Scanning modes - smooth scanning vs discreet

on my old controller and software, Benbox, it scanned very smoothly and quiet. The movements were more fluid. Lightburn seems to move to position, stop, burn a dot, move, stop, burn……… resulting in a very jerky movement of the laser. The Benbox software had a setting you could toggle between “Continuous” and “Discreet”. Discreet mode worked like Lightburn.

Is there a setting I’m missing? Can Lightburn control the laser the same way? the Benbox software was junk, even as a toy it could have been better. I just wonder if I can smooth out my lasing.

I’m using a Grbl 1.1 controller now.

Have you verified the original settings vs what you have now? It sounds like you might have max speeds or acceleration set too high in grbl.

I did not have access to grbl settings in the old s/w. I have accel cranked way up to save time. Things were taking forever. It was jerky still.

You can’t have both competing concepts of physics, otherwise everyone would do it. If you want to decrease the jerky, you need to turn your acceleration values down.

Which version of GRBL (1.1e? 1.1f?) Have you enabled laser mode in the controller settings? If not, it will pause with each spindle speed change, so that’s likely what’s happening.

Thanks. I’m still learning about g code controllers. I’m not sure I understand what your trying to tell me. It was jerky before I sped it up. I’m unclear.

I’m using grbl1.1g.

$32=1 (laser-mode enabled)

Turn your acceleration value DOWN

I will try a range of values and maybe record video

Cranking the accel way up won’t likely help much if your speed is limited, and ultimately if you’re using an 8-bit chip it’s going to have a maximum throughput it’s capable of.

It will also depend greatly on the content you’re engraving. If you were running simple black & white images with BenBox, but are trying to push dithered content with LightBurn, the dithered data will have a lot more gcode commands being sent per mm of picture, which is going to bog down the processor. Make sure you’re comparing apples to apples.

I found the problem Oz. Laser mode was off, just like you suggested. I accidentally erased all my settings with a brief short circuit a few days ago while jacking with the limit switches, and while I did reset all the other variables, clearly I missed that one. Thank you much for the help. It wont be the last time. Please don’t take my comments as complaining, I was sure it was a setting, but I thought for sure I had set it. I’m enjoying trying all the features of your program.

Happy to hear it was that easy. :slight_smile: