So I made the layers and cut the fill and the line utilizing the specs from before. I’m guessing there is something amiss.
Mel
This confirms the issue and explains why your initial results seemed to be different between Vcarve and LightBurn.
You should be able to adjust for this in the scanning offset adjustments.
Note that the initial offset is used to adjust the starting position. Meaning the correction for the entirety of the scan being offset. The line shift will allow you to adjust for the offset during bidirectional scan.
I’d suggest reverting to bidirectional scanning and retain the outline while you experiment with adjustment values.
I went ahead and set the same cut in VCarve using the same parameters and this was the outcome. Add it is cutting both ways.
Oh this is interesting.
Does Vcarve have the ability to export gcode? If so, can you save the gcode with a .txt extension and then upload here? Can you do the same with LightBurn?
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Here are the two Vcarve files in notepad.
Laser Fill.txt (1.1 KB)
Laser Line.txt (253 Bytes)
I was able to export LB as a gcode and save in notepad.
Lightburn Cut FIll.txt (1.5 KB)
At first glance here is what I see as some of the major takeaways:
- VCarve does not seem to have any scanning offset adjustment being applied. This is interesting. This tells me that it shouldn’t be necessarily required for your laser
- VCarve uses G0 movements to move between lines with M5 turning off the laser after each line whereas LightBurn uses G1S0 without an M5. LightBurn’s approach is more laser like in approach. This shouldn’t make a difference I don’t think however.
- VCarve is sending all commands in millimeters
- LightBurn has specified that instructions will be given in inches using G20
- VCarve coordinates seem to all be given in absolute coordinates. LightBurn is mostly relative positions
I don’t see any of these being a potential root cause so I’m wondering if this is possibly a firmware bug of some kind. The most likely of these I suspect is the inches units.
Can you do this?
- click on the units indicator in the Numeric Edits Toolbar in LightBurn. It should toggle between inches and mm. Make sure it’s indicating mm.
- check your speeds to make sure those still look good
- rerun the job
Does this change the outcome at all?
That’s disappointing. Can you save the gcode from the latest attempt and upload here please?
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Here is the gcode with the mm change.
Lightburn Cut FIll mm.txt (1.3 KB)
I can see that gcode is using millimeters for units so that’s obviously not it.
If you’re familiar at all with g-code I’d encourage you to try to work through each difference one at a time to see if you can identify the root cause but don’t think I’ll be able to step through each one remotely.
But in any case, if it’s not the units difference I don’t think it will necessarily be something you can modify on the LightBurn side to mimic the same behavior.
In any case, the offset scanning adjustment should be able to correct for this adequately.
I appreciate all the assistance. I will work on the offset scanning adjustment this week and see if I can correct it. Thanks again!!
Mel
Hey friend. I was working on the scanning offset and it seems to get worse. I have included a picture of my setup for testing and results. It appears that it is worse. Any thoughts?? And I am not sure at all about the numbers…
First make sure you have at least 5% overscan on your cut settings.
As for the adjustment it looks to me like you may be going in the opposite direction. Try negative values.
Will do. Thanks again!!
Also, don’t want to overwhelm you but it looks to me like you have a situation where the initial position is starting at the wrong place. This was evident in the test with the outline.
You would use the initial offset to correct for that. I’d suggest nailing one issue down first and then incrementing from there.
So, changed the settings to 5% overscan and added made the values negative. I think I may just give up.
Even the numbers have separated more…
The numbers should follow the same offset as the rest of the fill.
I’m looking at your initial results more closely. When you measured the offset, did you then halve the numbers before inputting them? It looks like you did not.
If not, can you take the initial numbers and halve them before entering?
So, I did not half them. I will try that…