Intent:
Burn a circle (png) on a leatherette patch through transfer tape.
Issue:
The etch is noticeably uneven.
What’s happening:
The laser tracks horizontally. The top and bottom of the circle have the most consecutive burn time as they’re the most horizontal. The etching there is thicker/deeper. The other edges are thin and shallow.
Without a picture showing orientation, I can only assume this is along the Xaxis. It is a known fact that the UV diode beam is rectangular with the beam smaller, and thus more powerful, in the Xaxis. Try rotating your scan 45 degrees to see if that helps average out the power distribution.
If you scan at a 45 degree angle, your Xaxis and Yaxis travel will be diagonal to the rectangle of the laser beam. If you travel cross corners for the X component, then 90 degrees will also be cross corners for the Y component. In other words, the path width will be the same.
As for your image, I cannot tell if that is a double burn or it is a backlash issue in the Yaxis direction.
My own Ortur LMPro2 does not like to move that fast, even with an upgraded 10w laser.
My second observation is that you are burning an image rather than an object. Your dither is set to grayscale. That is the single hardest setting to get good results from that you can use on your diode.
My suggestion is to use the TRACE command to make a copy of the image as an object.
Slow the engrave speed to 3000 mm/m
Set power to about 30%
Set number of passes to 1
Set overscan to 2.5%
Set your line interval to .1mm extra resolution does not help and can lead to over burning your material. It also makes your small job take much longer to complete. I would estimate your simplified project would run around 45-60 seconds
See if that helps. I burn my leather-ish patches without overlay of masking tape and I use Air “ON”.