I calibrated the steppers (parallel lines 300mm apart, each axis), adjusted $100 and $101. I checked belt tension, gantry fasteners, etc. I find with Lightburn a 300mm circle is not closing… and when burned in LaserGRBL it closes great, hard to find the start point. So it’s not hardware, and it’s the same gcode file in both GRBL and LB. Is there something within LB that I can adjust regarding circles, circle methods, etc.?
Stepper calibration is something that shouldnt be necessary in any newer machine like a creality
If you are having issues with your shapes is something in the hardware definitly not software
I would sugest you reset firmware to defaults with $RST=*
Make sure rotary is not enabled in any way too
then try this pattern and engrave it on a bit of cardboard and send picture of results?
Dot Test with Angle.lbrn (46.3 KB)
Edit: When you say same Gcode file for both GRBL and LB, if you save both to Gcoe and compare they are the SAME? Any chance you have tabs enabled on LB?
I had that sneak in on me once (as well as lead in, lead out), it was defaulted on the layer I was using, and I didn’t notice until later.
Thanks for the reply. Every CNC or Laser I’ve bought the axes needed calibration. In this case my Falcon 10W with air assist was off in X by -2mm (298mm vs 300mm) and Y was off +1mm (301mm vs 300mm), a few minor stepper adjusts and the dimensions were as perfect as I could measure (using a 12" Mitutoyo digital caliper), so starting with the cal seemed warranted. It made the circles more true and smooth, and in LB it did close up the circle but not completely. The gcode is identical line for line. I wrote it, only one file. G2/G3 functions. not interpolated lines. I’ll wait and check the tabs setting noted below - that seems a good thing to check before I reset anything, especially since Laser GRBL burned perfectly closed circles. Thank you for responding. I agree the factory settings should be dead on, but I’ve not found a machine yet where they were.
Also… good advice to check rotary is not enabled, will check that!
This will be my first step, thanks for the info!
I’ll burn the dot test tomorrow afternoon and share back the result, wife had me taking down inside decorations today and the outside ones come down tomorrow morning! Work before play unfortunately!
Thats fine! Good luck
And we know Wife has priority over hobbys… at least 99% of the times 
I’m finally able to update on my circles not closing. It turns out the reason I wasn’t seeing the issue with Lasergrbl was because the speed power settings were lower than Lightburn, when I thought I had them set exactly were the same. Following advice here… I went back to hardware and started from scratch… I disassembled the laser and took time to review everything. What I found is the belt on the left and right rails (Y axis) were not installed with sufficient alignment from the factory. The two rail belts were located about a half tooth off relative to each other on the end fastened by the factory. This skewed the Y axis side to side. I loosened the ends and adjusted so a tooth on each rail was identically positioned within the rails. To do this I used my CNC mill to make two plastic parts, basically a slot in a small piece of flat plastic, and machined the flat surface thickness to match the pitch of the belt, with clearance just enough to slide onto the belt from the side. With one on each side the belts were now exactly positioned at the same starting point. That solved the problem. At higher speeds I suspect the difference in the belt(s) was causing one side to not be at the same tooth location as the other, thus unable to close a circle or two lines meeting at a sharp angle. This didn’t seem to show up at lower speeds, causing me to think the issue was not hardware. Thanks all for the help! I’m now engraving and cutting with precision. My lesson learned is belts are not as repeatable as lead screws, they must be installed with precision, and I will need to make sure they are part of a regular maintenance, and buy some spare belt material!
Out of curiosity, how do you do this?
(I have the same laser!)
I an Excel file, if you send me your email I’ll share to you. Seems we can’t upload Excel files…? I didn’t write it, snagged it elsewhere on the internet - happy to share!