Glossary · Setting
Laser power
How strong the laser is, given in watts. What matters is whether the figure means the light power emitted or only the power consumption.
Explained in more detail
Optical power states how much light power actually comes out of the laser head. Electrical power is the module's power consumption; with diode lasers, the optical power is often only a quarter to a third of it. In the past, some sellers advertised 20 or 40 W, meaning the electrical input, while only about 5 to 10 W came out optically. For CO₂ tubes, the rated power counts as the maximum optical power, and in continuous operation you should usually use only 70 to 80% of it. In the software you set the power as a percentage of maximum power; together with the speed, this gives the energy per area.
Where does the term come from?
In the physical sense, power is energy per time and is measured in watts, named after James Watt. Optical refers to the light emitted, electrical to the energy drawn.
In practice
- Look in the data sheet for the addition “optical power” or “optical output power”. If only a wattage is given with no addition, ask or be sceptical.
- Power alone does not decide: a smaller focal spot with fewer watts can work more finely and at a similar speed to a large spot with more watts.
- With CO₂ tubes, it preserves the tube if you stay permanently below about 80% of rated power.
- Double the power does not mean double the cutting depth. Air assist, focus and passes play a part just as much.
Not to be confused
Not to be confused with the power consumption of the whole device including fan and controller. The percentage in the software always refers to the maximum power of the source.
Frequently asked questions
What does 40 W mean on a diode laser?
On current devices, usually 40 W of optical power. With older or very cheap offers, this may refer to the electrical power, in which case only 5 to 10 W of optical power often arrives.
How many watts does a laser need for cutting?
For 3 mm plywood, about 5 to 10 W optical is enough with a diode laser. For acrylic and thicker sheets in one pass, a CO₂ laser with 40 W or more is considerably faster.