Omtech USB475a User Manual page 44

5.3.4 Cleaning the Mirrors
The mirrors should be similarly cleaned if there is any debris or haze on their surface to improve performance and avoid
permanent damage. The 1st mirror is located in the back left of the machine beyond the far end of the Y axis. The 2nd
mirror is located on the Y axis at the left end of the X axis. The 3rd lens is located on top of the laser head on the X axis.
The most detritus accumulates on the 3rd mirror and it should be checked daily along with the focus lens. The 1st and 2nd
mirrors can be checked daily if desired but are usually fine if they are only checked once a week.
The semi-transparent mirror at the end of the laser tube should only be cleaned when the engraver is fully disconnected
from power and the tube is fully cooled. Clean all four mirrors with lens-cleaning tissue or with cotton wetted with
lens-cleaning liquid or isopropyl alcohol. The 3 positioning mirrors can be cleaned in place or removed for cleaning by
turning them anticlockwise. Take care not to touch the surface of any mirror directly. Clean with gentle circular motions
and avoid pressing hard enough to grind any debris or cause scratching. If any mirrors are removed for cleaning, reinstall
them by turning them into place clockwise while again being careful to avoid any scratching
5.4 Laser Path Alignment
Having a proper beam alignment is important for the overall efficiency of the machine and quality of its work. This
machine went through a complete beam alignment before shipping. When the engraver first arrives and about once a week
during normal operation, however, it is recommended that users confirm that alignment is still at acceptable levels and
that the mirrors and focus lens have not shifted due to the movement of the machine.
You will need to place a piece of tape at each stage of the laser path, marking it to confirm that that stage remains correctly
aligned. When it is not, you will use the laser tube's brackets or the screws on the back of the misaligned mirror to correct
the problem. Once the provided tape runs out, we recommend masking tape as it is easy to manage and use.
Performing a beam alignment can expose the operator to small amounts of radiation if performed carelessly.
Please follow these procedures correctly and always take caution when performing a beam alignment.
Perform a beam alignment at low power levels: 15% or less. Any higher percentage will cause the laser to ignite
the testing tape instead of marking it. Be sure that you set the Max. Power (not Min.) to 15%.
40