How to do insufficiency in pumping vacuum chamber

The evenness of the vacuum formed in the vacuum chamber during printing is closely related to the surface condition of the rubber pad. The rubber pad with a smooth surface has a suction nozzle at the corner and is close to the suction nozzle when the vacuum is applied. The place and the seal ring around the place will firstly adhere to the printing plate glass, which will hinder the air in the central part of the rubber pad from being drawn out, resulting in insufficient air suction and severely affecting the printing quality. To overcome this shortcoming, it is recommended to use the rubber pad. Put a piece of felt.