Laser marking is everywhere—from serial numbers on automotive parts to logos on electronics and traceability codes on medical devices. But not all lasers are created equal, and selecting the right type depends on your material and marking requirements.
Fiber lasers and ultraviolet (UV) lasers are two of the most commonly used technologies. Each excels in different applications, so understanding their capabilities is key to making the right choice.
In this article, we’ll clearly outline the differences between fiber and UV lasers technologies, how they interact with various materials, and how to determine which one best fits your marking needs.
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Fiber lasers use a specialized type of optical fiber to emit and amplify light. They operate in the infrared (IR) portion of the electromagnetic spectrum.
They are available with output powers ranging from 10s of watts into the multikilowatt level. Their combination of advantageous characteristics has made fiber lasers the most popular type of industrial laser for marking metals and hard plastics.
The output properties of fiber lasers impact marking in two key ways. First, IR light heats most materials, producing marks through thermal mechanisms. In other words, the fiber laser essentially burns, melts, or evaporates material to create a mark.
Second, IR light cannot be focused as tightly as shorter wavelengths, like visible and UV laser beams. This limits the ability to make extremely small, high-precision marks.
Taken all together, fiber lasers are efficient, reliable tools for performing high-speed marking of materials that aren’t heat sensitive. They’re great for deep laser engraving but typically aren’t used for marking very small or intricate marks.
Most UV marking lasers operate by frequency tripling the output of a near-infrared laser crystal. This process is more complex and less efficient than the way fiber lasers operate. As a result, UV laser are typically more expensive than fiber lasers, offer lower throughput, and have shorter operational lifespans.
The big advantage of UV lasers is that their light interacts with many materials primarily through photochemical mechanisms. This means the high energy UV photons directly break molecular bonds, rather than heating the material.
As a result, UV lasers can perform cold marking, meaning that they don’t heat up or otherwise affect that material surrounding or underneath the marked area. Plus, their shorter wavelength allows for extremely fine focusing. Finally, UV light is strongly absorbed by most materials, especially non-metallic materials, leading to shallow penetration and efficient processing.
Taken together, this means that UV lasers excel in producing high-resolution marks with sharp edges, fine detail, and tight tolerances. They are especially useful with thin, delicate or heat sensitive products.
Which laser is best for a specific material? The answer to that depends on the way the material interacts with the laser light, as well as practical considerations such as throughput, cost, and mark quality requirements.
Let’s look at some of the most important classes of materials.
While most metals naturally reflect infrared (IR) light, the high power of fiber lasers allows them to start the marking process by heating the surface. Once the metal begins to warm or melt, it absorbs the laser energy more easily, making marking more efficient.
That’s why fiber lasers are ideal for marking metals like stainless steel, aluminum, and titanium.
Fiber lasers can produce durable, high-contrast marks at high speeds, including deep laser engravings, colored marks (through oxide layer formation), and ablated text. This makes them ideal for applications like part traceability, aerospace and automotive components, industrial tools, and various metal packaging materials such as aluminum cans and foil pouches.
UV lasers are more rarely used for marking bare metals due to poor absorption and lower power output. However, they can mark coated or anodized metals by ablating the surface layer.
They can also perform black marking in very specialized cases. Black marking involves forming a thin, light-trapping oxide layer (no material removal) and is most commonly used on stainless steel.
For most industrial metal marking, fiber lasers offer the best combination of speed, durability, and cost-effectiveness.
Laser technology typically used for metals:
| Material | Fiber | UV |
|---|---|---|
| Aluminum | ✔ | |
| Anodized Aluminum | ✔ | ✔ |
| Chromium | ✔ |
|
| Stainless steel | ✔ |
|
| Metal, coated or painted |
| ✔ |
| Brass | ✔ | |
| Copper | ✔ | |
| Silver | ✔ | |
| Gold | ✔ | |
| Cast Iron | ✔ | |
| Titanium |
| ✔ |
| Metal foils |
| ✔ |
Plastics vary widely in chemical composition and may also contain additives to facilitate marking. So, laser choice is very application-specific.
In general, UV lasers are better suited to marking most plastics due to their ability to induce photochemical color change without melting or burning the surface.
In particular, they excel at producing high-contrast, crisp, and damage-free marks on common plastics like ABS, acrylic, polycarbonate, polyethylene, and PET.
These marks are created without heat distortion, foaming, or material degradation, which is particularly important in industries like medical devices, electronics housings, and cosmetics packaging. UV lasers are also ideal when working with colored plastics or multi-layer films where precise surface control is needed.
UV lasers are especially the choice when a mark is “mission critical.” That is, where a missing, unreadable, or incorrect mark could lead to injury, malfunction, or regulatory noncompliance.
Fiber lasers can mark some plastics. But their thermal interaction usually marks through foaming, carbonization, or melting, especially if the plastic lacks additives designed to absorb IR.
Fiber lasers remain an option for basic marks on certain compatible plastics, especially when speed or cost efficiency is a priority over mark quality or contrast.
Laser technology typically used for plastics:
| Material | Fiber | UV |
|---|---|---|
| ABS |
| ✔ |
| PA | ✔ | ✔ |
| PBT |
| ✔ |
| PC |
| ✔ |
| PC - glass filled | ✔ |
|
| PE | ✔ | ✔ |
| PES |
| ✔ |
| PET |
| ✔ |
| PET - glass filled | ✔ |
|
| PI |
| ✔ |
| PMMA (Acrylic) | ✔ | ✔ |
| POM |
| ✔ |
| PP | ✔ | ✔ |
| PPS |
| ✔ |
| PS |
| ✔ |
| PUR |
| ✔ |
| PVC |
| ✔ |
| Tritan |
| ✔ |
Most brittle materials, like glass, ceramics, stone, and sometimes even sapphire, can crack or shatter under even slight mechanical or thermal strain. When a small area on a part is rapidly heated, internal stress can develop due to uneven thermal expansion. This can lead to microfractures or structural failure.
This is where UV laser marking offers a key advantage. Unlike IR lasers, which mark through mostly thermal means, UV lasers produce a largely non-thermal, photochemical interaction. Their short wavelength (typically 355 nm) is strongly absorbed by most brittle materials – even those that appear transparent to the eye. All this keeps penetration depth shallow and enables surface modification with minimal overall heat input.
As a result, UV lasers can mark and laser engrave delicate materials like glass without causing cracks, often producing a frosted or lightly textured effect which is cosmetically attractive.
Their high resolution also allows for the creation of intricate features such as barcodes, logos, and serial numbers, making them ideal for marking items like sapphire watch faces, medical ceramics, and consumer glass displays. UV lasers can even produce sub-surface marks in some brittle materials.
In contrast, fiber lasers are generally poorly suited to these applications. Their longer wavelength is less readily absorbed by brittle materials, leading to deeper penetration and increased heat buildup. This thermal load can cause warping, chipping, or catastrophic cracking, particularly in transparent or polished substrates.
Additionally, IR light tends to pass through materials like glass and often reflects off ceramics. As a result, marking these materials usually requires special surface coatings or high-energy settings.
Laser technology typically used for brittle materials:
| Material | Fiber | UV |
|---|---|---|
| Ceramics |
| ✔ |
| Diamond |
| ✔ |
| Glass |
| ✔ |
| Granite |
| ✔ |
| Marble |
| ✔ |
| Sapphire |
| ✔ |
Here “organic materials” refers to a broad range of carbon-based compounds. These can be natural substances (like cellulose, proteins, or plant fibers) or synthetic polymers.
Paper, cardboard, polymer films, natural leather, both natural and synthetic fabrics, and rubber all belong in this group.
Virtually all these diverse materials are sensitive to heat, and are prone to burning, discoloration, or warping. Again, UV laser marking offers a clear advantage with these materials because of its cold marking process which minimizes charring and material distortion.
Because of this, UV lasers are used to apply lot numbers, expiration dates, or decorative elements onto films, labels, cartons, and blister packs. In textiles, they can mark or even cut fabric with precision without fraying. On leather or rubber gaskets, they provide branding, part numbers, or score lines with little deformation or material loss.
Fiber lasers are also used in select cases. In particular, they’re useful for marking thicker or coated substrates where some thermal effects are tolerable. However, they often cause burn-through, scorching, or a loss of flexibility, especially in thin films or textiles.
Cost-wise, fiber lasers are cheaper to operate, but the risk of damage to delicate organic materials usually rules them out for fine-feature work. When material integrity or aesthetic quality is critical, UV is the more dependable choice.
Laser technology typically used for organic materials:
| Material | Fiber | UV |
|---|---|---|
| Food |
| ✔ |
| Leather |
| ✔ |
| Fabric |
| ✔ |
| Cork |
| ✔ |
| Rubber |
| ✔ |
| Silicone |
| ✔ |
| Paper |
| ✔ |
| Cardboard |
| ✔ |
| Polymer film |
| ✔ |
While we've already covered most materials used in microelectronics, marking is so critical and technically specific in semiconductor and electronics packaging that it deserves separate attention.
In general, the technical demands of electronics marking are generally more stringent than most other industries. In particular, marking electronic components requires extreme precision and minimal thermal impact.
UV lasers are often ideal here because they interact photochemically, producing clean, legible, high-resolution marks with minimal heat-affected zones. They’re widely used for labeling microchips, IC packages, connectors, and even QR codes on silicon wafers or plastic casings.
The ability of UV lasers to produce permanent marks without distorting fine structures makes them the standard for traceability in electronics manufacturing. They’re also commonly used for marking multilayer materials and color-coded connectors.
Fiber lasers have more limited use in electronics. Their higher heat load can damage delicate surfaces or compromise insulation. However, they can be used on larger metal components, like enclosures, backplates, or power connectors, where durability is more important than feature size.
Laser technology typically used for semiconductor materials:
| Material or Component | Fiber | UV |
|---|---|---|
| Epoxy-based molding compounds | ✔ |
|
| Ceramics (e.g., alumina, LTCC) |
| ✔ |
| IC substrates (BT resin, glass, etc.) |
| ✔ |
| Interposers (glass, ceramic, silicon) |
| ✔ |
| Semiconductors (silicon, GaAs, etc.) |
| ✔ |
| Leadframes (copper, silver-plated, etc.) | ✔ |
|
| Finished IC packages (plastic encapsulated) |
| ✔ |
| Die (bare silicon) |
| ✔ |
| MEMS and sensors (varied materials) |
| ✔ |
| Wafer-level markings |
| ✔ |
| FPC (flexible printed circuits) |
| ✔ |
| Marking through clear films |
| ✔ |
| PCBs (FR4, flex, multilayer) |
| ✔ |
For some materials, the choice of laser marking technology may be obvious. But sometimes it’s not clear which option is the best.
In these instances, applications testing may be required to determine what type of laser marker will deliver the best mix of mark quality, speed, and cost.
At Laserax, we offer both UV and fiber laser systems (as well as CO₂), allowing us to take a technology-neutral approach. Our goal is simple – to identify the solution that delivers the best results for your specific marking challenge and then help you implement it.
Alex Laymon became President and Director of DPSS Lasers (now a Laserax company) in 1998. He previously served as the Vice President of Engineering at LiCONiX, following a series of technical positions that included Engineering Manager and Senior Laser Engineer. Mr. Laymon received his B.S. in Engineering Physics and his M.B.A. at Santa Clara University. His decades of expertise in UV lasers now contribute to Laserax's mission to shape the future of high-precision laser solutions.
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