All About Laser Power
Laser power is the commanded output level, commonly expressed as a percentage of the source's available power. A power percentage is meaningful only when interpreted alongside the specific laser source and calibration, scanning speed, pulse frequency, pulse duration, focused spot size, and material.
Physical effect
When the other parameters remain unchanged, increasing delivered power generally increases the rate at which laser energy reaches the material's interaction zone. Depending on the laser wavelength, material, and other process settings, additional delivered power may increase heating, melting, oxidation, vaporization, ablation, or photochemical change.
Maximum and minimum power
The Maximum Power setting defines the highest commanded output level used during the operation. On controllers that vary commanded power with motion speed, the Minimum Power setting can affect slower portions of a path, including corners and acceleration or deceleration regions. Because laser controllers do not all interpret Maximum Power and Minimum Power identically, confirm how the target laser and controller use both values before relying on them.
Examples
To produce a dark annealed mark on a compatible metal, power can be balanced with scanning speed and suitable pulse behavior to build controlled heat while limiting material removal. For clean coating removal, sufficient pulse intensity combined with faster scanning may ablate the coating while limiting heat transferred into the underlying material. A deeper engraving may use an appropriate power level with slower scanning, multiple passes, or both, followed by a lower-impact cleanup pass when the material and process support it.
Common mistakes
A commanded power percentage is not a direct wattage measurement, and the same percentage should not be copied between sources with different rated powers, such as 20 W and 100 W lasers. Increasing power can reduce engraving quality by enlarging the heat-affected zone, producing debris, warping thin material, damaging coatings, or exceeding the operating limits of the laser or material.
Testing
Use a small, controlled material test matrix and change one parameter at a time so you can evaluate both the intended mark and unwanted effects. Begin with conservative values within the manufacturer's permitted operating ranges, maintain appropriate enclosure, exhaust, supervision, and fire precautions, never bypass guards or safety interlocks, and never leave an operating laser unattended.