Hi All. I’m running a Thunderlaser 51 and having issues with circles not ending its cut in the same place as it starts so I’m getting a consistent 1mm-ish shift which makes all of the circles (no matter what the size) have a weird little shift in them. Any other shape with straight lines (squares, rectangles, etc don’t have any issues). Is there anyway to run some sort of calibration with Lightburn? Any help would be appreciated. Thanks.
I don’t know your controller, but under machine settings there is an option for Ruida to calibrate the stepper motors.
When you engrave a square 200X200mm, it should preferably be 200x200, otherwise you enter it as you measure and try again, it’s fairly easy to do - if that’s what’s wrong with your machine.
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It runs Ruida as well. I’ll run a test a measure to see what we get.
Looks like backlash - have a look at this post:
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Thank you. I’ll give it a try and let everyone know what happens.
That said. Went into Lightburn and tested a bunch of backlash minor settings to see what it effects. Ended up adjusting the x-axis 0.07 and boom. 
Thanks for the help. That seems to have fixed it.
Hi John, yes, I can see the uneven gaps here indicating some backlash in X;
Where did you make the adjustment for X by 0.07mm?.. here?;
Yes. That is were I made the adjustment
If you play with those numbers in both the X and the Y it starts moving the “skip” in a particular direction at the node locations. Y moved in up/down while the X move it sideways (as expected). I did think it strange that how many nodes on the shape seemed to also effect the output.
Just for general interest, here are a few of the other “versions” I ended up with while adjusting things. The middle one was interesting to me as it was a 0.5mm Y adjustment which seemed to only affect the nodes on the top and bottom of the pill shape.
Interesting, I haven’t ever used those controller based backlash settings, actually I think I tried once but cannot fully remember why I didn’t end up using it, I think it created jitters, slowing the job. That middle result suggests that the method of fixing the backlash could be reasonably simplistic/crude, the software option “Hide backlash” in LightBurn may work better on the whole.
I had this problem, discovered that the X axis wasn’t 90 degrees to the Y axis. Had to adjust the gantry.
Plus hide backlash option turned on.
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