Inconsistant etching

What would cause this to be so inconsistant? It etches fine and then starts chewing into the acrylic. The bed is even and the file is all the same.

It could be bad optical alignment. Variations of “power at the wheels” through the “drive train” (you like my horrible analogy?) is how I imagine it in my head.

As X and Y move, if your mirror alignment is not optimized, your laser beam will be moving up / down / left / right as it is entering the lens holder (aka laser head) thus changing the final reflection in the line to your material. This can cause the beam to be partially obstructed by the cone in some coordinates (weakening the perceived power), while in others not (increasing the power to the material).

I have attached to this post a LightBurn project I use on my machine after optical alignment to check for variations of power throughout the bed. It may not be the right size for your bed, but it could be easily scaled.

PowerDistributonTest.lbrn (468.1 KB)