Object XY size (50mm x 50 mm) in lightburn does not match cut size (50 mm x 34 mm)

LightBurn Software Questions
1

I just bought a Longer B1 diode laser (40W) as my first laser. I was trying to cut a test 50mm x 50 mm square and the cut I got was correct in the x axis (50mm) but not in the Y axis (34mm). Im pretty sure there must be a software setting that is incorrect but I don’t know where to look. I previously had problems with straight line cuts having bad scorching at the beginning and end of the runs. After looking through the internet I came across a video by a guy who showed the same problem with the longer B1 and indicated that this was due to it loading GRBL-M3 as the default driver, and not a standard GRBL driver. I changed to the standard GRBL and the cuts are much cleaner, but now I’m worried that i have inadvertently changed a calibration setting for the Y axis. Any help would be greatly appreciated.
Cheers, Tig

2

Make sure rotary is not enabled.
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3

I thought you had nailed it as the rotary was enabled. But turning it off didn’t change the output. I also tried reverting back to GRBL-M# but that made no difference either.

4

Try restarting Lightburn.

5

Hi, it turns out you were right about the rotary. Just turning it off doesn’t reset the output cut settings the Y axis dimensions remain locked in the rotary configuration and I had to go into the machine settings output setup to reset back to the original mm. Thanks for pointing me in the right direction.
Tig

1 Like
6

make sure your controller is TOP GRBL not GRBL-M3 or you will be running at 25% power only
Svalue max is set to 1000?

7

Hi Gil,
I’m assuming you mean the “top” GRBL in the list of 3 in lightburn, right? I set my driver to that and checked the S-value and it was at 1000 as you recommended. Everything seems to be ok for now, its just a pity that the machine settings do not self adjust when switching between using the standard configuration and using a rotary. I’m hoping to use both interchangeably in the future and I’m bound to occasionally forget to manually change each time.

Cheers, Tig

8

Correct yes. at times machin defulats to M3, but that Svalue Max is 254 so is too low on power

9

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