Test pattern prints fine in laserbox basic but not in lightburn

I’m new to the laser engraving so I might be doing something wrong. I’m currently evaluating lightburn for purchase and was running a test pattern and noticed that at 50 to 80 speed with 15% laser power that the test burns are not complete. Below are pics and screen shots of my software/firmware versions. If I run a similar test in Laserbox Basic, the pattern doesn’t show the same defects.
I’m at a lost of what to try next. I reloaded the D1 config file in lightburn, and re-flashed firmware on the D1.So any speed from 50 to 80 has this issue with 15% power. I don’t know if it would effect printing an image say at 80 and the image has a lighter area in it. Would the image present itself with the same issue?
Thank you,

I searched the internet and lightburn forums and didn’t see anyone else having this issue.

What was the orientation of the burn?

At first blush this feels like a firmware bug to me. Can you try using Constant Power Mode. Does that change the behavior?

All the burns were vertical. I did try constant power mode on another test and the results were the same.
I did reload the firmware and made sure that the firmware switch was in the disabled position after the firmware install. I’ll try to do more testing today.
Thank you

Can you see the laser light on the whole time that it’s expected? Or does the laser turn on late and turn off late, matching the unburned areas?

If I increase the overscanning a ridiculous amount the burn does get a bit wider but isn’t the 10 or 12mm wide as it should be.
As I mentioned before, the problem seems to show up with 15% power and mm/sec from 50 to 80.
I’ve tried, constant power, bi and unbi directional burning, cross hatch. Also, Reinstalling firmware, D1 config file (in lightburn).
If you look at the test, it shows an increasing slant to the unburned area from 50 to 80.
You would think if its a problem with LB software or Xtools firmware that others would be having the same problem, unless no one is running test patterns under 20% power.

I’m trying to determine if it’s an issue related to power level or timing. Is the laser actually on when it’s supposed to be? Or is the laser not on during the missing areas?

Typically patterns start at 10% so I’d be surprised if people weren’t also running at 20%.

My first reaction was that this would likely be a firmware issue because the g-code for this type of thing would typically be pretty straightforward and because xTool D1 has had a history of odd firmware bugs for many surprisingly common cases. I also assumed this might have something to do with dynamic power management that’s affected by speed.

It would be good if someone else with the D1 can run this and see if they can reproduce the issue.

Perhaps upload the .lbrn file to see if someone else can test it.

If you preview the burn with “shade according to power” on, does everything look as you’d expect?

I don’t know where “shade according to power” setting is but if you’re referring to the power scale setting, in all the examples you see, it was set to 100%.
I did try setting the power in the layer to 100 and set the power scale to 15% and ran the test again at 80 mm/sec and got the same results.
I’l ltry to upload the file today

Not referring to power scale. If you go into Preview. There’s an option for “shade according to power”.

Were you able to confirm whether or not the laser is on during the missed spots?

That wouldn’t surprise me. The gcode at the end should be the same.

Yes the shade option is enabled.
Can tell if the laser is off since the burn is only 5mm. I will make it much bigger which I think I would be able to tell.
LB also has a test under Menu Laser. Tried that one and got the same results.

I suspect the issues will appear only at the edges but would be an interesting test.

Yes the laser does turn off near the edge but only on items that are filled.
I lined each fill so to know how much was missing.
Top two were with lightburn and the second two using laserbox basic.

Uploading: 20220814_142032.jpg…

Maybe there is a setting in grbl that is messed up.
I about to email LB and XTool directly to see they have any suggestions.
BTW. Thanks for advice.

There’s nothing in GRBL that would directly affect this. And even if there were it’s pointless because xTool prohibit any configuration changes.

Based on what you’re seeing this is almost certainly a firmware issue. Taking it to xTool is definitely the right move.

Can you do one thing? Can you save the gcode for that last test burn and post here? Please save it with a .txt extension otherwise you won’t be able to upload here.

Just want to take a quick look to see if there’s anything obviously broken there.

Here is a closer look at the previous test. You can see in the laserbox basic 80/15 test, there is a ever so slight missing fill near the end. Seems evident here with the larger print ,that both exhibit the same fault only more noticeable in LB.
Here is the gcode of just the LB burn.
test pattern 4.txt (24.3 KB)

I don’t see anything obviously wrong in the gcode but it made me rethink something.

I’m wondering if this could be fixed with offset scanning. I’m curious if you’re getting weird behavior only at this particular speed for various reasons.

Try doing a fill with a high line interval where you can clearly see the separation between lines. You may want to burn onto something that’s easier to see the results. Perhaps cardboard or a dark cardstock.

Include the outer frame as a reference. Then measure the output.

Add an entry into Device Settings → Offset scanning adjustment specific to 80 mm/s. Be careful as the units may be different for offset scanning.