PWM issues adjusted with no change

In printing duplicate items - this case an alphabet puzzle - the further it progresses to the right or the left the further off-center it goes. In researching this issue, several suggestions were found.

  1. Send the file to the Ruida Controller and have it print from there - the result was no change.
  2. Change PWM settings in the Machine Settings > Vendor Settings - the result was also no change.

I tried the several different combinations of the x and y axis options of this I believe - maybe I missed one option perhaps but this doesn’t seem to be resolving it either.

The only work around is to send the items one at a time… and that can be time consuming - and not worth it on a file like this. Here is a picture of 1 row sent - appears to be OK. When I sent 3 rows at a time it started again. This picture attached is a retry of yesterday when all items in the file were sent as a whole to the machine which resulted in similar results. I’m not sure where to go from here and hope it can be resolved. Thanks.

If you don’t mind uploading the .lbrn2 file for us to examine, sometimes it’s there and others find it.

It’s worth running your code through the preview to see what it thinks it’s going to look like. Does this offset show up on the preview?

Not knowing how it’s supposed to run, it’s more difficult to advise a ‘debug’ path.

If it’s missing steps, it will ‘shift’ and remain there, this doesn’t appear to do this but that may depend on the tool path taken by the machine.

Are the images and text on different layers?

What kind of dpi/speeds are you running…?



Here’s the file. Hope we can solve the mystery.
Alphabet Puzzle - Production.lbrn2 (2.2 MB)

I just uploaded the file but didn’t pay attention to the other questions.
Running this through Preview looks normal - not off-set. Below is a screen shot of that.
Some different layers yes. Blue layer is my etch. There is one pink layer that is also etch but I wanted that separate beyond that even.
I just looked again and had 3 additional layers that didn’t have anything attached to them. I found the trash can on the right and was able to delete them. I didn’t know how to remove them before. These were deleted after the upload so they will show in the other file. Attached below is the screen shot of Preview and the updated alphabet puzzle with those 3 layers removed.

Alphabet Puzzle - Production.lbrn2 (2.1 MB)

Do you need flood fill on ? … It seems to have it’s issues, and it’s jumping all over the place…

I don’t know what to advise you… probably using flood fill to save time?

Good luck … hang in there


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Thanks. I am using flood fill but maybe if I don’t it will help I’ll try regrouping and going forward. I appreciate you bravely addressing my concern.

I’m not bad with Ruida, probably better than knowing how Lightburn does things.

Hang in there and see if someone drops in with some insight on what’s going on.

I assume the pwm was the falling or rising motor pulse and not the pwm power control frequency…

Good luck


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I usually do fill first. I would put the 01 layer first and do a preview. It fills them in order instead of all over the place.

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I will try that. I’m going to see if I can find out how to put more order in the way it prints. I do fill first because of the chance of the wood moving if cut happens first as it drops a little. Thanks Jeff

This DOC explains how to move the layers. In short select the layer you want to move and click the up and down arrows on the right.

Cuts and Layers - LightBurn Software Documentation

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So, still trying to still resolve this. I need to know if there is a way to set Lightburn to raster engrave instead of vector engrave. My thinking is that if I can put more order into this engrave/cut job maybe I wont find it falling off-center as it progresses. I know that time to raster engrave will be much longer than a vector engrave but when the laser head is bouncing all over is when it seems that the images and cut-outs are become uncentered.

‘Select’ the object, right click → Convert to Bitmap or Edit → Convert to Bitmap


When we first got our big laser, I did some test files. That consisted of raster engraving a 20mm square, and then vector engraving a perimeter offset 2mm, and duplicating that many times.
It would do a couple that were aligned perfectly, then the perimeter moved. Sometimes it was a parallel move, and a couple were a rhombus - base good, top offset.

Honestly I can’t remember the answer except I fine tuned the reverse niterval settings and a few other things - took 3 days of head-scratching and trying to logically get to the end of the question, and we finally did.
No problems ever since then.
One of the issues was slightly unequal tension between the left and the right Y timing belt. That helped it move squiffly at times.
Minor backlash issues vanished after I fixed the tension.

Honestly I cannot remember all the fixes, but you need to start at the bottom.

Glad you have it fixed…


Me too!
I think also running the test files much more slowly, also helped.
I think the misalignments may have come at only the extra higher speeds.
It’s easy to blame the vectors for cutting in the wrong place, but I tend to think they’re often correct, and the raster engraves were the ones shifting…
You can only ascertain that mathematically by setting up a grid and measuring it afterwards, so see which aspect is totally right and which one is misplaced.

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