Please enlighten me further if I am wrong, if the laser is set at 20 percent when LB is telling it to be zero, and 20 percent is enough to mark the material would it not just be on at 20 percent when it travels?
My understanding is that min should be set to just turn on a CO2 laser which is likely going to by way under 20 percent. The video in my reply does explain how to setup the min.
Hi, thanks for taking the time to respond! So I typically send the file and then hit start. I have tried hitting start from the controller and from lightburn itself. As for the usb cable, I have the one that came with the machine. It does look like yours and has the chokes but could it be that it’s just a faulty usb cord?
When you ‘start’ from LB, it sends and starts the job in one go. If you’re having issues, best to send it, then start from the panel.
I would definitely try another cable. Monoprice has good ones at reasonable prices.
You are wrong - read the docs on power setting.
Your understanding is incorrect.
A couple things, can you provide me a link to the power settings section of the docs you are referring to, I can’t find a section for that and really do want to read it. Are you saying there is no need whatsoever to actually test and find the proper min power setting for a CO2 laser?
And no, that’s not what I was saying
Thanks for the cut and paste I can say that is right for cutting but min power does play a role when doing grayscale images here is a link from another post. I am just trying to point out that my original response was not wrong, min power should be set properly and it is used in grayscale. Perhaps its not the cause of the random lines in this post but its a good start for the poster to set it right and try burning again to see if the issue goes away.
https://forum.lightburnsoftware.com/t/grayscale-engravings-very-light/11181/4?u=renegade1966
Hello Bo,
I already thought about the bad quality USB and tested something to be sure :
Instead of running the job in LightBurn, I just exported the Gcode, directly in my Spark xPRO v5 controller (this ESP32 has a SDCard were I can put my gcode directly), and launched this gcode directly from the GRBL webUI. Doing so, I totally exclude a transmission problem that could appear between Lightburn/computer and the GRBL board.
=> Results are the same : I still have unwanted lines (thous lines appears sometimes between 2 burned zone, sometimes in the overscan zone.
So the problem isn’t coming from LightBurn, neither from the USB cable. It could then come from :
Another strange thing, I only noticed lines that shouldn’t be burned, but never lines that should be burned but are not. Like if the laser might forget to turn off, but never forgets to turn on ? Or maybe is it just more difficult to notice ?
Any ideas ?
Stephanie you sound much more experience than I do, I am not sure what most of that means but if you find a solution or any helpful info can you let me know and I’ll do the same for you?
Hello Sarah,
I’m Stephane, not Stephanie ;p.
I’m not sure if we have exactly the same problem, and if it has the same origine. But yes, if I find something, I will try to share.
And I hope somebody else can help as well.
Thank you
Oh gosh sorry about that, my apologies Stephane!!
When doing grayscale engraving, Min Power is used for the white areas, and Max Power is used for the black areas. When the laser is moving between cuts, it is simply off, so neither Min or Max power affect this.
The original poster is pretty clearly not doing a grayscale engraving.
Yes, and neither me … I never tried greyscale engraving .
Have you seen this issue before? Any idea what could be causing such inconsistencies in the same file?
If you are looking to change and update this ‘Machines’ information, have a look at this section of the following post:
What firmware are you using to drive this setup?
It was entered by the person that set this account up in the first place, but fixed now so we can move on.
I ask for firmware used to drive this setup, so when you can.
Additionally, thank you for offering assistance, but you have a very different system from that of the OP, and your suggested corrective measures do not apply. We want to help you with the issues you are experiencing as well, but this has become confusing to follow.
I didn’t changed the original firmware on my Spark xPRO V5.
Mine is 1.3a, for a XYYZ machine (Workbee). Spark does list their firmware here : https://github.com/Spark-Concepts/xPro-V5/tree/main/Firmware
They are most probably based on GRBL-ESP32 (GRBL1.1) as this device has been launched last year.
I know that my global hardware is not common. But GRBL-ESP32 is common… The xPRO V5 is a standard ESP32 controller, Spark-concept did the job to propose it in a nice and easy to wire box.
So i think that if someone here has a problem with random lines engraving that shouldn’t, his experience can be helpful for other. Maybe I’m wrong (I’m new in laser engraving).
There’s some disagreement on Facebook as to whether these are true Ruida controllers, however if you actually ask Ruida, they’re made by Ruida. 
If you host a lot of files on your controller, it’s worth clearing those out occasionally, as they can cause the controller to behave a bit erratically. Also, when you use the rotary, after turning on the rotary switch and leaving the rotary setup window, power cycle the controller. Failing to do that can also cause odd issues, though this doesn’t look like that would be causing it.
Are you using a Windows or Mac machine to send to the laser?
Please go into the electronics compartments and search out the controller then take an image.
It’s really central to looking for an answer
Gary
