UV Laser vs. Fiber Laser Marking on PA66 GF25 Thermal Strips: Which Technology Fits Your Line?

UV Laser vs. Fiber Laser Marking on PA66 GF25 Thermal Strips: Which Technology Fits Your Line?

Published August 10, 2026

Ask five extrusion plant managers which laser technology is best for marking PA66 GF25 thermal break strips, and you will likely get five different answers. Fiber lasers (1064 nm) have been the default choice for years—they are powerful, inexpensive, and widely understood. But as European energy-efficiency directives tighten traceability requirements and as customers demand higher-contrast, longer-lasting marks, UV lasers (355 nm) are moving from niche to mainstream.

The truth is that both technologies produce acceptable marks on PA66 GF25—under the right conditions. The real question is which one delivers the consistency, permanence, and cost-per-meter your specific line requires. This guide compares the two technologies on the factors that actually matter to thermal strip producers, with data from real production lines running KINGVAN systems.

How Each Laser Marks PA66 GF25

The difference starts at the physics level, and it explains almost every downstream performance gap.

Fiber Laser (1064 nm): Thermal Carbonization

A fiber laser heats the polyamide matrix until it carbonizes, producing a dark mark. The glass fiber reinforcement (25% GF) absorbs little energy at 1064 nm, so the marking relies almost entirely on heating the polymer phase. The process is effective, but it is inherently a thermal process: the heat affected zone (HAZ) extends beyond the mark itself, and the depth of carbonization varies with moisture content, ambient temperature, and local fiber density.

UV Laser (355 nm): Photo-Ablation

A UV laser operates at roughly one-third the wavelength, and the energy is absorbed directly by molecular bonds in the polymer—a process called photo-ablation. The material is removed or modified in a controlled, shallow layer with a minimal heat affected zone. The result is a cleaner, higher-contrast mark with sharper edges and less surface disruption. For glass-fiber-reinforced polyamides, UV's shorter wavelength also interacts more uniformly with the composite surface.

Head-to-Head: Mark Quality and Contrast

For thermal break strips, mark quality is judged by contrast, edge sharpness, and readability after installation. Here is how the two technologies compare on typical PA66 GF25 production:

The contrast gap becomes decisive when you mark dark or colored strips. Many European window profile producers now color-code thermal strips, and a dark carbonized fiber mark can be nearly invisible on a black strip. UV's ablative "frosted" mark provides the contrast that dark substrates demand—one reason UV adoption is accelerating in markets moving to stricter EN 14024 traceability.

Throughput and Integration: What Changes on the Line

Marking speed on an extrusion line is rarely limited by the laser itself—it is limited by the marking window (the distance between the extruder and the cooling/pulling section) and the line speed. Both technologies can mark at line speeds of 20–40 m/min when configured correctly.

• Fiber lasers deliver high average power per euro, making them attractive for simple, high-speed alphanumeric coding on light-colored strips.
• UV lasers require a bit more power per mark for the same line speed, but the smaller spot size and higher precision allow smaller, denser codes—including the 2D Data Matrix codes increasingly required for full traceability.
• Galvo scanner speed is identical for both; the difference is in the number of passes needed to achieve target contrast. On dark strips, fiber may need multiple passes while UV achieves full contrast in one.

For a double-side, double-traction line running 40 m/min with inline quality inspection, a UV system with autofocus (such as the KINGVAN KV-UV series with MarkOS software) can sustain full traceability marking on both strip faces without slowing production.

Cost Analysis: Capex vs. Cost per Meter

There is no way around it: a UV laser source costs more than a fiber source of comparable average power. But the relevant metric for a production line is total cost per marked meter, which includes consumables, rejects, and rework.

• Fiber laser capex: Lowest entry cost. A 20–30 W fiber system is the budget-friendly choice for basic coding.
• UV laser capex: Typically 1.5–2.5× a comparable fiber system. The premium buys precision, contrast on dark substrates, and a smaller HAZ.
• Consumables: Comparable—both are maintenance-light, solid-state systems. Protective windows and optics cleaning cycles are similar.
• Rejects and rework: This is where UV often wins. On dark strips or high-contrast code requirements, fiber systems generate more unreadable marks, and each rejected bundle of strips is expensive—especially when the strips are already cut, packaged, and ready to ship.

Compliance and Traceability: The 2027 Factor

The regulatory landscape is shifting in favor of UV. European standards under the EN 14024 framework and national energy-efficiency programs increasingly require:

• Permanent, legible identification of thermal strip batches (manufacturer, date, material grade).
• Machine-readable codes for automated quality tracking from extrusion to window assembly.
• Marks that survive the strip's full service life—thermal cycling, UV exposure, and moisture—without fading.

UV-ablated marks tend to hold contrast better through thermal cycling because there is no deep carbonization layer that can degrade or flake. If your customers or auditors are asking for codes that remain scannable after years of service, that permanence is a decisive advantage.

Decision Framework: Which One Should You Choose?

Use this quick matrix to shortlist the technology for your line:

Practical Advice Before You Decide

If you are evaluating a new marking system, do three things before signing a purchase order:

1. Run a sample test on your actual strips. Send production samples—including your darkest material and your most complex code—to the supplier. Contrast and readability on your substrate is the only test that matters.
2. Ask for the marking window analysis. The supplier should calculate whether the laser can sustain your line speed within the available marking window, for both single- and double-side configurations.
3. Check the software and integration. Look for recipe management, barcode generation, and inline camera integration. MarkOS-class software makes parameter locking and traceability reporting practical on the shop floor.

Both fiber and UV lasers will put a mark on a thermal strip. The difference is in contrast on dark materials, edge quality for machine-readable codes, mark permanence through thermal cycling, and the cost of rejects over the system's life. For producers serving European window markets under tightening EN 14024 traceability requirements—or running dark, colored strips—UV is increasingly the technology that pays for itself.

Whichever direction you choose, define your mark quality standard in writing, test on real samples, and hold your supplier to the same metrics you hold your QC team.