Laser Marking Plastics: Fiber vs UV
Last updated: May 2026
Short answer: fiber lasers mark many industrial plastics with high contrast, and a MOPA fiber laser gives the cleanest marks without burning. But for heat-sensitive, clear, or premium plastics, a UV laser (cold marking) is the better tool. The plastic decides which, see fiber vs UV vs CO2 for the full picture.
Two ways to laser plastics
Fiber (1064 nm). A fiber laser marks plastics by carbonizing the surface (dark marks) or foaming it (raised light marks), and on many engineering plastics it produces strong light-on-dark or dark-on-light contrast. MOPA pulse control keeps the heat in check so you get clean marks instead of melted or scorched edges. Fiber is the workhorse for industrial plastics, cable and wire marking, and dark housings.
UV (355 nm). A UV laser marks cold, with almost no heat, so it handles clear, delicate, and high-end plastics that fiber would burn or distort, plus medical and electronics polymers where a flawless finish matters.
Which one for your plastic
- Industrial and dark plastics, cable and wire, ABS housings → fiber (MOPA).
- Clear, delicate, medical, or premium plastics → UV.
- Not sure? Our help me choose guide narrows it down.
What is it used for?
- Cable, wire, and connector identification.
- Electronics housings and keypads.
- Automotive and medical-device plastics.
- Consumer products and branding.
Which machine do you need?
For industrial plastics, a 20W to 30W MOPA fiber is the practical choice. For sensitive and clear plastics, a 5W to 20W UV machine. Many shops that mark a mix of materials run one of each.
Frequently asked questions
Can a fiber laser mark all plastics?
It marks many, especially plastics with laser-friendly additives, but results vary by polymer. Clear and heat-sensitive plastics often mark better with a UV laser.
Fiber or UV for plastics?
Fiber for industrial and dark plastics where high contrast matters; UV for clear, delicate, medical, or premium plastics that must not be heat-damaged.
Does the laser burn the plastic?
A MOPA fiber controls heat to minimize burning, and a UV laser avoids heat almost entirely, which is why UV is preferred for sensitive materials.
Can I get a light mark on dark plastic?
Yes. Fiber foaming produces a raised, lighter mark on dark plastic, a common way to get high contrast.
