Boss fiber (FM) & UV markers
Which marking method
Anneal · etch · engrave
Contrast + permanence pick it
The difference is how much material moves. Annealing removes nothing — the beam heats the surface to grow a colored oxide layer, leaving a mark flush with the surface. Surface etching (marking) melts a thin, high-contrast layer very fast. Deep engraving removes material over multiple passes for a mark you can feel and that survives wear. Choose by the contrast you need, the durability the part demands, and your cycle time. A fiber marker does all three on bare metal; a UV marker “cold marks” heat-sensitive and reflective materials with almost no heat.
1 · One beam, three depths
“Marking,” “etching,” and “engraving” get used loosely, but on a metal part they describe three distinct results on a single spectrum — the amount of material the laser moves. Get the vocabulary straight and the choice makes itself.
| Method | What happens | Feel | Speed | Durability |
|---|---|---|---|---|
| Annealing | Surface heated to grow a colored oxide — no material removed | Flush — smooth to the touch | Slower (controlled heat) | High — resists corrosion & cleaning |
| Surface etching / marking | A thin surface layer melts or ablates for high contrast | Very shallow, near-flush | Fastest | Good — survives handling; less than a deep mark under abrasion |
| Deep engraving | Material removed over multiple passes to form a recess | You can feel the mark | Slowest (multi-pass) | Highest — survives wear, machining & stamping |
The same fiber marker produces all three — the result is set by power, frequency, speed, and pass count, not by a different machine.
2 · Annealing — permanent color, nothing removed
Annealing uses controlled heat to grow a thin oxide layer on the metal’s surface, producing a black or colored mark that sits flush with the part. Because nothing is removed and the surface stays sealed, it’s the preferred method where corrosion resistance matters — medical devices, food-contact parts, surgical instruments, and anything that gets washed or sterilized.
- Best on: stainless steel and titanium, which oxidize into stable, high-contrast colors.
- Why choose it: the mark can’t harbor contaminants or start corrosion the way a cut-into-the-surface mark can, and it’s tamper-evident and permanent.
- The trade: it’s slower than a surface etch because the heat has to be controlled, and it needs a substrate that anneals well.
Color marking is annealing’s cousin
On stainless, tuning the oxide thickness produces controlled colors, not just black — a MOPA-class fiber source is what makes it repeatable. Color is real but finicky: it depends on that specific source’s pulse width, fill, and focus, so treat it as a capability to dial in on your machine, never a portable recipe.
3 · Surface etching & marking — fast, high contrast
Surface etching melts or ablates a very thin top layer to create a fast, high-contrast mark. It’s the workhorse of production marking: logos, part numbers, barcodes, serials, and labels where you need throughput and clear contrast but not depth.
- Anodized aluminum is the easiest job there is — the fiber beam bleaches the dye layer to a bright white mark with very little power at high speed, no consumables.
- Bare metals mark dark by melting a fine oxide/relief layer; contrast comes from the surface change, not depth.
- Why choose it: it’s the fastest method and reads clearly — ideal for high volume where the mark isn’t exposed to heavy abrasion.
4 · Deep engraving — material removed, survives anything
Deep engraving runs the beam over the same path many times to cut a recess into the metal — a mark you can feel and that survives wear, cleaning, machining, and stamping. It’s the choice for tooling and die identification, stamped or forged part marks, and anything that has to remain legible after a hard service life.
- Why choose it: maximum durability. An engraved mark outlasts a surface etch anywhere abrasion, heat, or corrosion would erase a shallow mark.
- The trade: it’s the slowest method — depth is built pass by pass — so reserve it for parts that actually need the permanence.
5 · How to choose
Needs a corrosion-proof, flush mark (medical, food, surgical) → anneal
Nothing removed, surface stays sealed, mark can’t harbor contaminants. Stainless and titanium anneal best.
Needs the fastest high-contrast mark at volume → surface etch
Logos, serials, barcodes, labels. On anodized aluminum this is nearly instant and bright white.
Must survive wear, machining, or stamping → deep engrave
Tooling, dies, forged and stamped parts. You trade speed for a mark you can feel that won’t wear away.
Heat-sensitive, reflective, or very fine work → reach for UV
See the next section — a UV marker “cold marks” with almost no heat where a fiber source would be too aggressive.
6 · Fiber, UV, or CO₂ for metal marking?
The method is one decision; the laser source is the other. For metal, fiber is the workhorse and UV is the specialist; CO₂ isn’t built for it.
| Source | Wavelength | Best for | Notes |
|---|---|---|---|
| Fiber (FM) | ~1.06 µm | The default for metal — anneal, etch, and deep engrave on bare and coated metals | Absorbed efficiently by metal; no consumables; does all three methods |
| UV | ~355 nm | Heat-sensitive, reflective, and very fine work; glass and sensitive plastics | “Cold marking” — photo-ablates with minimal heat-affected zone; gentle, high-detail |
| CO₂ | ~10.6 µm | Not ideal for bare metal | Reflects off shiny metal; marks metal only with a marking spray/coating — fiber is the right tool |
Parameters are starting points, not recipes
Marking settings — power, frequency, speed, passes — vary enormously by machine wattage, lens, and galvo. Published tables (including any you find here) are starting points to build a test grid from, not spec. Run a small power-and-speed grid on scrap for each material before a production run. Boss FM/UV recommended starting points per material are being confirmed and will be added here.
Frequently asked
Marking vs engravingQWhat’s the difference between marking, etching, and engraving?
They sit on one spectrum of how much material the laser moves. Marking (annealing) changes the surface color or oxide without removing material. Etching melts a shallow, high-contrast layer. Engraving removes material for a mark you can feel. Choose by how much depth, contrast, and durability the part needs.
QCan a fiber marker mark stainless without removing material?
Yes — that’s annealing. The beam heats the surface to grow a controlled oxide layer, producing a black or colored mark flush with the surface. It’s the preferred method for medical, food, and corrosion-sensitive parts because nothing is cut into the surface.
QHow do I mark anodized aluminum?
A fiber laser bleaches the dye layer to a bright white mark with very little power and high speed. It’s fast, high-contrast, and needs no consumables — one of the easiest marking jobs there is.
QWill a laser mark survive wear and corrosion?
An annealed or deep-engraved mark resists abrasion and corrosion far better than a surface etch. For parts exposed to wear, cleaning, or weather, choose annealing (flush, corrosion-safe) or deep engraving (a recess that outlasts abrasion), and validate the mark against your read and durability requirements.
QCan a CO₂ laser mark metal?
Only with a marking spray or coating, and not efficiently — CO₂’s wavelength reflects off bare metal. For metal marking a fiber source is the right tool; a UV source is the specialist for heat-sensitive or very fine work.
7 · Related guides & next steps
- Lens & field size for markers — the other marking decision: matching lens and field to part size and detail.
- Choosing a CO₂ laser lens — the same spot-vs-detail trade-off on the CO₂ side.
- Fiber laser power guide — when the job is cutting metal instead of marking it.
Need a permanent mark you can stand behind?
Match the marking method to the right machine.
Anneal, etch, or engrave — the method is only half the decision. Tell a Boss Laser specialist the part, the material, and the durability you need, and we’ll point you to the right fiber or UV marker.