtime.

Additionally, a fiber laser’s wavelength is shorter than that of a CO2 laser, so it produces a more closely focused spot. This allows it to cut thinner materials faster than a CO2 laser.

At Alpha Lazer, we specialize in turnkey solutions of fiber laser systems for customers in a variety of industries, including large manufacturers, small fabrication shops, steel service centers, and aerospace equipment companies. We can help you find the most cost-efficient fiber laser table for your fabrication needs. As a company dedicated to building long-term relationships with our customers, we provide free and unlimited lifetime support to help you use our cutting machines to their fullest potential. For information about our customizable fiber laser systems, contact Alpha Lazer today.