HELP: Engraving line shifting on x-axis consistently at same spot

Hello everyone, sorry to bother you with my problems :slight_smile:

I hope this is the right space to post, but I think it is as I think my issue depends on a software issue.

I am having an issue with a project I am working on. It’s the first time I am using Lightburn, I used to use LaserGRBL but I wanted to step up my game. I use an Atomstack X20 pro and I transmit the jobs to the engraver through a SD card.

It’s essentially a map of my town that is split in 9 panels, and the thing is that some of them are coming out perfectly, while 3-4 of them have this weird x-axis shifting that occurs at the same line for a given panel. You can see an example of that in the picture below, illustrating the panel n.5 that has a line shifting in the lower area of the map:

A few closer pictures to show you the issue:

I don’t know what the problem could be. Since it’s happening consistently at the same spot I think I can rule out the possibility of a hardware/physical issue, correct?

I think it may have something to do with Lightburn export settings, but then again why are some other panels coming out great with no issues? Also, I wouldn’t know how to mess with those export settings.

I also thought it could have something to do with a badly soldered wire, but I think it’s not that because the shifting would not happen consistently at the same spot, correct?

Please let me know if you have any piece of advice, I’m kinda lost here :slight_smile:

Thanks a lot!

May be a problem when the buffer on the controller fills and restarts ?

Hey man,

Thanks so much for taking the time to read my post and think about it.
Although I have to confess… I don’t have a clue of what you’re talking about :joy:
This probably has to do with my poor knowledge of CNC machine softwares.
What do you mean by “buffer on the controller feeds and restarts”? Apologies for my ignorance!

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The buffer is a limited amount of memory on the controller if the job fills that lightburn waits til enough of the job has run to send the next bit of the job, there is usually a pause while it reads the new data to process and may be starting just a little bit off from where it finished the last lot of data.

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That’s an interesting theory, but isn’t it weird that it happens so early in the engraving job? I would expect that to happen in a very long project, whereas this engraving job only lasts 1 hour and a half (and the issue comes up after 20minutes, less than 25% of the job)

And if that was the cause, is there a way to avoid that issue? Thanks mas

P.S.: I should also mention that I’m not feeding the project to the machine through the cable, but through an SD card

The time into the job is not the issue its the amount of data, BUT the fact you are using an SD card would reduce the likely hood that this is the cause of the issue.

I have a feeling that you’re engraving an image close to the edge of the work area.

LightBurn applies overscan to allow the laser engraver head some room to slow down.
If the engrave head bumped one of the machine rails it may lose that motion from that point forward.

To see if your project is pretty close to the edge, Click the Preview Icon in the top row of LightBurn and activate the “Show Traverse Moves” switch along the bottom row.

Now the project can be previewed in Black and the travel (and the Overscan) can be seen.

If you’d like to Capture the screen with the Preview window open we may be able to confirm that the Overscan was a contributing factor.

Hey man,

thanks a lot for your answer. That’s exactly what happened, I figured it out a few days ago (sorry for not telling earlier).
Anyway your answer was way more complete than what I would have written and it’ll be useful for users that have the same issue :smiley:
Also, I had not checked the traverse moves, I just got to the solution by a trial-and-error approach, but now that you’ve given me this tip I have double-checked that and found out that it was indeed the problem.

Thank you John!

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