1. Focus Lens for contamination: Clean focusing mirror.
2. Focus relief Laser engraving machine equipment whether changes: re-adjust the focus.
3. Light path is offset: careful adjustment of the optical path. .
4. Reflective lens is contaminated or damaged: Clean or replace the reflective lenses.
5. Laser power is energized: Checking laser power supply circuit so that it is normal.
6. Laser tube is damaged or aging: Replace the laser tube.
7. Laser power supply is damaged: Replace the laser power.
8. Cooling water is circulating flow: clear cool water.
9. The cooling water temperature is normal or not: Replace the clean cooling water to the temperature to normal.
Original link: http://www.stylecnc.com/faq/Why-the-laser-of-a-laser-engraving-machine-becomes-weaker-than-before-.html