Deposition of debris on the laser lens
Engraving laser optics are exposed to any dust and sticky fumes which may be produced during the engraving process. These are propelled from the engraving area at high velocities and can therefore stick to the laser optics causing hot spots on the lens.
This contamination of the engraving laser optics can cost money as it causes the engraving to be of poor quality and therefore be rejected.
Contamination also causes downtime of the engraving laser for tedious and time consuming cleaning.
In many cases the contamination "Hotspots" can even damage the laser optics which are expensive to replace.