Same Settings Producing Different Results: Draw 2mA in Fill Mode, Drawing 10mA in Line Mode

I’m having an issue with Lightburn on an OMTech 60 watt laser that is weird. I’m engraving 1/8" Baltic plywood.

300mm speed / 8% power

When engraving: works fine draws about 2 mA
When line mode and/or line/fill mode draws 10 mA and burns through the plywood.

In my mind, it should not be drawing 10mA in line mode at 8% power.

Max power 8% and Min power 8%

Anyone have any ideas?

Thank you in advance for your time!

Let me ask the question a different way…

If you adjust your laser for 300mm speed and 8% power, does your machine draw the same milliamperage in Fill and Line modes?

Thank you…

Hi Mark, have you checked the ‘line (after fill)’ tab?
Cuts/layers, double click the project, 3 tabs, common, advanced and line(after fill) probably find it need to be adjusted.
Had a very similar problem a few days ago.

Thank you for the reply! I went and did some carving to see if that was it, but it was not. The settings (fill/line) were not set, so I set them. The fill worked fine as always, but when it went to do the line the Ruida controller showed 8%, but the amp meter jumped up to 10 mA as if set to 20%.

I notice the Ruida controller show max 20% before running a project, and I was going to try to lower that to 8% as the Ruida’s max for a test, but I could not figure out how to change that outside of Lightburn. It is as if I’m going to do a line, it’s going to run at 20%…

Thanks again for the suggestion, if you think of something else to try I’ll try it!

More Tests:
So OMTech had me run the included “Test” file using RDWorks…it came out perfect. The bottom images are burns only using Lightburn at the listed percentages. It appears to burn at very low power, especially when the laser slows or tight lettering.

Thank you,
Mark C.


did you check “default” in the cut settings by any chance?

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If you enabled the “default” it will use the power / speed settings that you have set on the controller.

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During cutting / engraving you can see there what settings it currently uses.

Hi Enno,
Thank you for the reply! No, I checked those today and they are still in the position as shown above. What’s weird is, I’m not sure that the laser should even fire at 5%, but all percentage burns the milliwatt meter jumped to 10 mA and stayed there until completed. It does this with LB in “Line” mode everytime.

Hi Mark, still can’t work out your problem.
The only thing i can think of, have you tried putting the ‘minimum’ power setting to zero?
You’re right, it shouldn’t be burning at 5%, mine burns at 9% but no lower.

Thank you very much for responding!
I read your post and just tried that…it still burns through (see photos). There is something wrong with something, but I can’t tell what…

Also, you can see the 4 squares at 5%, 10%, 15%, 50% (all 235mm/s & 1% min). They all are the same and drew about 14mA each…the same amperage.

maybe you can have a look what minimum and maximum you have set in your vendor settings. If in Vendor settings min is set to 12% you do change all settings in lightburn but the machine will not go lower than 12%, neither will the min power adjust on your display.

And maybe post a screen shot of each of the settings, not what you have set in lightburn

Hi Enno,
Thank you for your reply again! I have attached a pic of the vendor settings as they were/are. I’ve also gone in and set the min and max on the Ruida controller to the same values, but I’ve not had a chance to do a test burn until tomorrow. LB Support has replied and suggested the vendor settings and Pulse Wave Modulation (PMW) setting. I do not see where that is adjustable through user settings, and I don’t think that’s it because the test file on the controller, where they do the plexi-glass burns, carves nicely on the 1/8" plywood. There is almost no burn through, and I’m thinking it’s only the default setting for the plexi that is causing what little there is.

so the vendor settings look good, the min and max you set on the machine will do nothing except for when you “pulse” or ! when you check “default” in your cutting settings…

Thank you for the info on the controller!
I did some testing yesterday, the engraving (fill) works great, so it’s only line that’s an issue. I’ve emailed tech support expressing that I don’t know where to adjust PWM, they mentioned if set at 50% or above LB settings wouldn’t matter, and they mentioned power supply calibrated, but because it engraves well I can’t help to think either of those are an issue. The lines on the OMTech test file even look good. I did ask if previous versions of LB were available for download, maybe a older version will act differently…worth a try. I’ve included a vid of it engraving.

Thanks again,
Mark C.

please show your cut settings of the line? like this:

Here are the settings for the video’s cuts:

Here are the settings, and results, for the below “Line” engrave I did this afternoon:

Yesterday I downloaded LB Ver 9.15 and had the same results. Earlier versions Windows 10 won’t let me download, and gave a warning that it could harm my system, not sure why that was, but I suspect it was a general warning due to the age and version of the file? I see the power supply has a variable pot on it, but since engraving is working ok, I’m hesitant to adjust that.

I can’t understand why fill engraving works and draws little amps, but line is as if something triggers it to jump way up on power.

This morning I ran some tests with these ridiculous settings and the amp meter still jump right up to 18 mA and burned through.