Flood fill leaving small parts unmarked

[jpjacobs (jj)]

Hello,

I am facing a small issue with flood fill where it leaves small areas unmarked where the laser has stopped marking at a previous point and then moves back there later to finish the marking. They are tiny, but they are visible.

I have calibrated the machine using the Lightburn tutorial videos and I am very happy so far, except this minor detail.

Here you can see the small parts left unmarked:

Here are my settings:

Machine is a CO2 galvo laser. Brand new.

I have tried no flood fill and that comes out great, so I am assuming the hardware/calibration is ok?
I have also tried lower speeds but that does not make a difference either.

I am not sure if this is a setting, calibration or hardware issue since I am fairly new to galvo lasers and I was wondering if someone can help me out getting this sorted?

Any input will be greatly appreciated.
Thanks!

[JohnJohn (John Johnson)]

Flood fill is very sensitive to machine dynamics. It’s generally used for large rectangular shapes.

You may have more success with Bi-directional fill.

This may be helpful:

Fill Mode - LightBurn Software Documentation

[jpjacobs (jj)]

Hello,

Alright. That makes sense.

I see a lot of videos of fiber lasers using flood fill, so it should be possible, right?
Are there any guidelines on how to possibly improve this?

Thanks a lot

[LightBurn (Oz)]

Basically what’s happening is that if there is any slop in the motion parts of the machine, when it goes past a section and returns to fill it in later, it’s not getting all the way there. The proper way to fix this is to tune the belts, tighten pinion gears, etc, and make sure everything is as snug as it’s supposed to be.

If that isn’t enough, then I wouldn’t recommend using Flood Fill. It’s intended for diodes and slow systems - with CO2 machines you’ll almost always get faster results by scanning across whole words at once anyway.