Round on top, oval on back, metal cutting 2mm CS

[tavib]

Hi all,
On a chinesse machine, good overall but sometimes have issues. Like now.
Metal cutting 2mm using O2 on 300w laser with MetalCut software.
The circles on top are ok, but oval on the back. Please see the attached picture.

I noticed that the laser beam shape is not round but oval. I admit that maybe the laser beam is not perfect perpendicular on the metal plate, but it is centered on the nozzle (1mm gap).
I also cut a piece of plywood 8mm to test, circle and square and they are ok, no slanted cuts. It happens only on metal cutting.
Also I cut a square on the same metal plate and the cuts are ok, not slanted. Only on circles or curves. And it happens from like the 0 (zero) point when change x to y and vice versa, I mean with a circle:
first quadrant slanted to exterior, the second kind to interior (not as hard as the first one) , third again slanted ext like the first one, and the forth like the second.
I suspect the beam shape ?!? I mean it is not x/y mechanical issue or like speed/acc ...I think.
Any suggestions are appreciated
English not my native language, sorry for mistakes.
Thank you for reading!
Hugo

[lasersparts]

Hello, yes the problem is your laser head/ last mirror beam is not perpendicular to the cutting surface, you need to adjust it
Best wishes

[tavib]

Hi,
Thank you for the answer, I'm working at this.
After I'll have a good result I'll write here.
Just a thought, let's say the beam is perpendicular on cutting surface but the beam shape is oval, not round, can give this problem? The beam oval shape can be because of the previous mirrors, before the last one on the head.
Thank you again