Neje Laser Unobstructed Focus Knob

Yet another Focus knob ?

Yes but this one lets the cooling air through!

I found many focus knob on TI but all obstruct the important cooling air flow.

Adapted for the 15mm Neje lens, but you can resize using your slicer...

Also adapted to the LONG FOCUS LENS https://s.click.aliexpress.com/e/_AYpshn
Have you ever noticed that when you cut a thick material, the sides of the workpiece are no longer perpendicular?
It is because of the focus, the beam is thin over a small distance, the more the laser goes down into the material the larger the diameter of the beam and therefore the laser power is no longer concentrated in a fine beam...
Thanks to the long focus, you can cut thicker materials because the laser beam remains concentrated into a fine beam over a longer length.

Also for any 33x33mm laser size

Check also my other design related to the neje laser ...
https://www.thingiverse.com/thing:4626761

If you have problems using Lightburn instead of Neje software, simply follow this guide.
https://www.northlakeswoodwork.com/blog/2020/7/5/affordable-laser-engraving-lightburn-setup-for-neje-master-2

As a simple return, please like and post your print !