Vacuum coating is to vapor-deposit metal aluminum copper and other materials on the surface of a roll-shaped plastic film by heating in a vacuum environment. Vacuum coating equipment is composed of vacuum equipment and vacuum system. The vacuum system mainly uses diffusion pump as the main pump to achieve vacuum.

Existing vacuum system, regardless of whether the vacuum equipment is in working state or shutdown state, the diffusion pump is in continuous evacuation state. If the vacuum equipment is in a shutdown state, the valve cover above the diffusion pump will fall to cover the air inlet of the diffusion pump, and the diffusion pump will pump itself; when the vacuum equipment is working, the remaining pumps will pre-pump to meet certain conditions. Generally, when it is 3-5Pa, the valve cover above the diffusion pump is lifted, and the diffusion pump pumps the vacuum equipment. In this kind of vacuum system, the diffusion pump continues to work when the vacuum equipment is in a shutdown state, which wastes a lot of electric energy, consumes a lot of energy, and leads to high production costs.