Circle not perfect

Well,

first i made the laser myself with the furtherfabrication.com documentation in october 20.

The laser is CO2, 100W.

I have a working area of 1.2m x 1m.

I will add some pictures, it’s not finish at 100% but it’s operationnal.

Now,

  • i tested all belts, retighten all screws, change my linear rail and put some grease. I don’t find hard zone on the linear rail or on the others belts.
  • i tried a little circle (2cm) on each corner, and middle. I always have the problem, my circle is like a little lime (where is my mojitooo ?)…
  • i cleaned the lens, change the speed…

Nothing…

I founded some older job (circle key ring), the circle is perfect… I really have no idea…