Lightburn with GRBL controller goes nuts

Hi all!

I recently purchased a Lightburn license after over a year of struggling with Laserweb. So far I love it! I’m just running into one problem. During large jobs my laser either freezes up (as does Lightburn) or the laser head goes nuts at starts running off into an odd direction. This only happens on large and complex jobs. I’ve tried Lightburn on both Ubuntu Linux and OSX with similar issues.

My hardware is a DIY 700x700 laser bed with an Arduino running GRBL with a Protoneer CNC shield. Everything works perfectly until the machine either locks up or sends the laser head off into the corner of the bed to crash. The Lighburn interface shows as “busy”. The console reports nothing.

I’m way inside boundaries . . . I don’t think that’s the issue.

There are no errors shown in any interface.

Can someone tell me where to start trouble shooting the issue?

Thank you!

This sounds like a USB dropout or communication issue, possibly. Which version of GRBL are you using, and which device profile are you using in LightBurn?

When you say “large jobs”, can you be more specific? It might also be port sleeping - check here for some common USB issues: How to troubleshoot connection issues with USB

Hi and thanks! I’m running GRBL 1.1f . . . I’m having the same issues on OSX and Linux. Autohome is not turned on. I’ll try a new cable? Is there any other log file I can check for issues?

By large jobs I mean jobs that run +15 minutes or so. Lots of small cuts . . .

You could try saving the gcode from LightBurn and using another app to send it to the controller, like OctoPrint. If the other app had the same behavior it would point to a hardware issue. If the issue is the USB connection, usually it just stops or the board resets, and I wouldn’t be given a reason - it would be the equivalent of a cable being unplugged.

If it’s something in the board itself, or firmware, that’s causing it to freeze up, there’d be no indication of anything wrong at all from the LightBurn side.

Interesting . . . I extracted the gcode and ran it through UGS and it still randomly locks up. I swapped the cable a few times and rerouted it with no success. I guess it’s the controller . . . booooooo.