The coated board used in the can-making industry, commonly known as coated steel, is made of PET, PC, PE or PP film and metal plates (galvanized plate, cold-rolled plate, aluminum plate and stainless steel plate). The inner side of traditional metal cans must be painted, and the substance bisphenol A contained in the painting method will have harmful effects on human body and environment, especially edible cans. The birth of metal plate film covering technology is the progress of metal can production. With its wide application, the traditional metal can production process and technology will be subverted, and productivity, production cost, cleanliness and sanitation, environmental protection and other aspects will also make a big step forward.