Power of Laser keep going up and down

I have been trying to burn some 0.5mm brass and the power seems to keep going up and down even when set at the same percentage. I thought it was a file issue so i redid the file and it still happens, it was working fine before and getting amazing results but now the laser seems to burn with a lot more power.

This is generally due to a focus change… It’s critical with a fiber, especially with a shorter lens.

Do you have the same frequency settings? Do you have a q-switch or mopa?


I did not change the focus, or any other settings internally in Lightburn. I did 2 burns and the first came out burnt and the second one came out fine. I am burning on brass and I did a bunch of burns and got consistent results for about 6 or 8 pieces and then the issue happened and now seems to be fine. I do not want it to occur again, is there something I can do to keep it consistent? I have a q-switch 50W laser

This depends on what’s causing it…

The problem with these machines, unlike co2 or dpssl, is that there are only a few parts and they are not really user serviceable. There seems to be little information about the innards, so a user has to hack on a $7K machine, if you break it, it’s costly…

Most of these you can change out control boards or sources, but there is only power, controller, laser source and galvo head/lens… There isn’t much you have control over.

I assume these brass was all the same… I had to modify one of my file with a new batch from the same place and it apparently was different… same part numbers, same description… ?

I wish I had a good, satisfactory answer, but no… sorry…

If you can go back to the vendor and ask them, it may be a good idea. Many don’t help, but neither have I…

I’ll keep my eye on the thread…

Good luck…


1 Like

Assuming each piece was placed in exactly the same place on the table:
Could a couple of your pieces be maybe a little dirty? even some finger oil will possibly cause what you describe. If you bought blanks one side may react differently then the other side whether visibly different or not.
If different positions on the table, dirt/ smudged/ smoke on the lens, table and galvo head not exactly parallel, things like that will cause what you describe.

Yes I have been placing the brass pieces in the same spot and the table is level to the head. I sand the brass piece and then clean it with Isopropyl alcohol to keep it as clean as possible. The lens is clean and the brass is wiped one more time before burning. I do not know what could be causing it considering what you mentioned, what you are saying makes sense but i dont know if it applies to my machine.

1 Like

“makes sense but i don’t know if it applies to my machine.”
Doesn’t sound like it. Unfortunately if it isn’t something simple you are in for troubleshooting hardware.
Throwing spaghetti at the wall:
Are you running any other programs on the computer?
Do the lights dim or get brighter in the room when this happens?
Does the fan sound different?
Anything else that might indicate unstable house current?
Sorry, not going to be much more help.

If this is a solution for you it’s probably not the best…

I had an issue with a short lens and brass coins… There was an uneven anomaly that was present with different art work, speeds and so forth…

I managed to get a usable coin by using a longer lens… Wish I could tell you what happened but the lens change resolved the problem…


1 Like

Yeah I do have a transformer to cover it from US power to EU power, could that be a reason?

I see, I do not want to resort to fixing it by changing lens as it will take me time to get it back to working with the quality I am getting. I will try to figure this issue out, if not, might try fixing by calling in a professional and seeing if they can resolve that.


This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.