Glossary · Processes
Fibre laser
A laser whose light is generated in a glass fibre. It is the standard for permanently marking and engraving metal.
Explained in more detail
In a fibre laser, a glass fibre doped with ytterbium is the laser medium, pumped by laser diodes. The wavelength is 1064 nm in the near infrared, which metals and many plastics absorb well. Marking lasers work in pulsed mode, typically with 20 to 100 W average power and pulse frequencies in the range of about 20 to 100 kHz for Q-switched sources. A galvo scanner almost always steers the beam, and the work area depends on the F-theta lens, often 110 × 110 mm to 300 × 300 mm. It handles wood and clear plastics only poorly.
Where does the term come from?
The name comes from the glass fibre in which the light is amplified. Elias Snitzer described the principle as early as 1961, and fibre lasers have been widespread for material processing since about the 2000s.
In practice
- For jewellery, tools, nameplates and stainless steel mugs, a fibre laser is the first choice, but not for wood.
- Manufacturers usually quote the lifetime of the source at around 100,000 hours, and there are no wear parts as with a CO₂ tube.
- Deep engraving in metal works through many passes; at 30 W for 0.5 mm depth, this often takes several minutes per area.
- The beam is invisible. Most machines show the position with a red pilot laser, which says nothing about how dangerous the laser is, however.
Not to be confused
Fibre laser and MOPA are not opposites: MOPA is a type of fibre laser with adjustable pulse duration. The simpler, more common type is called Q-switch.
Frequently asked questions
Can a fibre laser engrave wood?
In principle yes, but the results are usually uneven and prone to burning. Diode or CO₂ lasers are better suited for wood.
How many watts does a fibre laser need for engraving?
20 W is enough for marking. For deeper engravings and faster work, 30 to 60 W is usual; cutting thin sheet metal takes considerably more.