Alignment of lines and fill

I’ll cut right to the chase, lines do not appear to be aligning with the infill that they surround. I have a complex shape (top in the photo) where the gaps around the infill should all be the same thickness. In the simple shape (bottom in the photo) the gaps are pretty much what they are supposed to be. You can also see the cut is very uneven around the outside of the ornament. I use this exact file on a K40 and I get results that match the LightBurn design file.

My initial thoughts are certainly are hardware problem. I do not know what tests to run to prove it. I have tinkered with a lot of settings and hardware. Here are the things I can remember:

  • Cut acceleration in half (now it is 950 mm/sec2)
  • Tightened belts
  • Reduced fill speed to 100 mm/sec
  • Reduced line speed to 15 mm/sec
  • Ensured pulley set screws are tight and on the flat portion of the stepper motors.
  • Tightened V-Slot wheels
  • Cleaned tracks of V-Slot (the laser has less than an hour of runtime on it)
  • Changed micro stepping to 1/16
  • Many other things that I don’t remember but needed to be done because the laser build was just completed.

This is a custom laser. I am running the most recent version of FluidNC, 3.5.1

Any thoughts are appreciated!

Alright, I must have done something to LightBurn. I went back to my K40 to fulfill an order, and now it is displaying the same symptoms as my new laser. In the picture, the ornament with no name was just burned on the K40 and it shows the same sort of issue. The other two ornaments were from a week ago before I started messing with LightBurn to setup the new laser. As you can see the K40 was previously burning these without any issue. I need to fix this issue ASAP as I have orders to fulfill!!!


How does it look in the preview window?

It looks like you messed around with your design, it’s not centered anymore.
The uneven engraving itself, I think could be attributed to the difference in material, with plywood a “normally known” problem, unfortunately.

Now I see your preview, you must have moved your laser or your object during the engraving process.

…is there a specific reason why you are running an old version of LightBurn?

The object on the K40 is taped to the bed, I really don’t think it moved. I’ll burn another just to prove it because anything is possible. I’ve burned 1000’s of this design and had very few if any issues and never this issue in particular.

Im on an older version because this version has worked perfectly fine for me for many years. Why spend money if I don’t have a reason to. I’ve been using the same laptop, usb cable, and laser for almost 4 years. Although I can say I swapped out usb cables recently to see if that cable was a potential source of error. I ended up switching back because the new usb cable was doing the same thing.

Honestly this is very strange that I didn’t have this issue until I added a second laser setup to light burn. Ever since then, it seems as though both lasers are showing the same or similar problems.

I am no longer attributing this to my hardware considering the circumstances outlined in the posts above.

This is almost certainly not the case. There are people that have many concurrent devices configured so there’s nothing inherent in that. The Preview bears out that the laser path is most likely being generated fine. You could confirm this by examining the g-code. I’ve never seen LightBurn generate bad g-code for core movements so I think the chances of that in this case are low.

The fact that both lasers are exhibiting the issue is likely a coincidence or it’s possible that there’s something in the design that’s putting more mechanical stress on the machines so they’re failing in similar ways. Are you using flood fill for these?

Bottom line is that somewhere in the chain you’re missing steps. My first inclination is loose belts but you say you’ve checked for that. If not that I’d think that the stepper motors are missing steps.

Are you willing to share .lbrn file for review?

It looks very “mechanical” to me, but let’s see the file with this error.