Laser Marking and Engraving
Laser marking alters the surface with a focused beam — annealing, etching or engraving it — to make permanent, contact-free marks.
- Part
- Finishing
- Revised
- 2026-08-11
At a glance
- Family
- Subtractive
- Typical tolerances
- Annealed marks remove no measurable material; etching removes 0.0001–0.001 in (2.5–25 µm); engraving removes 0.001–0.020 in (0.025–0.5 mm). Beam positioning within the marking field is typically within a few thousandths of an inch
- Surface finish
- Annealing leaves the surface texture unchanged; etching and engraving leave a matte, micro-roughened cavity
- Typical volumes
- 1 to millions of parts; variable data such as serial numbers costs the same as static artwork
- Lead time
- Same day to 5 business days; artwork is a file, so there is no tooling lead time
- Materials
- Metal, Plastic, Wood, Glass, Ceramic
What it is
Laser marking uses a focused, galvanometer-steered beam to change a surface permanently — annealing it, oxidizing it, foaming it, bleaching a dye, or ablating material away. It is contactless, needs no consumables or tooling, and the artwork is a file, so serial numbers, date codes and 2D data matrix codes cost the same as a static logo.
The distinction that matters on a drawing is between marking and engraving. Annealed marks on stainless and titanium change color with no measurable material removal and leave the surface passive and crevice-free, which is why they are specified for surgical instruments and implants. Ablative etching removes roughly 0.0001–0.001 in (2.5–25 µm). True engraving removes 0.001–0.020 in (0.025–0.5 mm) and requires many passes. Source selection follows the material: 1064 nm fiber lasers for metals and many engineering plastics, 10.6 µm CO₂ for organics, wood, acrylic and paper, and 355 nm UV for heat-sensitive polymers and medical work.
How it works
- Choose the source. A fiber laser at 1064 nm couples efficiently into metals and is the default for industrial part marking. CO₂ at 10.6 µm couples into organics — wood, leather, paper, acrylic, coated glass — and does almost nothing on bare metal. UV at 355 nm works by photochemical bond breaking rather than heat, giving clean marks on sensitive polymers with minimal heat-affected zone.
- Set the focus. The beam is focused by an F-theta lens that both focuses and flattens the field. A smaller field gives a smaller spot and higher power density; a larger field marks bigger parts at lower resolution. Depth of field is limited, so the marked surface must sit within roughly ±0.040 in (±1 mm) of focus for consistent results on typical setups.
- Mark. Galvanometer mirrors steer the beam across the field at speeds up to several thousand millimeters per second. Power, frequency, pulse duration, scan speed, line spacing and pass count together determine whether the result is an anneal, an etch or an engraving.
- Verify. Cosmetic marks are inspected visually or by contrast measurement. Data matrix codes on direct part marking are graded against the AIM DPM methodology in ISO/IEC TR 29158, which is the correct thing to specify rather than "must be readable".
Mark types
Annealing heats stainless steel or titanium below the melt point so a controlled oxide layer forms, producing a black or colored mark with essentially no material removal and no disturbance of the surface. Etching or ablation melts and vaporizes a thin layer, producing high contrast quickly. Foaming on plastics creates gas bubbles that scatter light, giving a light mark on a dark polymer. Carbon migration darkens plastics and coated surfaces. On dyed anodized aluminum, a standard fiber laser bleaches the dye to a light mark, while a MOPA fiber laser with adjustable pulse duration can produce a black mark instead — the reason MOPA sources are specified for anodized control panels.
Design guidelines
Specify the mark type, not just the artwork
"Laser mark per drawing" leaves the shop to choose between an anneal, an etch and an engraving, which produce very different surfaces. State the method, the required contrast or depth, and the acceptance criterion. For medical and aerospace parts, state whether material removal is permitted at all.
Keep the mark zone flat and in focus
Depth of field is limited — typically around ±0.040 in (±1 mm). A mark that runs across a curved or stepped surface will change appearance as it goes out of focus. Provide a flat mark pad, or specify rotary-axis marking for cylindrical parts.
Size text to the process, not to the CAD
Practical minimum character height for a reliably legible fiber-laser mark is around 0.020–0.040 in (0.5–1 mm); go smaller and legibility depends on the specific setup and viewing condition. Data matrix codes need enough cell size and enough contrast to grade — specify cell size and a minimum grade rather than an overall code dimension.
Decide where marking sits in the routing
Mark after anodizing to cut or bleach through the color for high contrast; mark before anodizing to have the anodic film cover an engraved mark uniformly. On stainless medical devices, marking is typically followed by passivation, because ablative marking can locally disturb the passive layer.
Know which materials resist marking
Bare aluminum and copper reflect 1064 nm strongly and mark poorly without high power or a marking compound; copper and gold often require a green laser. Clear plastics transmit the beam and need an additive or a coated surface. Glass marks by micro-fracturing and can chip. Confirm on the actual production material and finish, not on a look-alike coupon.
Do not use engraving depth as a strength feature
Deep engraving removes 0.001–0.020 in (0.025–0.5 mm) and creates a stress raiser. Keep deep marks away from fillets, fatigue-critical surfaces and thin walls, and off any surface subject to cyclic loading.
| Feature | Recommended | Limit | Why |
|---|---|---|---|
| Annealed mark | No measurable removal | Stainless and titanium only | Oxide color change, surface stays passive |
| Etched mark depth | 0.0001–0.001 in (2.5–25 µm) | — | Single or few passes, high contrast |
| Engraved depth | 0.001–0.020 in (0.025–0.5 mm) | Many passes; slow | Removal rate falls as the cavity deepens |
| Depth of field | ±0.040 in (±1 mm) | Provide a flat mark pad | Appearance changes out of focus |
| Minimum character height | 0.020–0.040 in (0.5–1 mm) | Verify on the actual finish | Legibility depends on contrast and viewing |
| Data matrix codes | Specify cell size and ISO/IEC TR 29158 grade | — | "Readable" is not a specification |
Cost drivers
Laser marking has essentially no consumable cost and no tooling cost. The economics are machine time plus setup, which makes it cheap at high volume and unusually cheap at volume one.
- Cycle time. Marking time scales with marked area and pass count. An annealed logo takes seconds; a deep engraving that removes 0.010 in over a large area takes minutes and dominates the price.
- Fixturing. Repeatable part location is the setup cost. A simple nest for a flat part is trivial; multi-axis or rotary fixturing for cylindrical or contoured parts is real tooling.
- Source type. Standard fiber marking is the cheapest. MOPA, UV and green sources cost more per hour and are specified only when the material or the required mark demands them.
- Verification. Contrast measurement, code grading to ISO/IEC TR 29158 and traceability documentation are separate line items on regulated work.
- Downstream operations. Passivation after marking on stainless medical parts, or re-anodizing, adds a process step that often exceeds the marking cost.
Cost-reduction tactics:
- Mark the smallest area that satisfies the requirement — area drives cycle time directly.
- Use an anneal or a shallow etch where a legible permanent mark is all that is needed; depth is expensive.
- Design a flat mark pad into the part so a simple nest fixture works and no rotary axis is required.
- Consolidate all marking content — logo, part number, serial, code — into one field so the part is loaded once.
- Where hundreds of identical parts need identical artwork with no variable data, compare against pad or screen printing, which can be faster per piece on large marked areas.
Questions
6 questionsWhat is the difference between laser marking, etching and engraving?
Marking by annealing changes the surface color through a controlled oxide with no measurable material removal. Etching or ablation removes roughly 0.0001–0.001 in (2.5–25 µm). Engraving removes 0.001–0.020 in (0.025–0.5 mm) and needs many passes. Annealing is specified where the surface must stay passive and crevice-free, such as on surgical instruments.
Which laser source do I need for my material?
Fiber at 1064 nm for metals and many engineering plastics — the industrial default. CO₂ at 10.6 µm for organics, wood, acrylic, leather and paper; it does almost nothing on bare metal. UV at 355 nm for heat-sensitive polymers and medical work, because it marks photochemically with a minimal heat-affected zone.
Can you laser mark anodized aluminum?
Yes, and it is one of the most common applications. A standard fiber laser bleaches the dye to produce a light mark on a dark anodized surface. A MOPA fiber laser with adjustable pulse duration can instead produce a black mark on light anodize, which is why MOPA sources are specified for control panels and nameplates.
Should I laser mark before or after anodizing?
After, if you want high contrast from cutting or bleaching through the color. Before, if you want the anodic film to cover an engraved mark uniformly for corrosion protection. On stainless medical devices, marking is normally followed by passivation because ablative marking can disturb the passive layer.
How small can laser-marked text be?
Practical minimum character height for reliably legible fiber-laser marking is around 0.020–0.040 in (0.5–1 mm), though legibility depends on contrast, surface finish and viewing conditions. For 2D data matrix codes, specify cell size and a minimum grade to ISO/IEC TR 29158 rather than an overall code size.
Which materials are difficult to laser mark?
Bare aluminum and copper reflect 1064 nm strongly and mark poorly without high power or a marking compound; copper and gold often need a green laser. Clear plastics transmit the beam and require an additive or a coated surface. Glass marks by micro-fracturing and can chip, so it is usually marked through a coating.