Laser beam calibration

We have a laser cutter from Aliexpress [1]. After some tests we pulled out the Nano board and replaced it with a Mini Gerbil [2]. Until last week we were happy with the machine and the results. We recongnised a pretty “wedged” kerf but it did not bother us too much.

When we cut small part in the top left corner, everything is fine (our workpeice area is 500 by 400mm and the tube should provide 50W). But we struggeled with cutting in the center.

My first idea was to recalibrate the mirrors with this tutorial [3]. That will happen tommorow.

Is it correct, that I should be able to recalibrate the mirrows so we get (almost) equal laser power over all the workpiece area?

Thanks for your support :slight_smile:

[1] https://de.aliexpress.com/item/32315846861.html?spm=a2g0s.9042311.0.0.27424c4dakfcfp
[2] https://awesome.tech/product/mini-gerbil-2-axis-controller-for-k40-laser-cutter/
[3] https://k40.se/k40-laser-lens-mirror/mirror-alignment/

Even if you can get get the mirrors perfectly adjusted, you will not reach the same power on the whole cutting area. The travel distance of the laser beam is different, dependigng on the head position, and particles (smoke) in the air do scatter the beam which causes power loss. You will get the most power on the back left and the worst on front right. For this reason we always try to adjust the mirrors the best we can in the front right position, because the other positions anyways get more power.

Hi Claudio :slight_smile:
I’m aware of that behavoiur. But that is a problem which every mirror based CO2 cutter has. The question is, will it cut through even on a bad spots like bottom right? Usually I add 20% safety (I reduce the cutting speed accordingly) and I’m fine.

Are you sure the bed is level? It might be a focus problem too if it isn’t.

Unfortuneately I was not able to do the calibratiom today. But we definitely will check the bed level. :slight_smile: