Different engrave settings today - why?

last month I was getting an excellent medium brown engrave with 135MM/S at 20% power
today had a very very light engrave at 135MM/S with 35% power
my machine is 80 watt CO2 laser
I did make some machine setting changes but dont exactly know which ones
Any clues as to what I did wrong ??

Without knowing what you changed it’s possible it could be a few things:

  1. Has the power you need to get the same engrave increased over slowly/over time? or did it happen immediately after a change you made?
  2. Did you change the DPI/Lines per Inch?
  3. Have you checked your beam/mirror/tube alignment? This can slowly get out of wack over time as your machine vibrates which will reduce the cut/engrave power
  4. How old is your tube? These are a consumable and have to be replaced eventually


last week I was trying to find out the machines lowest power level, it was set at 20% and had been performing correctly, never had this issue, always had consistent power
this problem started to day and I increased the low power level back to 20% and then found my carriage was now reversed , was left to right using the red pointer, so found the move button and changed the setting and now that works ok.
After all that I upped the engrave to 60 % with same speed and getting an acceptable engrave burn - but why the change.
I bought this machine used a year ago and have never aligned the mirrors. so i will follow your suggestion on that.
thank you

Generally these don’t fail like that overnight.

The part that makes a laser work is really the lens… there is little useful intensity in an unfocused beam.

If you tube is operating and you have these three, the

  • beam aligned
  • proper focus
  • clear optical path

It will work.

Where/how did you change this low power back to 20%.?

Either you don’t understand the machine or you are leaving something out. A power change, via the console or the software will not cause the machine in any way to operate anything backwards. That should have been a red flag that you probably ‘broke’ something.

Before modifying anything, figure out how to back it up. If you break something it’s an easy fix, just reload the backup. Any chance you did that?

Russ makes good video and his explaination works for me. This is a good alignment video. The equipment he is using has more adjustments than you probably have, but the procedure is good.

I’d suggest, at least of a check of the alignment.

Good luck


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I understand the machine , I likely did not explain the situation properly. first off I had not used the machine for three weeks. last time I used it I was changing my minimum power percentages to find out the lowest power levels that my machine is capable ofl

Today after three weeks of non use my gantry went in the opposite direction when I used the red pointer in lightburn. I was trying to find out why so I tried to find the reason. I did end up changing the user origin which corrected the direction.
I may have also changed one or more options which could have changed the power settings.

I did move my machine last week to make some clean up however I dont think it would have anything to do with lens alignment.
I will Check The alignment in the next few days when I get a chsnce

You changed the origin somehow. That is not the laser, that is the Lightburn. Somehow that got changed, did you reinstall Lightburn or something similar.? This doesn’t change, unless you bought the gremlin option.

One of the key parts is not working properly, as I mentioned.

Check your alignment. It is probably ok, but when you move them too much you can cause issues. Simply shakes things loose. Mines on wheels and it’s pretty stable when I roll it around.

When you check the beam at mirror 1 (m1). Since you will be there anyway, might as well check the tem state. I doubt this is a problem as the issue is pretty acute. But it’s easy to check. Make these very light in color so you can see the power distribution in the beam…

Best of luck


I did not reinstall lightburn and I do have the licenced version. With the time I do have at my disposal I have bee watching the video on tube and mirror alignment which you mentioned. I look forward to checking the alignment. My machine is on 4 casters with level floor and doubt the previous move around would have dislodged the mirrors. We shall see

Then you just need to check the alignment. That should give you something to go on.

Good luck


Today I got the time to try to adjust my mirrors , overall the alignment was I would say about 75% -85% ok, I decided to have a look at the focal lens - found it had 1/4 inch burn mark facing the work and two crack lines spreading out, When I tried cleaning with isopropryl it easily broke the lens in two pieces. I have ordered a few new lenses from Cloudray. I’ll be down for a couple of weeks

I don’t think alcohol is good for a lens. It’s ok for mirrors but it causes issues with lenses. Suggest you pick up a few packages of lens cleaning tissue…

Sorry about the loss…

This is what I meant, really not tissues…

Good luck


ok good to know

Good to see you’ve found the problem. I had a similar problem with the engraving being rather random, sometimes good but mostly blurry and un even, I decided to clean the mirrors and check the lens only to find the lens locking ring was slack so the lens had been bouncing around while engraving, cleaned the lens and refitted properly and it’s now working better than every, so I guess the lens has been coming loose over the last few times it was used!


I’ve seen a couple of times where the lens holder had piece of debris and the lens was actually tilted in the lens holder.

This has some bizarre effects… rare, but weird…

Don’t know how your lens mounts. I buy O rings and cut a chunk out so they fit the inside tube circumference. Allows you to snug up the lens by feel. They are real cheap from ACE hardware…


have you checked the focus, and is it the same type of wood that was previously used.

It would be handy if you could mark this ‘solved’… if that’s the case.

Good luck


The focus had not changed from the last job I did.
I would say the problem is solved , however I wont know for sure until I install the new lens. The lens and new mirror set will hopefully be here by end of this week. thanks to all for your suggestions

Don’t mark it solved until it is… Why new mirrors? Just curious.

Good luck


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