I'm making the assumption that the burr you are referring to, is on the side of the cut, and not the dross below the cut.
The size of that burr, is just a factor of your cut conditions. If you need a perfectly smooth hole, then you are not going to get that with a laser.
Pulse freq, pulse duration, speed, assist gas, focus, and power all have an effect on that burr. When conditions are the best they can be, that burr will be minimal, but still present. |