The invention a method used to make coating machine vacuum room reach high vacuum degree increasingly. Its feature is that when vacuum pumping reaches high vacuum while the pumping speed falls, it opens charge valve to fill 99.99% or over high purity nitrogen for 15-30 minutes, controls total pressure at 1* 10-2Pa, closes the charge value to continue pumping to need. It can increase vacuum pump assembly exhaust capacity and the residual gas discharge to effectively improve vacuum degree of the coating room, shorten time to further improve the quality of the coated film. It has the advantages of low cost, saving time, simple operation wide application range etc. |