UV laser – A hobbyist walkthrough tests laser marking on 3D-printed plastics and finds that clean, professional results aren’t guaranteed by “any laser.” UV (355 nm) stands out for crisp marks across the widest range of materials, while fiber lasers and CO2 systems shine
For anyone who’s tried to make a 3D-printed part look “finished,” laser marking can sound like the easy answer. Put names, serial numbers, or other information on plastic—fast, clean, professional. Then reality shows up in the burn marks.
That’s the question [Stefan] tackles in an informative video from CNC Kitchen: whether the different laser options available to hobbyists and workshops can actually create clean. high-contrast marks on 3D-printed plastics. He brings an unusually hands-on mindset. printing a range of plastics in different colors and then pushing multiple laser machines at the same job.
The basic mechanics are simple, but the outcome is anything but. When the laser hits the material, its energy is dumped into the surface. Depending on the plastic and the laser. that energy can cause pigment bleaching. microfoaming. charring. melting. or ablation—vaporizing the surface. The goal is the same across every attempt: the right combination of laser and material. tuned to produce a crisp. high-contrast mark.
[Stefan] doesn’t just try one setup. He printed samples of PLA. PETG. ASA. TPU. and polycarbonate. each in different colors. and tested them with several different laser technologies. including a UV laser (355 nm wavelength). a blue diode laser (450 nm wavelength). a MOPA fiber laser (1. 064 nm wavelength). and a CO2 laser (10. 600 nm wavelength).
The results—while achievable—still aren’t plug-and-play. [Stefan] lands on a key takeaway: there isn’t a one-size-fits-all solution for marking plastic. The cleanliness of the final text depends heavily on pairing the correct laser type with the right settings and the target material.
Still, one laser consistently separates itself from the rest. Overall, the UV laser was the most suited to marking 3D-printed plastics. [Stefan] says it produced the cleanest results across the widest range of materials with the least fiddling. The MOPA fiber laser also worked, but he describes it as more of a metal-marking tool. He notes that fiber lasers have been seen etching super-fine PCB traces. and that while strong results are possible. it isn’t quite in its element with plastics. Other lasers could deliver good marks under the right circumstances. but they’re generally best suited to cutting tasks rather than marking thermoplastics.
With all of these tests stacked side by side—different plastics. different colors. and four laser types—the story is less about finding the “best laser” in theory and more about respecting what plastic actually demands. When the tuning is right, the marks come out sharp. When it isn’t, the surface reacts the way polymer does: unpredictably.
If you want the closeups and the full set of details, [Stefan] lays out the entire process in his video here: https://www.youtube.com/watch?v=jA-E5CGcBxI.
laser marking 3D printing plastics UV laser CO2 laser fiber laser MOPA PLA PETG ASA TPU polycarbonate CNC Kitchen electronics
So UV lasers can just mark any plastic? Guess everyone’s been doing it wrong.
I read UV and my brain went to skin cancer and now I’m nervous. Like why are we zapping stuff for serial numbers lol. Also PLA is what most people use right?
Fiber vs CO2… I don’t even know the difference but I’m pretty sure my buddy’s cheap diode laser would still work if you “turn it up.” Like if it burns it means it’s working, right? The article says it can char/melt though so maybe not?
This is basically like tattooing plastic and hoping it doesn’t turn into a blob. They keep listing wavelengths and materials like that somehow helps normal people. PLA/PETG/TPU all react different, but then they say there’s no one-size-fits-all… okay yeah duh. Still wild CO2 at 10,600 nm is even a thing for hobbyists.