Just started noticing this happening. What causes this to happen? I cut it at 10mms 19 mAh.
What material is that?
That appears to be the backside of the object. The blackness would be cause by flashback form what is most likely the a honey comb bed. It is most pronounced in the corners, so I suspect you are running the same max and min power settings.
I agree with Anthony, flashback from honeycomb bed. You can elevate the material off the bed to minimize this effect, but the beam reflects or bounces off the bed as it travels past the spaces of the honeycomb.
Yes I am running the same power on both, why would I not?
Acrylic is what it is.
When cutting, your Ruida controller ramps between Min Power and Max Power as it changes speed during the cut. Min Power is used when moving from a stop, and Max Power is used “at speed”. With your Min Power setting the same or close to your Max Power setting, there is less ramp down in the corners causing overburn. If you’re cutting below 10mm/sec, make them the same.