Summary: The most important difference between fiber, CO2, and UV laser markers is the wavelength of light they produce: fiber lasers are 1090 nm (infrared), CO2 lasers are 10600 nm, and UV lasers are 355 nm. Shorter wavelengths carry more energy and a higher absorption rate, which determines what each laser can mark. Fiber lasers are optimized for metals but cannot mark transparent objects. CO2 lasers excel on paper, resins, wood, rubber, and transparent materials such as glass and PET, but cannot effectively mark metal. UV lasers perform "cold marking" with minimal heat stress and are ideal for delicate electronics, medical devices, and pharmaceutical packaging. Provided by KEYENCE.
| Laser type | Wavelength | Category |
|---|---|---|
| UV laser | 355 nm | Ultraviolet |
| Fiber laser | 1090 nm | IR (infrared) |
| CO2 laser | 10600 nm | Infrared (10x the fiber wavelength) |
Short wavelengths typically have more energy and a higher absorption rate than long wavelengths. As a result, a laser's wavelength affects its ability to mark certain materials.
Fiber lasers pump light through rare-earth elements in glass fibers to create the beam. The process builds energy as light travels through the fiber, creating intense infrared radiation. This wavelength penetrates metal surfaces and creates chemical reactions that form permanent marks.
A CO2 engraver mixes carbon dioxide gas with nitrogen and helium in a sealed tube. Electric current excites the gas mixture, producing infrared light that gets focused through mirrors.
UV lasers use crystals to convert infrared light into ultraviolet radiation through a process called frequency tripling, which creates the short wavelength needed for precise work.
Fiber lasers have a 1090 nm wavelength, making them IR lasers. They can mark a wide range of materials but are optimized for metal marking. Their high power makes them suited to annealing and engraving applications. They cannot mark transparent objects, because IR light passes straight through.
Typical applications include engraving (painting after marking) on vehicle body frames, black-annealed marking on bearings, high-speed 2D code marking on engine blocks, etching on key cylinders, laser cutting of aluminum board, and burr removal on frame ICs.
Fiber laser systems excel at marking stainless steel, aluminum, and titanium parts in automotive manufacturing, and handle high-volume production lines where speed matters most.
CO2 lasers have 10x the wavelength of standard wavelength systems. They are effective on paper, resins, wood, rubber, and transparent materials such as glass and PET. It is nearly impossible to mark metal with a CO2 laser marker because the laser light is not absorbed.
Typical targets include cartons, bottles, design marking, glass wafers, weatherstripping, and electronic PCBs. CO2 lasers work best on cardboard packaging, acrylic displays, and wooden furniture where organic materials need processing, and they cut through thick materials that other systems cannot process effectively.
UV lasers use a highly absorbable wavelength (355 nm). This high absorption rate allows "cold marking" — marking without extra heat stress — so UV lasers are ideal for applications that require high contrast or minimal product damage.
Typical targets include multicolor automotive relays, earbuds, chemical bottles, copper lead frames, steel tools such as scissors, and food packaging film. UV laser technology is well suited to delicate electronics, medical devices, and pharmaceutical packaging, where the cold marking process prevents heat damage to sensitive components.
Fiber laser systems dominate metal marking applications. The infrared wavelength penetrates steel, aluminum, and brass surfaces efficiently, creating annealed marks, etched patterns, and deep engravings that survive harsh environments.
UV lasers can also mark metals — including highly reflective metals that fiber lasers cannot, such as copper, silver, or gold. However, fiber systems typically provide faster processing speeds for most metal applications. CO2 lasers cannot mark metals effectively, because the long wavelength reflects off metallic surfaces instead of being absorbed.
UV laser technology excels at marking plastic materials without causing heat damage or melting. The short wavelength creates clean, precise marks on polymers, resins, and flexible films, preventing the thermal stress that other laser types might cause.
CO2 lasers work well on certain plastics and excel at glass marking. The longer wavelength creates frosted effects on glass surfaces through controlled heating. Fiber lasers struggle with transparent materials because infrared light passes through without being absorbed effectively.
| Material | Fiber laser | CO2 laser | UV laser |
|---|---|---|---|
| Metal (iron) | High visibility | Low visibility | Low visibility |
| Metal (copper) | Low visibility | Low visibility | High visibility |
| Resin (PE) | High visibility | Low visibility | High visibility |
| Cartons | Low visibility | High visibility | High visibility |
| Transparent targets | Low visibility | High visibility | Low visibility |
| Pouches | Low visibility | Low visibility | High visibility |
Results may vary depending on the material and its status. The above results only represent an example.
Fiber lasers can quickly mark the widest range of materials and typically produce the most contrast on metals. However, fiber lasers cannot mark transparent materials and will sometimes damage the marking surface.
UV lasers provide the most contrast on resins, with the added benefit of creating damage-free marks.
CO2 lasers burn the target with heat, making them ideal for marking wood, paper, ceramic, and transparent targets.
Consider your primary material type first. Metal parts require fiber lasers for deep penetration and lasting marks. Organic materials like paper and wood respond better to CO2 laser energy. UV lasers are a wise choice when high-precision marking is required on delicate materials such as plastics, semiconductors, and medical devices, because no heat-related damage occurs to sensitive surfaces.
Production speed also influences the choice. Fiber lasers handle high-speed operations with minimal maintenance needs. UV systems work slower but provide superior quality on delicate materials. CO2 lasers offer excellent versatility across non-metal materials.
Facility layout, employee safety, and operational efficiency also matter. Fiber lasers may require less maintenance and downtime. CO2 lasers, which can be bulkier, might need specific space considerations. UV lasers, with their precision and minimal heat, may be favored where sensitive materials and worker safety are prioritized.
Most laser systems work best with specific material types rather than being universal solutions. UV lasers can handle both materials effectively, while fiber lasers excel at metals but struggle with plastics.
Fiber lasers last 100,000+ hours, CO2 lasers need maintenance every 10,000–20,000 hours, and UV lasers provide 10,000–15,000 hours of service life. KEYENCE lasers are typically rated for 3 to 10 times longer than the standard, depending on the wavelength.
UV lasers are specifically designed for electronics and pose minimal risk when proper safety protocols are followed.
Fiber laser systems provide the best performance for most metal marking applications with excellent speed and quality.
CO2 lasers cannot effectively mark metals because the long wavelength reflects off metallic surfaces instead of being absorbed.
UV lasers have a shorter wavelength and thereby a higher absorption rate, meaning they are able to mark a larger variety of plastics, including different colored plastics.
Choose based on your primary materials: fiber for metals, CO2 for organic materials, and UV for delicate materials requiring precision.
Source: KEYENCE, "Fiber vs. CO2 vs. UV: Which Laser Marker Should I Choose?" https://www.keyence.com/products/marker/laser-marker/resources/laser-marking-resources/fiber-vs-co2-vs-uv-which-laser-marker-should-i-choose.jsp