Fiber, UV and CO₂ lasers each suit a different material. A fiber source marks bare metal. A UV source marks heat-sensitive plastics and glass without scorching them. A CO₂ source marks organics such as wood, leather and packaging. A MOPA fiber source adds colour on stainless steel. Your material, more than your budget, decides the source.
Which laser marking source fits which material?
Match the source to the material first, then size the power. A fiber marker at 10, 20, 30 or 50 W handles steel, aluminium and most metals. A UV marker at 3 or 5 W and 355 nm suits plastics, glass and other heat-sensitive parts. A CO₂ marker at 20, 30 or 100 W marks wood, leather, paper, acrylic and packaging, down to a 0.4 mm character. A MOPA source, a fiber variant, adds colour on stainless steel. The reason material comes first is simple. Each source sits at a different wavelength, and a wavelength a metal soaks up will pass straight through clear plastic. Pick the wavelength your part absorbs, and the mark comes out crisp and permanent. Pick the wrong one, and you either scorch the part or leave no mark at all.
How each source marks the surface
A laser marks by putting light of one wavelength into a surface that absorbs it. A fiber laser runs near 1064 nm, a wavelength bare metal drinks in, so it etches or anneals steel at up to 7,000 mm/s. A CO₂ laser runs at 10.6 µm, which organics and coatings absorb well while bright metal reflects it, so it marks wood and packaging and skips steel. A UV laser runs at 355 nm and works by cold marking. Its photons break surface bonds instead of heating the part, so a UV marker writes on clear plastic and glass at up to 10,000 mm/s with no burn. Read the wavelength as the key spec, because it decides which materials the beam can touch at all.
Fiber for metal parts
Fiber is the source for bare metal, and most marking jobs on a factory floor are metal. Our fiber markers come at 10, 20, 30 and 50 W, run at 20 to 80 kHz, and cover fields of 100×100, 150×150 or 200×200 mm at up to 7,000 mm/s. That range marks serial numbers, data-matrix codes, logos and traceability marks on steel, stainless, aluminium, brass and coated metal. A lower-watt unit anneals a dark, flush mark on stainless for medical and food parts, where a smooth surface matters. A higher-watt unit engraves deeper on hard tool steel. The mark is permanent, uses no ink and touches nothing, so there is nothing to refill and no contact to wear the part. A clean surface also marks more evenly, which is why some shops run a laser cleaning pass over oxidised or oily metal first. Send the metal and the mark you need, and a supplier sets the power.
UV for plastics, glass and heat-sensitive parts
UV is the source when heat is the enemy. Our UV markers run at 3 or 5 W, at 355 nm, and are water-cooled for steady output at up to 10,000 mm/s. Because UV marks cold, it writes on ABS, PET, PVC, silicone and other plastics without the melt ridge or yellowing a hotter source leaves behind. It also marks glass, and it puts fine, high-contrast codes on electronics and medical plastics where a scorch mark would fail inspection. The 355 nm wavelength is the reason. The part absorbs short-wave light right at the surface and the bonds break there, so the heat-affected zone stays tiny. For a cosmetic bottle, a silicon wafer or a sterile plastic housing, that clean, damage-free mark is why buyers pick UV over a fiber source.
CO₂ for wood, leather, paper and packaging
CO₂ is the source for organic and non-metal materials. Our CO₂ markers run at 20, 30 or 100 W, at 20 to 25 kHz, over fields of 70×70, 110×110 or 175×175 mm, down to a 0.4 mm minimum character. That covers wood, leather, paper, acrylic, cardboard and most coated packaging, marked at up to 7,000 mm/s. A carton line uses it to date-code and batch-code boxes as they pass. A workshop uses it to engrave a logo into a wooden handle or a leather tag. The 10.6 µm wavelength is absorbed by these materials and reflected by bare metal, so CO₂ marks the packaging around a product yet not the steel part inside it. Match it to the softer, non-metal side of your bill of materials.
MOPA for colour on stainless steel
MOPA is the source for colour on stainless steel. A MOPA laser is a fiber variant at 1064 nm whose pulse length you can tune, and that control is what lets it grow coloured marks on stainless and anodised aluminium. The colour is a thin oxide layer the beam builds on the surface, not a dye or an ink. According to a peer-reviewed study of nanosecond laser coloration on 304 stainless steel, the final colours come from oxide pigments the laser forms, tuned by scanning speed, repetition rate and pulse width, and that same oxide layer also helps the mark resist corrosion (Nanosecond laser coloration on stainless steel surface, PMC). Which exact colours a given part can hold depends on the alloy and its finish, so we confirm the colour window per order. Send a sample, and we prove the palette before you buy.
The safety cost is the same for every source
The source you choose does not change your laser-safety bill, because fiber, UV and CO₂ marking lasers are all Class 4. According to OSHA, a Class 4 laser is an immediate skin and eye hazard from either the direct or the reflected beam, and it can also present a fire hazard (OSHA, Laser Hazards). That means an enclosure, interlocks and rated eyewear on every one of these markers, whichever wavelength it runs. UV adds one wrinkle worth budgeting for. Its water-cooled head needs the chiller kept in service, or the output drifts. Treat safety as a fixed cost of owning any marking laser, not as a reason to pick one source over another. A good supplier quotes the enclosure and interlocks with the machine, so the safe setup ships as one package.
Match the source to your part and your marks
Start from two facts about the job: the material and the mark it has to carry. A steel bracket that needs a permanent serial number points to a fiber marker. A plastic medical housing that must stay unscorched points to UV. A run of printed cartons points to CO₂. A stainless panel that needs a coloured logo points to MOPA. Traceability rules raise the stakes on some parts, and the FDA's UDI system, for one, requires many reusable medical devices to carry a permanent mark directly on the device. A permanent laser mark meets that kind of rule at up to 7,000 mm/s on a fiber line, where an ink code would rub off. Our applications page shows where each process earns its place. List your parts, note the material and the mark on each, and the source almost picks itself.
Fiber vs. UV vs. CO₂ vs. MOPA at a glance
Each source owns a different material. The table below sums up where a fiber, UV, CO₂ or MOPA marker fits, with the real power, wavelength and speed to ask for on each.
| Source | Best material | Power | Wavelength | Marks at |
|---|---|---|---|---|
| Fiber | Steel, aluminium and most bare metal | 10–50 W | 1064 nm | Up to 7,000 mm/s |
| UV | Plastics, glass and heat-sensitive parts | 3–5 W | 355 nm, cold | Up to 10,000 mm/s |
| CO₂ | Wood, leather, paper, acrylic and packaging | 20–100 W | 10.6 µm | Up to 7,000 mm/s, 0.4 mm character |
| MOPA | Colour on stainless and anodised aluminium | Fiber-class, tunable pulse | 1064 nm | Confirmed per part |
Frequently asked questions
Which laser marking source works on metal? Fiber. Our fiber markers run 10 to 50 W at 20 to 80 kHz and mark steel, stainless and aluminium at up to 7,000 mm/s.
Can one laser mark both metal and plastic? Not cleanly from a single source. Fiber suits metal and UV suits heat-sensitive plastic, so a shop that runs both usually buys one of each.
What marks glass without cracking it? UV. Its 355 nm cold marking writes on glass with almost no heat, so the part does not craze.
How do I get coloured marks on stainless steel? A MOPA source. It grows a coloured oxide layer on the surface, and the colour range is confirmed per alloy and finish.
What is the smallest character these lasers can mark? Our CO₂ markers reach a 0.4 mm minimum character, and fiber and UV hold fine detail on metal and plastic too.
Get the marking source matched to your parts
Tell us your material, the mark you need and how many parts you run, and we will recommend the marking source and power that fit. Request a quote and we will reply with a configuration and a price.