Reason 1: Too much negative focus at the focal point of the ring hole

When the focal point of the rim hole has too much negative focus, the cutting process may back-stick to the surface of the protective mirror, resulting in burnt spots. In order to solve this problem, it is recommended to raise the focal point of the aperture. This will prevent the surface of the protective mirror from being directly affected by heat and reduce the generation of burnt spots.

Reason 2: Too small blowing delay

Reason 4: Inappropriate perforation energy